Physiology

Question 1

All of the following statements about the thyroid hormones T3 and T4 are true EXCEPT
A) T3 and T4 cause an increase in basal metabolic rate
B) Secretions from the thyroid gland are controlled by hormones released from the anterior pituitary.
C) Low body temperature will lead to an increase in T3 and T4 release from the thyroid
D) Secretion of T3 and T4 occurs when thyrotropin releasing hormone (TRH) binds to receptors on cells in the thyroid gland.

Answer 1

Secretion of T3 and T4 occurs when thyrotropin releasing hormone (TRH) binds to receptors on cells in the thyroid gland.

Question 2

A mutation in the alpha subunit of a G-protein results in much faster GTPase activity (the
conversion of GTP to GDP occurs much faster). This mutated G-protein is coupled to a G-protein coupled receptor for norepinephrine and has adenylyl cyclase as an effector protein. Compared to the normal G-protein activity, activation with this mutated alpha subunit would result in

Answer 2

Lower levels of cAMP

Question 3

Steroid hormones

Answer 3

Typically cause changes in transcription levels

Question 4

A high surface area to volume ratio in an animal will result in
A) More rapid increases in body temperature when the environment is hot.
B) More rapid decreases in body temperature when the environment is cold.
C) an animal who is better equipped to take advantage of short-duration (daily) torpor to conserve energy.
D) More than one of the above
E) All of the above

Answer 4

All of the above

Question 5

Which of the following would cause sweating in a human?
A) cooling of the blood going to the hypothalamus
B) an increase in current body temperature
C) a decrease in set point for body temperature
D) More than one of the above
E) All of the above

Answer 5

More than one of the above

Question 6

Which mechanism is the most significant reason why action potentials are “all
or none” events with each action potential being separated and distinct from the other?

Answer 6

inactivation of voltage-gated sodium channels

Question 7

Which of the following blood vessels has the greatest amount of blood pressure?

Answer 7

The artery carrying blood to the feet of a giraffe

Question 8

Your roommate Taylor S comes back from organic chemistry lab all excited about a new chemical she has created that
constricts precapillary sphincter muscles in your digestive system and kidneys. She immediately injects it into your vein
and you say, “That was ‘bad, blood’ should not contain that chemical. We are never ever getting back together. I am
finding another roommate.” A drug the constricts precapillary sphincter muscles in the digestive system and kidneys will cause

Answer 8

Increased blood flow to your brain

Question 9

In the checkout line at the store, little Joey wants a toy, but Joey’s parents refuse to purchase one. In protest, little Joey holds his breath. Which of the following result from the stopping of external respiration while internal respiration continues?

Answer 9

Increase in partial pressure of carbon dioxide in blood

Question 10

All of the following increase the rate of diffusion of oxygen from air to blood across the alveolar wall EXCEPT
A) Increasing the concentration of oxygen in air
B) Decreasing the concentration of oxygen in blood
C) Decreasing the distance between air and blood
D) Increasing the surface area of the alveoli
E) Decreasing the solubility of oxygen in water

Answer 10

Decreasing the solubility of oxygen in water

Question 11

As you go from a state of rest to a state of vigorous exercise, all of the following changes will occur EXCEPT
A) ATP levels in the cell will decrease slightly
B) Glycogen synthesis will increase
C) the rate of phosphofructokinase activity will increase
D) levels of glucose and glucose-6-phosphate will decrease slightly
E) rate of ATP synthesis will increase

Answer 11

Glycogen synthesis will increase

Question 12

Where is the concentration of oxygen the lowest and the concentration of carbon dioxide the highest?

Answer 12

In venous blood of the systemic circulatory system

Question 13

Injecting a drug that prevents calcium from binding to troponin would cause

Answer 13

Inability of muscle to contract

Question 14

Compared to fast-twitch muscle, slow-twitch muscle

Answer 14

Has more mitochondria

Question 15

What predominant ion flux (movement) is occurring across the membrane during the rising phase of the action potential? What is the direction of movement?

Answer 15

Na+ (Sodium)
Into cell

Question 16

A novel cell is found with a resting membrane potential of -130 mV. Which of the following manipulations would cause this very negative resting membrane potential?

Answer 16

A decrease in extracellular potassium concentration

Question 17

Your other roommate Olivia R comes back from Organic Chemistry lab all excited about a new compound she has synthesized that blocks delayed rectifier potassium channels. Olivia thinks injecting it will be “Good 4 U” but you are thinking, “Bad idea, right?” Blocking delayed rectifier potassium channels would

Answer 17

Cause slower repolarization after an action potential

Question 18

When an action potential reaches the end of the axon neurotransmitter molecules are released into the synapse. The arrival of the action potential opens specific ion channels which lead to release of neurotransmitter. What ion is permeable through these channels and what opens (gates) these channels?

Answer 18

Ca (Calcium)
Change in voltage

Question 19

Before we mess around with normal cardiovascular physiology answer the following question. At what location in the systemic circulatory system is blood pressure monitored by the nervous system?

Answer 19

Carotid

Question 20

A drug is injected that speeds up your heart rate. What effect will speeding up the heart rate have on blood pressure in arteries of the systemic circulatory system?

Answer 20

Increase

Question 21

The manipulation in B will cause a compensatory response. What will happen to the sympathetic nervous system throughout the body to compensate for the effect the manipulation in B has on blood pressure?

Answer 21

Decreased activity

Question 22

Name 2 specific effects the change in sympathetic activity you indicated in C will have on the cardiovascular system. (Name the tissue or organ affected and the direction of change of function)

Answer 22

• Heart Rate decrease
• Strength of contraction decrease
• Constriction of precapillary sphincter or resistance decrease
• Muscle tension on walls of veins or “squeezing” in walls of veins decrease

Question 23

An increase in carbon dioxide in blood leads to a more acidic pH. Explain the reason for this and be sure to mention the enzyme that is responsible.

Answer 23

In the presence of carbonic anhydrase, CO2 is combined with water to form carbonic acid with dissociates into HCO3- and H+.

Question 24

As fully oxygenated blood in an artery with 100% saturated hemoglobin (Hg) enters a capillary bed in active tissue, oxygen unbinds from hemoglobin. What is the single, most important, reason why oxygen unbinds from hemoglobin when blood enters active tissue?

Answer 24

Lower partial pressure of oxygen

Question 25

When you go from sitting on your couch to running as fast as you can for 20 minutes, you oxygen consumption in your body increases from 250 ml O2/min to 2,500 ml O2/min. Some of this increase in VO2 is due to changes in your heart and some is due to changes in the blood going through your body. Explain one change in your heart and one change in the blood that explains this 10 fold increase in oxygen delivery to the body.

Answer 25

Heart:
Heart Rate increases – more beats per minute
Strength of contraction increases – more blood per beat
Blood:
Less oxygen left in venous blood due to 1. Lower PO2 in active muscle, 2. Bohr Shift due to increased
CO2, increased temperature or increased concentration of H+ (lower or more acidic pH)