Ruminant Nutrition Exam 2

1. Which structure is most directly responsible for coordinating the activity of both the anterior and posterior pituitary?

A. Adrenal cortex
B. Hypothalamus
C. Adrenal medulla
D. Pancreas

2. Which statement correctly distinguishes the anterior and posterior pituitary?

A. Both produce all of their own hormones
B. The posterior pituitary produces hormones while the anterior pituitary only stores them
C. The anterior pituitary produces its own hormones, while the posterior pituitary stores and releases hormones produced by the hypothalamus
D. Neither is regulated by the hypothalamus

3. A hormone released by the anterior pituitary that acts on the adrenal gland is:

A. CRH
B. ACTH
C. ADH
D. Insulin

4. Which sequence correctly represents the major HPA-axis pathway?

A. Adrenal → hypothalamus → pituitary → CRH
B. Hypothalamus → CRH → anterior pituitary → ACTH → adrenal cortex
C. Pituitary → CRH → hypothalamus → ACTH → adrenal medulla
D. Hypothalamus → ACTH → pituitary → cortisol

5. A major physiological stimulus that activates the HPA axis is:

A. Stress
B. Low protein intake only
C. Increased insulin
D. Decreased glucagon

6. The circadian clock influences the HPA axis primarily by:

A. Eliminating cortisol production
B. Providing timing-related input into the stress-response system
C. Preventing CRH secretion
D. Directly producing ACTH

7. Which hormone is produced by the hypothalamus in response to stress and stimulates the anterior pituitary?

A. ACTH
B. CRH
C. Cortisol
D. Aldosterone

8. ACTH ultimately stimulates the adrenal gland to produce:

A. Mineralocorticoids only
B. Glucocorticoids
C. Insulin
D. Vasopressin

9. Which adrenal region is located in the center of the adrenal gland?

A. Zona glomerulosa
B. Zona fasciculata
C. Zona reticularis
D. Medulla

10. The adrenal medulla primarily produces:

A. Catecholamines
B. Glucocorticoids
C. Mineralocorticoids
D. Androgens

11. Which adrenal cortical zone produces glucocorticoids?

A. Zona glomerulosa
B. Zona fasciculata
C. Zona reticularis
D. Medulla

12. The zona reticularis primarily produces:

A. Androgens
B. Catecholamines
C. Aldosterone
D. Insulin

13. Aldosterone is an example of a:

A. Glucocorticoid
B. Catecholamine
C. Mineralocorticoid
D. Gonadotropin

14. Which pairing is correct?

A. Zona glomerulosa — glucocorticoids
B. Zona fasciculata — mineralocorticoids
C. Zona reticularis — androgens
D. Medulla — aldosterone

15. If a student experiences a sudden stressful event, which response would be expected?

A. Reduced sympathetic activity and reduced heart rate
B. Increased sympathetic activity and increased epinephrine
C. Increased insulin and decreased epinephrine only
D. Complete suppression of the HPA axis

16. Why does sympathetic activation during stress increase heart rate?

A. To decrease oxygen delivery
B. To prepare the body to respond to a stressful situation
C. To prevent blood from reaching muscles
D. To stop metabolism

17. Which statement about ACTH is supported by the lecture material?

A. ACTH can only be produced by the anterior pituitary
B. ACTH can also be produced independently by immune cells
C. ACTH is produced exclusively by the adrenal medulla
D. ACTH directly produces insulin

18. Why might immune cells produce ACTH?

A. To completely shut down the immune system
B. To provide another route for activating the stress-response pathway during infection
C. To increase insulin secretion
D. To prevent cytokine signaling

19. Which sequence best represents the HPA response to stress?

A. Stress → CRH → ACTH → glucocorticoids
B. Stress → ACTH → CRH → insulin
C. Stress → insulin → ACTH → aldosterone
D. Stress → glucagon → CRH → vasopressin

20. Negative feedback within the HPA axis is important because it:

A. Causes unlimited glucocorticoid production
B. Prevents the system from remaining excessively activated
C. Eliminates ACTH permanently
D. Prevents stress from affecting the hypothalamus

Metabolic Hormones

21. Insulin is generally secreted in response to:

A. Food intake, particularly carbohydrate availability
B. Complete fasting only
C. Dehydration only
D. Low blood volume

22. The primary effect of insulin on blood glucose is to:

A. Increase circulating glucose indefinitely
B. Promote storage/use of glucose and reduce circulating glucose
C. Prevent cells from responding to glucose
D. Convert all glucose directly into protein

23. Glucagon generally has an effect opposite to insulin because it:

A. Promotes access to glucose reserves when blood glucose is low
B. Always lowers blood glucose
C. Prevents glucose from entering the blood
D. Completely shuts down metabolism

24. Which situation would most strongly favor glucagon secretion?

A. High circulating glucose after a carbohydrate-rich meal
B. Decreased circulating glucose
C. Immediately after a high-carbohydrate meal
D. Increased insulin signaling

25. Insulin and glucagon are best described as:

A. Identical hormones
B. Complementary regulators that act in opposing directions to help regulate blood glucose
C. Hormones produced exclusively by the adrenal gland
D. Hormones that both always increase blood glucose

26. Which hormone is associated with the sympathetic fight-or-flight response and mobilization of fuel reserves?

A. Insulin
B. Vasopressin
C. Epinephrine
D. Prolactin

27. Compared with glucagon, epinephrine is described in the lecture as:

A. Having essentially no metabolic effects
B. Producing a stronger, more extensive mobilization of fuel reserves
C. Always lowering blood glucose
D. Being secreted only after eating carbohydrates

28. A person eats a carbohydrate-rich meal. Which response would be expected?

A. Blood glucose rises, insulin rises, and glucagon decreases
B. Blood glucose falls immediately, glucagon rises, and insulin disappears
C. Blood glucose remains unchanged and insulin decreases
D. Epinephrine becomes the dominant hormone

29. Why does glucagon decrease after a high-carbohydrate meal?

A. The body needs to prevent glucagon from opposing insulin's glucose-lowering effects
B. Glucagon is destroyed by the stomach
C. Glucagon only exists during sleep
D. Insulin directly converts glucagon into glucose

30. A high-protein meal causes a rise in amino acids but does not necessarily cause the same large rise in blood glucose as a high-carbohydrate meal. Why?

A. Protein is composed primarily of carbohydrates
B. Amino acids are not the same as circulating glucose
C. Protein immediately blocks insulin
D. Glucagon cannot respond to protein intake

31. According to the lecture, insulin may increase following a high-protein meal even without a major rise in blood glucose because:

A. Food intake can stimulate insulin secretion in anticipation of nutrient availability
B. Protein is converted immediately into blood glucose
C. Insulin only responds to amino acids
D. Glucagon is absent during protein digestion

32. During a high-protein meal, why can glucagon increase?

A. The body may need to maintain blood glucose as glucose is being used for energy
B. Glucagon prevents all glucose metabolism
C. Protein directly destroys insulin receptors
D. Glucagon is only released when blood glucose is extremely high

33. Which cells in the pancreas are associated with maintaining basal levels of insulin and glucagon?

A. Alpha and beta cells
B. Neurons and glial cells
C. Adrenal cells only
D. Kidney epithelial cells

Vasopressin & Water Balance

34. Vasopressin is also known as:

A. ACTH
B. ADH
C. CRH
D. TSH

35. Vasopressin is:

A. Produced by the adrenal cortex and stored in the pancreas
B. Produced by the hypothalamus and stored/released by the posterior pituitary
C. Produced by the anterior pituitary and stored in the kidney
D. Produced by the kidney and stored in the adrenal medulla

36. The primary function of vasopressin is to:

A. Promote water retention
B. Promote glucose storage
C. Increase protein digestion
D. Decrease blood volume

37. Why is vasopressin particularly important for maintaining body-fluid concentrations?

A. The body must regulate the relationship between water and dissolved substances such as salts
B. Water has no effect on solute concentration
C. The kidneys cannot respond to hormones
D. Vasopressin directly produces sodium

38. A person consumes a very salty meal. Which response would be most consistent with the lecture?

A. Increased water retention
B. Complete elimination of water retention
C. Immediate loss of all blood volume
D. Permanent suppression of vasopressin

39. Vasopressin acts directly on which cells?

A. All cells equally
B. Cells of the nephron that possess vasopressin receptors
C. Red blood cells
D. Adrenal medulla cells only

40. Activation of the vasopressin receptor promotes insertion of:

A. Insulin receptors
B. AQP2 aquaporin channels
C. Sodium-potassium pumps into red blood cells
D. ACTH channels

41. What is the functional consequence of inserting AQP2 channels into the appropriate kidney-cell membrane?

A. Increased water reabsorption
B. Increased glucose secretion
C. Decreased water movement into the body
D. Increased protein digestion

42. Which statement correctly compares AQP2 and AQP3 according to the lecture?

A. Both are completely controlled by vasopressin
B. AQP2 is regulated by vasopressin, while AQP3 is not
C. AQP3 is regulated by ACTH
D. Neither allows water movement

43. Increased water reabsorption caused by vasopressin can lead to:

A. Increased blood volume and blood pressure
B. Decreased blood volume only
C. Complete loss of sodium
D. Decreased blood pressure in every situation

44. If vasopressin levels decrease, the kidney would generally be expected to:

A. Retain more water
B. Reabsorb less water
C. Increase AQP2 insertion
D. Increase blood volume through water retention

Integrated/Application Questions

45. A person experiences severe stress. Which combination is most likely?

A. Decreased CRH, decreased ACTH, decreased glucocorticoids
B. Increased CRH, increased ACTH, increased glucocorticoids
C. Increased insulin only
D. Decreased sympathetic activity and decreased epinephrine

46. A researcher blocks CRH release from the hypothalamus. Which downstream hormone would most directly decrease as a result?

A. ACTH
B. Insulin
C. Vasopressin only
D. Aldosterone directly

47. Suppose ACTH secretion from the anterior pituitary increases substantially. Which response would be most directly expected?

A. Increased glucocorticoid production by the adrenal cortex
B. Increased insulin production by the pancreas
C. Increased AQP2 production by the nephron
D. Decreased adrenal activity

48. A patient has high blood glucose and high insulin secretion after a meal. Which additional change would best support the body's attempt to restore glucose homeostasis?

A. Increased glucagon secretion
B. Decreased glucagon secretion
C. Increased epinephrine secretion
D. Increased ACTH secretion

49. A person has low blood pressure and the body needs to increase blood volume. Which combination could contribute to this response?

A. Vasopressin-mediated water retention and aldosterone-mediated sodium retention
B. Insulin and decreased water retention
C. Glucagon and decreased sodium retention
D. Decreased vasopressin and decreased aldosterone

50. Which statement best demonstrates the overall physiological principle emphasized throughout the lecture?

A. Physiological systems generally rely on only one pathway to maintain homeostasis
B. Hormones act independently and rarely influence one another
C. Multiple interacting pathways can regulate the same physiological variable and provide backup or complementary control
D. The endocrine system functions independently of the nervous system

Practice exam 2

1. Which of the following is a primary function of the skeletal system?

A. Hormone secretion

B. Support, shape, and protection

C. Gas exchange

D. Digestion

2. Which type of skeleton is located outside the body?

A. Endoskeleton

B. Hydroskeleton

C. Exoskeleton

D. Cytoskeleton

3. A skeleton that relies primarily on internal fluid pressure to provide support is a:

A. Exoskeleton

B. Endoskeleton

C. Cytoskeleton

D. Hydroskeleton

4. The cytoskeleton primarily provides:

A. Cellular structure and support

B. Protection from predators

C. Body-wide skeletal support

D. Joint movement

5. Which comparison between an exoskeleton and endoskeleton is correct?

A. Both are located outside the body

B. Exoskeleton is external; endoskeleton is internal

C. Exoskeleton is internal; endoskeleton is external

D. Both are composed only of bone

6. If neuron A sends a signal to neuron B, neuron A is the:

A. Postsynaptic neuron

B. Presynaptic neuron

C. Motor end plate

D. Target neuron

7. Neuronal relays are generally:

A. Bidirectional

B. Random

C. Unidirectional

D. Always inhibitory

8. In a negative neuronal relationship, if neuron A fires, neuron B:

A. Does not fire

B. Fires more strongly

C. Always releases hormones

D. Becomes presynaptic

9. In a positive neuronal relationship, if neuron A fires, neuron B:

A. Stops firing

B. Fires

C. Becomes inactive permanently

D. Releases calcium into the blood

10. In the relay A → B → C → D, neuron A directly interacts with:

A. C

B. B

C. D

D. All three neurons

11. A neuronal relationship is determined by the behavior of the:

A. Postsynaptic neuron only

B. Presynaptic neuron and the relationship between the neurons

C. Muscle fiber only

D. Endocrine gland

12. If neuron A's axon connects to neuron B's dendrite, neuron A is:

A. Presynaptic

B. Postsynaptic

C. The motor end plate

D. The synaptic cleft

13. A muscle fiber is best described as a:

A. Sarcomere

B. Muscle cell

C. Myofibril

D. Thick filament

14. Which sequence correctly represents increasing levels of muscle organization?

A. Muscle fiber → myofibril → sarcomere

B. Sarcomere → muscle fiber → myofibril

C. Myofibril → muscle fiber → sarcomere

D. Sarcomere → myofibril → muscle fiber

15. The functional contractile unit of a muscle fiber is the:

A. Myosin

B. Sarcomere

C. Myofibril

D. Actin

16. The thick filament in skeletal muscle is primarily composed of:

A. Myosin

B. Actin

C. Troponin

D. Tropomyosin

17. The thin filament in skeletal muscle is primarily composed of:

A. Myosin

B. Actin

C. Calcium

D. ATP

18. Muscle contraction involves interaction between:

A. Actin and myosin

B. Calcium and ATP only

C. DNA and RNA

D. Troponin and ATP only

19. ATP is important during cross-bridge cycling because it:

A. Permanently attaches myosin to actin

B. Allows myosin to detach from actin and provides energy

C. Blocks calcium release

D. Prevents muscle contraction

20. Rigor occurs when:

A. Calcium cannot bind troponin

B. Actin disappears

C. Myosin remains attached to actin

D. ATP production increases

21. Rigor mortis occurs primarily because:

A. Excess ATP prevents contraction

B. ATP is unavailable for myosin detachment

C. Calcium cannot enter the blood

D. Actin is destroyed

22. A contraction in which the muscle produces force while shortening is:

A. Eccentric

B. Isometric

C. Concentric

D. Passive

23. A contraction in which the muscle produces force while lengthening is:

A. Concentric

B. Eccentric

C. Isometric

D. Reflexive

24. The neuromuscular junction is the connection between:

A. A motor neuron and a muscle fiber

B. Two endocrine glands

C. Two muscle fibers

D. A bone and a tendon

25. The specialized region of the muscle cell membrane at the neuromuscular junction is the:

A. Motor end plate

B. Sarcomere

C. Sarcoplasmic reticulum

D. T-tubule

Correct answers

Ruminant Nutrition Exam 2

Correct answers for practice exam 2