107 module 1 Flashcards
(544 cards)
1
Q
six levels of structural organisation of human
A
chemical, cellular, tissue, organ, system and organismal.
2
Q
four major classes of tissue
A
epithelial, muscle, connective and nerve.
3
Q
system
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related organs that preform a common function
4
Q
organ
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specific structures composed of two or more types of tissues
5
Q
Organismal
A
all the parts of the body function that constitute a living organism
6
Q
how many body systems?
A
eleven
7
Q
eleven systems of the body
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integumentary, muscular, skeletal, nervous, endocrine, lymphatic and immune, cardiovascular, respiratory, digestive, urinary and reproductive
8
Q
epidermis function and position
A
outermost, vitamin D production, protects deeper tissues and covers the surface
9
Q
integumentary system components
A
skin: consisting of the epidermis, dermis and hypodermis.
10
Q
dermis function and position
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feeds epidermis, middle layer
11
Q
hypodermis function and position
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fat stores, innermost and attaches skin to deeper layers
12
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dermis components
A
hair follicles, hairs, sebaceous glands, sweat glands, nails, sensory receptors
13
Q
sensory receptors
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in the dermis that detects pain and temp, pressure and touch
14
Q
nails
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in epidermis and dermis which stiffens and protects digits
15
Q
hair follicles, hair and sebaceous glands
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in dermis: sensation from innervation, protection and lubricates hair shaft and epidermis
16
Q
skeletal muscles division
A
appendicular and axial muscules
17
Q
skeletal muscle functions
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skeletal movement, controls entrance and exits to digestive, respiratory, and urinary systems. produces heat, protects soft tissues and supports skeleton
18
Q
axial skeleton function
A
provides support and positioning of the axial skeleton
19
Q
overall function of tendons and aponeuroses
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translate contractile forces into tasks (flexion and extension).
19
Q
appendicular muscle function
A
support and move limbs
20
Q
muscular system components
A
skeletal muscle (appendicular and axial) and tendons + aponeuroses.
21
Q
tendon function
A
part of skeletal muscle systeM: fibrous rope like connection between muscle and bone
22
Q
aponeuroses function
A
part of skeletal muscle system which are sheet like tendons connecting muscle to muscle (some can be to bone)
23
Q
Skeletal system components
A
axial and appendicular skeleton. Bones, joints, cartilage and ligaments. Red and yellow bone marrow.
24
cartilage
found at bone interfaces
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Axial skeleton (skeletal system)
protects the brain and spinal cord, sense organs and soft tissues of thorax.
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appendicular skeleton (skeletal system)
provides internal support and positioning of the external limbs and supports and enables muscle to move the axial skeleton
27
Red bone marrow
red blood cell production in bones (flat bones) such as pelvis, sternum and skull.
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Bone
stores minerals and consist of yellow + red bone marrow
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yellow bone marrow
energy storage of fat cells found in medullary cavity of long bones.
30
nervous system components
CNS and PNS. CNS: brain, spinal cord and special senses
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brain in the CNS
controls complex integrative activities and controls voluntary and involuntary activities.
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Spinal cord of CNS
relays info to and from brain, preforms less complex integrative activities such as the reflex arc
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special senses of CNS (also PNS apart from optic nerve)
sensory input to brain relating to sight, hearing, smell, taste and equilibrium.
34
Endocrine system
Pineal gland, hypothalamus and pituitary, pancrease, adrenal gland, thymus, parathyroid gland and thyroid, kidneys and gonads
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pineal gland
day night rhythms (melatonin)
36
hypothalamus and pitutiary
control many endocrine glands, regulates growth and fluid balance
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thyroid gland
metabolic rate
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parathyroid gland
calcium levels
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thymus
maturation of lymphocytes
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adrenal galnds
water and mineral balance + tissue metabolism
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kidneys
red blood cell production, blood presssure up and calcium levels
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pancreas
glucose control
43
gonads
sexual characteristics and reproduction
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What does the pituitary do in terms of growth?
produces growth hormone which goes to the liver and produces IGF-1 -> stimulates bones, muscle and tissues grow.
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Too much growth hormone as a child from pituitary
Gigantism
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Too much growth hormone as an adult from pituitary (tumor)
acromegaly
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lymphatic system components
lymphatic vessels and fluid, B and T cells. Lymph nodes including tonsils, spleen and thymus`
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lymphatic vessels
contractile vessels that carry lymph fluid and lymphocytes from peripheral tissues to veins of CV system. Drains
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lymphatic fluid
lipids from gut and fluid from tissues
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B and T cells in the lymphatic system
cells that carry out immune responses
51
spleen of the lymphatic system
monitors circulation blood cells, engulfs pathogens, recycle red blood cells, produce immune responses.. like a large lymph node
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thymus of the lymphatic system
controls development and maintenance of the T cell lymphocytes.
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cardiovascular system components
heart, blood vessels, arteries capillaries veins and blood
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Heart function CS
propels blood and maintains blood pressure
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blood vessels: CAPILLARIES AND VEINS
CV S
Arteries go from heart to capillaries, and in capillaries diffusion between blood and interstitial fluids. Veins return blood from capillaries to heart
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BLOOD IN THE CARDIOVASCULAR SYSTEM
transport CO2 and O2. transport nutrients and hormones, remove waste and temp regulation, defense against illness and acid base balance.
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Respiratory system components
nasal cavity and paranasal sinuses, pharynx, larynx , trachea, bronchi, luntgs and diaphragm
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pharynx function
conducts air to larynx
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nasal cavity and paranasal sinuses function
filter and warm and humidify air and detect smells
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larynx
protects opening to trachea, vocal cords for vocalisation
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trachea
conducts air (cartilage keeps it open)
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bronchi
conducts air between trachea and lungs
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lungs
air movement, gas exchange of O2 and CO2 in alveoli, acid base control
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diaphragm
muscle for air movement.
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digestive system
oral cavity, salivary glands, pharynx, oesophagus, stomach, small intestine, liver, gallbladder, pancreas and large intestine + anus
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oral cavity
DS: breaks up food working with teeth an tongue
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salivary glands
buffers and lubricant, enzymes that begin digestion
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pharynx
solid food and liquids to the oesophagus, chamber shared with respiratory system
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stomach
secretes acid and enzymes and hormones
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oesophagus
deliver food to stomach
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small intestine
digestive enzymes, buffers and hormones', absorbs nutrients
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liver
secretes bile, regulates nutrients in blood
g
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gallbladder
concentrates bile
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pancreas
digestive enzymes, buffers and endocrine cells
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large intestine and anus
water removal and waste storage and removal..
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urinary system components
kidney, ureters, bladder and urethra
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kidneys in urinary system
forms and concentrates urine, regulate pH and ions, blood vol and pressure, endocrine function
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ureters
conducts urine to bladder
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urethra
conducts urine to exterior
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EPO
erythropoietin, glycoprotein hormone produced by the interstitial fibroblasts in kidney which promotes erythropoiesis in bone marrow, increases RBC production which allows the blood to have a greater carrying capacity for oxygen.
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male reproductive system
testes, accessory ortgans and external genitalia
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testes of male
produce sperm and also hormones in the endocrine system as well (RS)
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Accessory organs of the male reproductive system
epididymis, ductus deferens, seminal glands, prostate gland and urethra.
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epididymis
sperm maturation
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ductus deferens
sperm from epididymis
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seminal glands and prostate gland
seminal fluid
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male external genitalia of the RS
reproduction and thermal. Control testes.
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reproductive system females
ovaries, uterine tubes, uterus, vagina and external genitalia, mammary glands.
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ovaries
oocytes and hormones (ES and RS)
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uterine tubes
oocyte delivery, location of fert
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vagina and external gen
RS, lubrication, sperm reception and birth canal
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mammary glands
nutrition for new-born modified sweat gland and also part of the integumentary as well as RS.
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epithelial tissue
covers body surface, lines hollow organs, cavities and ducts, forms the glands of the body. Arranged in continuous sheets as single or multiple layers.
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function of epithelial tissue
selective barriers (limit/aid transfer), secretory and protection from abrasion
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All the cell junctions that hold epithelial tissue together
tight junctions, adherens junctions, gap junctions, desmosomes, hemidesmosomes.
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Cytoskeleton
made up of microfilaments (ACTIN: BROWN) and intermediate filaments (KERATIN: PURPLE). These hold the cell shape, link cytoplasm to the membrane, tie cells together and aid muscle contraction.
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Microfilaments
part of the cytoskeleton, ACTIN. Is brown and in bundles beneath cell membrane and cytoplasm, maintains cell shape, ties cells together and aid muscle contraction.
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Intermediate filaments
KERATIN, PURPLE and functions for strength of the cytoskeleton.
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TIGHT JUNCTIONS
FOUND IN STOMACH, BLADDER AND INTESTINES:
- individual sealing strands
- TRANSMEMBRANE
- PROTEINS CLAUDIN and OCCLUDINS
- keep cell polarity by preventing migration of proteins between apical and basal surfaces
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TIGHT JUNCTIONS PROTEINS
CLAUDINS AND OCCLUDINS
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ADHERENS JUNCTIONS
Belt, OTHER LESS CONTINUOUS can be called adhesion plaques, more basal located than tight junctions.
Have a PLAQUE layer of proteins on inside of cell to join actin to cadherins.
PROTEINS: caderhins to span the gap and catenins to link cadherins to ACTIN.
PREVENTS CELL SEPARATION AND RESIST TENSION FORCES LIKE IN CONTRACTIONS.
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ADHERENS JUNCTIONS PROTEINS
CADHERINS AND CATEININS. CADERHINS SPAN THE GAP AND CATENINS LINK CADERHINS TO ACTIN.
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DESMOSOME JUNCTIONS
lateral wall, have plaque just like adherens junctions
- resist SHEARING FORCES
- CADHERIN SPANS GAP AND BINDS TO DESMOPLAKIN
- links cell surface to keratin
- keratin spans from one desmosome to another on other side for structural integrity (EG MUSCLE CELLS)
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DESMOSOME JUNCTIONS PROTEINS
CADHERINS TO SPAN THE GAP WHICH BINDS TO DESMOPLAKIN THEN LINKED TO KERATIN
104
GAP JUNCTION PROTEINS
ConnexIN, 6 make a ConnexON -> 2 make a GAP JUNCTION.
104
GAP JUNCTION
DIRECT CONNECTION BETWEEN CELLS
- made of 6 proteins called ConnexIN which form a ConnexON/Hemichannel.
- 2 hemichannels on either sides of two cells make a GAP JUNCTIOn
- 1kDA small molecules go through
104
HEMIDESMOSOME
connect epithelia to basement membrane
- links cellular basal intermediate filament (KERATIN) to basement membrane
- INTEGRIN LINKER PROTEIN spans the space and binds to LAMININ in BM and to keratin in the intermediate filament in cytoplasm.
- locks cytoskeleton down onto basement membrane
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HEMIDESMOSOME PROTEINS
INTEGRIN SPANS THE SPACE AND LINKS TO LAMININ IN BM, AND TO KERATIN IN THE INTERMEDIATE FILAMENT IN CYTOPLASM
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JUNCTIONAL COMPLEX
tight junction, adherens junction and desmosome
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BASEMENT MEMBRANE
found between epithelium and connective tissue, made up of the basal lamina and reticular lamina. All epithelia overlay basement membrane.
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BASAL LAMINA
one part of the basement membrane, secreted by epithelial cells, containing collagen, laminin, other proteoglycans and glycoproteins.
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RETICULAR LAMINA
One part of the basement membrane. produced by cells of the underlying layer of connective tissue known as fibroblasts. containing fibrous proteins such as fibronectin and collagen etc.
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Epithelia does not contain nerves
and do not contain blood vessels, the basement membrane is an important conduit for bringing nutrients to the epithelium as nutrient and waste exchange takes place by diffusion from the vessels in the connective tissue.
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Functions of the basement membrane
supports overlying epithelium, provides surface along which epithelial cells can migrate during growth and wound healing, protection acting as a physical barrier, participates in the filtration of the kidney
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Two types of epithelial tissues
glandular epithelia (secretory cells predominate) and (cover exposed surfaces and internal cavities)
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COVERING AND LINING EPITHELIA
classified via arrangement and shapes of cells.
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Arrangement of covering and lining epithelia divisions
simple (single layer for absorption, secretion, filtration).
stratified: two or more layers (protective)
pseudostratified: appears to have multiple layers but not all cells reach apical surface, all cells are in contact with basement membrane (actually simple epithelium).
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Shape of covering and lining epithelia divisions
1) squamous: flat and thin (helps allow passage by diffusion)
2) cuboidal: tall as they are wide (secretion and absorption)
3) columnar: more tall than wide (secretion and absorption)
4) transitional: stratified epithelium, can change from cuboidal to flat depending on organ shape (EG BLADDER).
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Simple squamous epithelium
most delicate, where there is filtration (kidney), diffusion (lung) and secretion (serous membranes).
Specialised subtypes: MESOTHELIUM: lines pericardial, pleural, peritoneal cavities
ENDOTHELIUM: inside heart and blood/lymphatic vessels.
Thin and flat, irregular like jigsaw.
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mucociliary escalator
cillia that move, bigger than microvilli.
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simple cuboidal epithelium
where there is secretion and absorption, distance between adjacent nuclei is approx height of epithelium. No specialised subtypes. Location examples: pancreatic ducts, parts of kidney tubules etc.
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simple columnar epithelium
Come in two major subtypes: non-cilliated and cilliated. Simple columnar epithelium can have cilia or microvilli.
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NON CILIATED SIMPLE COLUMNAR EPITHELIUM
single layer, microvilli on apical surface, have goblet cells interspersed. Found on gut mucosa from stomach to anus; ducts of many glands; GALL BLADDER. fUNCTION: secretion and lubrication, abs.
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CILIATED SIMPLE COLUMNAR EPITHELIUM
have goblet cells. In some bronchioles, uterine fallopian tubes, sinuses etc. Function: synchronous movement assist motility of mucus and foreign objects or oocytes.
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stratified squamous epithelium
cells further from nutrition are thinner and less active. Located where mechanical or chemical stress are severe, apical cells are packed with keratin in places where mechanical stress and dehydration are a major issue.
SPECIALISED SUBTYPES:
KERATINISED (DRY TRAUMA): skin. AND NON KERATINISED (WET TRAUMA)-> vagina, mouth throat anus etc.
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pseudo stratified columnar epithelium
all cells contact BM, SUBTYPES: CAN BE CILIATED ( cilia on some cells with goblet cells that secrete mucus). OR NON CILIATED with no cilia and no goblet cells.
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ciliated pseudo-stratified columnar epithelium
most upper airways and secrete mucus + moves it
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non-ciliated pseudo-stratified columnar epithelium
larger ducts of glands, epididymis, part of male urethra and function: absorption and protection.
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GLANDULAR EPITHELIA
glands consist of a single cell or a group of cells that secrete substances into ducts, onto surface or into blood. classified according to where they secrete substances. FUNCTION IS SECRETION. DIVIDED INTO EXOCRINE AND ENDOCRINE.
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ENDOCRINE GLAND
part of the glandular epithelia: secrete directly into blood via transversing interstitial fluid: example: pituitary, pineal, thyroid, generally distant strong effects.
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EXOCRINE GLAND
secrete into ducts that empty onto the surface of a covering or lining epithelium. sweat and salivary glands, oil glands, wax glands, GENERALLY LOCAL EFFECTS.
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organ with both exocrine and endocrine glandular tissues
pancreas, pancreatic duct and endocrine cells in pancreatic islet.
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single cell gland
goblet cells, exocrine gland.
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3 characteristics used to describe structure of multicellular glands
1) structure of duct
2) structure of secretory area
3) relationship between the two
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SIMPLE VS COMPOUND MULTICELLULAR GLANDS
SIMPLE: if there is a single duct that does not divide on its way to gland cells.
COMPOUND: if the duct divides one or more times on its way to gland cells.
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connective tissue
binds, strengthens and supports OTHER BODY tissues, major transport system (blood), major site of stored energy reserves (fat/adipose).
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features of connective tissue (compared to epithelia)
Unlike epithelia, CT is not found on body surfaces, and can be highly vascular. Apart from cartilage. Like epithelia, it is supplied by nerves (except cartilage).
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Connective tissue is composed of
extracellular matrix and cells.
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Connective tissue extracellular matrix
is made up of ground substance and protein fibres (three major types)
The protein fibres are secreted by cells in the ECM/CT called fibroblasts
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fibroblasts
secretes proteins that make up the extracellular matrix of the connective tissue
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the structure of the extracellular matrix...largely...
dictates the connective tissue qualities
- cartilage: firm and rubbery)
- bone (ECM hard and inflexible).
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Ground substance
part of the extracellular matrix, composed of water, proteins (gelatin) and polysaccharides (glycosaminoglycans)
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glycosaminoglycans
part of the ground substance in the extracellular matrix. GAGS join to core proteins to form proteoglycans which are long unbranched polysaccharides (repeating disaccharide unit)
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sulphated GAGS
allow binding to water: dermatan sulphate. heparin, keratan and chondroitin. These bind to core proteins to form proteogylcans.
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non-sulphated GAG
hyaluronic acid. does not bind directly to protein backbone but is joined to various proteoglycans. It is not sulphated or covalently bound to a core protein.
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GAGS and hyaluronic acid function
Highly polar and attract water -> collectively with the GAGS trap water to make ground substance jelly like. HA binds cells together, lubes joints and maintains shape of the eyeball.
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hyaluronidase
dissolves hyaluronic acid, is produced by white blood cells, sperm and some bacteria. THis makes ground substances more liquid so they can move easily in it or makes access to the egg easy for sperm (moving through extracellular matrix).
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Chondroitin sulphate
type of GAG. support and provide adhesive features of cartilage, bone, skin and blood vessels.
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KERATAN SULPHATE
found in bone, cartilage and cornea of eye
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DERMATAN SULPHATE
found in skin, tendons, blood vessels and heart valves
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Abnormal periorbital ECM and thyroid disease (exophthalmos)
common inn younger women, goitre (swollen thyroid gland), autoimmune over-activation of thyroid and autoimmune action on fibroblasts in ECM of eye (exophthalmos)
SWELLING OF ECM + INC MUSCLE SIZE AND FAT: deposition of GAGS and influx of water increase orbital contents
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three different types of protein fibres in connective tissue extracellular matrix
collagen fibres, reticular fibres and elastic fibres.
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collagen fibres
one of the types of protein fibres in the ECM, very strong but flexible to resist PULLING forces. Features vary in diff tissues (more water around collagen in cartilage than in bone) Collagen 25% of body, most abundant protein.
Common in: bone, cartilages, tendons and ligaments
PARALLEL BUNDLES
150
Collagen fibres function
resist pulling forces, very strong and flexible, 25% of body (most abundant) and thick.
151
where can collagen fibres be found and what do they look like
bone, cartilage, tendons and ligaments. PARALLEL BUNDLES!
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reticular fibres
composed of collagen (fine bundles)with coating of glycoprotein (more protein than sugar), mabe by fibroblasts and forms part of the basement membrane. Thinner branching (form networks in vessels) and spreads through tissue (esp adipose, nerve fibres and smooth muscle tissues)
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Reticular fibres function
provide strength and support makes up part of basement membrane and forms networks in vessels and thru tissues esp adipose, nerve fibres and smooth muscle tissues
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reticular fibres structure
thinner and branching-> spreads thru tissue
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elastic fibres
fibrous network, consist of protein ELASTIN surrounded by glycoprotein fibrillin for strength and stability. Can be stretched 150% without breakage. Found in skin, BV and lung. Thinner than collagen fibres
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elastic fibres structure
fibrous network, thinner than collagen fibres and can be stretched 150% without breaking.
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elastic fibres function
consist of protein elastin and surrounded by glycoprotein fibrillin to give it strength and stability
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mafan syndrome how
hereditary, defect in elastic fibres (dom mutation chromosome 15) coding for fibrillin. Body produces growth factor beta that increases growth cuz it doesn't bind normally to fibrillin. Fibrillin is a large glycoprotein that contributes to a structural scaffold for elastin
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Marfan syndrome symptoms
CAuses long limbed and often with chest deformity. Normal life but need medical vigilance to control BP. May have weakened heart valves and arterial walls, 1/20k
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Cells that make up connective tissue
fibroblasts and adipocytes
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fibroblasts in connective tissue location
widely distributed in connective tissues and are migratory
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fibroblasts in connective tissue function
secrete components of the matrix (fibres and ground substance) also takes part in making basement membrane
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adipocytes in connective tissue location
under the skin and around organs
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adipocytes in connective tissue function
store fat (triglycerides)
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macrophages (histiocytes)
phagocytic cells in fixed and wandering forms in connective tissue.
FIXED: in the lung they are dust cells
Kupffer cell in liver and langerhans cell in the skin, wandering in connective tissue: sites of infection/inflam and injury.
166
plasma cells
b-lymphocytes = produce antibodies. Many CT sites, esp in gut, lung, salivary glands, lymph nodes, spleen and red bone marrow.
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Leucocytes
white blood cells, eg neutrophils and eosinphils that migrate out from blood.
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mast cells
produce histamine = dilates vessels. Found alongside blood vessels.
168
CT proper
part of the mature connective tissue which are loose and dense CT
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How is connective tissue classified
embryonic and mature
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Mesenchyme (embryonic)
gives rise to all other CT, consists of all CT cells (mesenchymal cells) in a semi fluid ground substance containing reticular fibres
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mucous embryonic CT
has widely scattered fibroblasts embedded in jelly like ground substance and supports umbilical cord of foetus.
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Mature connective tissue
CT proper: loose and dense, Fluid CT: blood and lymph, Supporting CT: cartilage and bone
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fluid CT
under mature CT, blood and lymph CT
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supporting CT
bone/osseous tissue and cartilage CT.
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loose connective tissue
AREOLAR connective tissue (most common), and adipose CT.
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areolar connective tissue
loose CT, most common, 3 types of fibres (cartilage, reticular and elastic), loose with more cells and less fibres. Widely distributed around almost every structure
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areolar CT function
widely distributed around almost every tissue for strength, elasticity and support, acting as packing material.
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ADipose CT
mature -> loose CT: adipocytes dominant with central triglyceride droplet. white adipose (energy storage) and brown(heat production)
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where is adipose CT found and what does it do
found in areolar CT on ass, flanks, abdomen and orbit of eye, insulation, energy source and temp control
174
Reticular connective tissue
composed of type III collagen, which forms a network that makes the framework for many organs and glands.
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DENSE REGULAR CT
Dense CT with regular subtype (more fibres less cells).
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where is dense regular CT found
tendons (muscle to bone)
ligaments (b-b)
aponeuroses (m-m and b-nm)
regularly arranged collagen
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dense regular CT structure
shiny white colour, collagen fibres are not a living tissue, slow healing
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dense irregular CT
found in high concentrations in body parts where support is needed to prevent the effects of forces that pull in multiple directions.
178
dense elastic CT
contains elastin fibers in addition to collagen fibers, which allows the tissue to return to its original length after stretching. Dense elastic tissues give arterial walls the strength and the ability to regain original shape after stretching
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Hyaline cartilage ct (description)
cartilage ct = ECM (dense rubbery gel) + Cells. Consist of dense network of collagen and elastic fibres. Abundant, relatively weak and resilient gel in which fibres are present but not obvious.
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Hyaline cartilage ct function and where its found
found at anterior ends of ribs, respiratory cartilage (nose, trachea and bronchi), nasal septum, ends of long bones and for flexibility and movement.
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bone/osseous tissue
bones are organs composed of several CT types including bone tissue (can be compact or spongy), part of the supporting CT of the mature CT branch. Bone CT is extracellular matrix with cells.
180
compact bone
cortical bone, outer layer of bone and forms the shaft of long bones. Composed of many rod-shaped units known as either osteons or haversian systems.
181
spongy bone
cancellous bone, porous inner bone tissue that lies beneath compact bone, bone marrow found around this bone tissue. Lacks osteons. Part of the supportive CT under mature CT.
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compact bone function
stores calcium and phosphorous for protection and support
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spongy bone function
stores triglycerides (yellow marrow) and produces red blood cells (red marrow)
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cells within the bone (ECM + CELLS)
four types, osteogenic cells , osteoblasts, osteocytes and osteoclasts
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osteogenic cells
mesenchymal stem cells, develop and start to lay down collagen, become trapped and become osteoblasts. Part of bone CT as the cell compartment of CT in the supportive and mature CT.
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osteoblast
bone-forming cells, lay down more collagen, mineralisation process starts. LAY DOWN NEW BONE
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osteocytes
mature bone cells derived from osteoblasts trapped within the ECM, maintain bone tissue and involved in exchange of nutrients and wastes. Have gap junctions
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bone cell development into bone
osteogenic cells -> osteoblasts -> osteocytes. Then there is osteoclasts that degrade bone
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osteoclasts
multinucleated cells, large, formed from the fusion of blood monocytes and break down bone, REMODEL NEW BONE AND REABSORB DEAD BONE
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structure of osteon
lamellae, lacunae, canaliculi and central (haversian) canal. Osteons are aligned along lines of stress (long axis of bone shaft)
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lamaellae
concentric rings of mineral salts for hardness. Calcium phosphate and calcium hydroxide form hydrOXYAPATITE and collagen for tensile strength
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lacunae
small spaces between lamellae that contAIn mature bone cells (osteocytes)
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canaliculi
minute canals containing EC fluid and minute osteocytic processes that radiate from lacunae and provide routes for oxygen, nutrients and waste.
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central (haversian) canal
blood, lymph and nerves
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order of components in osteons
lamellae, lacunae, canaliculi and central (haversian) canal.
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chondroblasts
lay down hyaline cartilage callus
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Blood CT
liquid mature CT, consists of blood plasma (liquid ECM) and formed elements (red, white cells and platelets). BLOOD CT = ECM (PLASMA) + CELLS
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FORMED ELEMENTS OF BLOOD
erythrocytes
leukocytes (has four subtypes)
and platelets
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erythrocytes
cells in blood CT: transport CO2 and O2
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leukocytes
cells in blood CT:
-neutrophils
- basophils
- eosinophils
and lymphocytes
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platelets
in blood CT: from megakaryocytes in red marrow for clotting
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neutrophils and monocytes (macrophages)
phagocytic and engulfs bacteria (leukocytes in blood CT)
194
basophils (mobile) and mast cells
release substances (histamine), that intensify inflammatory reaction: leukocytes in blood CT
195
eosinophils
effective against certain parasitic worms and involved in acute allergic response -> leukocytes in blood CT
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lymphocytes
responsible for the immune response under leukocytes in blood CT
197
skeletal muscle description
~650 named in the body, usually attached to bones via tendons, appear striated under microscope and contraction usually under conscious control (voluntary, sometimes not always - posture). Fibres are cylindrical
198
smallest skeletal muscle
1.25 mm stapedius, stabilises smallest human bone in ear and prevents hyperacusis; tympanic reflex; bells palsy; facial n
199
longest skeletal muscle
up to 60cm, satorius. Hip flexor, abudctor, lateral rotator, knee: flexor.
200
stapedius
smallest skeletal muscle
201
hyperacusis
stapedius nerve damage-> extra loud sound perception
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skeletal muscle structure and function
attached to bones by tendons, long cells (1mm - 30cm+); striated; and multinucleate (many peripheral nuclei pushed to the side), voluntary control and functions include heat, protection, motion and posture.
203
striations on skeletal muscle
due to highly organised arrangement of myofibrils within the cells, thick and thin myofilaments overlapping
204
sarcomere
basic functional unit of a myofibril, z discs separate sarcomeres. (thick and thin arranged).
204
muscle fibre structure
outer muscle cell membrane called sarcolemma, inside sarcoplasm with myofibrils that have striations
205
myofibrils
2um diameter, more or less fill the cytoplasm (sarcoplasm), of the muscle fibre and extend its entire length within cell. COMPOSED OF 2 TYPES OF FILAMENTS (myofilaments), thin and thick.
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myofilaments
in myofibrils:
- thick: myosin 16nm diam 1-2 um long
- thin: actin: 8 nm, diam 1-2um long
myofilaments don't extend the whole length of cell but arranged in sarcomeres.
207
Epimysum
surrounds anatomical muscle
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perimysium
surrounds fascicles
209
endomysium
around muscle fibres (cell) - layer for capillaries/nerves.
210
CT of skeletal muscle in order
epimysium -> perimysium -> endomysium -> sarcolemma and sarcoplasm.
211
myofibril components and structure
thick and thin myofilaments
212
A band
dark, middle part, contains all the thick filaments
213
I band
thin filaments, but no thick filaments
214
H zone
thick filaments but no thin filaments
215
M line
middle of sarcomere that holds thick filaments together when it slides
216
Z disc
passes through centre of I band (between sarcomeres) made up of actinins that link filaments of adjacent sarcomeres
217
actinins
link filaments of adjacent sarcomeres, titin's link z disc to M line -> providing resting tension on I land (molecular spring)
218
cardiac muscle
striated, single central nucleus and fibres join end to end through intercalated discs
219
intercalated discs
JOIN cardiac muscle fibres end-end, containing desmosomes (bind intermediate filaments) providing adhesion in contraction and gap junctions (comms) (co-coordinated and rapid conduction).
220
cardiac muscle tissue
still have actin and myosin and sarcomeres, involuntary control -> heart -> striated, single central nucleus, branched and intercalated discs
221
purkinje fibres
specialised muscle cells that conduct electrical activity around the heart, they have less myofibrils and more specialised connexins (gap junctions).
222
smooth muscle location and desc
no striations, located on walls of hollow internal structures (intestines - peristalsis), BV walls for constriction, iris of eye, reproductive, digestive, respiratory, urinary and skin arrector pili
222
Smooth muscle cell shape
short, small and spindle shaped, about 30-200 um long, 3-8 um thickest in middle. Involuntary and non-striated (smooth).
223
smooth muscle structure
contains thick and thin filaments (myosin and actin), thin filaments attach to dense bodies (functionally similar to z discs). Dense body: major protein is actin. Intermediate filaments (non contractile elements) also connect to dense bodies.
224
smooth muscle under contraction
during contraction, tension is transmitted to intermediate filaments (dont contract) and the cell twists as it contracts about these stable rods.
225
nervous tissue
essential component of the nervous system that is divided into the CNS (brain spinal cord and optic nerve) and PNS
the PNS is all nervous tissue outside the CNS
226
PNS
peripheral nervous system: all nervous tissue outside CNS (brain, spinal cord and optic nerve)
- afferent and sensory division; information to CNS
- efferent and motor division; information from CNS to organs (muscles and glands).
227
The nervous system helps to
maintain homeostasis, initiates voluntary movements, and responsible for perception, behavior and memory.
228
nervous tissue contains two types of cells
neurons (nerve cells that can be very large) and neuroglia (supportive cells, usually small), neurons are the longest cells in body up too 1m, spinal cord to toe (sciatic nerve)
conscious and unconscious control.
229
neurons structure
have cell body into which short branched dendrites convey nerve impulses (action potentials), from which a longer, single axon conducts nerve impulses to another neuron or tissue. They do not divide and have a high metabolic rate (die rapidly without O2)
230
dendrites
receiving/input part of neuron, coming out of cell body conducting action potentials.
231
axon
carries nerve impulses away from neuron, output portion of neuron
232
types of neurons
multipolar, bipolar, unipolar and anaxonic neuron
233
multipolar neurons
2 or more dendrites and a singular axon, most common neurons in the CNS, all motor neurons (control skeletal muscle) are in this class, some of the longest (spinal cord to toe muscles)
234
bipolar neurons
two distinct processes
- single dendrite branching from cell body but can branch further (can branch at tip not cell body)
- single axon
- rare and small 30um
- special sense organs, sight, smell, hearing, relay info from receptor to neurons.
235
unipolar neurons
dendrites and axon continuous
- cell body off to one site
- whole length from where dendrites converge called axon
- most sensory nerves are unipolar
- very long (1m) like motor nerves CNS-toe tip
236
anaxonic neuron
rare and function poorly understood, anatomy cannot distinguish dendrites from axons, found in brain and special sense organs, cross comm between neurons
237
neuroglia
CNS and PNS, make up ~50% of CNS (glue), smaller than neurons but numerous (5x50x), do not propagate action potentials but can comm. Can divide within mature nervous system.
238
neuroglia function
physical structure of nervous tissue, repair framework of nervous tissue, undertake phagocytosis, nutrient supply to neurons and regulate interstitial fluid in neural tissue
239
CNS NEUROGLIA: ASTROCYTES
star shaped, largest, most numerous of neuroglia (syncytium network)
- support ( microfilaments) and repair (scar)
- comm with neurons via gliotransmitters -> glutamate
- maintain environment around neuron via regulation ions
- maintain blood brain barrier via endothelium. Wrap around vessels and influence permeability.
240
CNS NEUROGLIA: OLIGODENDROCYTES
form insulating multilayered myelin sheath (protein lipid layer) around CNS axons, can myelinate more than one neuron cells axon and accelerates a cells action potential
241
CNS NEUROGLIA: MICROGLIA
phagocytic (Resident macrophages -> protection)
242
CNS NEUROGLIA:
astrocytes, oligodendrocytes, microglia and ependymal cells.
243
ependymal cells
CNS NEUROGLIA-> produce CSF, line CSF filled ventricles in brain and central canal of spinal cord
- these single layers of predominantly cuboidal cells have cilia (flow) and microvilli (Sampling). Located in ventricles and in other locations where CSF is found
CSF mechanical buffer moves nutrients and waste
244
PNS NEUROGLIA
schwann cells and satellite cells
245
schwann cells
PNS neuroglia
- PNS ver of oligodendrocytes, form insulating myelin sheath around axons or can just support and surround several non myelinated axons ( ONE SCHWANN CELL PER AXOn for myelination but more if just support)
246
satellite cells
PNS neuroglia
- surround neuron cell bodies
- support and fluid exchange (equiv to astrocytes in CNS).
247
the tiny passageways in the bony matrix that allow osteocytes to communicate with each other are called
canaliculi
247
the mammary gland belongs to the
integumentary and reproductive system
248
hydrolysis of ATP ->
to adp and inorganic phosphate releases energy
249
ATP cycle
transfer of energy between complex and simple molecules in the body with ATP as the mediator.
- anabolic reactions transfer energy from ATP to complex molecules + release heat
-catabolic reactions transfer complex molecules to ATP
250
catabolic reactions and atp
transfer energy from complex molecules to ATP, releasing heat -> SImple molecules to as glycerol, aa, glucose and fatty acids
251
anabolic and atp
transfers energy from ATP to complex molecules, releasing heat and making complex molecules like glycogen, proteins and triglycerides
251
fuel is needed to generate ATP
carbohydrates - broken down to simple sugars
protein - into aa
FATS- simple fats
252
fate of glucose summary
glucose in blood -> cells via insulin
or storage (glucose cross linked together called glycogen in liver and skeletal muscle.
storage -> blood via glucagon when needed
cell -> cellular resp -> cellular work most times
252
cellular respiration steps summary
controlled release of energy from organic compounds to ATP
1. glycolysis
2. oxidation of pyruvate
3. citric acid cycle
4. oxidative phosphorylation
253
cellular resp equation
glucose C6H12O6 + 6O2 -> 6CO2 + 6H2O + ENERGY
253
where does glycolysis occur
cytosol
254
where does pyruvate oxidation and krebs cycle occur
matrix of mitochondria
255
where does oxidative phosphorylation occur
across inner membrane
256
what we need to know abt glycolsis
the lysis of glucose (6C) into pyruvate (2x3C)
2 atp invested, 4 atp out net 2 and 2 NADH
257
what step links glycolysis to krebs
pyruvate oxidation to acetyl coA
258
pyruvate oxidation
need O2 in mito matrix. produces no ATP but 1 NADH per pyruvate (2 per glucose) and 1 CO2, the 2 carbon acetyl coA can then enter krebs cycle. oxidation occurs via coenzyme A
259
Citric acid cycle output
in mitochondria matrix
- 2ATP
6 NADH
2 FADH
4 CO2
per glucose molecule
needs O2
260
which are electron donors for electron transport chain made in GLYCOLYSIS AND CAC
FADH2 and NADH
261
extraction of energy from glucose ends
at the citric acid cycle, completes the extraction of energy from glucose
262
citric acid intermediates can..
be used in other metabolic pathways where the product of one reaction is substrate for the next
262
substrate phosphorylation
ATP generated by direct transfer (from a substrate) of a phosphate group to ADP, glycolysis and citric acid cycle make ATP via substrate phosphorylation
263
oxidative phosphorylation
ATP is generated from the oxidation of NADH and FADH2 and the subsequent transfer of electrons and pumping of protons.
264
how does glycolysis and citric acid cycle make ATP
substrate phosphorylation
265
what we need to know ETC:
NADH AND FADH2 oxidised to donate electrons, occurs in inner membrane and aerobic, electrons transfer protein to protein along chain in series of redox reactions. At each transfer each electron gives up a small amount of energy which enables H+ ions to be pumped into intermembrane space
O2 pulls electrons down chain -> final acceptor -> reduced to water
266
chemiosmosis
H+ ions in intermembrane space rush down conc gradient (chemiosmosis) through ATP synthase, cause the turbine within ATP synthase to turn. rotation of atp synth enables phosphorylation of ATP to ATP
267
products of chemiosmosis per glucose
26-28 ATp per glucose.
268
ETC and chemiosmosis makes atp via
oxidative phosphorylation, what they are collectively.
269
which phosphorylation is more efficient
oxidative, bulk of ATP production occurs here.
270
what drives ATP synthase turbine
fall of electrons down chain enables movement of H+ ions into intermembrane space and generates proton gradient to drive ATP synthase
271
cyanide on oxidative phosphorylation
prevents passage of electrons to O2 at complex 4 -> death of cell
272
cellular resp is versatile
we can derive energy from more than just glucose, fats, proteins and more complex carbs generate ATP also, monomers enter glycolysis and citric acid cycle at different points
273
control of cellular resp
phosphofructokinase is the gatekeeper for glycolysis, catalyses step 3 where glycolysis becomes irreversible. INHIBITED BY CITRATE AND ATP (Products of cellular resp)
Stimulated by AMP, AMP accumulates when ATP used rapidly
274
PFK
gatekeeper for glycolysis -> irreversible step 3 of glycolysis. INHIBITED BY HIGH CITRATE AND ATP AND STIMULATED BY AMP.
275
homeostasis: hypoglycemia
beta cells in pancreatic islets -> insulin -> effectors: all body cells -> inc rate of glucose transport into target cells, inc rate of glucose use and ATP generation and inc conversion of glucose to glycogen
276
homeostasis: hyperglycemia
low blood sugar -> alpha cells in pancreatic islets -> secrete glucagon -> liver skeletal muscle and adipose cells -> inc breakdown of glycogen to glucose in liver and skeletal muscle.
277
what happens if u lose function of insulin
diabetes mellitus, ability to produce or respond to insulin is impaired -> abnormal metabolism of carbs and elevated levels of blood glucose >7 mmol/L fasting
277
insulin
produced by beta cells in islets of langerhans in pancreas, function to promote glucose uptake into the cells (for ATP production or storage in liver).
278
glucagon
produced by alpha cells in the islet of langerhans in pancreas to stimulate breakdown of glycogen to inc blood sugar levels
278
diabetes mellitus
no glucose in cells
no ATP from glucose and no glycogen stored for harder times
279
type 1 diabetes
body does not produce enough insulin, as beta cells of pancreas are destroyed, often autoimmune or genetic or through environmental factors. affects 5-10% of diabetics onset usually children/adolescent. Requires insulin replacement
280
type 2 diabetes
body produces insulin but receptors dont work (insulin resistance), most >90% diabetics are type II, usually adults over 40, can be linked to other pathologies and obesity.
281
paracrine signaling and example
local, growth factors such as fibroblast growth factor -FGF1
281
total ATP from cellular resp inc glycolysis
30-32
282
local signalling
cell communication that can be divided into paracrine and synaptic signalling. Can have autocrine (on itself)
283
synaptic signalling
local, neurotransmitters such as acetylcholine-ACh
284
signals that act from a distance
endocrine signaling (hormonal)
285
endocrine signaling
hormones secreted from endocrine cells travel via circulatory system to act on target cells, eg insulin
286
cell signalling
1. reception, transduction and response
during the transduction pathway multiple proteins may be activated typically via phosphorylation
287
1. RECEPTION (CELL SIGNALING)
signalling protein (primary messenger) binds to receptor protein and results in shape/chemical state change in receptor protein
288
2. TRANSDUCTION (CELL SIGNALING)
altered receptor activates another protein (g-protein/adenylyl cyclase), the activated protein (often enzyme) may cause a relay of changes (relay molecules known as SECOND MESSENGERS) eg cAMP, IP3, multiple other proteins may be activated.
- each activated proteins causes series of change often via phosphorylation -> phosphorylation cascade.
289
3. RESPONSE (CELL SIGNALLING)
all of the activated proteins cause one or more functions to occur in the cell -> where cell does something lol
290
GPCR
span membrane 7 times (transmembrane), diverse functions (development, sensory reception etc). Associated with many diseases, 1/3 of modern drug targets).
291
structure determines function
only target receptors bind to their signal ligand -> exquisite control: only certain cells at certain times will have particular receptors -> signal occurs where its needed
292
receptors for water soluble molecules
are membrane bound such as G protein coupled receptor, tyrosine kinase and ligand gated ion channels
293
receptors for lipid soluble molecules
are not membrane bound , located in cytoplasm or inside nucleus -> lipid soluble hormones: test, estrogen , progesterone ... thyroid hormones bind to receptors in cytoplasm and move to nucleus as a complex.
294
GPCR couple with what
g proteins, which are in an off or on state (molecular switches) depending on whether or not GTP IS BOUND
295
G protein
couples with gpcr and is a molecular switch that can be turned on or off depending on whether or not GTP is bound
296
what happens when signal molecule/ligand binds to gpcr receptor
at rest, receptor is unbound, g protein has GDP and enzyme inactive
2. ligand binds to receptor, active gpcr and gtp displaces gdp enzyme still inactive
3. g protein dissociates from receptor and enzyme is activated to elicit cell response
4. g [rpteom has gtpase activity promoting release from enzyme -> revert to rest
297
receptor
molecule/protein that responds to a specific ligand
298
ligand
a signalling molecule that binds specifically to another protein
299
ion channel
membrane protein through which specific ions can travel
300
ion channel receptor
membrane protein through which specific ions can travel in response to ligand binding
301
ligand gated ion channels/receptors
channel receptors contain a gate, binding of ligand (eg neurotransmitter) at a specific site on receptor elicits change in shape. Channel opens / closes as the receptor changes shape, ions can pass through channel
302
ligand gated ion channel process
at rest ligand is unbound and gate is closed, upon ligand binding, gate opens and specific ions can flow into cell, following ligand dissociation the gate closes back to resting.
303
which body system relies heavily on ligand gated ion channels
the nervous system, released neurotransmitters bind as ligands to ion channels on target cells to propagate action potentials
304
protein kinases
enzymes that transfer a phosphate group from one ATP to another, typically activating protein -> thye phosphorlyate
305
signal transduction pathways
series of protein kinases adding a phosphate to the next kinase
306
phosphatases
enzymes that dephosphorylate (remove phosphate) rendering protein inactive but recyclable. `
306
serine and threonine residues in signal transduction pathways
typically these are phosphorylated, therefore mutations affecting these residues could be detrimental.
307
use of a second messenger
sometimes a small molecule is included in the cascade -> second messengers EG. cAMP and calcium ions
308
cAMP in GPCR signalling
activated enzyme is adenylyl cyclase -> converts atp to cAMP
cAMP acts as a second messenger and activates downstream proteins eg PKA which phosphorylates other proteins.
309
calcium as a second messenger
low Ca2+ inside cell ~100nm and very high Ca2+ outside cell more than 1000 fold/higher, maintenance of conc via calcium pumps is important
- out of cell, into er and into mitochondria
310
Ca2+ and IP3 in GPCR signalling
activated protein phospholipase C cleaves PIP2 (phospholipid) into DAG and IP3
IP3 diffuses through cytosol and binds to gated channel in ER
Calcium ions flow out of ER down conc gradient and activate other proteins toward a cellular response
311
Why are there so many steps in signal transduction
amplification of response, provides multiple control joints, allows for specificity of response (temporal, spatial) despite molecules in common, allows for coordination with other signaling pathways.
312
cellular responses list
gene expression
Alteration of protein function to gain or lose an activity
* Opening or closing of an ion channel
* Alteration of cellular metabolism
* Regulation of cellular organelles or organisation
* Rearrangement/movement of cytoskeleton
* A combination of any of these
The transduction of a signal leads to the regulation of one or more cellular activities
313
what does the transduction of a signal allow?
The transduction of a signal leads to the regulation of one or more cellular activities
314
signal transduction turn off
all signals are on for a limited time, activation usually promotes the start of deactivation so that signaling is of a short period of time ensuring homeostatic equilibrium
- cell ready to respond again if required
315
what breaks down cAMP
phosphodiesterase and coffee inhibits PDE
316
inhibition of PDE in therapeutics and caffeine
inhibition of phosphodiesterase (breaks down cAMP) can also be a therapeutic approach to viagra as it inhibits a specific cGMP- degrading PDE and also caffeine inhibits PDE
317
adrenaline example of cell signaling
adrenaline acts through GPCR, activates cAMP and two protein kinases in phosphorylation cascade -> results in active glycogen phosphorylase which can convert glycogen to glucose 1 phosphate.
AMPLIFICATION MEANS THAT ONE ADRENALINE MOLECULE CAN RESULT IN 10^8 GLUCOSE 1 PHOSPHATES
318
gene expression
process of going from DNA to functional product (the central dogma) DNA -> RNA -> PROTEIN
319
Genotype and phenotype relationship
our genotype and its interaction with the environment determines our phenotype
320
three main steps of gene expression
transcription, processing and translation
321
transcription steps
initiation: polymerase binds to promoter, elongation: moves downstream through the gene transcribing RNA and termination: detaches after terminator reaction
322
is promoter upstream or downstream
upstream
323
terminator is upstream or downstream
downstream
324
template strand
on the bottom and read along 3' to 5' also known as the non coding strand
325
TATA box
typically ~25 NT upstream in the promoter region
326
transcription initiation process
1. eukaryotic promoter TATA box ~25 nt upstream
2. transcription factors including tata box binding protein bind to DNA
3. RNA POL II can now bind with more transcription factors to form transcription initiation complex and transcription begins
327
transcription elongation
10-20 nt exposed at a time when DNA unwound, complementary RNA nt added to 3' end of growing transcript. Hydrogen bonds form on template strand bases and phosphodiester bonds on adjacent RNA bases). Double helix reforms as transcript leaves template strand.
328
how many nt exposed at a time when DNA unwinds
10-20 nt
329
what direction does the RNA come out in, in transcription elongation
in the 5' to 3' direction
330
is rna considered mRNA after termination?
no, it is considered as pre-mRNA and ready for further processing
331
termination
after transcription of the polyadenylation signal (AAUAAA) nuclear enzymes release the pre-mRNA and RNA polymerase dissociates from the DNA. Fidelity (proofreading) is less than for DNA replication.
332
second step mRNA processing
capping, tailing and splicing of the pre-mRNA
333
capping of the pre-mRNA
a modified guanine nucleotide is added to the 5' end
334
tailing of the pre-mRNA
50-250 adenine molecules (polyA) are added to the 3' end
335
splicing of the pre-mRNA
introns are removed from the transcript
336
why mRNA processing? (capping, tailing and splicing)
capping and tailing are though to facilitate export, confer stability and facilitate ribosome binding in cytoplasm
337
exons
reigons that remain in mature RNA (includes UTR)
338
UTR
untranslated regions at 5' and 3' ends of mRNA
339
introns
intervening regions that do not remain in mature RNA.
339
Where does spicing occur?
spliceosome: a large complex of proteins and small RNAs
introns are removed from the transcript and exons are rejoined to form mature RNA
340
spliceosome
a large complex of proteins and small RNAs
341
alternative splicing
process by which different combinations of exons are joined together, this results in the production of multiple forms of mRNA from the same pre-mRNA population
342
Alternative splicing allows for multiple gene products from the same gene
~20000 genes, could be many times that number of proteins
343
introns and exons size
introns tend to be large and exons tend to be small
344
protein sequence determines
its final structure, structure determines function and DNA mutations can affect ability of the protein to function.
345
also three steps of translation
initation, elongation and termination
346
translation overview
codons are translated into aa, tRNA molecules within cytosol with specific anticodons carry corresponding aa, H bonds form between mRNA and anticodon of appropriate tRNA, aa is added via PEPTIDE bonds to growing polypeptide chain
347
what kind of bonds are aa added to polypeptide chain in translation
peptide bonds
348
Ribosome binding sites
A site: holds next in line tRNA (APE BACKWARDS) P holds tRNA carrying growing polypeptide, E site is where tRNAs exit. Made of large and small subunit
349
ribosome binding sites in order
E,P and A (ape spelt backwards)
350
A site of ribosome
holds next in line t RNA
351
E site of ribosome
where tRNAs exit
351
P site of ribosome
holds tRNA carrying growing polypeptide
352
tRNA structure
anticodon at the bottom, which allow specific binding or hydrogen bonding to a certain RNA codon. aa attachment site at the top where aa will be able to bind.
353
initiator tRNA
tRNA carrying methionine MET
353
translation initation
small ribosomal subunit with initiator tRNA already bound, binds 5' cap of mRNA, small ribosomal subunit scans downstream to find translation start site AUG, H bonds form between initiator anticodon and mRNA, large ribosomal subunit then binds completing initiation complex
354
is energy required for translation intiation
yes, GTP is required for assembly
355
translation elongation steps
codon recognition, peptide bond formation and translocation
355
peptide bond formation in translation elongation
second step, large subunit rRNA catalyses peptide bond formation and removes it from tRNA in P site onto the tRNA on A site
356
translocation: translation elongation
moves tRNA from A to P site, tRNA in P site moves to E and released, energy is required (GTP)
356
translation termination steps
1. ribosome reaches stop codon on mRNA,
2. release factor promotes hydrolysis
3. ribosomal subunits and other components dissociate
356
empty tRNAs
reloaded in cytoplasm using aminoacyl-tRNA synthetases.
356
translation elongation: codon recognition
first step, base pairs with complementary anticodon GTP invested to increase accuracy/efficiency.
356
regulation step on ribosome in gene expression
regulatory proteins can block translation, variable mRNA life-spans
356
stop codons of translation
UAG, UAA or UGA
356
translation termination
1. ribosome reaches stop codon on mRNA (stop codon in A site bound by a release factor)
2. Release factor promotes hydrolysis and bond between p site tRNA and last amino acid is hydrolysed (releasing polypep).
3. ribosomal subunits and other components dissociate, hydrolysis of 2 GTP molecules required and ribosome components can be recycled.
357
gene expression is tightly regulated
transcription: transcription factors need to assemble and DNA needs to be accessible, RNA PROCESSING: capping, extent of polyadenylation, alternate splicing and producing an mRNA able to be translated, specific proteins assist in nuclear export of mRNA
357
Housekeeping proteins(control of gene expression)
continuously produced, protein and mRNA are present in large quantities (tubulin), typically have longer half life in cells
357
n-terminus of primary structure
amino end
357
amino acid side chains
the side chains (r groups) determine properties of each aa
357
c-terminus
carboxyl end
357
other proteins in control of gene expression (not house keeping)
are produced in response to sitmuli as required, cell signaling (ligand binding a cell surface receptor, or activating an intracellular receptor), signal transduced and may enter nucleus to activate transcription, results in the production of a short lived protein to carry out required function.
358
how many standard coded for amino acids
20
359
peptide bonds
are covalent bonds between aa (relatively strong)
360
does the polypeptide stay in primary structure
the polypeptide starts to form secondary structures as soon as it leaves the ribosome
361
secondary structure
alpha helix and pleated sheet, held by weak H bonds to form.
361
tertiary structure
3D shape stabilised by side chain reactions
362
Protein processing and sorting
all translation commences on free ribosomes, many proteins are processed and sortered through RER and golgi but not all.
362
quartnary structure
multiple proteins associated together to form functional protein, not all proteins form this
363
proteins destined to function in the cytosol complete translation...
on free ribosomes
364
proteins that go through the endomembrane system complete translation at....
fixed ribosomes on the RER.
365
Signal peptide
N terminus of protein around 20 aa,
366
SRP
signal recognition particle
367
signal peptides direct ribosomes to RER
1. polypep synthesis begins
2. SRP binds to signal peptide
3. SRP binds to receptor protein
4. SRP detaches and polypep synthesis resumes
5.signal cleaving enzyme cuts of signal peptide.
6. completed folds into final conformation
368
membrane protein ends
remain anchored to membrane and go to golgi via vesicles for further maturation
369
secretory protein last step
such as insulin is solublised in lumen and go to golgi via vesicles for further maturation
370
Post translational modifications
phosphorylation, methylation,acetylation,biotination, carboxylation, cleavage etc. Some occur within golgi others in cytosol.
371
Post translational modifications can do...
can confer activity, eg via phosphorylation or enzyme cleavage, or ability to interact with other molecules (biotinylation, methylation of histones or direct to particular locations (ubiquitination for proteasome degradation).
372
somatic cell division
mitosis: diploid to diploid.
373
reproductive cell division
meiosis- diploid to haploid
374
why do somatic cells divide?
growth and development, tissue renewal, results in two daughter cells that are genetically and functionally identical to parent cell.
375
do all somatic cells divide
many but no all, some alot more than others
376
eukaryote cell cycle
interphase (G1, S and G2) then mitotic phase of cytokinesis and mitosis (TELOPHASE, ANAPHASE, METAPHASE and PROPHASE).
377
the cell theory
states that all organisms are made of cells and all cells come from pre-existing cells.
378
interphase
made of G1 Growth or gap phase 1, S: synthesis of DNA and G2: growth or gap phase 2
379
G1
growth of gap phase, first part of interphase: most cellular activities are occurring here, duration variable (cell type specific)
380
S: synthesis of DNA
second part of interphase: synthesis of DNA, DNA replication occurs, strands are separated at the H bonds holding nucelotides together. New strand of DNA is synthesised opposite each of the old strands.
381
PMAT: MITOTIC PHASE (MITOSIS + CYTOKINESIS).
prophase, metaphase, anaphase, telophase and cytokinesis
382
G2
growth or gap phase 2, last part of interphase. checks for correct DNA synthesis, prepares for the mitotic phase (synthesis of proteins and enzymes required), replication of centrosomes is completed
383
interphase components
centrosomes, uncondensed chromosome, nuclear envelope and plasma membrane
384
prophase components
nuclear envelope still intact, mitotic spindle (microtubules) forming, chromosome with two sister chromatids -> late prophase: fragments of nuclear envelope, condensed chromosome and spindle tracks
385
metaphase components
condensed chromosomes align on central plane in cell
386
Anaphase components
seperated chromosomes, chromosomes are pulled apart using microtubules to organising centres
387
telophase components
end of PMAT: cleavage furrow, nuclear envelope forming
388
during interphase the DNA
replicates
388
during prophase the DNA
condenses: two identical chromatids per chromosome called sister chromatids
388
during anaphase, sister chromatids
separate before the nuclear envelope reforms in telophase
389
during metaphase chromosomes
line up
390
daughter cells are 'identical' to
parent cell
391
what controls mitotic cell cycle
mitotic cell cycle checkpoints: G1 checkpoint, M checkpoint and G2 checkpoint.
392
G1 checkpoints
is the DNA undamaged? Is cell size and nutrition OK? appropriate signals present? if not: exit to G0 otherwise it continues through cycle.
393
M checkpoints
are all chromosomes attached to spindles? Without full chromosome attachment, stop signal is received, if yes, go ahead signal received.
394
meiosis 1 stages
prophase I
metaphase I
anaphase I
telophase I
PMAT
395
meiosis
occurs in gonads (ovaries and testes), produces gametes which are haploid (23n) fertilisation then restores diploid number of chromosomes (2n) *PRODUCES cells genetically DIFFERENT from parent cell.
396
meiosis II
prophase II
metaphase II
anaphase II
telophase II
PMAT!!
397
tetrad
4 chromatids
398
prophase I meiosis I
homologous chromosomes pair up, forming tetrads, and crossing over occurs, leading to genetic recombination, and the nuclear envelope breaks down
399
Metaphase I
segregating homologues. Homologous chromosome pairs, called tetrads, align along the cell's equator (metaphase plate), with each pair's members facing opposite poles, preparing for separation in anaphase.
400
Anaphase 1 meiosis I
The two chromosomes of each bivalent separate and move to the opposite ends of the cells. The sister chromatids are attached to each other.
401
Telophase I and cytokinesis
cleavage furrow forms, cell about to divide
402
key difference between meiosis I and II
no DNA replication phase, not preceded by DNA replication
403
PROPHASE II MEIOSIS II
same as Prophase I. where chromosomes condense, the nuclear envelope breaks down (if present), and the spindle apparatus forms, preparing the cells for the second meiotic division
404
METAPHASE II
the chromosomes line up individually along the metaphase plate
405
ANAPHASE II
segregating sisters now, so they are haploid. the sister chromatids separate and are pulled towards opposite poles of the cell.
406
telophase II and cytokinesis
haploid daughter cells forming. chromosomes arrive at opposite poles and begin to decondense, nuclear envelopes form, and cytokinesis follows, dividing the cytoplasm into four haploid, genetically unique cells
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Mitosis versus meiosis
Homologs seperate in telophase I MEIOSIS whereas MITOSIS sister chromatids seperate here. Genetic diversity in meiosis.
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meiosis form tetrads at prophase which causes
interactions -> recombination and exchange of genetic material (sequence differences between two parents). At metaphase, the tetrads line up
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DNA REP mitosis vs meiosis
mitosis: occurs during interphase before mitosis begins
meiosis: occurs during interphase before meiosis I but not II
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number of divisions mitosis vs meiosis
mitosis: one, including prophase, prometaphase, metaphase, anaphase and telophase
meiosis: two
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synapsis of homologous chromosomes (mitosis vs meiosis)
mitosis: does not occur
meiosis: occurs during prophase I along with crossing over between non sister chromatids.
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no. of daughter cells and genetic comp mitosis vs meiosis)
mito: 2 each genetically identical, same chromosome no.
meiosis: 4, each haploid, genetically different from parent cell and from each other.
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sources of genetic variation
independent assortment at metaphase I (2^23>8 million possible combos), crossing over at prophase 1(~1-3 crossover events per pair) and fusion between two gametes. MEIOSIS!
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independent assortment
at metaphase and source of genetic variation in meiosis, 2^23 > 8 million possible combinations.
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germ line mutations
passed on to future progeny
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local/somatic mutations
during cell division, not whole body-- local effects
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large scale alterations (mutations)
chromosomal rearrangements
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small scale alterations (mutation)
one or a few nucleotides altereds
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small scale mutations can be
substitutions or insertions/deletions
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substitutions (mutation) effects
where on base is replaced by another - can have minimal or major effect
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insertions/deletions effects
can have major effect if within coding sequence, can cause frameshift
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substitution mutations can be
silent, missense or nonsense
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indels (insertion deletion mutations) can be
can cause frameshift if 1 or 2 nt or maintain frame at 3 nt
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coding strand is in what direction
5'-3'
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silent mutation
DNA changed, RNA changes but protein is the same -> still codes for the same amino acid
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missense mutation
eg GGC codon becomes AGC: gly becomes Ser -> effect depends on residue role of the new amino acid. Different amino acid than the usual one.
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nonsense mutation
early stop codon, mutation causes a stop codon to form where it shouldnt resulting in a truncated protein
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frameshift via insertion
inserting a nt into sequence, shifts all nt downstream, changing the aa being read
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deletion frameshift
eg. missing one nt -> protein completely altered from point of frameshift and can have rlly bad effect
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3 nucleotide-pair mutation
no frameshift but missing one amino acid, frame maintained and downstream residues are intact.
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triplet repeat expansion
causes huntingtons disease -> lots of extra glutamines.
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sickle cell anemia mutation
wild type B-globin has GAG glu residue but mutates to GUG=val residue
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differences in residue side chains in sickle cell compared to normal B globin
Glutamic acid is hydrophilic and gets changed to valine in sickle cell which is hydrophobic -> when O2 is low the protein will fold in different way to create rigid fibrils.
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MPF
made up of two proteins, cyclin and cyclin dependant kinase. MPF is a specific cyclin (cdk complex and key for G2 checkpoint)
432
what does MPF do
important for G2 checkpoint of the cell cycle, phosphorylates many other proteins and allows mitosis to commence
432
cyclin
a protein that fluctuates throughout cell cycle
433
Cyclin dependant kinase
kinase that is activated when attached to a cyclin.
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how does cyclin accumulate throughout cell cycle
accumulates through S and gets to its peak at G2 so that MPF can form and activate steps of mitosis -> going through mitosis cyclin is degraded and recycled -> cdk released and cycle repeats
435
molecular mechanisms that help regulate the cell cycle (G2)
G2 checkpoint uses MPF, the fluctuation of MPF activity and cyclin concentration determines if mitosis should proceed
436
checkpoints of the cell cycle rely on what signals
rely on stop and go cell signals/molecules. Genes that keep proliferation in check or stimulate cell proliferation.
437
mutations in STOP and GO genes (regulatory checkpoints of the cell cycle)
can cause cancer, the cell cycle could proceed when it shouldnt and results in uncontrolled cell growth -> tumors
438
How does uncontrolled cell growth occur (cell cycle checkpoints)
Mutations in STOP and GO genes, the cell cycle could proceed when it shouldnt and result in uncontrolled cell growth resulting in tumors
439
how do cancer causing DNA mtuations arise
genetic predisposition (in all cells of body): inherited from parents or de-novo -> issue or deficiency in gene or acquired (common): locally in one cell initally
439
acquired cancer causing DNA mutations
locally, in one cell initially, UV damage, smoking, carcinogens, viruses, drugs and treatments eg. chemo
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genetic predisposition mutations
in all cells of the body, typically inherited from parents or de novo- an issue or deficiency in a gene (typically one copy eg.p53 or BRCA).
441
in cancer, the genes affected by DNA changes are often
overactivation of proto-oncogenes or deactivation of tumor supressor genes-> both alterations can result in uncontrolled cell growth
442
proto-oncogenes
genes that normally stimulate cell proliferation,
443
tumor supressor genes
genes that normally keep proliferation in check
444
proto-oncogene to oncogene mutation
results in increased function (g-protein) Ras protein continuous GTPase activity -> with or without growth factor bound to receptor -> pathway constantly active. (usually growth factor binds to receptor which in turn GTPase activates Ras. OVEREXPRESSION OF PROTEIN -> INC CELL DIVISION
445
two proto-oncogenes that can mutate to oncogenes
Ras - GTPase or Myc - transcription factor.
446
oncogene
cause uncontrollable cell growth
447
deactivated tumor suppressor genes
loss of function (breaks) eg. TP53, BRCA1 and BRCA2, P53. Eg. mutation in p53 which usually inhibit cell cycle when it detects damage, mutated version defected or missing transcription factor -> inhibitory protein absent -> cell cycle not inhibited
448
Cancer doesnt just occur from one mutation (malignant tumor)
can be multiple mutations which creates malignant cells: loss of tumor supressor genes, activation of ras oncogene -> additional mutations resulting in maligant tumor (Carcinoma)
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