Unit 5 Midterm and FINAL

Question 1

List the main functions of the nervous system.

Answer 1

1. Detects stimuli
2. Processes and interprets information
3. Motor output - sends command to body structures by activating the effector organs, our muscles or glands.

Question 2

Describe the special functional characteristics of neurons.

Answer 2

1. Highly specialized cells that conduct electrical signals from one part of the body to another.
2. Extreme longevity - They can live and function for over 100 years.
3. They do not divide
4. Have an exceptionally high metabolic rate requiring continuous and abundant supplies of oxygen and glucose.

Question 3

Neuron cell bodies in the CNS are found where? About what percent of neurons cell bodies are found here?

Answer 3

About 99% of all neuron cell bodies are found in the gray matter of the CNS.

Question 4

Neuron cell bodies in the PNS are found where? About what percent of neurons cell bodies are found here?

Answer 4

About 1% of all neuron cell bodies are found in the ganglia of the PNS.

Question 5

Explain how neurons are classified by structure and function. For each category list the different types of neurons and explain how each fits into the category.

Answer 5

Neurons are classified by structure according to the number of processes that extend from the cell body.
Multipolar - many processes extend from the cell body (all are dendrites except for a single axon)
Bipolar - two processes extend from the cell body (one a fused dendrite and the other an axon)
Unipolar - One process extends from the cell body and forms central and peripheral processes which together comprise an axon.
Neurons are classified by function according to the direction the nerve impulse travels relative to the CNS.
Sensory Neuron - (afferent neurons) make up the sensory division of the PNS and transmit impulses toward the CNS. from sensory receptors in the PNS.
Motor Neurons - (efferent neurons) make up the motor division of the PNS and carry impulses away from the CNS to effector organs (Muscles and glands)
Interneurons - lie between motor and sensory neurons. They link together into chains that form complex neuronal pathways.

Question 6

What structural type of neuron is most common? About what percent of neurons are this type?

Answer 6

About 99% of neurons in the body are multipolar neurons.

Question 7

Describe the general role of neuroglia in the CNS.

Answer 7

They provide a supportive scaffolding for neurons and cover all nonsynaptic parts of the neurons, insulating the neurons and keeping the electrical activities of adjacent neurons from interfering with each other.

Question 8

List the neuroglia of the CNS and provide a detailed description of the primary function(s) for each and explain the significance of the function.

Answer 8

1. Astrocytes - a) regulating neurotransmitter levels by increasing the rate of neurotransmitter uptake in regions of high neuronal activity b) Signaling increased blood flow through capillaries in active regions of the brain. c) controlling the ionic environment around the neurons.
   Significant because they help regulate activities to keep the neuron functioning correctly.
2. Microglial Cells - They are phagocytes (the macrophages of the CNS) and they migrate to and then engulf invading microorganisms and injured or dead neurons.
   Significant because they keep the cell healthy
3. Oligodendrocytes - line up in small groups and wrap their cell processes around the thicker axons in the CNS, producing insulating coverings called myelin sheaths.
   Significant because it prevents leakage of electrical current from the axon and increases the speed of impulse conduction along the axon.

Question 9

List the main neuroglial cell of the PNS. Describe its primary function and explain the significance of the function.

Answer 9

Schwann cell - surround all axons in the PNS and form myelin sheaths around many of these axons.
Significant because it greatly speeds impulse conduction.

Question 10

Describe the structure and function of a Node of Ranvier.

Answer 10

Gaps in the myelin sheath between Schwann cells occurring at regular intervals of about 1mm apart.
Function: regenerating the electrical signal allowing it to jump from the membrane of one gap to the next.

Question 11

Describe what is found in areas of white matter and gray matter of the CNS. Define tract as it applies to the CNS.

Answer 11

White matter - millions of axons and neuroglia
Gray matter - neuron cell bodies, dendrites, short nonmyelinated neurons, and neuroglia.
Tract - axons traveling to similar destinations form axon bundles within the white matter called tracts.

Question 12

In simple terms what is a “reflex arc?”

Answer 12

simple chains of neurons that cause our simplest reflexive behaviors. Our reflexes.

Question 13

List the five components of a reflex arc and describe the role that each has in the reflex.

Answer 13

1. Receptor - site where stimulus acts
2. Sensory neuron - transmits the afferent impulses to the CNS.
3. Integration center - center that contains one or more synapses in the gray matter of the CNS.
4. Motor neuron - conducts efferent impulses from the integration center to an effector.
5. Effector - the muscle or gland cell that responds to the efferent impulses by contracting or secreting.

Question 14

Define filtration as it applies to renal function. About how much fluid per day is filtered by the kidneys?

Answer 14

Squeezing out water in small molecules into the tubule

Kidneys filter about 180 liters per day.

Question 15

Define reabsorption as it applies to renal function. About how much fluid per day is reabsorbed by the kidneys?

Answer 15

Recovering water and molecules from tubule to blood
Over 125 liters per day is reabsorbed in the kidneys and another 54 liters reabsorbed elsewhere as we secrete only about 1.5 liters per day.

Question 16

Define secretion as it applies to renal function.

Answer 16

Molecules are put into the tubule

Question 17

What type of capillary is found in a renal corpuscle? What makes these capillaries different anatomically from “regular” body capillaries?

Answer 17

Fenestrated capillary - they have pores spanning the endothelial cells that restrict the passage of the largest elements such as blood cells.

Question 18

What type of capillary is a “regular” body capillary?

Answer 18

Continuous capillary

Question 19

List the main parts of the nephron.

Answer 19

Renal corpuscle and a renal tubule

Question 20

The first section of the nephron tubule is the what? What type of epithelium line it? What specialized structures are found on the apical surface, and what is their function? What are the main components of the filtrate that are absorbed here? What region of the kidney is it found?

Answer 20

The proximal convoluted tubule
Cuboidal epithelial cells
Long microvilli on their apical surface which increase the surface area of the cells maximizing their capacity for resorbing glucose, amino acids, water, and sodium from the filtrate.
Confined entirely to the renal cortex.

Question 21

The second section of the nephron tubule is the what? What are the main components of the filtrate that are abosrbed here? What region of the kidney is it found?

Answer 21

Nephron loop (loop of Henle)
Absorbes water and ions such as sodium and potassium chloride
Contained in the medulla

Question 22

The Third section of the nephron tubule is the what? What type of epithelium line it? What are the main components of the filtrate that are absorbed here? What region of the kidney is it found in?

Answer 22

Distal convoluted tubule
Simple cuboidal epithelium
Adjustable reabsorption of ions
Contained in the renal cortex

Question 23

the last section of the uriniferous tubule is the what? What are the main componenets of the filtrate that are absorbed here? What region of the kidney is it mainly found?

Answer 23

Collecting ducts
Absorbes water
Runs straight through the renal cortex into the deep medulla.

Question 24

Name the two classes of nephrons and list how common each type is. Describe what makes these nephrons different anatomically and functionally.

Answer 24

85% Cortical Nephron - have nephron loops that dip only a short distance into the medulla.
15% Juxtamedullary nephron - renal corpuscles lie near the cortex-medulla junction and have nephron loops that deeply invade the medulla and thin segments that are much longer than those of cortical nephrons. The longer loops in conjunction with nearby collecting ducts, contribute to the kidney’s ability to produce a concentrated urine.

Question 25

The capillaries which surround the nephron are called what? What is their function?

Answer 25

Peritubular capillaries - readily absorb solutes and water from the tubule cells after these substances are resorbed from the filtrate.

Question 26

List the main cells of the juxtaglomerular apparatus. Describe the function of each type. Explain the importance of each function.

Answer 26

1. Macula densa - detect filtrate concentration and help adjust filtrate production rate (helps keep the bodily fluids regulated)
2. Granular cells - surround the afferent arteriole and secrete the hormone renin which helps regulate blood pressure, ion balance, and water balance (regulates blood pressure)
3. Mesengial cells - secrete erythropoietin

Question 27

What is the function of a ureter? a ureter collects urine from where and delivers it to where?

Answer 27

Slender tubes that carry urine from the kidneys to the bladder

Question 28

What type of epithelium lines the ureters? What is the specialized function of the epithelium?

Answer 28

Transitional epithelium

Function - distention (expand)

Question 29

What type of epithelium line the bladder? What is the specialized function of the epithelium?

Answer 29

Transitional epithelium

Function - distention (expande)

Question 30

What type of muscle tissue is found in the bladder? What is the special name given to the muscle of the bladder?

Answer 30

Smooth muscle tissue

Detrusor

Question 31

The tubular organ that drains the urine from the bladder is the what? List the two rings of muscles at its base. What type of tissue is each made of?

Answer 31

Urethra
Internal urethral sphincter - smooth muscle
External urethral sphincter - skeletal muscle

Question 32

What are the anatomical and functional difference between the male and female urethras? What is significant about these differences? How do the differences relate to the health of the individual and to specific common medical procedure?

Answer 32

Females urethra is just 3-4 cm long and bound to the anterior wall of the vagina by CT.
Males urethra is about 20 cm long and has three named regions (prostatic, membranous, and spongy) and carries ejaculating semen as well as urine from the body.
Because women’s urethra is so short it makes them more prone to urinary tract infections and sexually transmitted infections.

Question 33

Describe the primary functions of the gonads in males and females.

Answer 33

Males - testes produce sperm

Females - ovaries produce eggs

Question 34

Describe the anatomy of each of the mechanisms that regulate the temperature of the testes.

Answer 34

The scrotums superficial position provides an environment that is essential for sperm production:

1. Pampiniform plexus - venous network in the scrotum which surrounds the testicular arteries and absorbs heat from the arterial blood, cooling it before it enters the testes and thereby keeping the testes cool. (Heat exchange between the artery and the vein.)
2. Cremaster Muscle - bands of skeletal muscle that elevate the testes to warm in cold conditions. under hot conditions these muscles relax so the testes hang low to increase surface available for cooling and move the testes further away from the body.
3. Dartos Muscle - Layer of smooth muscle in the superficial fascia that wrinkles the scrotal skin to bring the testes close to the body and warm them and falls away to cool them.

Question 35

At about what temperature is sperm production optimal?

Answer 35

95 degrees F

Question 36

Describe the function of the main types of cells found in the testes.

Answer 36

1. spermatogenic cells - in the process of forming sperm
2. Sertoli cells - Surround the spermatogenic cells and assist sperm production by:
   - conveying nutrients to them
   - create tight junctions between the cells to keep T-cells out.
   - secrete testicular fluid into the tubule lumen which helps push sperm through the tubule and out of the testes.
3. Leydig cells - make and secrete the male sex hormones (androgens.)

Question 37

Sometimes greater omentum or a section of small intestine is forced through the abdominal wall. The most commonplace for this to occur in males (and females) is at the what? When it occurs it is called an what?

Answer 37

Inguinal canal

Inguinal hernia

Question 38

The anatomical term for a mature ovarian follicle is?

Answer 38

Antral follicle

Question 39

Describe the process of ovulation. How does the oocyte get released?

Answer 39

Ovulation is signaled by the sudden release of a large quantity of luteinizing hormone (LH) from the pituitary gland, just before day 14.
The ovarian wall over the follicle bulges, thins, and oozes fluid; enzymes digest a hole in the wall and the oocyte exits, surrounded by its corona radiata.

Question 40

The first phase of the ovarian cycle is the what? It lasts about how long? What is happening in the ovary at this time?

Answer 40

Follicular phase lasts about 14 days

The follicle develops

Question 41

The second phase of the ovarian cycle is the what? It lasts about how long? What is happening in the ovary at this time?

Answer 41

Ovulatory phase lasts about 1 day

Enzymes digest a hole in ovary wall and mature follicle (antral follicle) exits with its surrounding corona radiata.

Question 42

The last phase of the ovarian cycle is the what? It lasts about how long? What is happening in the ovary at this time?

Answer 42

Luteal phase lasts about 14 days
The part of the follicle that stays in the ovary collapses and becomes the corpus luteum which is an endocrine gland that secretes estrogens and progesterone which acts on the mucosa of the uterus, signaling it to prepare for implantation.

Question 43

When a oocyte is released from the ovary what exactly is it released into?

Answer 43

Pelvic cavity

Question 44

List the structures which physically support the uterus.

Answer 44

1. Mesometrium - largest division of the broad ligament
2. Paired round ligaments
3. Ovarian ligaments
4. Muscles of the urogenital and pelvic diaphragms (pelvic floor muscles)

Question 45

The uterus may descend into the vaginal canal (especially with age) What is this called? The procedure commonly used to treat the condition is called a what? (includes the removal of the uterus.

Answer 45

Prolapse of the uterus

Fixed by a histerectomy

Question 46

Where in the uterus should a developing offspring implant? If it implants anywhere else the condition is called a what?

Answer 46

Body of the uterus (endometrium)

Ectopic pregnancy

Question 47

What type of epithelium lines the uterus?

Answer 47

simple columnar

Question 48

What is the name of the glands of the uterus? What is their function?

Answer 48

endometrial gland

secrete nutrients

Question 49

The specialized vessels that serve the mucosa of the uterus are called what? Describe the process of what they do that is so special (that is different from other vessels.)

Answer 49

Spiral arteries - undergo degeneration and regeneration during each successive menstrual cycle, and they undergo spasms that cause the functional layer to shed during menstruation.

Question 50

List the three phases of the uterine cycle. About how long does each last?

Answer 50

Proliferative phase (day 6-14) 
Secretory phase (day 14-28)
Menstrual phase (day 1-5)