week 13

Question 1

1) Which of the following is consistent with homeostasis?

A) as body temperature rises, sweating occurs to cool the body
B) when a person drinks large quantities of water, urine output decreases to raise blood volume
C) elevated blood glucose levels cause insulin secretion to decline
D) decreases in blood pressure cause a corresponding decrease in heart rate
E) as blood pressure falls, blood flow to the heart decreases

Answer 1

1) Which of the following is consistent with homeostasis?

A) as body temperature rises, sweating occurs to cool the body *
B) when a person drinks large quantities of water, urine output decreases to raise blood volume
C) elevated blood glucose levels cause insulin secretion to decline
D) decreases in blood pressure cause a corresponding decrease in heart rate
E) as blood pressure falls, blood flow to the heart decreases

Question 2

2) In positive feedback, the initial stimulus produces a response that

A) suppresses the stimulus.
B) has no effect on the stimulus.
C) interferes with the completion of the process.
D) exaggerates the stimulus. *
E) impedes the stimulus.

Answer 2

2) In positive feedback, the initial stimulus produces a response that

A) suppresses the stimulus.
B) has no effect on the stimulus.
C) interferes with the completion of the process.
D) exaggerates the stimulus. *
E) impedes the stimulus.

Question 3

3) An example of a receptor in a negative feedback loop controlling body temperature would be

A) temperature sensors on the skin that detect a stimulus.
B) sweat glands that increase secretion.
C) regulatory centers that send commands to an effector.
D) effectors that cause blood vessels to dilate.
E) sweat glands that act like effectors.

Answer 3

3) An example of a receptor in a negative feedback loop controlling body temperature would be

A) temperature sensors on the skin that detect a stimulus. *
B) sweat glands that increase secretion.
C) regulatory centers that send commands to an effector.
D) effectors that cause blood vessels to dilate.
E) sweat glands that act like effectors.

Question 4

4) This type of feedback amplifies the effects of a system.

A) negative
B) positive
C) neutral
D) depressing
E) all of the above

Answer 4

4) This type of feedback amplifies the effects of a system.

A) negative
B) positive
C) neutral
D) depressing
E) all of the above

Question 5

6) A feedback system consists of three basic components: a control centre, a receptor and a (an)

A) modulator
B) generator
C) integrator
D) effector
E) regulator

Answer 5

6) A feedback system consists of three basic components: a control centre, a receptor and a (an)

A) modulator
B) generator
C) integrator
D) effector *
E) regulator

Question 6

7) Osmometer cells sense changes in the concentration of blood plasma; therefore, they must be

A) receptors.
B) control centers.
C) stimulators.
D) modulators.
E) effectors.

Answer 6

7) Osmometer cells sense changes in the concentration of blood plasma; therefore, they must be

A) receptors. *
B) control centers.
C) stimulators.
D) modulators.
E) effectors.

Question 7

8) Which of the following is an example of a positive feedback loop?

**A) A neuron is stimulated, thus opening membrane channels to allow sodium ions to leak from the extracellular fluid to the intracellular fluid. This causes more membrane channels to open, thus allowing more sodium ions to enter the intracellular fluid. **
B) Baroreceptors notify the brain that the blood pressure has increased. The brain then notifies the blood vessels to dilate, thus lowering the blood pressure.
C) Low levels of glucose in the blood cause the pancreas to release less insulin (a hormone that lowers blood glucose).
D) Elevated body temperature is sensed by cells in the brain. As a result, sweat is produced, and heat is lost as the water in the sweat evaporates.
E) Receptors detect deficient amounts of calcium ions in the blood. The receptors notify the parathyroid gland, which then releases a hormone that causes more calcium ions to be retained in the blood.

Answer 7

8) Which of the following is an example of a positive feedback loop?

A) A neuron is stimulated, thus opening membrane channels to allow sodium ions to leak from the extracellular fluid to the intracellular fluid. This causes more membrane channels to open, thus allowing more sodium ions to enter the intracellular fluid. *
B) Baroreceptors notify the brain that the blood pressure has increased. The brain then notifies the blood vessels to dilate, thus lowering the blood pressure.
C) Low levels of glucose in the blood cause the pancreas to release less insulin (a hormone that lowers blood glucose).
D) Elevated body temperature is sensed by cells in the brain. As a result, sweat is produced, and heat is lost as the water in the sweat evaporates.
E) Receptors detect deficient amounts of calcium ions in the blood. The receptors notify the parathyroid gland, which then releases a hormone that causes more calcium ions to be retained in the blood.

Question 8

9) Which of the following cannot be present if homeostasis is maintained?

A) negative feedback loops
B) disease or disorder
C) positive feedback loops
D) minor fluctuations in a controlled condition such as body temperature
E) changes in the composition of the ECF

Answer 8

9) Which of the following cannot be present if homeostasis is maintained?

A) negative feedback loops
B) disease or disorder *
C) positive feedback loops
D) minor fluctuations in a controlled condition such as body temperature
E) changes in the composition of the ECF

Question 9

10) In a negative feedback mechanism, the response of the effector

A) reverses the original stimulus.
B) enhances the original stimulus.
C) has no effect on the original stimulus.
D) is usually damaging to the body.
E) creates a cycle that leads away from homeostasis.

Answer 9

10) In a negative feedback mechanism, the response of the effector

A) reverses the original stimulus. *
B) enhances the original stimulus.
C) has no effect on the original stimulus.
D) is usually damaging to the body.
E) creates a cycle that leads away from homeostasis.

Question 10

11) Homeostasis is the condition in which the body maintains

A) the lowest possible energy usage.
B) a relatively stable internal environment, within limits.
C) a static state with no deviation from preset points.
D) a changing state, with an unlimited range.
E) a relatively stable external environment, within limits.

Answer 10

11) Homeostasis is the condition in which the body maintains

A) the lowest possible energy usage.
B) a relatively stable internal environment, within limits. *
C) a static state with no deviation from preset points.
D) a changing state, with an unlimited range.
E) a relatively stable external environment, within limits.

Question 11

12) Interstitial fluid is the fluid

A) inside blood vessels.
B) inside cells.
C) between the cells.
D) inside lymph vessels.
E) that is consumed as part of the diet.

Answer 11

12) Interstitial fluid is the fluid

A) inside blood vessels.
B) inside cells.
C) between the cells. *
D) inside lymph vessels.
E) that is consumed as part of the diet.

Question 12

13) Which of the following is not considered to be an extracellular fluid?

A) the fluid inside cells
B) the fluid inside blood vessels
C) the fluid between cells
D) the fluid inside lymphatic vessels
E) the fluid around the brain and spinal cord

Answer 12

13) Which of the following is not considered to be an extracellular fluid?

A) the fluid inside cells *
B) the fluid inside blood vessels
C) the fluid between cells
D) the fluid inside lymphatic vessels
E) the fluid around the brain and spinal cord

Question 13

14) Which of the following best describes the endocrine system?

A) It transmits regulatory signals via nerve impulses.
B) It absorbs nutrients.
C) It contains hair, skin, and nails.
D) It produces blood cells that transport oxygen.
E) It transmits regulatory signals via the release of hormones into the blood.

Answer 13

14) Which of the following best describes the endocrine system?

A) It transmits regulatory signals via nerve impulses.
B) It absorbs nutrients.
C) It contains hair, skin, and nails.
D) It produces blood cells that transport oxygen.
E) It transmits regulatory signals via the release of hormones into the blood. *

Question 14

15) Which of the following is true of the endocrine system but not the nervous system?

A) directs long term processes such as pregnancy and puberty
B) communicates via chemical signals
C) regulates activities of muscles and glands
D) A and B are correct.
E) A, B and C are correct.

Answer 14

15) Which of the following is true of the endocrine system but not the nervous system?

A) directs long term processes such as pregnancy and puberty *
B) communicates via chemical signals
C) regulates activities of muscles and glands
D) A and B are correct.
E) A, B and C are correct.

Question 15

16) Which of the following statements about the endocrine system is NOT correct?

A) It uses hormones, which are transported by the blood, to communicate with distant tissues.
B) Its hormones must bind to specific receptor sites in order to have effects on a tissue.
C) It targets are limited to muscles, glands and nerves.
D) It may take seconds, hours, or days to respond to a stimulus.
E) Its actions may last seconds, hours, or days.

Answer 15

16) Which of the following statements about the endocrine system is NOT correct?

A) It uses hormones, which are transported by the blood, to communicate with distant tissues.
B) Its hormones must bind to specific receptor sites in order to have effects on a tissue.
C) It targets are limited to muscles, glands and nerves. *
D) It may take seconds, hours, or days to respond to a stimulus.
E) Its actions may last seconds, hours, or days.

Question 16

17) Which mediator is considered to be both a neurotransmitter and a hormone?

A) insulin
B) norepinephrine (nordrenaline)
C) thyroid hormone
D) somatotropin
E) aldosterone

Answer 16

17) Which mediator is considered to be both a neurotransmitter and a hormone?

A) insulin
B) norepinephrine (nordrenaline) *
C) thyroid hormone
D) somatotropin
E) aldosterone

Question 17

18) Which of the following is NOT an endocrine gland?

A) thyroid gland
B) adrenal gland
C) sudoriferous gland
D) pituitary gland
E) parathyroid gland

Answer 17

18) Which of the following is NOT an endocrine gland?

A) thyroid gland
B) adrenal gland
C) sudoriferous gland *
D) pituitary gland
E) parathyroid gland

Question 18

19) Which of the following does NOT contain endocrine tissue?

A) hypothalamus
B) thymus
C) heart
D) gall bladder
E) kidney

Answer 18

19) Which of the following does NOT contain endocrine tissue?

A) hypothalamus
B) thymus
C) heart
D) gall bladder *
E) kidney

Question 19

20) The anterior pituitary gland responds to gonadotropin releasing hormone (GnRH), but the posterior pituitary gland does not. Why?

A) Only anterior pituitary gland is permeable to GnRH.
B) Only the anterior pituitary gland is vascular.
C) Only the anterior pituitary gland is connected by neurons to the hypothalamus.
D) Only the anterior pituitary gland is connected to a duct carrying GnRH.
E) Only the anterior pituitary gland has receptors for GnRH.

Answer 19

20) The anterior pituitary gland responds to gonadotropin releasing hormone (GnRH), but the posterior pituitary gland does not. Why?

A) Only anterior pituitary gland is permeable to GnRH.
B) Only the anterior pituitary gland is vascular.
C) Only the anterior pituitary gland is connected by neurons to the hypothalamus.
D) Only the anterior pituitary gland is connected to a duct carrying GnRH.
E) Only the anterior pituitary gland has receptors for GnRH. *

Question 20

21) The hypothalamus

A) is a link between the endocrine and nervous systems.
B) release oxytocin and ADH into the blood but does not produce them.
C) regulates the posterior pituitary gland via releasing and inhibiting hormones.
D) A and B are correct.
E) A, B and C are correct.

Answer 20

21) The hypothalamus

A) is a link between the endocrine and nervous systems. *
B) release oxytocin and ADH into the blood but does not produce them.
C) regulates the posterior pituitary gland via releasing and inhibiting hormones.
D) A and B are correct.
E) A, B and C are correct.

Question 21

22) The pituitary gland

A) lies in the cribiform plate of the ethmoid bone.
B) consists of two lobes, the adenohypophysis and the neurohypophysis.
C) develops from outgrowths of endoderm.
D) A and B are correct.
E) A, B and C are correct.

Answer 21

22) The pituitary gland

A) lies in the cribiform plate of the ethmoid bone.
B) consists of two lobes, the adenohypophysis and the neurohypophysis. *
C) develops from outgrowths of endoderm.
D) A and B are correct.
E) A, B and C are correct.

Question 22

23) The anterior pituitary gland

A) contains two cell types and secretes four different hormones.
B) is regulated largely by positive feedback mechanisms and hormones from the pineal gland.
C) regulates the function of some other endocrine glands by secreting hormones called tropins.
D) A and B are correct.
E) A, B and C are correct.

Answer 22

23) The anterior pituitary gland

A) contains two cell types and secretes four different hormones.
B) is regulated largely by positive feedback mechanisms and hormones from the pineal gland.
C) regulates the function of some other endocrine glands by secreting hormones called tropins. *
D) A and B are correct.
E) A, B and C are correct.

Question 23

24) Which of the following is correct?

A) Only females produce prolactin.
B) Increased levels of stress may cause increased secretion of ACTH.
C) MSH is required for normal thyroid function in humans.
D) LH inhibits ovulation.
E) TSH stimulates calcitonin production.

Answer 23

24) Which of the following is correct?

A) Only females produce prolactin.
B) Increased levels of stress may cause increased secretion of ACTH. *
C) MSH is required for normal thyroid function in humans.
D) LH inhibits ovulation.
E) TSH stimulates calcitonin production.

Question 24

25) The posterior pituitary gland

A) is also called the adenophysis.
B) contains pituicytes and the axons of neurons that originate in the hypothalamus.
C) synthesizes ADH and OT.
D) releases ADH and OT into the hypophyseal artery.
E) All of these are correct.

Answer 24

25) The posterior pituitary gland

A) is also called the adenophysis.
B) contains pituicytes and the axons of neurons that originate in the hypothalamus. *
C) synthesizes ADH and OT.
D) releases ADH and OT into the hypophyseal artery.
E) All of these are correct.

Question 25

26) The hormone oxytocin

A) is made by females, but not males.
B) inhibits uterine contractions.
C) stimulates ejection of milk from the breast.
D) may be responsible for arousal before sexual intercourse.
E) helps retain the attachment between the placenta and the uterus.

Answer 25

26) The hormone oxytocin

A) is made by females, but not males.
B) inhibits uterine contractions.
C) stimulates ejection of milk from the breast. *
D) may be responsible for arousal before sexual intercourse.
E) helps retain the attachment between the placenta and the uterus.

Question 26

27) The thyroid gland

A) lies posterior and superior to the larynx.
B) contains follicular cells that secrete calcitonin.
C) contains parafollicular cells that secrete T3/T4.
D) helps regulate metabolism and Ca2+ levels.
E) is embedded within the parathyroid gland.

Answer 26

27) The thyroid gland

A) lies posterior and superior to the larynx.
B) contains follicular cells that secrete calcitonin.
C) contains parafollicular cells that secrete T3/T4.
D) helps regulate metabolism and Ca2+ levels. *
E) is embedded within the parathyroid gland.

Question 27

A) are embedded within the thyroid gland.
B) contain chief cells, which secrete PTH.
C) are controlled by negative feedback mechanisms.
D) A and B are correct.
E) A, B and C are correct.

Answer 27

A) are embedded within the thyroid gland.
B) contain chief cells, which secrete PTH.
C) are controlled by negative feedback mechanisms.
D) A and B are correct.
E) A, B and C are correct. *

Question 28

29) The adrenal glands

A) lie superior and medial to the kidneys.
B) have an inner medulla derived from embryonic ectoderm.
C) have an outer cortex that secretes hormones critical to maintenance of homeostasis.
D) A and B are correct.
E) A, B and C are correct.

Answer 28

29) The adrenal glands

A) lie superior and medial to the kidneys.
B) have an inner medulla derived from embryonic ectoderm.
C) have an outer cortex that secretes hormones critical to maintenance of homeostasis.
D) A and B are correct.
E) A, B and C are correct. *

Question 29

30) An eight-year old child spent the day eating sweets. He ate cookies for breakfast, ice cream for lunch and lollies for dinner. How did his body maintain his blood glucose level within normal range?

A) by increasing glucagon secretion
B) by increasing cortisol secretion
C) by increasing insulin secretion
D) by increasing hGH secretion
E) by increasing ACTH secretion

Answer 29

30) An eight-year old child spent the day eating sweets. He ate cookies for breakfast, ice cream for lunch and lollies for dinner. How did his body maintain his blood glucose level within normal range?

A) by increasing glucagon secretion
B) by increasing cortisol secretion
C) by increasing insulin secretion *
D) by increasing hGH secretion
E) by increasing ACTH secretion

Question 30

31) The fight-or-flight response

A) is the body’s immediate response to a real or perceived threat to survival.
B) elevates heart and respiration rates and blood glucose level.
C) decreases urinary and digestive functions.
D) activates the renin-angiotensin-aldosterone pathway.
E) All of these are correct.

Answer 30

31) The fight-or-flight response

A) is the body’s immediate response to a real or perceived threat to survival.
B) elevates heart and respiration rates and blood glucose level.
C) decreases urinary and digestive functions.
D) activates the renin-angiotensin-aldosterone pathway.
E) All of these are correct. *

Question 31

32) Which of the following disorders and hormonal imbalances is correctly matched?

A) diabetes insipidus: decreased insulin response
B) acromegaly: excessive hGH secretion after epiphyseal plates close
C) diabetes mellitus: decreased ADH secretion
D) pheochromocytoma: excessive thyroid hormone production
E) cretinism: excessive cortisol production

Answer 31

32) Which of the following disorders and hormonal imbalances is correctly matched?

A) diabetes insipidus: decreased insulin response
B) acromegaly: excessive hGH secretion after epiphyseal plates close *
C) diabetes mellitus: decreased ADH secretion
D) pheochromocytoma: excessive thyroid hormone production
E) cretinism: excessive cortisol production

Question 32

33) The underlying pathogenic mechanism for both type 1 and type 2 diabetes is

A) pancreatic β cell destruction.
B) lack of insulin receptors.
C) lack of exercise and chronic overeating.
D)
E) pancreatic α cell destruction.
E) impaired glucose transport into cells.

Answer 32

33) The underlying pathogenic mechanism for both type 1 and type 2 diabetes is

A) pancreatic β cell destruction.
B) lack of insulin receptors.
C) lack of exercise and chronic overeating.
D)
E) pancreatic α cell destruction.
E) impaired glucose transport into cells. *

Question 33

34) Which of the following manifestations would you not expect to observe in a person suffering from type I diabetes mellitus?

A) glycosuria
B) decreased appetite
C) hyperglycaemia
D) increased thirst
E) polyuria

Answer 33

34) Which of the following manifestations would you not expect to observe in a person suffering from type I diabetes mellitus?

A) glycosuria
B) decreased appetite *
C) hyperglycaemia
D) increased thirst
E) polyuria

Question 34

35) Soon after a meal rich in carbohydrates, the concentration of glucose in the blood vessels leading to and from the liver was measured. Which of the following would be CORRECT?

A) the glucose content of the blood entering and leaving the liver would be much greater than normal.
**B) the glucose content of the blood entering the liver would be higher and the blood leaving the liver would contain much less glucose than normal. **
C) the glucose content of blood leaving the liver remains about the same but there would be a greater glucose content of blood entering the liver.
D) the glucose content of the blood entering and leaving the liver remains fairly constant and is not affected by the a meal of carbohydrates.
E) none of the above.

Answer 34

35) Soon after a meal rich in carbohydrates, the concentration of glucose in the blood vessels leading to and from the liver was measured. Which of the following would be CORRECT?

A) the glucose content of the blood entering and leaving the liver would be much greater than normal.
B) the glucose content of the blood entering the liver would be higher and the blood leaving the liver would contain much less glucose than normal. *
C) the glucose content of blood leaving the liver remains about the same but there would be a greater glucose content of blood entering the liver.
D) the glucose content of the blood entering and leaving the liver remains fairly constant and is not affected by the a meal of carbohydrates.
E) none of the above.

Question 35

36) Symptoms of hypoglycaemia include:

A) hunger, mental confusion, and diaphoresis
B) flushed skin and dehydration
C) rapid respirations and fruity smelling breath
D) tachycardia and polyuria
E) all of the above

Answer 35

36) Symptoms of hypoglycaemia include:

A) hunger, mental confusion, and diaphoresis *
B) flushed skin and dehydration
C) rapid respirations and fruity smelling breath
D) tachycardia and polyuria
E) all of the above

Question 36

37) The signs and symptoms of hypoglycaemia reflect the fact that:

A) muscle cells need glucose for normal function.
B) glucose is the only source of energy for nervous tissue.
C) hypoglycemia decreases cerebral blood flow.
D) hypoglycemia inhibits the release of counterregulatory hormones such as the catecholamines.
E) all of the above.

Answer 36

37) The signs and symptoms of hypoglycaemia reflect the fact that:

A) muscle cells need glucose for normal function.
B) glucose is the only source of energy for nervous tissue. *
C) hypoglycemia decreases cerebral blood flow.
D) hypoglycemia inhibits the release of counterregulatory hormones such as the catecholamines.
E) all of the above.

Question 37

38) If you knew a person was suffering from an overdose of insulin, the best remedial step would be to give the person

A) unsweetened tea.
B) large amounts of cold water.
C) a saline solution drink.
D) a non-diet soft drink.
E) none of the above.

Answer 37

38) If you knew a person was suffering from an overdose of insulin, the best remedial step would be to give the person

A) unsweetened tea.
B) large amounts of cold water.
C) a saline solution drink.
**D) a non-diet soft drink. **
E) none of the above.

Question 38

39) A characteristic common to all hormones is that they:

A) exert their effects by altering the rate of a body reaction
B) are secreted at a uniform rate
C) must be produced in large quantities to exert their effects
D) always exert their actions at the site of secretion
E) none of the above

Answer 38

39) A characteristic common to all hormones is that they:

A) exert their effects by altering the rate of a body reaction *
B) are secreted at a uniform rate
C) must be produced in large quantities to exert their effects
D) always exert their actions at the site of secretion
E) none of the above

Question 39

40) Hormones reach their target organs by:

A) travelling through the bloodstream
B) paracrine mechanisms in which they act locally on cells other than those that produced the hormone
C) autocrine action in which they regulate the action of the cell producing the hormone
D) all of the above mechanisms
E) none of the above mechanisms

Answer 39

40) Hormones reach their target organs by:

A) travelling through the bloodstream *
B) paracrine mechanisms in which they act locally on cells other than those that produced the hormone
C) autocrine action in which they regulate the action of the cell producing the hormone
D) all of the above mechanisms
E) none of the above mechanisms

Question 40

41) The chemical mediators of the endocrine system must bind to ___________________ on target cells before they can initiate changes in those cells.

Answer 40

41) The chemical mediators of the endocrine system must bind to ___________________ on target cells before they can initiate changes in those cells.

Answer: receptors

Question 41

42) The chemical mediators used by the endocrine system are called __________________.

Answer 41

42) The chemical mediators used by the endocrine system are called __________________.

Answer: Hormones

Question 42

43) ___________________________ glands secrete small amounts of chemical mediators into the interstitial fluid; other glands secrete products directly into ducts.

Answer 42

43) ___________________________ glands secrete small amounts of chemical mediators into the interstitial fluid; other glands secrete products directly into ducts.

Answer: Endocrine

Question 43

44) The electrolyte critical for thyroid hormone synthesis is ________________________.

Answer 43

44) The electrolyte critical for thyroid hormone synthesis is ________________________.

Answer: Iodide

Question 44

45) __________________________ , also known as islets of Langerhans, are the endocrine tissues of the pancreas.

Answer 44

45) __________________________ , also known as islets of Langerhans, are the endocrine tissues of the pancreas.

Answer: Pancreatic islets

Question 45

46) Hormones, such as insulin and glucagon, which have opposing effects are described as ______.

Answer 45

46) Hormones, such as insulin and glucagon, which have opposing effects are described as ______.

Answer: antagonistic

Question 46

47) Glucagon is secreted by ____________________ cells of the Islets of Langerhans.

Answer 46

47) Glucagon is secreted by ____________________ cells of the Islets of Langerhans.

Answer: alpha cells

Question 47

48) The adrenal __________________ releases adrenalin (epinephrine) and noradrenalin (norepinephrine).

Answer 47

48) The adrenal __________________ releases adrenalin (epinephrine) and noradrenalin (norepinephrine).

Answer: medulla

Question 48

49) Hormones act on specific _________________ tissues.

Answer 48

49) Hormones act on specific _________________ tissues.

Answer: target

Question 49

50) The hormone responsible for milk production is _________________________.

Answer 49

50) The hormone responsible for milk production is _________________________.

Answer: prolactin

Question 50

51) Approximately 30 minutes after falling from a tree, a ten year-old boy arrives at the emergency department of PMH by ambulance. He has suffered a head injury that includes his pituitary gland being completely severed from its attachment to the hypothalamus of the brain.

(a) What immediate homeostatic consequence will the staff of the Emergency Department have to manage in relation to the death of his pituitary gland tissues?

(2 marks)

Answer 50

51) Approximately 30 minutes after falling from a tree, a ten year-old boy arrives at the emergency department of PMH by ambulance. He has suffered a head injury that includes his pituitary gland being completely severed from its attachment to the hypothalamus of the brain.

(a) What immediate homeostatic consequence will the staff of the Emergency Department have to manage in relation to the death of his pituitary gland tissues? (2 marks)

Answer: - Marked increase in diuresis (uncontrolled) (1mark)
- leading to dehydration (1mark)

Question 51

52) Explain why hyperglycemia occurs in type I diabetes mellitus and give TWO complications. (5 marks)

Answer 51

52) Explain why hyperglycemia occurs in type I diabetes mellitus and give TWO complications. (5 marks)

Answer:
Lack of insulin → cells not to be able to take up glucose → hyperglycemia.
Complication → blindness, MI, stroke, renal disease, foot ulcer

Question 52

53) Cells communicate with one another using a language of chemicals. List one role each of the following plays in cellular communication.

a. hormones
b. cell membranes
c. receptor molecules (3 marks)

Answer 52

Answer:
A) Hormones attach to cells and influence their activity in some specific fashion.
B) Cell membranes contain the receptor molecules for those hormones that use membrane-bound receptors to achieve their effects.
C) Receptor molecules are chemicals that hormones bind to. Specific receptors are used to identify target cells to a given hormone. The hormone-receptor complex initiates the response of the target cells.

Question 53

54) Hormone Z, responsible for maintaining normal blood levels of chemical A, binds to membrane-bound receptors on its target cells. These target cells use G-protein and cyclic AMP to carry out the response of hormone Z. Predict the consequences if a drug is taken that inhibits the action of cyclic AMP. (1 mark)

Answer 53

54) Hormone Z, responsible for maintaining normal blood levels of chemical A, binds to membrane-bound receptors on its target cells. These target cells use G-protein and cyclic AMP to carry out the response of hormone Z. Predict the consequences if a drug is taken that inhibits the action of cyclic AMP. (1 mark)

Answer: If the action of cyclic AMP is inhibited, then the action of hormone Z is inhibited.