Biology

Question 1

The Four Tenets of Cell Theory

Answer 1

1. All living things are composed of cells
2. The cell is the basic functional unit of life
3. Cells only arise from pre-existing cells
4. Cells carry genetic info in the form of DNA

Question 2

Cristae

Answer 2

Folds of the inner mitochondrial membrane
Contains enzymes and molecules essential for ETC

Question 3

Binary Fission

Answer 3

Replication of prokaryotic cells to form two identical daughter cells
Simpler than mitosis
Method of mitochondrial replication

Question 4

Peroxisome

Answer 4

Aids in beta-oxidation of very-long-chain fatty acids
Also helps synthesize phospholipids and contains some enzymes for the pentose phosphate pathway

Question 5

Microtubules

Answer 5

Largest diameter of cytoskeleton filaments. Hollow polymers of tubulin. Motor proteins are kinesin and dynein. Make up flagella and cilia. Organized at centrioles (MTOC)–> attach to sister chromatids during mitosis at their kinetochores and pull them apart.

Question 6

Microfilaments

Answer 6

Thinnest of the filaments. Polymers of actin. Motor protein in myosin. Roles in muscle contraction and cytokinesis.

Question 7

Intermediate Filaments

Answer 7

Diverse group of filaments, ranging in diameter. Include keratin, desmin, lamins, and vimentin. Aid in cell to cell adhesions and help maintain the cytoskeleton. Great tensile strength.

Question 8

Parenchyma

Answer 8

Functional part of an organ. Composed of epithelial cells.

Question 9

Stroma

Answer 9

Structural tissue of an organ. Composed of connective tissue.

Question 10

Connective tissue

Answer 10

Cells produce proteins that maintain ECM. Provide structural framework so that epithelial and other cells can carry out organ/structures’ functions. Ex: bone, cartilage, tendons, ligaments, blood, adipose

Question 11

Archaea

Answer 11

• Usually exist under extreme conditions
• Use alternate energy sources (photosynthetic, chemosynthetic, inorganic compounds from the environment)
  
  • Similar to bacteria because they are single-celled organisms and lack membrane-bound organelles. Also have a circular chromosome
• Similar to eukaryotes because they both have RNA polymerases
• Resistant to many antibiotics
• Reproduce by binary fission/budding

Question 12

Classification of bacteria by shape

Answer 12

Cocci: spherical
Bacilli: rod-shaped
Spirilli: spiral-shaped

Question 13

Obligate anaerobes

Answer 13

Organisms that cannot survive in the presence of oxygen

Question 14

Aerotolerant anaerobes

Answer 14

Anaerobes that are unable to use oxygen in metabolism, but are not harmed by its presence

Question 15

Facultative anaerobes

Answer 15

Organisms that can toggle back and forth between anaerobic and aerobic metabolism depending on availability of O2

Question 16

Gram-Positive vs Gram-Negative

Answer 16

Gram-Positive: stain purple, thick cell wall of peptidoglycan, contains lipoteichoic acid
Gram-Negative: stains pink-red, thinner cell wall of peptidoglycan encased by an outer cell membrane, contains phospholipids and lipoproteins (which trigger a relatively dramatic immune response by the host)

Question 17

Differences between prokaryotes and eukaryotes

Answer 17

• Cell wall
• Membrane-bound organelles / presence of nucleus
• Ribosomal subunit size (30S and 50S in prokaryotes, 40S and 60S in eukaryotes)
• Location of electron transport chain (cell membrane in prok, inner mitochondrial mem in euk)

Question 18

Genetic Recombination

Answer 18

Transfer of genetic material between prokaryotes. Increases genetic variation. Methods: transformation, conjugation, transduction, transposons

Question 19

Transformation

Answer 19

Uptake of foreign genetic information from environment

Question 20

Conjugation

Answer 20

“Mating” of bacteria, Requires contact of two cells. Conjugation bridge forms between donor and acceptor cells. Male (+) donor must have genes for sex factors (usually a plasmid but not always - Hfr).

Question 21

Transduction

Answer 21

Transfer of genetic material by viral vector (bacteriophage)

Question 22

Transposons

Answer 22

Genetic elements that can insert or remove themselves from genomes

Question 23

Hfr cell

Answer 23

Donor cell in which sex factor genes have been integrated into genome. Stands for “high frequency” in terms of conjugation. Engages in conjugation often (what a slutty little Hfr cell)

Question 24

Bacterial colony growth phases

Answer 24

Lag –> Exponential –> Stationary –> Death

Question 25

Viral structure

Answer 25

- Can be single- or double-stranded RNA or DNA - Covered by a protein coat (capsid) - May be enveloped by lipid-containing shell (makes these viruses more easily attacked)

Question 26

Positive-sense RNA virus

Answer 26

Virus enters host cell and acts as mRNA, so it can be immediately translated by host cell. Contains genes for its own viral RNA-dependent RNA polymerase

Question 27

Negative-sense RNA virus

Answer 27

Acts as a template for mRNA that will encode for the "desired" viral proteins. Must contain gene for RNA replicase to ensure that complementary strand is synthesized

Question 28

Retroviruses

Answer 28

Single-stranded RNA with reverse transcriptase gene. In host cell, complementary DNA is synthesized with the reverse transcriptase. Viral DNA is then incorporated into host cells genome --\> gets replicated every cycle of mitosis, host has it forever. Ex: HSV

Question 29

Lytic cycle

Answer 29

Virus maximizes machinery of the host cell to reproduce as much as possible until the cell bursts and virions are released. Relatively non-advantageous to the virus because then it can no longer use the cell to replicate and spread

Question 30

Lysogenic cycle

Answer 30

Virus integrates into host cell's genome and gets replicated every time the cell divides. These viruses are known as proviruses. Infection with one provirus decreases susceptibility of the cell to superinfection (infection with multiple proviruses).

Question 31

Prions

Answer 31

Proteins that cause misfolding of cells' proteins. Convert alpha-helices to beta-sheets --\> decreases solubility --\> causes aggregation that disrupts cell processes

Question 32

Viroids

Answer 32

Short, circular, single-stranded RNA that silences genes

Question 33

Ampulla

Answer 33

Widest part of the Fallopian Tube. Location of fertilization

Question 34

Cortical reaction after penetration by sperm

Answer 34

Release of Ca2+ ions, triggered by the penetration of the cell membrane of the ovum by the sperm. Depolarizes the membrane of the ovum, which prevent fertilization of the ovum by more than one sperm and increases the metabolic rate

Question 35

Zygote

Answer 35

Fertilized ovum. Officially occurs after depolarization of the ovum membrane. Surrounded by the fertilization membrane

Question 36

Monochorionic/monoamnionic twins

Answer 36

Monozygotic twins that share the same chorion and amnion

Question 37

Monochorionic/diamniotic

Answer 37

Identical twins that each have their own amnion but share the same chorion

Question 38

Dichorionic/diamniotic twins

Answer 38

Monozygotic twins that have different amnions and chorions

Question 39

Cleavage (embrygenesis)

Answer 39

Rapid mitiotic cell division that occurs as the zygote moves to the uterus. Increases nucleus:cytoplasm and surface area:volume ratios

Question 40

Indeterminate cleavage

Answer 40

Results in cells that can still develop into complete organisms. Monozygotic twin orginate from indeterminately cleaved cells

Question 41

Determinate cleavage

Answer 41

Results in cells that are already committed to differentiation into a certain type of cell

Question 42

Morula

Answer 42

Small solid ball of cells. Immediately after embryo stage. Undergoes blastulation

Question 43

Blastulation

Answer 43

Morula becomes a hollow ball of cells known as a blastula.

Question 44

Blastocyst

Answer 44

Mammalian blastula. Hollow mass of trophoplast cells that surround the blastocoel and the inner cell mass

Question 45

Trophoblast cells

Answer 45

Cells on the outside of the blastula that later give rise to the chorion and placenta

Question 46

Inner cell mass

Answer 46

Cells of the blastula that protrude into the blastocoel and later give rise to the organism

Question 47

Chorion

Answer 47

Extraembryonic membrane that develops into the placenta. Contains chorionic villi that penetrate the endometrium

Question 48

Umbilical cord and its blood vessels

Answer 48

Connects embryo to placenta. Has two arteries and one vein. The vein brings oxygen and nutrient-rich blood from the placenta to embryo. Arteries carry deoxygenated blood and waste back to the placenta

Question 49

Yolk sac

Answer 49

Site of early blood cell development. Supports the embryo until the placenta is developed

Question 50

Allantois

Answer 50

Involved in early fluid exchange between the embryo and yolk sac. Surrounded by the amnion and chorion

Question 51

Amnion

Answer 51

Tough membrane filled with amniotic fluid. Serves as a shock absorber to protect the embryo

Question 52

Gastrulation

Answer 52

Generation of three distinct cell layers

Question 53

Archenteron

Answer 53

The membrane invagination into the blastocoel during gastrulation. Later develops into the gut

Question 54

Blastophore

Answer 54

Opening of the archenteron. In deuterostomes like humans, it develops into the anus

Question 55

Ectoderm

Answer 55

Outer-most germ layer. Includes skin, hair, nails, face, lens of the eye, lower anal canal. Also includes the nervous system, adrenal medulla, and inner ear

Question 56

Mesoderm

Answer 56

Middle germ layer of cells. Includes bones, muscles, circulatory system, gonads. Specifically includes connective tissue of the digestive and respiratory systems and the adrenal cortex

Question 57

Endoderm

Answer 57

Inner-most germ layer. The linings of the digestive and respiratory tracts and their accessory organs

Question 58

Germ layer of the adrenal medulla

Answer 58

Ectoderm

Question 59

Germ layer of the adrenal cortex

Answer 59

Mesoderm

Question 60

The process of fetal nerve development

Answer 60

Neurulation. Notochord (mesodermal cell) forms, forming the long axis of the organism. Then induces overlying ectodermal cells to form neural folds surrounding neural grooves. The folds grow and fuse into the neural tube, which gives rise to the CNS. Each fold has a neural crest cell at the tip, which migrate outward to form the PNS. Finally, ectodermal cells migrate over the neural tube to cover the NS.

Question 61

Neural crest cells

Answer 61

Located at the tips of the neural folds. Migrate outward to form the PNS

Question 62

Neural tube

Answer 62

Gives rise to the CNS. Made by fusion of neural folds. Made of ectodermal cells

Question 63

Teratogens

Answer 63

Substances that interfere with embryonic development. Ex: alcohol, drugs, viruses, bacteria, and environmental toxins

Question 64

Spina Bifida

Answer 64

Birth defect. Exposure of some portion or all of the spinal cord to the outside world. Due to maternal deficiency in folic acid. Wide range of severity of effects

Question 65

Induction

Answer 65

Ability of one group of cells to influence the differentiation of nearby cells in embryonic development

Question 66

Stages of cell specialization

Answer 66

1. Specification: reversilby designated as a certain cell type 2. Determination: irreversibly committed to a specific lineage, may be due to morphogens 3. Differentiation: the cell actually changing structure, function, and biochemistry to be able to achieve a certain function

Question 67

The first instance of differentiation in embryonic development

Answer 67

After the 16-cell stage of the morula. Differentiates into trophoblast cells or inner cell mass

Question 68

Potency of Adult Stem Cells

Answer 68

Multipotent

Question 69

Morphogens and common examples

Answer 69

Molecules that cause determination of cells. Ex: TGF-beta, sonic hedgehog (Shh), and epidermal growth factor (EGF)

Question 70

Inducers

Answer 70

Growtth factors that induce differentiation or mitosis

Question 71

Complete regeneration

Answer 71

Re-growth of damaged/removed tissue with identical tissue

Question 72

Incomplete regeneration

Answer 72

Repair of damaged or removed tissue with non-identical tissue

Question 73

Senescence

Answer 73

Biological aging at cellular and organism levels. At cellular levels, cells no longer divide possibly due to shortened telomeres

Question 74

Telomerase

Answer 74

A reverse transcriptase that synthesizes the ends of chromosomes to prevent senescence. Found in germ cells, fetal cells, and tumore cells

Question 75

Roles of the Placenta

Answer 75

Prevents mixing of fetal and maternal blood. Allows diffusion of O2, nutrients, antibodies, and waste (for removal)

Question 76

Umbilical arteries

Answer 76

2. Carry de-oxygenated blood away from the fetus.

Question 77

Umbilical vein

Answer 77

Only 1. Carries oxygen and nutrient-rich blood from the placenta to the fetus

Question 78

Fetal Shunts

Answer 78

Three of them: foramen ovale, ductus arteriosus, ductus venosus. Developed by the fetus to bypass slow-developing organs upon which it does not rely. These organs are the lungs and liver.

Question 79

Foramen ovale

Answer 79

Shunt in fetuses that connects the right atrium to the left atrium to bypass the right ventricle. Thus the blood is pumped through the aorta instead of the pulmonary system (avoids the lungs)

Question 80

Ductus arteriosus

Answer 80

In fetal development, shunts leftover blood from the pulmonary artery to the aorta

Question 81

Ductus venosus

Answer 81

In fetal development. Causes blood to bypass the liver by shunting blood from the placenta (in the umbilical vein) directly into the inferior vena cava.

Question 82

Key Features of the First Trimester

Answer 82

Development of the heart, eyes, gonads, limbs, and liver. Cartilaginous skeleton begins to harden into bone. Brain is fairly developed by the end

Question 83

Key Features of the Second Trimester

Answer 83

A lot fo growth. Face takes on human appearance. Fingers and toes elongate

Question 84

Key Features of Third Trimester

Answer 84

Further rapid growth and brain development (although growth slows right before birth). Selective transport of antibodies from the mother.

Question 85

Parturition

Answer 85

Vaginal childbirth

Question 86

Hormones involved in childbirth

Answer 86

Prostaglandins and oxytocin. Control the rhythmic contractions of uterine muscle (smooth muscle)

Question 87

Nerves vs Tracts

Answer 87

Nerves are in the PNS and can carry more than one type of information, their cell bodies are grouped together in ganglia. Tracts are in the CNS and can only carry one type of information, and their cell bodies are grouped in nuclei.

Question 88

Location of most ribosomes and ER in neurons

Answer 88

Soma

Question 89

Axon hillock

Answer 89

Transition region of the neuron from soma to axon. Function: integrating incoming signals and triggering AP if appropriate

Question 90

Astrocytes

Answer 90

Nourish neurons and for the blood-brain barrier

Question 91

Blood-brain barrier

Answer 91

Controls the transmission of solutes from the bloodstream into nervous tissue

Question 92

Ependymal cells

Answer 92

Line the vetnricles of the brain and produce cerebrospinal fluid

Question 93

Cerebrospinal fluid

Answer 93

Physically supports the brain and acts as a shock-absorber

Question 94

Microglia

Answer 94

Phagocytic cells that ingest and break down waste products and pathogens in the CNS

Question 95

Oligodendrocytes vs Schwann cells

Answer 95

Both produce myelin for neurons. Oligodendrocytes are in the CNS and Schwann are in the PNS

Question 96

Types of glial cells/neuroglia

Answer 96

Astrocytes, ependymal cells, microglia, oligodendrocytes, Schwann cells

Question 97

Methods of neurotransmitter-removal from the synapse

Answer 97

Enzymatic breakdown (ex: ACh), reuptake carriers taking leftover NT back into the presynaptic cell (ex: NE, dopamine, serotonin), or simple diffusion away from the synapse (ex: NO)

Question 98

Supraspinal circuits

Answer 98

Neural pathways that involve the brain/brainstem

Question 99

White matter

Answer 99

Axons encased in myelin sheaths. Found on the inside of the brain and the outside of the spinal cord.

Question 100

Grey matter

Answer 100

Made of neural dendrites and unmyelinated cell bodies. Found on the surface of the brain and in the middle of the spinal cord

Question 101

Dorsal root ganglia

Answer 101

Cell bodies of sensory neurons entering the spinal cord

Question 102

Vagus nerve

Answer 102

Cranial nerve X. Responsible for parasympathetic innervation of the thoracic abdominal cavity

Question 103

Neurotransmitter of the Parasympathetic NS vs Sympathetic NS

Answer 103

Para: both pre- and postganglionic neurons release ACh. Sympathetic: preganglionic neuron releases ACh, postganglionic neuron releases NE

Question 104

Temporal summation

Answer 104

Integration of multiple neural signals near each other in time

Question 105

Spatial summation

Answer 105

Refers to the addition of multiple signals near each other in time

Question 106

Haploid

Answer 106

Only having one of each chromosome in a pair. Germ cells/gametes are haploid

Question 107

Restriction Points in Mitosis

Answer 107

G1-\>S: Controlled by p53. Also G2-\>M: checks for enough organelles and cytoplasm

Question 108

S phase

Answer 108

Results in every chromatid being replicated and then boudn with its identical sister chromatid at the centromere

Question 109

What proteins control progression of the cell cycle?\

Answer 109

Cyclins, CDKs, transcription factors

Question 110

Prophase

Answer 110

Chromatin condenses into chromosomes. Polarization of centrioles/MTOC occurs (found in centrosomes, outside nucleus). Nuclear membrane dissolves, allowing microtubules to connect centrosomes to chromosomes at the kinetochores. Mitotic spindle forms

Question 111

Metaphase

Answer 111

Kinetochores fibres align the chromosomes at the metaphase plate (equitorial plate)

Question 112

Anaphase

Answer 112

Kinetochore fibres shorten, pulling apart sister chromatids

Question 113

Telophase

Answer 113

Reverse of prophase: chromosomes uncoil, spindle disappears, new nuclear membrane forms

Question 114

Cytokinesis

Answer 114

Separation of cytoplasm and organelles through pinching of dinucleate cell by actin ring

Question 115

Meiosis I

Answer 115

Separation of homologous chromosomes. Results in haploid daughter cells.

Question 116

Reductional division

Answer 116

Cell division that results in decrease of ploidy

Question 117

Meiosis II

Answer 117

Separation fo identical sister chromatids. No change in ploid (haploid).

Question 118

Equatorial Division

Answer 118

Ploidy is conserved in this kind of cell division

Question 119

Prophase I

Answer 119

Condensation of chromatin into chromosomes. Nuclear mem dissolves, Meiotic spindle forms. Crossing over occurs

Question 120

Metaphase I

Answer 120

Different from mitosis because here, homolgs align across from each other on either side of the metaphase plate and are held by 1 spindle fibre, not 2

Question 121

Pathway fo Sperm

Answer 121

SEVE(N) UP: seminiferous tubules, epididymis, vas deferens, ejaculatory duct, (nothing), urethra, penis

Question 122

Semen

Answer 122

Sperm mixed with seminal fluid: a mix of fluids from seminal vesicles (fructose), prostrate gland (provide alkaline properties), and bulbouretrhal gland (lubricant)

Question 123

Spermatogenesis

Answer 123

1. Spermatogonia (diploid stem cell) goes through S stage to form... 2. Primary spermatocyte (diploid) goes through meiosis I to form... 3. Secondary spermatocyte (haploid) goes through meiosis II to form... 4. Spermati (haploid) goes through maturation to form... 5. Spermatozoa

Question 124

Ovaries

Answer 124

Produce estrogen and progesterone. Filled with thousands of follicles (that will eventually give rise to eggs\_

Question 125

Follicles

Answer 125

Nourish and protect ova (eggs)

Question 126

Ovulation

Answer 126

1 egg is released from follicle into the peritoneal sac/abdominal cavity. Then gets drawn into the fallopial tube/oviduct that leads into the uterus.

Question 127

Oogenesis

Answer 127

1. Primary oocyte (2n and arrested in prophase I) undergoes Meiosis I to become... 2. Secondary oocyte (n) only proceeds through metaphase II if sperm penetrates the sona pellucida and corona radiata, so that it then becomes... 3. Mature ovum (n) then completes meiosis II to become a zygote

Question 128

Roles of LH and FSH in Male Sexual Development

Answer 128

Both released from anterior pituitary is response to GnRH from hypthalamus LH: Triggers increased testosterone production in the Cells of Leydig in the testes FSH: Stimulates Sertoli cells and ups sperm maturation

Question 129

Roles of LH and FSH in Female Sexual Development

Answer 129

Both released from anterior pituitary is response to GnRH from hypthalamus LH: Triggers release of progesterone from corpus luteum FSH: Triggers increased production of estrogens

Question 130

Estrogen

Answer 130

In embryos, causes reproductive tract to develop. In adults, causes thickening of the uterin lining (endometrium) each month.

Question 131

Progesterone

Answer 131

Helps maintain and develop endometrium (but not the initial thickening - that is estrogen). By the end of the first trimester, it is released from the placenta rather than the corpus luteum.

Question 132

Menstrual cycle hormone levels by stage

Answer 132

Follicular phase: estrogen and progesterone are low. GnRH, LH, and FSH are on the rise. Rising estrogen levels cause GnRH, LH, FSH to level off Ovulation: Estrogen levels have gotten so high that is now causes (+) feedback-\> SPIKE in FSH, LH, GnRH. Surge of LH triggers release of ovum from ovary to abdominal cavity Luteal phase: Estrogen remains high. Progesterone steadily climbs (motivated by LH). Neg feedback causes decline of GnRH, LH, and FSH Mestruation (no implantation): decrease in LH then progesterone, and eventually a rise in GnRH for next cycle

Question 133

Hormones in pregnancy

Answer 133

Blastocyst secretes human chorionic gonadotropin (hCG) - very similar to LH.

Question 134

Human chorionic gonatotropin (hCG)

Answer 134

Responsible for maintining release of progesteron from the corpus luteum during first trimester until the placenta is developed enough. Released from blastocyst. Only possible it zygote implants in endometrium. Very similar to LH.

Question 135

Menopause

Answer 135

Ovaries become less sensitive to FSH and LH

Question 136

Compare durations of effects of peptide hormones vs. steroid hormones

Answer 136

Peptide hormones' effects usually have rapid onset but are short lived, whereas steroid hormones are slower to take effect but sustain for longer period of time

Question 137

Direct hormones

Answer 137

Have major effect on non-endocrine tissues

Question 138

Tropic hormones

Answer 138

Have major effect on other endocrine tissues

Question 139

Albumin

Answer 139

A nonspecific steroid hormone carrier protein

Question 140

Are steroid hormones active when bound to their carrier proteins?

Answer 140

No

Question 141

What are the catecholamine hormones

Answer 141

Epinephrine and norepinephrine

Question 142

Thyroxine and triiodothyronine

Answer 142

Thyroid hormones that regulate metabolic rate. They are amino acid derivatives. Effects are slow in onset but are long lasting

Question 143

Hypothalamus

Answer 143

Gland in the brain that serves as the bridge between the nervous and endocrine systems. Secretes tropic hormones that act on the anterior pituitary

Question 144

GnRH

Answer 144

Gonadotropin-releasing hormone. Released from hypothalamus. Stimulates release of FSH and LH from anterior pituitary

Question 145

GHRH

Answer 145

Growth hormone-releasing hormone. Released from hypothalamus. Stimulates release ofgrowth hormone from the anterior pituitary

Question 146

TRH

Answer 146

Thyroid-releasing hormone. Released from hypothalamus. Stimulates release of TSH from anterior pituitary.

Question 147

CRF

Answer 147

Corticotropin-releasing factor. Released from hypothalamus. Stimulates release of ACTH (adrenocorticotropic hormone) from anterior pituitary

Question 148

PIF

Answer 148

Prolactin-inhibiting factor. It is actually dopamine released from the hypothalamus. Inhibits the release of prolactin from the anterior pituitary

Question 149

Hypophyseal Portal System

Answer 149

Blood vessels between the hypothalamus and the anterior pituitary

Question 150

How does the hypothalamus signal release of hormones from the posterior pituitary? Which hormones?

Answer 150

Axons of the neurons of the hypothalamus extend down to the posterior pituitary and signal release of oxytocin and antidiuretic hormone (ADH/vasopressin)

Question 151

Oxytocin

Answer 151

Produced by hypothalamus but secreted by posterior pituitary. Stimulates uterine contractions during labor and milk letdown during lactation. Also plays a role in bonding.

Question 152

Vasopressin

Answer 152

AKA antiduretic hormone (ADH). Release is motivated by excessively high osmolarity of the blood. ADH causes increased water resorption by the kidneys to decrease osmolarity of the blood. Produced by hypothalamus but secreted by posterior pituitary

Question 153

Prolactin

Answer 153

Stimulates milk production by acting directly on the mammary glands. Released by the anterior pituitary when dopamine levels decrease. Dopamine has an inhibitory effect on the release of prolactin.

Question 154

Endorphins

Answer 154

Decrease the perception of pain. Released from the anterior pituitary. The action of endorphins is mimicked by morphine

Question 155

Growth Hormone

Answer 155

Released from the anterior pituitary. Promotes the growth of bone and muscle by preventing the uptake of glucose in the tissues that are not growing and stimulating the breakdown of fatty acids to increase the availability of glucose for bones and muscles

Question 156

Epiphyseal plates

Answer 156

The regions of origin of bone growth. They seal shut during puberty

Question 157

Gigantism

Answer 157

Condition characterized by excess growth hormone in children before their epiphyseal plates seal shut

Question 158

Dwarfism

Answer 158

Deficit in growth hormone before a child's epiphyseal plates shut.

Question 159

Acromegaly

Answer 159

Excess levels of growth hormone in adults (after shutting of epiphyseal plates). Excessive growth of smaller bones mainly in hands, feet, and head

Question 160

What events and receptors trigger the release of ADH (and from where)?

Answer 160

Triggers: low blood volume sensed by the baroreceptors, or high blood osmolarity as sensed by the osmoreceptors ADH is produced in the hypothalamus but secreted from the posterior pituitary

Question 161

Mechanism of action of ADH

Answer 161

Increases the permeability of the collecting duct so that more water is absorbed from the filtrate in the nephron --\> more water is retained in the body

Question 162

Positive feedback loop of ____ (hormone involved in smooth muscle contraction)

Answer 162

Oxytocin; positive feedback loop exists in that the uterine contractions stimulated by oxytocin trigger the release of more oxytocin, which causes stronger and stronger contractions

Question 163

Function of the thyroid

Answer 163

Setting basal metabolic rate, promoting calcium homeostasis

Question 164

Triiodothyronine and thyroxine

Answer 164

Amino acid hormones released by the thyroid that set basal metabolic rate by increasing cellular respiration. Formed by iodination of the tyrosine in the follicular cells of the thyroid.

Question 165

Calcitonin

Answer 165

Release from the thyroid gland is triggered by high levels of Ca2+ in the blood. Increases Ca2+ excretion from the kidneys, decreases Ca2+ absorption in the gut, and increases storage of Ca2+ in the bone

Question 166

Hypothyroidism

Answer 166

Deficiency of thyroid hormones. Characterized by being cold/lowered body temperature, slowed respiratory rate and HR, weight gain, and lethargy.

Question 167

Hyperthyroidism

Answer 167

Excessive amounts of thyroid hormone. Symptoms include increased body temp/being hot all the time, weight loss, increased breathing and heart rates, and heightened activity level

Question 168

Parathyroid hormone

Answer 168

Counteracts calcitonin to increase levels of Ca2+ in the blood. Does so by decreasing Ca2+ excretion in the kidneys, increasing absorption of Ca2+ in the gut (via Vitamin D), and increasing resorption of Ca2+ in the bones (releasing it into the blood) Regulates Phosphorus homeostasis by increasing resorption of phosphate from bone and decreasing reabsorption in the kidney (increases the phosphate excreted in urine). They cancel each other out so that there are no drastic changes in phosphate levels Activates vitamin D which is required for absorption of Ca2+ and PO4^2- in the gut.

Question 169

Corticoids (place of secretion and the three classes)

Answer 169

Secreted from the adrenal cortex. Classes: glucocorticoids, mineral corticoids, and cortical sex hormones

Question 170

Glucocorticoids - the two main ones

Answer 170

Cortisone and cortisol. They are corticosteroids released from the adrenal cortex that regulate blood glucose by increasing gluconeogenesis and decrease protein synthesis. Also decrease inflammation and the immunological response. Cortisone is a "stress hormone"

Question 171

Mineralocorticoids - main example

Answer 171

Govern salt and water homeostasis. The main ex. is aldosterone, which increases Na+ reabsorption and decreases reabsorption of K+ and H+ in the distal convoluted tubule and collecting duct of the nephron. Results in more K+ and H+, and less Na+ excreted in the urine

Question 172

Describe the system that governs release of aldosterone

Answer 172

Renin-angiotensin-aldosteron system. Low BP causes the juxtaglomerular cells of the kidney to secrete renin. Renin cleaves angiotensinogen (previously inactive) into angiotensin I. Angiotensin-converting enzyme (ACE) in the lungs converts angiotensin I to angiotensin II, which then triggers the cortex to release aldosterone to motivate Na+ and water reabsorption in the nephron --\> increases blood volume --\> increases blood pressure

Question 173

Cortical sex hormones

Answer 173

Androgens and estrogens. Plays a smaller role in male physiology because the testes secrete so much testosterone and other androgens.

Question 174

The 3 Functions of Corticosteroids (the 3 S's)

Answer 174

Sugar (glucocorticoids) Salt (mineralocorticoids, mainly aldosterone) Sex (cortical sex hormones)

Question 175

Catecholamines

Answer 175

Class of amino acid-derived molecules, specifically, epinephrine and norepinephrine which trigger the sympathetic NS.

Question 176

Islets of Langerhans - the types of cells and what they secrete

Answer 176

Hormone-producing cells in the pancreas. Three types: alpha (secretes glucagon), beta (secretes insulin), and delta (secretes somatostatin)

Question 177

Glucagon

Answer 177

Increases blood glucose levels during times of fasting by triggering glycogenolysis, gluconeogenesis, and degradation of protein and fat

Question 178

Insulin

Answer 178

Counteracts glucagon. Induces muscle and liver cells to take up glucose from the blood and store it as glycogen. Also induces fat and protein synthesis

Question 179

Polyuria and polydipsia in diabetes mellitus

Answer 179

Increased urination and thirst (respectively) because the the excessive amount of glucose in the blood overwhelms the kidneys' filtration system, so glucose winds up in the urine and takes too much water with it because glucose is osmotically active (ie urine concentration increases greatly in DM patients)

Question 180

Type I Diabetes

Answer 180

Autoimmune destruction of beta cells in the pancreas. Low or absent levels of insulin. Treatment involves insulin injections

Question 181

Type II Diabetes

Answer 181

Insulin receptors become desensitized to insulin due to high-carb diets and obesity (as well as genetic factors). Insulin cannot affect cells, so they do not take in glucose, thus keeping blood glucose levels high. Treatment involves lifestyle changes and medications that help the body use the insulin it produces

Question 182

Somatostatin

Answer 182

Inhibitor of both insulin and glucagon secretion. Release is triggered by high blood glucose and high amino acid concentrations. Secreted by both the pancreas and the hypothalamus (where is inhibits the release of growth hormone)

Question 183

Gonadotropins

Answer 183

LH and FSH In males, trigger release of testosterone from the testes. In females, trigger release of estrogen and progesterone from the ovaries.

Question 184

Pineal gland

Answer 184

Deep in the brain. Secretes melatonin, which likely regulates circadian rhythms. Also receives projections from the retina but is not involved in vision (likely means that pineal gland reacts to darkness and may cause "sleepiness")

Question 185

Erythropoietin

Answer 185

Hormone produced in the kidneys that stimulates bone marrow to produce more RBCs. Secreted in response to low O2 levels in the blood

Question 186

Atrial natriuretic peptide

Answer 186

ANP. Released from the heart when chamber cells are stretched due to excess blood volume. Acts to increase Na+ excretion (increases urine volume, decrease blood volume and thus, pressure)

Question 187

Nares

Answer 187

AKA nostrils

Question 188

Vibrissae

Answer 188

Nasal hairs

Question 189

Pharynx vs Larynx

Answer 189

Pharynx is located behind the nasal cavity and is allows passage of air and food. Larynx is designed only for the flow of air. The opening is covered by the epiglottis to keep food out of the respiratory tract. Contains vocal cords

Question 190

Trachea

Answer 190

Cartilaginous structure of respiratory tract through which air passes after the larynx.

Question 191

Flow of air during inhalation

Answer 191

Nares -\> Pharynx -\> Larynx -\> one of the two bronchi -\> bronchioles -\> alveoli

Question 192

Surfactant

Answer 192

Detergent that covers alveoli, reducing surface tension.

Question 193

Pleurae

Answer 193

The membranous sacs surrounding each lung

Question 194

Visceral pleura

Answer 194

The surface of the pleura that is adjacent to the lungs. Innermost surface of the intrapleural space

Question 195

Parietal pleura

Answer 195

The surface of the pleura that lines the chest cavity

Question 196

Intrapleural space

Answer 196

Space within the membranous sacs (pleurae) surrounding each lung. Filled with a thin layer of fluid

Question 197

Muscles responsible for inhalation

Answer 197

Diaphragm and external intercostal muscles

Question 198

What is the driving force of air rushing into the lungs during inhalation?

Answer 198

The low pressure in the intrapleural space compared to the lungs: Upon inhalation, the diaphragm flattens and the volume of the chest cavity increases, thus decreasing pressure in the intrapleural space, allowing the lungs to expand, then decreasing the pressure inside the lungs below atmospheric pressure. Air rushes into the lungs from the atmosphere

Question 199

Mechanism of Exhalation

Answer 199

Does not have to be an active process. Relaxation of the diaphragm and external intercostals causes decrease in chest cavity volume -\> increase in intrapleural pressure -\> this along with the recoil of the lungs causes the lung pressure to exceed atmospheric --\> pushes air out of lungs

Question 200

How does one speed up exhalation?

Answer 200

Contraction of the internal intercostal muscles and abdominal muscle. They oppose the external intercostals and pull the rib cage down.

Question 201

Vital Capacity

Answer 201

The difference between maximum and minimum volume of air in the lungs VC = total lung capacity (TLC) - residual volume (RV)

Question 202

Tidal volume

Answer 202

Volume of air inhaled or exhaled in a normal breath

Question 203

Expiratory reserve volume

Answer 203

Volume of additional air that can be forcibly inhaled after a normal inhalation

Question 204

Inspiratory reserve volume

Answer 204

Volume of additional air that can be forcibly inhaled after a normal inhalation

Question 205

Ventilation center

Answer 205

Control center of breathing. Neurons in the medulla oblongata. Respond to the response of chemoreceptors that are sensitive primarily to high partial pressures of CO2. When CO2 concentration is too high (hypercarbia), ventilation center will increase respiratory rate in order to exhale more CO2

Question 206

Driving force behind gas exchange

Answer 206

Difference in partial pressures of O2 and CO2 between the deoxygenated blood that arrives at the alveoli and inside the alveoli themselves

Question 207

Natural respiratory response to increased altitude where less oxygen is available

Answer 207

Body increases respiratory rate to try and get more oxygen into the body --\> decreases CO2 concentration --\> Hb is triggered holds on more tightly to oxygen rather than release it to the blood. To make up for this, the body makes more RBCs in order to increase O2 delivery to the cells

Question 208

Thermoregulation via the repiratory system

Answer 208

Vasodilation (dissipates heat) and vasoconstriction (conserves heat) in the capillaries of the nasal cavity and trachea. Resp system can also transfer heat to the environment through the evaporation of water in mucous secretions (ex: dogs panting)

Question 209

Lysozyme

Answer 209

Enzyme present in the nasal cavity that attacks the peptidoglycan cell walls of gram-positive bacteria

Question 210

Mucociliary escalator

Answer 210

Refers to the mechanism of mucous in the airway trapping foreign matter, then cilia propelling the mucus up to the oral cavity to be swallowed or expelled.

Question 211

Immune cells of the lungs

Answer 211

Macrophages: engulf and digest pathogens, signal the rest of the immune system that there is an invader. Mast cells: have pre-made antibodies on their surfaces, so when the right substance bonds to the antibody, an immune response is induced. These antibodies are responsive to pollens and molds

Question 212

Respiratory response to acidemia

Answer 212

High H+ is sensed by the chemoreceptors in the blood-brain barrier --\> increases respiratory rate to decrease [CO2], which promotes the bicarbonate buffer system in the blood to shift to in the direction that consumes H+.

Question 213

Spirometer

Answer 213

Can measure 3 out of 4 lung volumes: inspiratory reserve, exhilatory reserve, and tidal volumes, but cannot measure residual volume

Question 214

Atrioventricular valves

Answer 214

Separate the ventricles from the atria. The tricuspid valve (right) and the mitral/bicuspid valve (left)

Question 215

Semilunar valves

Answer 215

Separate the ventricles from the vasculature. Pulmonary valve (right) and aortic valve (left)

Question 216

Mitral valve

Answer 216

AKA bicuspid valve. Separates the left atrium and ventricle (blood flows from atrium to ventricle)

Question 217

Tricuspid valve

Answer 217

Separates the right atrium and right ventricle

Question 218

Pulmonary valve

Answer 218

Separates the right ventricle from the pulmonary circuit

Question 219

Systole

Answer 219

Period of ventricular contraction. AV Nodes close and blood is pumped out of the ventricles

Question 220

Atrial kick

Answer 220

Additional amount of blood that is forcefully pushed into the ventricles by atrial systole. About 5-30% of cardiac output

Question 221

SA Node

Answer 221

Origin of electrical impulses in the heart. Generates 60-100 signals per minute without requiring any stimulation. Located in the wall of the right atrium

Question 222

AV Node

Answer 222

Stimulated by the SA Node. Sits at the junction of the atria and ventricles. Signal is slightly delayed here in order to allow the ventricles to fill completely before they contract

Question 223

Bundle of His

Answer 223

Receives stimulation from the AV Node. Located in the interventricular septum (wall). Passes signals on to the Purkinje Fibers

Question 224

Perkinje Fibers

Answer 224

Distribute electrical signal evenly throughout ventricular muscle.

Question 225

Intercalated discs in cardiac muscle (definition and function)

Answer 225

Connect the cardiac muscle cells, many through gap junctions so that their cytoplasms are connected. This allows coordinated ventricular contraction

Question 226

Myogenic activity

Answer 226

Possessed by the heart in that it does not need any neurological input to contract.

Question 227

Vagus Nerve

Answer 227

Parasympathetic innervation of the heart

Question 228

Diastole

Answer 228

Semilunar valves are closed as the ventricles fill with blood from the atria. Pressure decreases during relaxation

Question 229

Cardiac output and stroke volume

Answer 229

CO: Total blood volume pumped by a ventricle in a minute. SV: Volume of blood pumped out of the heart by a single beta CO = HR \* SV CO is usually about 5 liters per minute

Question 230

Endothelial cells (and their role in vasculature)

Answer 230

These cells line all blood vessels. They are able to secrete chemicals that control vasodilation/vasoconstriction, allow WBCs to pass through during inflammation, and release chemicals that aid in blood clotting in the event of a wound.

Question 231

Compare: elasticity, resistance to flow, and mechanism of blood movement of arteries and veins

Answer 231

Arteries: highly elastic, thick smooth muscle walls, high resistance to flow, elastic recoil of the walls keeps arterial pressure high Veins: inelastic, although they can stretch to accommodate HIGH volumes of blood - so low resistance. Blood movement is governed by skeletal muscle movements and valves to prevent backflow.

Question 232

Varicose veins

Answer 232

Veins that become enlarged where blood has pooled due to failed valves. Women are at higher risk of developing them during pregnancy because of increased total blood volume and the fetus pushing on their inferior vena cava

Question 233

Portal systems (and what are the three in the body?)

Answer 233

Connections of two distinct capillary beds in series (may be separated by vessels in between) Three in the human body: hepatic, hypophyseal, and renal portal systems

Question 234

Hepatic portal system

Answer 234

Blood leaving the capillary bed of the gut will go through the hepatic portal vein and then the hepatic capillary bed before returning the heart

Question 235

Hypophyseal portal system

Answer 235

Allows for paracrine signaling of the hypothalamus directed onto the anterior pituitary. Capillary bed on the hypothalamus connects directly to the capillary system on the anterior pituitary

Question 236

Renal portal system

Answer 236

Blood leaving the capillaries of the glomerulus enters an efferent arteriole before surrounding the nephron in the vasa recta (a second capillary bed)

Question 237

Hematopoietic cells

Answer 237

Stem cells in bone marrow that give rise to all blood cells (RBCs, WBCs, and platelets)

Question 238

Functions of erythrocyte structure/makeup/shape

Answer 238

Biconcave because it increases surface area, allows passage through tiny capillaries, lack of membrane-bound organelles allows maximum space for Hb molecules, and lack of mitochondria specifically means that the cells will not use up the O2 they are carrying.

Question 239

Spleen

Answer 239

Recycles RBCs because they cannot divide (due to no nucleus)

Question 240

Hematocrit

Answer 240

Refers to the percentage of blood that is red blood cells. Normal ranges are females 36-46% and males 41-53%

Question 241

Hemoglobin

Answer 241

Molecules within RBCs that bind to O2 for transport. Normal ranges in females and males are 12-16 g-dL and 13.5-17.7 g/dL, respectively

Question 242

Granulocytes (def. and the types)

Answer 242

Leukocytes that contain cytoplasmic granules that contain compounds that are toxic to foreign invaders. Involved in allergic reactions, allergies, pus formation, and destruction of bacteria. Types: neutrophils, eosinophils, basophils

Question 243

Agranulocytes

Answer 243

WBCs that do not contain granules Monocytes/macrophages and lymphocytes (T and B cells)

Question 244

Different sites of maturation of lymphocytes

Answer 244

B-cells matured in the bone marrow. T-cells matured in the thymus

Question 245

Macrophages (def and examples)

Answer 245

Phagocytose foreign matter, like bacteria. Each organ's macrophages have their own name. Ex: Microglia in brain Langerhans cells in skin Osteoclasts in bone

Question 246

Erythropoietin

Answer 246

Hematopoietic chemical released by the kidney that stimulates RBC development

Question 247

\_\_\_\_ are the surface proteins of RBCs, and include A, B, and O

Answer 247

antigens

Question 248

Hemolysis

Answer 248

Rupture or destruction of blood cells. Occurs if a person receives the wrong blood type (i.e. patient with type A blood receives anti-A antibodies from either B blood or AB blood, which trigger an immunes response because the proteins appear to be foreign)

Question 249

People with type B blood naturally produce anti- __ antibodies

Answer 249

A

Question 250

Rh factor

Answer 250

Signifies the presence (Rh+) or absence (Rh-) of the D allele. Mainly important in maternal/fetal medicine.

Question 251

Erythroblastosis fetalis

Answer 251

Condition in which the mother is Rh- and the fetus is Rh+. Anti-Rh antibodies produced by the mother can diffuse into fetal blood through the placenta and cause hemolysis (fatal to the fetus). Today it is preventable by medicine. It is only a problem after the first child because the mother will not start making the fatal antibodies until after the gestation period (it is an issue for any future pregancies)

Question 252

Sphygmomanometer

Answer 252

Measures the gauge pressure in the systemic circulation

Question 253

Blood pressure is expressed as the ratio between...

Answer 253

Systolic pressure (ventricular contraction) to diastolic pressure (ventricular relaxation)

Question 254

In which vascular structure is the largest drop in blood pressure

Answer 254

Arterioles

Question 255

Pressure differential equation (blood pressure)

Answer 255

delta P = CO \* TPR TPR = total peripheral resistance

Question 256

What cells and what conditions trigger the renin-angiotensin-aldosterone system?

Answer 256

Low perfusion past the juxtaglomerular cells of the kidney

Question 257

Oxygen saturation

Answer 257

The percentage of Hb molecules in the blood saturated by oxygen

Question 258

Structure of Hb

Answer 258

Each Hb has 4 heme groups, each of which contain a central iron atom that undergoes changes in oxidation state to bind to O2

Question 259

Predominant form of CO2 in the blood

Answer 259

bicarbonate ion (HCO3-)

Question 260

Carbonic anhydrase

Answer 260

Catalyzes the reaction of CO2 and water to form carbonic acid (a weak acid)

Question 261

Effect of decreased pH on Hb-O2 binding affinity

Answer 261

The increased concentration of H+ allows H+ to bind to Hb and lower its affinity for O2 --\> shifts Hb curve right (this is the Bohr effect)

Question 262

Bohr effect

Answer 262

increased acidity of the blood leaving to a rightward shift in Hb-O2 binding curve (greater unloading of O2 to the tissues, as is what happens and what it needed after during high intensity exercise, which produces CO2 and lactic acid)

Question 263

Fetal Hb has a ___ affinity for oxygen. Why

Answer 263

Lower - because fetuses lack 2,3-BPG (2,3-biphosphoglycerate) which decreases the binding affinity of Hb for O2.

Question 264

How do carbohydrates, amino acids, and fats enter the bloodstream from the GI tract?

Answer 264

Carbs and am. acids: diffuse into capillaries at small intestine and then enter circulation via hepatic portal system Fats: get absorbed into lacteals in small intestine, bypassing the hepatic portal system via the thoracic duct, where they are packaged into lipoproteins

Question 265

Starling forces (describe the opposing pressures)

Answer 265

Hydrostatic: This is the pressure of the fluid pushing out on the blood vessel walls. Generated by contraction of the heart and the elasticity of the arteries. Greater than osmotic pressure on the arteriole side of capillary beds, but then drops below it on the venule side as elasticity decreases Osmotic/oncotic: The "sucking" pressure of the solutes in the blood, motivating water to flow into the bloodstream to dilute blood concentration (mainly of plasma proteins). Remains constant

Question 266

Lymph (and how is it returned to the bloodstream?)

Answer 266

Fluid of the lymphatic system, which takes up interstitial fluid and recycles it. Lymph is returned to the bloodstream through the thoracic duct

Question 267

Components of blood clots

Answer 267

Coagulation factor proteins and platelets

Question 268

Tissue factor

Answer 268

A protein that is exposed when blood vessels are damaged. Sensed by coagulation factors, signaling their release from the liver, in the same way that platelets recognize collagen upon vessel damage.

Question 269

Thrombin

Answer 269

Major player in coagulation. It is activated by thromboplastin from prothrombin. It is able to convert fibrinogen to fibrin

Question 270

Fibrin

Answer 270

Clot-formation protein. Activated by thrombin. Causes aggregation of fibers into a net that catches RBCs and other platelets to form a stable clot over the damage.

Question 271

Thrombus formation

Answer 271

blood clotting

Question 272

alpha\_IIb-beta\_3 integrin molecules

Answer 272

Adhere to fibrinogen to help form bridges between platelets in scabs.

Question 273

Plasmin

Answer 273

Protein that achieves breakdown of blood clots. Formed through activation of plasminogen

Question 274

Which blood type can be given to a patient without knowing their blood type?

Answer 274

O-

Question 275

Lymph nodes

Answer 275

Location for communication between immune cells so that they can mound an attack. B-cells can be activated here

Question 276

Gut-associated lymphoid tissue (GALT)

Answer 276

Immune tissue in close proximity to the GI tract. Specifically includes tonsils, adenoids, Peyer's patches and lymphoid aggregates int eh appendix

Question 277

T/F: eosinophils are granulocytes

Answer 277

TRUE: the only granulocytes are eosinophils, basophils, and neutrophils; all the rest of the immune system cells are agranulocytes

Question 278

Defensins

Answer 278

Antibacterial enzymes found on the skin

Question 279

Lysozyme

Answer 279

A nonspecific bacterial enzyme that is secreted in saliva and tears

Question 280

n

Question 281

Cell-mediated immunity

Answer 281

Subsection of the specific immune response driven by T-cells

Question 282

Humoral immunity

Answer 282

Subsection of the specific immune response driven by B-cells. Called humoral because the antibodies dissolve in the blood rather than inside of the specified cell

Question 283

Complement system

Answer 283

Nonspecific response component involving a set of proteins that can punch holes in the cells walls of bacteria

Question 284

Interferons

Answer 284

Proteins that prevent viral replication and dispersion. Cause neighboring cells to produce less viral and cellular proteins, as well as decrease the permeability of the cells, making it harder for a virus to infect them. They also upregulate MHC class I and II which increases antigen presentation and detection of the infected cells by the immune system. Interferons are responsible for many of the flu-like symptoms present due to viral infection

Question 285

Macrophages

Answer 285

Always present in tissue in inactive form --\> gets activated upon infection --\> phagocytoses invader via endocytosis --\> digests it with enzymes--\> MHC binds to antigens and presents them on the surface of the cell

Question 286

MHC I vs MHC II

Answer 286

I: present in ALL nucleated cells in the body. MHC-I pathway is known as the endogenous pathway because any protein produced or processed (like an antigen digested from a pathogen) within a cell can be presented by MHC I. Triggers killer T cells II: only present in antigen-presenting cells like macrophages, dendritic cells, and some B- and skin cells. Takes in antigens from the environment and then presents them on the surface to trigger BOTH adaptive and innate responses. "Exogenous pathway" because the antigen was in antigen-form prior to being taken up by the cell.

Question 287

Pattern recognition receptors / toll-like receptors

Answer 287

TLRs and the most well-known PRRs on the surfaces of dendritic cells and macrophages. PRRs are able to recognize the type of invader in order to trigger production of the correct cytokines to recruit the right types of immune cells

Question 288

NK cells

Answer 288

Natural killer cells that are able to detect the down-regulation of MHC (characteristic in infected and cancer cells) and trigger apoptosis to minimize overall damage of other cells

Question 289

Neutrophils

Answer 289

Most popular leukocyte in the blood and are very short-lived. Phagocytic, and they target bacteria, following them via chemotaxis, up the concentration gradient of the bacteria until they find the source. Neutrophils can also find bacteria that have been opsonized by B-cells (marked with an antibody by a B-cell). Dead neutrophil accumulation forms pus

Question 290

Pus

Answer 290

Accumulation of dead neutrophils

Question 291

Opsonization

Answer 291

Marking of a cell with an antibody

Question 292

Eosinophils

Answer 292

Mainly involved in allergic response. Release large amounts of histamine, which enhances immune responses by vasodilating and increasing leakiness of the blood vessels --\> inflammation

Question 293

Basophils

Answer 293

Less common player in allergic responses. Low population in the blood when the immune system is at rest, Have large, purple granules. Closely related to mast cells. Relase histamines

Question 294

Mast cells

Answer 294

Granulocytes with small granules. Exist in the lungs, mucosa, and epithelium. Release histamines in response to allergens --\> inflammatory response

Question 295

Antibody structure

Answer 295

Y-shaped with two light and two heavy chains held together by disulfide and non-covalent interactions

Question 296

Naive B-cells undergo ____ and the ____ region in order to produce the correct antibodies against the pathogen at hand

Answer 296

Hypermutation; antigen-binding region

Question 297

Isotype switching

Answer 297

Process of cells switching which type of antibody (5 types) they produce based on the type of cytokine that is stimulating them

Question 298

Describe the two daughter cells that are produced from proliferation of a naive B-cell

Answer 298

Plasma cell: produces large amounts of antibodies. eventually die Memory B-cell: Stays in the lymph node, waiting for re-exposure to the same antigen. can last a lifetime

Question 299

Positive selection of T-cells

Answer 299

Allowing the maturation of only the T-cells that can respond to the presentation of the antigen on MHC

Question 300

Negative selection of T-cells

Answer 300

Causing apoptosis in cells that are activated by proteins produced by the organism itself (self-activating)

Question 301

Thymosin

Answer 301

Peptide hormone that facilitates T-cell maturation. Secreted by thymic cells

Question 302

Helper T-cells

Answer 302

Present CD4+ cell markers. Recruit other immune cells. These cells are lost in HIV and prevents the immune system from mounting an appropriate response to infection. Respond to antigens presented on MHC-II molecules (exogenous antigen-presenting --\> so these cells are most effective again bacterial, fungal, and parasitic infections)

Question 303

Cytotoxic T-cells

Answer 303

Present CD8+ markers on surface. Promote apoptosis of infected cells by directly injecting proapoptotic chemicals into the cell. Repond to antigens on MHC-I molecules, which present endogenous antigens, so T\_c cells are most effective against viral infections

Question 304

Suppressor/regulatory T-cells

Answer 304

Exrpress CD4+ by also Foxp3. Function by toning down the immune response once an infection has been adequately attacked. These cells turn off automatically to prevent autoimmune disease

Question 305

Degranulation of Mast Cells leads to \_\_\_\_

Answer 305

The release of histamines

Question 306

Agglutination

Answer 306

Antibodies sometimes cause this formation of large insoluble complexes that can be phagocytized.

Question 307

Roles of dendritic cells in both innate and adaptive immunity

Answer 307

Innate: antigen-presenting cells in the skin Triggers the adaptive response by signaling the proper T and B cells. The T cells, specifically are helper T cells and release interferon-gamma, which activates macrophages and increases their ability to kill bacteria

Question 308

Interferons

Answer 308

Cytokines released by virally infected cells that decrease the likelihood of neighboring cells becoming affected. Neighboring cells' membranes decrease in permeability, experience reduced rates of translation and transcription, the body as a whole experiences symptoms due to the interferons, like fever, malaise, aches, etc.)

Question 309

Mechanism of CD8+ T-cells

Answer 309

They recognize the MHC-I/antigen complex presented on the surface of infected cells and then directly inject proapoptotic chemicals into the cell, killing it before it can spread its virus to neighboring cells in the form of virions.

Question 310

What is the body's immune response to viruses that downregulate MHC-I?

Answer 310

NK cells (as part of the innate response) realize this unusual downregulation and consequently trigger apoptosis

Question 311

Self-antigens

Answer 311

Proteins present on the surface of cells in the body that signal the cell is healthy and normal.

Question 312

Autoimmunity

Answer 312

Disorder of the immune system that occurs when immune cells attack self-antigens.

Question 313

"Education" of immature T and B cells

Answer 313

Referring to the elimination of immature T and B cells in the thymus and bone marrow (respectively) that attack self-antigens. This process prevent autoimmune disorders, although it does sometimes fail.

Question 314

Active immunity

Answer 314

The type of immunity achieved by vaccination. Presentation of a weakened form of the pathogen causes the body to produce antibodies and memory cells against it so that the immune cells can mount a response more quickly in the event of natural exposure to the pathogen.

Question 315

Passive immunity

Answer 315

Achieved by transferring antibodies to a different individual

Question 316

Lymph nodes

Answer 316

Small bean-shaped structures along the lymph vessels that contain a lymph vessel, and artery, and a vein. The provide a space for immune cells to be exposed to possible pathogens

Question 317

Thoracic duct (what is it and where does it lead)

Answer 317

Large lymph duct that most lymph vessels lead to. Located in the posterior chest. Then delivers lymph to the subclavian vein near the heart

Question 318

Functions of the Lymphatic system

Answer 318

Drainage of the excess fluid left in tissues (due to decreased hydrostatic pressure and the venous ends of capillary beds). Also transports fats in the form of chylomicrons from the GI tract into the bloodstream via lacteals.

Question 319

Lacteals

Answer 319

Small lymphatic vessels located at the center of each villus in the small intestine

Question 320

Chyle

Answer 320

Milky white lymphatic fluid that is filled with chylomicrons

Question 321

Germinal centers

Answer 321

Collections of lymph nodes where B-cells can interact and mature

Question 322

Clonal selection

Answer 322

Activation of only the T-cells that bear the correct receptors for a specific antigen

Question 323

Intracellular vs Extracellular Disgestion

Answer 323

Intracellular: involves the oxidation of glucose and fatty acids for energy Extraceullular: extraction of said nutrients from the food in the GI tract

Question 324

Alimentary canal

Answer 324

Lumen of the digestive tract that runs from the mouth to the anus. It is technically "outside" the body because it directly ineteracts with the outside world

Question 325

Order of structures in the GI tract, and the accessories

Answer 325

Order: mouth, pharynx, esophagus, stomach, small intestine, large intestine, anus, rectum Accessories: salivary glands, pancreas, liver

Question 326

Enteric nervous system

Answer 326

Neurons that govern the function of the digestive tract, stimulating peristalsis to move food through. Functions independently from the brain and spinal cord

Question 327

Mastication

Answer 327

Chewing. Increases the surface area to volume ratio so that enzymes can effectively target as much food as possible

Question 328

Innervation of the salivary glands

Answer 328

by the parasympatheic NS

Question 329

Enzymes of saliva

Answer 329

Salivary amylase: hydrolyzes starches into smaller sugars (AKA ptyalin) Lipase: hydrolyzes lipids

Question 330

Structure of the esophagus

Answer 330

The top third is skeletal muscle and innervated by the somatic NS (voluntary), the bottom third is smooth muscle and innervated by the enteric system (involuntary), and the middle third is a mix of both. Swallowing the bolus into the esophagus happens through the upper esophageal sphincter. The bolus exits into the stomach through the lower esophageal (cardiac) sphincter

Question 331

Four anatomical regions, curves, and lining of the stomach

Answer 331

Fundus and body (contain gastric glands), and antrum and pylorus (contain pyloric glands). Lesser curvature refers to the interior curve. Greater curvature refers to the external curve. Lining: Rugae

Question 332

Gastric glands (what are they and name the 3 cell types)

Answer 332

Def: Innervated by the vagus nerve (parasymp NS), respond to signals of sight, taste, and smell of food. Cells types: mucous, chief, and parietal

Question 333

Chief cells in the stomach

Answer 333

Secrete pepsinogen (the zymogen form of pepsin) for protein breakdown

Question 334

Parietal cells

Answer 334

In the stomach. Release HCl to cleave pepsinogen into pepsin. Also secrete intrinsic factor.

Question 335

Pepsin

Answer 335

Cleaved from pepsinogen by H+ ions secreted by parietal cells. Mechanism involves cleavage of peptide bonds near aromatic amino acids.

Question 336

Intrinsic factor

Answer 336

A glycoprotein that helps proper absorption of vitamin B12

Question 337

Pyloric glands (in stomach)

Answer 337

Contain G-cells that secrete gastrin, which induces parietal cells in the stomach to secrete more HCl and signals stomach contractions

Question 338

Chyme

Answer 338

The semifluid result of the stomach's enzymes and contractions on the food that was ingested.

Question 339

The small intestine

Answer 339

3 parts: duodenum, jejunum, and ileum Main function is chemical digestion, with some minor absorption in the jejunem and ileum

Question 340

Duodenum

Answer 340

First portion of the small intestine. Food enters it through the pyloric sphincter. Releases enteropeptidase and brush-border enzymes: maltase, isomaltase, lactase, sucrase and peptidases. Also secretes hormones like secretin and cholecystokinin (CCK) into the bloodstream

Question 341

Brush-border enzymes

Answer 341

Present on luminal surface of cell surface lining the duodenum. Break down dimers and trimers of biomolecules into absorbable monomers

Question 342

Aminopeptidase

Answer 342

Found in the duodenum. Removes the N-terminal amino acid from a peptide

Question 343

Enteropeptidase

Answer 343

Activates trypsinogen to trypsin. Also activates procarboxypeptidases A and B

Question 344

Secretin

Answer 344

Peptide hormone that causes pancreatic enzymes to be released into the duodenum. Regulates the pH of the GI tract by regulating HCl secretion. An enterogastrone: a hormone that slows motility through digestive tract to increase time of chyme exposed to enzymes

Question 345

CCK

Answer 345

Released from the duodenum in response to the entrance of chyme. Function is to stimulate the release of both bile and pancreatic juices

Question 346

Bile salts

Answer 346

Amphipathic molecules that aid in mechanical digestions - helps emulsify fats and cholesterol into micelles --\> makes them available to pancreatic lipase

Question 347

Endocrine vs Exocrine cells of the Pancreas

Answer 347

Endocrine: Islets of Langerhans Exocrine: Acinar cells (produce pancreatic juices)

Question 348

Pancreatic amylase

Answer 348

Breaks down large polysaccharides into smaller ones

Question 349

The pancreatic peptidases

Answer 349

Trypsinogen, chymotrypsinogen, and carboxypeptidases A and B (all get activated into their functional forms by enteropeptidase)

Question 350

Pancreatic lipase

Answer 350

Breaks down fats into free fatty acids and glycerol

Question 351

Major and minor duodenal papillae

Answer 351

Ducts through which the pancreas' acinar cells secrete their products into the duodenum

Question 352

Bile ducts

Answer 352

Connect the liver to the gallbladder (for storage) and the small intestine (for secretion).

Question 353

Hepatic portal vein

Answer 353

Delivers blood to the liver from the abdominal portion of the digestive tract because it is nutrient-rich and can be processed by the liver before draining into the inferior vena cava on its way to the heart.

Question 354

Functions of the liver

Answer 354

Detoxification of certain endogenous and exogenous compounds. Activates some drugs. Bile production. Processing of nutrients, and some storage. Synthesis of certain proteins like albumin and clotting factors.

Question 355

Components of bile

Answer 355

Bile salts, cholesterol, and pigments

Question 356

Bilirubin

Answer 356

The major pigment of bile. Byproduct of the breakdown of hemoglobin. Get attached the a protein in the liver and then secreted into bile for excretion

Question 357

Jaundice

Answer 357

Yellowing of the skin that occurs when the liver is unable to excrete bilirubin

Question 358

Proteins produced by the liver (and their functions)

Answer 358

Albumin: maintains oncotic pressure in the blood and carries many drugs and hormones Clotting factors: blood coagulation

Question 359

Cirrhosis of the Liver

Answer 359

Scarring of the liver. Results in portal HTN/backup of fluid which can result in vomiting blood from the burst blood vessels. Hinders clotting factor production and the body's ability to discard ammonia. Can also lead to carcinoma

Question 360

Gallbladder

Answer 360

Stores and concentrates bile. Pushes bile out into the biliary tree in response to the release of CCK

Question 361

Mode of transport of simple sugars and amino acids from the lumen of the small intestine

Answer 361

Secondary active transport and facilitated diffusion

Question 362

Transport of fatty acids from lumen of small intestine into cells

Answer 362

Short-chain fatty acids: diffusion into epithelial cells and then transport to liver through the hepatic portal circulation Long-chain fatty acids, cholesterol, and triacylglycerides: get packaged into chylomicrons which then enter the lymphatic system via lacteals

Question 363

Mechanism of water intake in the small intestine

Answer 363

As solutes are absorbed, water is motivated to move with them out of the lumen to maintain proper osmolarity. Water moves transcellularly ( across cell mem) and paracellularly (squeezing between the cells) to reach the blood

Question 364

Main function of the large intestine and its three major sections

Answer 364

Function: water absorption Sections: cecum, colon, rectum

Question 365

Cecum

Answer 365

First part of the large intestine. Accepts fluid from the small instestine through the ileocecal valce. Also the sight of attachment of the appendix

Question 366

Colon

Answer 366

Four sections: ascending, transverse, descending, and sigmoid colons. Main function is to absorb water and salts to dehydrate the remaining material to feces.

Question 367

Internal vs external sphincters of the anus

Answer 367

Internal is under involuntary autonomic control External is under somatic control

Question 368

Bacteria in the large intestine produce\_\_\_\_\_

Answer 368

Vitamin K, which is essential for the production of clotting factor and biotin

Question 369

Renal Hilum

Answer 369

A deep slit in the center of the medial surface of each kidney. Spans the width of the renal pelvis. Renal artery, vein, and ureter exit through this.

Question 370

Flow of blood in the kindeys

Answer 370

Renal artery - Afferent arterioles - Glomeruli - Efferent arterioles - vasa rectra (around the Loop of Henle) - venules - Renal vein

Question 371

Order of structures in the nephron

Answer 371

Bowman's capsule - proximal convoluted tubule - descending then ascending limbs of the loop of Henle - distal convoluted tubule - collecting duct

Question 372

Detrusor muscle

Answer 372

Type of muscle that lines the bladder

Question 373

Sphincters of the urethra

Answer 373

Internal: smooth muscle, involuntary External: skeletal muscle, voluntary

Question 374

Describe the innervation of the bladder and what causes excretion

Answer 374

The bladder is innervated by the autonomic NS. Parasympathetic neurons are activated by stretch receptors telling the brain that the bladder is full -\> causes the bladder to contract, inducing a shape change that also causes the internal sphincter to contract. The person then has the conscious choice whether to relax the external sphincter.

Question 375

Pressure difference between Glomerulus and Bowman's Space

Answer 375

Hydrostatic pressure in the glomeruli is higher than the oncotic pressure that is drawing water out of Bowman's Space, so there is net filtration

Question 376

Does glucose diffuse out the glomeruli into Bowman's space?

Answer 376

YES - although most of it is reabsorbed into the body later in the urinary tract.

Question 377

Volume of blood filtered by the kidneys per day

Answer 377

180 L

Question 378

Secretion in the kidney

Answer 378

Movement of solutes from the blood to the filtrate anywhere besides Bowman's Space. Regulates levels of ions in the blood and helps remove molecules that were too big for filtration through the glomerular pores

Question 379

Proximal convoluted tubule

Answer 379

Site of major Na+ reabsorption. Filtrate is isotonic to the interstitium because a lot of other solutes and water move. Secretion of H+, K+, ammonia, and urea into the nephron from the interstitium. Reabsorption of amino acids, glucose, and vitamins occurs here

Question 380

Descending limb of the Loop on Henle

Answer 380

Permeable only to water. Dives deep into the renal medulla, the osmolarity of which gets higher and higher it goes inwards (as the loop travels down). More and more water is reabsorbed as the bottom of the loop is approached.

Question 381

Countercurrent multiplier system

Answer 381

Flow of filtrate through the loop of Henle is in the opposite direction from the flow of blood through the vasa recta, allowing for maximum reabsorption of water because this way, the filtrate is constantly exposed to hypertonic blood

Question 382

Ascending limb of the Loop of Henle

Answer 382

Permeable only to salts. Maximizes reabsorption of salts by taking advantage of the increasing medullary osmolarity. As the concentration of salts in the interstitium decreases and the filtrate is traveling up the loop, more and more salts will flow out of the loop and into the interstitium for return to the bloodstream via the vasa recta

Question 383

Diluting segment

Answer 383

The portion of the ascending loop at the transition from the inner to outer medulla. Characterized by larger cells lining the tubule that hava lot of mitochondria --\> faciltate active transport of Na+ and Cl- out of the filtrate. The only portion of the nephron that can create urine that is more dilute than the blood

Question 384

Compare volume and tonicity of the filtrate at the beginning and end of the loop of Henle

Answer 384

Beginning: the filtrate is isotonic to the blood End: filtrate is slightly diluted compared to the blood MAJOR change: volume of the filtrate has significantly decreased, indicating great reabsorption of water

Question 385

Distal convoluted tubule

Answer 385

Subject to regulation by aldosterone, which promotes Na+ reabsorption. Water follows Na+ back into the body, too, so this concentrates the filtrate. DCT is also a site of secretion of waste from the body

Question 386

Collecting duct

Answer 386

Site of most water reabsorption --\> determines the concentration of the urine. Permeability here is controlled by aldosterone and ADH. Increased permeability means that more water is reabsorbed, concentrating the urine (occurs due to high levels of ADH / aldosterone.

Question 387

Where is glucose reabsorbed from the filtrate in the kidney?

Answer 387

PCT, along with amino acids, Na+, and vitamins

Question 388

Juxtaglomerular cells

Answer 388

Release renin when stimulated by low blood pressure

Question 389

Effect of ACE inhibitors

Answer 389

Prevent the conversion of angiotensin I to angiotensin II, which is supposed to directly promote release of aldosterone from the adrenal cortex. Therefore, aldosterone is not released so blood pressure remains low or is prevented from getting too high

Question 390

Aldosterone

Answer 390

A steroid hormone produced in the adrenal CORTEX that alters the abilities of the DCT and collecting duct to reabsorb sodium (which motivates water to flow with it

Question 391

Vasopressin / ADH

Answer 391

A peptide hormone synthesized by the hypothalamus and excreted by the posterior pituitary in response to increased blood osmolarity --\> acts to change permeability of the collecting duct to take reabsorb more water to dilute the blood back to normal

Question 392

Blood pressure regulation by the kidneys

Answer 392

Vasoconstriction by the afferent arteriole will decrease blood pressure in the glomeruli, which stimulates the release of renin, leading to aldosterone-release to help increase reabsorption of Na+ (and effectively, water). Retention of water increases blood pressure. Vasodilation of the afferent arteriole follows this pathway to decrease blood pressure by NOT stimulating release of renin

Question 393

Response of the kidneys to increased blood pH

Answer 393

Increase reabsorption of H+ and increase excretion of HCO3-

Question 394

The three layers of the skin

Answer 394

Going from deepest to surface: hypodermis, dermin, epidermis

Question 395

Stratum basale

Answer 395

The deepest layer of the epidermis (which is the surface of the skin). Contains stem cells and is responsible for the proliferation of keratinocytes, which predominately make up the skin and produce keratin

Question 396

Stratum spinosum

Answer 396

Second deepest layer of the epidermis. Cells are connected to each other. The site of Langerhans cells (macrophages specific to the skin)

Question 397

Stratum granulosum

Answer 397

Middle layer of the epidermis (third from the top). Site of keratinocyte death and loss of nuclei

Question 398

Statum lucidum

Answer 398

Only present in thick, hairless skin like on the soles of feet or on palms

Question 399

Stratum corneum

Answer 399

Outermost layer of the epidermis. Has several dozen layers of flattened keratinocytes, forming a barrier against pathogens and prevents loss of fluids and salt. Contains openings for sweat and sebaceous glands

Question 400

Layers of the epidermis

Answer 400

Thinl: Come, Let's Get Sun Burned Stratum corneum, stratum, lucidum, stratum granulosum, stratum spinosum, stratum basale

Question 401

Sebaceous glands

Answer 401

Secrete an oily substance (sebum) into hair follicles that lubricates the skin

Question 402

Melanocytes

Answer 402

Melanin-producing cells in the stratum basale.

Question 403

Dermis

Answer 403

Middle layer of the skin under the epidermis and above the hypodermis. Site of origins of sweat glands, blood vessels, and hair follicles. Also contains several sensory receptors. Upper sublayer of this section is the papillary layer and beneath it is the reticular layer. Sensory receptors: Merkel cells (pressure and texture sensations), Meissner's corpuscles (light touch), Ruffini endings (stretch), Pacinian corpuscles (pressure and vibration)

Question 404

Hypodermis

Answer 404

Lowest layer of the skin. Contains fat and fibrous tissue

Question 405

Thermoregulation by the skin

Answer 405

Sweating: postganglionic cholinergic sympathetic neurons (special!) innervate sweat glands and trigger secretion when body temp is high. Cooling occurs due to evaporation of sweat from the skin Piloerection: arrector pili muscles in the skin contract, causing hair to stand up, which helps trap a layer of heated air near the skin. Shivering: converts ATP into mechanical and thermal energy, warming the body Insulation: white fat and, more common in infants, brown fat which has much less efficient electron transport meaning that more heat energy is released as fuel is burned

Question 406

Where is Na+ reabsorption active in the nephron?

Answer 406

PCT, thick portion of the ascending loop, DCT. It is passive in the thin portion of the ascending loop because [Na+] is so high by the time the urine reaches the bottom of the loop after descending

Question 407

Red fibers of skeletal muscle

Answer 407

Slow-twitch. Relatively high myoglobin content and function aerobically. Have a lot of mitochondria for oxidative phosphorylation. Predominant in muscle that must sustain contraction, like those responsible for contraction

Question 408

White muscle fibers

Answer 408

Fast-twitch. Lower myoglobin and relatively fewer mitochondria. Dominant in muscles that contract quickly but also fatigue quickly

Question 409

Nucleation of each of the muscle types

Answer 409

Skeletal: multinucleate Smooth: uninucleate Cardiac: primarily uninucleate, although some are dinucleate

Question 410

Intercalated discs

Answer 410

Structures that connect cardiomyocytes and have many gap junctions that allow the transfer of ions between cells, allowing for simultaneous depolarization of neighboring cells

Question 411

Myogenic activity

Answer 411

Contraction of muscle without input from the nervous system. Smooth and cardiac muscle cells are capable of this

Question 412

Effect of epinephrine on the heart

Answer 412

Binds to adrenergic receptors on the cardiac muscle cells and triggers a cascade that increases Ca2+ concentration in the cells, which increases contraction

Question 413

Titin

Answer 413

Protein in the sarcomere that anchors actin and myosin together, thus preventing excessive stretching

Question 414

Parts of the Sarcomere (ie all of the lines, bands, and zones)

Answer 414

Z-line: the boundary of the sarcomere M-line: middle of the sarcomere that runs down the middle of the thick filaments I-band: region containing only thin filaments H-zone: contains only thick filaments A-band: contains thick filaments in its entirety (the only one of these zones that remains constant in length throughout contraction)

Question 415

Myofibrils

Answer 415

Skeletal muscle cell structures of sarcomeres attached end-to-end. Surrounded by the sarcoplasmic reticulum

Question 416

Sarcoplasmic Reticulum

Answer 416

A modified ER than encases the myofibrils and contains a high [Ca2+]

Question 417

Sarcoplasm

Answer 417

Modified cytoplasm in skeletal muscle cells

Question 418

Sarcolemma

Answer 418

Cell membrane of a myocyte. Able to distribute action potentials across entire cell using T-tubules

Question 419

Muscle fiber

Answer 419

Another name for a skeletal muscle cell. Contains many myofibrils in parallel

Question 420

The role of Ca2+ in skeletal muscle contraction

Answer 420

Depolarization from T-tubules reaches the sarcoplasmic reticulum, releasing Ca2+ into the cell. Ca2+ binds to troponin which induces a conformational change in tropomyosin, effectively exposing the myosin-binding site

Question 421

Steps of the cross-bridge cycle

Answer 421

Myosin binding site is already exposed and myosin is carrying ADP+P\_i. Rapidly successive release of ADP and P\_i provides energy for the power stroke which pulls the actin over the myosin, shortening the sarcomere. New ATP then binds to myosin, decreasing its affinity for actin, so it unbinds. This ATP is then partially hydrolyzed, which recocks the myosin head back into place for another cycle

Question 422

Mechanism of relaxation

Answer 422

ACh is decreased in the NMJ by acetylcholinesterase, allowing the sarcolemma to repolarize, leading to a decrease in Ca2+ release. SR also takes up Ca2+. This causes tropomyosin to re-cover the myosin-binding sites on actin and the sarcomere is allowed to re-lengthen

Question 423

Tonus

Answer 423

Constant low-level contraction, present in blood vessels

Question 424

Latent period

Answer 424

Time between reaching threshold for contraction and the onset of contraction. During this time, action potentials are traveling over T tubules to the SR and Ca2+ is released from there.

Question 425

Tetanus (as the physiological phenomenon)

Answer 425

Muscles are exposed to such frequent and prolonged stimulation that they are unable to relax. Results in muscle fatigue. Occurs in the disease tetanus and, to a lesser degree, under normal conditions, too.

Question 426

Creatine phosphate

Answer 426

One of the energy reserves in skeletal muscle cells. "Stores" ATP through the following reaction creatine + ATP \<=\> creatine phosphate + ADP creatine phosphate undergoes dephosphorylation to produce ATP when the cell needs it

Question 427

Oxygen debt

Answer 427

The difference between the amount of O2 needed by the muscle cell and the amount actually present. Myoglobin helps minimize this by storing O2 through high-affinity binding and then releasing it during times of extreme exercise.

Question 428

Myglobin

Answer 428

One of skeletal muscle cells' energy stores. Binds with high affinity to O2 to hold in reserve to be able to keep aerobic respiration going when O2 is running low.

Question 429

Shift in the myoglobin-O2 binding curve during exercise

Answer 429

Rightward shift, indicating decreased affinity of myoglobin for oxygen. This allows unloading of the O2 so that the muscle cell can use it in aerobic respiration

Question 430

From which germ layer is bone derived?

Answer 430

Embryonic mesoderm

Question 431

Cancellous bone

Answer 431

Spongy bone. The inside contains bony points called trabeculae surrounded by bone marrow. In the core of bones

Question 432

Segments of long bones

Answer 432

Diaphyses (the shafts) swell at each end into the metaphyses, which terminate into epiphyses

Question 433

Red bone marrow

Answer 433

Filled with hematopoietic stem cells that give rise to blood cells

Question 434

Yellow bone marrow

Answer 434

Composed of fat and is relatively inactive

Question 435

Epiphyseal plate

Answer 435

AKA growth plates. Located at the internal edge of each epiphysis. During puberty, they are filled with mitotic cells and contribute to growth until the plates close

Question 436

Periosteum

Answer 436

Protective sheath around long bones, the cells of which are capable of differentiating into bone-forming cells. Essential for bone growth and repair

Question 437

Bony matrix and osteons

Answer 437

Osteons are the structural units of the bony matrix and allow for even distribution of organic and inorganic materials. Each osteon is laid out in concentric circles known as lamellae, surrounding a central microscope channel, which contain blood vessels, nerve fibers, and lymph vessels

Question 438

Lacunae

Answer 438

The spaces int eh bony matrix between lamellae. They house osteocytes. Interconnected with each other by canaliculi in order to exchange nutrients and wastes between the osteocytes and both types of canals

Question 439

Osteoblasts

Answer 439

Build new bone

Question 440

Osteoclasts

Answer 440

Macrophages present in bone that cause breakdown of old bone, thus releasing the Ca2+ and phosphate into the bloodstream

Question 441

Parathyroid hormone

Answer 441

Responds to low Ca2+ levels in the blood by triggering bone resorption, thus increasing Ca2+ and phosphate levels in the blood

Question 442

Vitamin D

Answer 442

Activated by parathyroid hormone. Promotes bone resorption, thus recycling old bone to allow formation of new, healthier bone

Question 443

Calcitonin

Answer 443

Response to high levels of Ca2+ in the blood and triggers bone formation, thus lowering Ca2+ in the blood

Question 444

Chondrin and Chondrocytes

Answer 444

Chondrin is the firm but elastic matrix that makes up cartilage. It is secreted by cells called chondrocytes

Question 445

Endochondral ossification

Answer 445

Hardening of cartilage into bone. Responsible for formation of most long bones in the human body

Question 446

Intramembranous ossification

Answer 446

Undifferentiated embryonic connective tissue (mesenchymal tissue) is transformed into and replaced by bone. This is how the bones of the skull are formed

Question 447

Synovial fluid

Answer 447

Lubricates the joint. Secreted by the synovium into the joint/articular cavity

Question 448

Origin and insertion

Answer 448

Origin: the end of a muscle that has the larger attachment to bone, usually proximal Insertion: the end of the muscle that has the smaller attachment to bone, usually distal

Question 449

Which chemical forms most of the inorganic components of bone?

Answer 449

Hydroxyapatite crystals

Question 450

Locus

Answer 450

Location of a gene on a chromosome. Each gene has a particular one

Question 451

Penetrance

Answer 451

The proportion of individuals in a group carrying a certain allele and actually express the phenotype

Question 452

Expressivity

Answer 452

Describes varying phenotypes despite identical genotypes

Question 453

Mendel's second Law of Independent Assortment

Answer 453

Inheritance of one genotype does not affect the inheritance of another

Question 454

In which phase of meiosis does recombination occur?

Answer 454

Prophase I

Question 455

Transforming principle

Answer 455

Bacteria can increase genetic variability by sharing genes with members of their species in close proximity. Discovered by Griffith

Question 456

Transposons

Answer 456

Elements that can freely insert and remove themselves from a genome. They can disrupt a gene is they attach in the middle of one

Question 457

Chromosome-level mutations are \_\_\_\_-scale ompared to nucleotide-level mutaitons

Answer 457

large

Question 458

Translocation mutation

Answer 458

When a segment of DNA from one chromosome is swapped with a segment of DNA from another chromosome

Question 459

Inborn errors of metabolism

Answer 459

Defcts in genes required for metabolism

Question 460

Genetic Leakage

Answer 460

Flow of genes between species. Sometimes to produce hybrid offspring like mules

Question 461

Genetic drift

Answer 461

Changes in the gene pool of a species due to chance. Causes a reduction in genetic variability

Question 462

Inbreeding depression

Answer 462

Overall reduced fitness of the population due to inbreeding and consequent decrease in genetic variation

Question 463

Recombination frequency

Answer 463

The likelihood that two alleles are separated from each other during recombination. Tightly linked genes have recombination frequencies near 0 percent, whereas weakly linked genes have RFs near 50%. Analysis of these values allows us to create a genetic map

Question 464

Conditions of Hardy-Weinberg Equilibrium

Answer 464

All five must be met to achieve a stable gene pool and NO evolution: 1. Population is very large (no gen. drift) 2. There are no mutations in the gene pool 3. Mating between individuals is the population is random (no sexual selection) 4. There is no migration of individuals into or out of the population 5. The genes in the population are equally successful at being reproduced

Question 465

Hardy-Weinberg equations

Answer 465

p+q = 1 p^2 + 2pq + q^2 = 1 p: the frequency of the dominant allele q: the frequency of the recessive allele

Question 466

Rate of occurence of the dominant phenotype (H-W equation)

Answer 466

p^2 + 2pq

Question 467

Inclusive fitness

Answer 467

A measure of an organism's success in the population, based on the number of offspring, the ability to support the offspring, and then the ability of the offspring to support others

Question 468

Punctuated equilibrium

Answer 468

Theory of evolution that was theorized by studying the fossil record. It supports the idea that species would be relatively stagnant and not evolving over long periods of time and then go through short bursts of evolution

Question 469

Modes of natural selection

Answer 469

Stabilizing selection, directional selection, and disruptive selection

Question 470

Stabilizing selection

Answer 470

Keeps phenotypes within a certain range by selecting against extremes. Ex: birthweight remains in a narrow range because either extreme can be dangerous

Question 471

Directional selection

Answer 471

Emergence and dominance of an initially extreme phenotype

Question 472

Disruptive selection

Answer 472

Two extreme, distinct phenotypes are selected over the norm. These distinct phenotypes are known as polymorphisms

Question 473

Polymorphisms

Answer 473

Naturally occurring differences in the form between members of the same population. Ex: light and dark coloration of butterflies in the same species

Question 474

Adaptive radiation

Answer 474

Concept that describes the rapid rise of a number of different species from a common ancestor. It is promoted by rapid environmental changes or isolation of small groups of the ancestral species

Question 475

Niche

Answer 475

An environment (encompassing habitat, resources, and predators) for which a certain species is adapted to survive in

Question 476

Prezygotic reproductive isolation

Answer 476

Mating between species is no longer possible due to evolution. Zygote cannot even form

Question 477

Postzygotic reproductive isolation

Answer 477

Allows gamete fusion, but the zygote is not stable or viable enough to survive. Two groups can no longer mate with each other due to speciation apart

Question 478

Molecular clock model

Answer 478

The degree of genomic similarity correlates with the amount of time since two species split off from the same common ancestor

Question 479

Where are post-transcriptional modifications carried out? What about post-translational?

Answer 479

P-transcrip: In the nucleus P-transl: A couple of locations are possible including the cytoplasm, ER, and Golgi

Question 480

Euploidy

Answer 480

Having one or more complete sets of chromosomes

Question 481

Tissue with the highest number of glucagon receptors

Answer 481

Liver. NOT skeletal muscles because the primary function of glucagon is to increase blood glucose levels, and skeletal muscles' glycogen stores are not broken down for release into the bloodstream, rather, the muscles use the glucose themselves

Question 482

Endosome

Answer 482

A collection of intracellular sorting organelles

Question 483

In beta-oxidation, which carbons wind up in which products?

Answer 483

C1 and C2 wind up in the acetyl-CoA (the two-carbon molecule) C3 (and above) wind up on the acyl CoA - the remaining fatty acid chain

Question 484

Describe the effect on SDS-PAGE of a protein having an abundance of negative charged residues in its peptide chain prior to SDS denaturation

Answer 484

Many negativeley charge residues will result in SDS-PAGE producing an estimate of the protein's weight that is less than the actual value because the the negative charge induced by SDS plus the existing negative charge intensifies the charge so much that the protein will travel further in the gel towards the positive end (indicating smaller size) than what is accurate

Question 485

Passive Immunity

Answer 485

The transfer of active humoral immunit in the form of ready-made antibodies, from one individual to another. Ex: diffusion of antibodies from mother to fetus through the placenta

Question 486

Contrast Anaphase I and Anaphase II of Meiosis What are the resulting ploidies of meiosis I vs II?

Answer 486

Anaphase I: Separation of homologous chromosomes Anaphase II: Separation of sister chromatids Cells after meiosis I: 2 haploid cells, 2 sister chromatids of each chromosome After meiosis II: 4 haploid cells, 1 sister chromatid of each chromosome

Question 487

Autosomal genes

Answer 487

Genes that are NOT located on X or Y chromosomes. They are expressed to the same extent in males and females

Question 488

Males tend to exhibit X-linked disorders ____ frequently than females in the population because...

Answer 488

more; they only have one X chromosome, so the "dominant" X allele has to be the one that is on there (the single allele), in contrast to females who can have an abnormality on one X chromosome be canceled out by a normal allele on their other X chromosome In short: males only have one allele for x-linked genes so they would have to express it

Question 489

Genes that are located close to each other on a chromosome have a _____ chance of being separated in recombination

Answer 489

Low

Question 490

Parallel evolution

Answer 490

Describes when two closely related species (with a common ancestor) develop similar characteristics due to a similar environment

Question 491

Divergent evolution

Answer 491

Describes the evolution of two species descended from a common ancestor, but now inhabit distinct environments, so have now developed different characteristics

Question 492

T/F: Genes that are rarely expressed are likely found on Euchromatin

Answer 492

False - genes that are located on the loosely wrapped euchromatin are more available for transcription machinery to access them, so it makes more sense for low-expression genes to be located in the more tightly coiled heterochromatin

Question 493

Describe the use of Hybridization to detect gene expression

Answer 493

Determine whether there is a specific mRNA of interest by incubating cytosol from the cell of interest with a fluorescently labeled complementary RNA. The degree of fluorescence after washing away the unbound mRNAs shows the degree of hybridization, which can be used to determine the amount of mRNA of interest present in the cytosol sample.

Question 494

DNA Mismatch Repair Machinery (def and mechanism)

Answer 494

Corrects mismatched bases in DNA strands during replication - does NOT repair RNA. Mechanism: Upon detection of a mismatched base, a nuclease enzyme cuts out the erroneous nucleotide and a couple of its neighboring nucleotides, and then repairs the sequence with DNA polymerase. DNA ligase seals the nicks

Question 495

Synapsis

Answer 495

During prophase I of meiosis when homologous chromosomes recognize each other and line up side by side to form a tetrad. Allows cross over to occur, thus increasing genetic diversity

Question 496

Epitope and bond-type

Answer 496

The antibody binding region on an antigen. Antibody binds noncovalently

Question 497

Ubiquitin tags

Answer 497

Label proteins for destruction by flagging them to be sent to the proteasome

Question 498

Lysosome vs Proteasome

Answer 498

Lysosome degrades secretory proteins that entered the cell via endocytosis, whereas proteasome degrades cytosolic proteins that were sent to it due to ubiquination

Question 499

k\_cat

Answer 499

Turnover number of an enzyme. Equal to the number of substrate molecules converted to product per second under saturating conditions

Question 500

Slope of a Lineweaver-Burke plot

Answer 500

Km/Vmax

Question 501

Effect of Urea on Proteins

Answer 501

Urea denatures the proteins by exposing hydrophobic groups and interfering with H-bonding in the amino acid backbone. Increases unfolding

Question 502

Average weight of a single Amino Acid

Answer 502

110 Da

Question 503

How is the tertiary structure of a protein stabilized?

Answer 503

Via noncovalent interactions between amino acid sidechains ONE EXCEPTION: disulfide bonds (covalent) can occur between Cys sidechains, require an oxidizing environment (cannot happen in the cytosol because it is a reducing environment)

Question 504

Ternary complex

Answer 504

A group of 3 bound molecules with at least one of them being a protein May either bind in a specific order or random

Question 505

Native PAGE

Answer 505

Takes place in a gel that is free of any detergents or reducing agest, which means that the native structure of the protein is retained

Question 506

Succinate-Ubiquinone Reductase

Answer 506

Complex II of the ETC, also called succinate dehydrogenase. An oxidoreductase that moves electrons from succinate to Complex III. The first e carrier in Complex II is FADH2, and then the carrier that takes the e to Complex III is ubiquinone (reduced to ubiquinol).

Question 507

As the ETC progresses, the reduction potentials of the electron carriers gets \_\_\_\_\_\_\_\_\_.

Answer 507

Higher!

Question 508

Stereospecific reactions of the Citric Acid Cycle

Answer 508

Formation of D-isocitrate via Aconitase Formation of L-malate via fumarase

Question 509

Fructose -2.6-bisphosphate

Answer 509

Synthesis of this enzyme is triggered by insulin - it then activates PFK-1 --\> driving glycolysis. Also inhibits gluconeogenesis by allosterically inhibiting the catalytic activity of F1,6BP Increases net catabolism of glucose

Question 510

Innervation of the adrenal medulla

Answer 510

ONLY innervated by the sympathetic nervous system

Question 511

Respective cellular locations of fatty acid oxidation and synthesis

Answer 511

Oxidation: mitochondria (primarily - note that longer chains must start out in the peroxisome) Synthesis: cytosol

Question 512

Chaperones

Answer 512

Proteins that facilitate proper folding and prevent aggregation

Question 513

Signal sequences

Answer 513

Portions of mature mRNA located in the 5' region. They signal the ribosome that translation needs to finish occurring at the location of the Rough ER

Question 514

Full name of NADH

Answer 514

Nicotinamide adenine dinucleotide + hydrogen

Question 515

Endomembrane system

Answer 515

The portion of the cell that is responsible for modifying proteins that will be secreted (e.g. cleavage of insulin into its mature form)

Question 516

Major Histocompatibility Complex

Answer 516

Group of genes that encode for proteins involved in immune system's ability to recognize the self

Question 517

Increased levels of which hormone indicate increased levels of stress?

Answer 517

Cortisol

Question 518

Quorum Sensing

Answer 518

The ability of cells to detect and respond to cell population density by appropriate regulation of genes

Question 519

Functions of Liver Cells

Answer 519

* Regulation of blood glucose via glycogenolysis, glycogenesis, and gluconeogenesis * Storage of glycogen, minerals (iron), and vitamins * Synthesis of macros like plasma proteins (albumin, clotting factors), fats, ketone bodies, and cholesterol * Production and secretion of bile * Breakdown/detoxification of numerous drugs and metabolic waste products

Question 520

Nuclear Localization Sequence

Answer 520

Short sequence of amino acids that mediates transport of the protein from the cytoplasm into the nucleus

Question 521

Cell type that lines Bowman's Capsule

Answer 521

Simple squamous epithelial