Deck 13: The Endocrine System

Question 1

The hypothalamic releasing hormones

A) are produced by glial cells
B) are transported along nerve axons to their target cells
C) are steroid hormones
D) control the release of the anterior pituitary hormones

Answer 1

D

Question 2

Each hormone will only interact with one receptor.

Answer 2

False

Question 3

Gonadotropin releasing hormone (GnRH)

A) is released into the hypothalamic-hypophyseal portal circulation
B) stimulates the release of both follicle stimulating hormone and lutenizing hormone
C) Both of the choices are correct.
D) Neither of the choices is correct, it is secreted in posterior pituitary

Answer 3

C

Question 4

Each organ has a specific set of hormone receptors.

Question 5

The anterior pituitary is regulated

A) autonomously
B) by hormones from the hypothalamus
C) by direct contact with neurons from the hypothalamus
D) indirectly by the pineal gland

Question 6

The anterior pituitary

A) is also called the adenohypophysis
B) develops from the hypothalamus
C) only stores hypothalamic hormones; it does not produce its own hormones
D) produces primarily steroid hormones

Question 7

The endocrine secretions from the hypothalamus are

A) released into the first capillary bed of the hypothalamic hypophyseal portal circulation
B) released into the second capillary bed of the hypothalamic hypophyseal portal circulation
C) directly delivered along nerve axons to their target cells
D) delivered to thalamus to provide tropic feedback

Question 8

Testosterone has which of the following properties or mechanisms of action?

A) diffuses into the cell before binding to its receptor
B) causes autophosphorylation of the receptor upon binding
C) upon binding to the receptors activates production of cAMP
D) is transcribed and translated in response to GnRH

Question 9

What is the function of the hormone somatostatin secreted by the hypothalamus?

A) it inhibits secretion of growth hormone
B) it inhibits production of luteinizing hormone
C) it stimulates secretion of growth hormone
D) somatostatin is not produced in the hypothalamus at all

Question 10

Hormones will only produce a response in cells that express their receptors.

Question 11

When a hormone is present in high levels for a long time, the number of receptors on target-cells may decrease. This is called

A) sensory adaptation
B) paracrine regulation
C) up-regulation
D) down-regulation

Question 12

The inhibition of thyroid-stimulating hormone (TSH) secretion by an increased blood concentration of thyroid hormones is an example of

A) positive feedback
B) negative feedback
C) accentuation
D) sensitization

Question 13

Early experiments on the pituitary gland included cutting or tying up the infundibulum. Damage to infundibulum will affect the function of

A) the posterior pituitary only
B) the anterior pituitary only
C) both lobes of the pituitary
D) will not affect pituitary function at all

Question 14

Alexandra has developed an autoimmune disease causing her to have constant low levels of cortisol (hypocortisolism). Would you expect to find changes in the number of Alexandra's cortisol receptors?

A) no
B) yes, down-regulation
C) yes, up-regulation

Question 15

Glucagon is a peptide hormone that increases blood glucose levels. Based on this information where in the cell would you search for glucagon receptors?

A) on the surface of the cell membrane
B) in the cytoplasm
C) in the nucleus
D) on the endoplasmic reticulum

Question 16

Corticotropin releasing hormone (CRH)

A) is released in response to various stressors
B) stimulates the production of somatotropin
C) inhibits the release of thyrotropin from the adenohypophysis
D) stimulates insulin release from pancreatic beta cells

Question 17

Cells from the hypothalamus influence which lobe(s) of the pituitary gland via a portal system?

A) anterior
B) posterior
C) both
D) neither

Question 18

Some hormones exhibit synergistic or antagonistic effects on each other. Which of the hormones below, do you think, exhibit synergy on blood sugar levels?

A) epinephrine and insulin
B) glucagon and insulin
C) epinephrine and glucagon
D) cortisol and insulin

Question 19

All hormones require a specific transport protein to help them travel in blood from the organ they were secreted from to the target cells.

Question 20

Which of the following hormones interact with a receptor in the nucleus?

A) thyroid-stimulating hormone
B) estradiol
C) parathyroid hormone
D) norepinephrine

Question 21

In the 1950s cutting the infundibulum, a thin string of tissue connecting the brain to the pituitary gland, lead to the discovery of the relationship between the pituitary and the brain. What were the symptoms observed after the procedure?

A) blindness
B) water retention and edema
C) lack of ovulation
D) excessive growth (gigantism)

Question 22

Which of the following anterior pituitary hormones stimulates the gonads to secrete progesterone in females or testosterone in males?

A) follicle stimulating hormone
B) luteinizing hormone
C) prolactin
D) progesterone

Question 23

The effects of ADH involve which of the following?

A) increase in contractions of the uterus
B) positive feedback via sexual arousal
C) osmoregulation by promoting water retention in kidneys
D) decrease of blood volume by increasing the phosphate levels in plasma

Question 24

Thyroglobulin is

A) a necessary component of a complete diet
B) a protein that stores thyroid hormones
C) the enzyme that converts iodide to iodine
D) a protein that transports thyroid hormones in blood

Question 25

It is a well-known fact that alcohol has a dehydrating effect on the body. What is the mechanism behind this effect?

A) Alcohol "poisons" the kidneys and causes water retention.
B) Alcohol binds to water and decreases diuresis.
C) Alcohol inhibits ADH production by hypothalamic neurons.
D) Alcohol activates the anterior pituitary to secrete aldosterone.

Question 26

The pituitary stalk aka infundibulum is a thin string of tissue that connects the hypothalamus and pituitary. What structures important for the physiology of the pituitary gland can be found in the pituitary stalk?

A) nerve fibers of hypothalamic-hypophyseal tract
B) veins of hypothalamic-hypophyseal portal circulation
C) axons of neurons from paraventricular and supraoptic nuclei
D) All of the choices are correct.

Question 27

Which one of the hormones listed below is NOT produced by the anterior pituitary?

A) growth hormone
B) gonadotropin-releasing hormone
C) thyroid stimulating hormone
D) prolactin

Question 28

The synthesis of TSH is

A) negatively regulated by TRH
B) positively regulated by thyroxine levels
C) regulated both by TRH and thyroxine levels in blood
D) at the top of HPA axis and therefore is not regulated by other hormones

Question 29

The coupling of the monoiodotyrosines and diiodotyrosines

A) takes place when they are still bound to the thyroglobulin
B) is the post translational modification of thyroxin
C) takes place in lysosomes before secretion
D) requires thyroxin binding globulin to proceed

Question 30

Which of the hypothalamic hormones that control the anterior pituitary is NOT a peptide hormone?

A) CRH
B) TRH
C) Somatostatin
D) PIH

Question 31

Thyroxine (tetraiodothyronine)

A) is more potent than triiodothyronine in peripheral tissues
B) is deiodinated in target cells to the biologically more potent triiodothyronine
C) has no biological activity and is a form of hormone removed by kidneys
D) is a transport protein for thyroid hormones

Question 32

Oxytocin is a hormone responsible for labor and delivery, but males have oxytocin too.

Question 33

Antidiuretic hormone (ADH) is synthesized in the

A) anterior pituitary
B) posterior pituitary
C) hypothalamus
D) kidneys

Question 34

What are the target cells for prolactin?

A) myoepithelial cells in the mammary glands
B) milk producing cells in the mammary glands
C) certain neurons in the hypothalamus
D) the smooth muscle cells in the uterus

Question 35

Decreased secretion of ADH leads to a syndrome called diabetes insipidus. If this disease was not genetic, but happened as a result of trauma, where would the doctors look for the possible damage?

A) anterior pituitary
B) hypothalamic-hypophyseal portal circulation vessels
C) hypothalamus
D) thalamus

Question 36

Both anterior and posterior pituitary lobes use portal circulation to deliver hormones to the peripheral endocrine organs

Question 37

What symptoms would you expect to see after the surgical removal of the posterior lobe of the pituitary gland?

A) impaired growth
B) slower stress response
C) lower BMR (basal metabolic rate)
D) polyuria

Question 38

What is the chemical nature of thyroglobulin?

A) steroid
B) amine
C) glycoprotein
D) metaloprotein

Question 39

The amount of ADH that is secreted by the posterior pituitary gland varies with changes in blood

A) osmolarity
B) oxygenation
C) glucose level
D) decarboxylation

Question 40

TSH levels in blood are often used by doctors to adjust doses of thyroid hormone replacement medications such as Synthroid. Why is TSH a good indicator of circulating thyroid hormone levels?

A) because TSH is negatively regulated by thyroxine levels
B) because TSH is positively regulated by thyroxine levels
C) because TSH synthesis takes place in the cytoplasm of thyroid cells
D) because TSH controls the production and secretion of TRH

Question 41

Which of the following hormones most significantly increases the basal metabolic rate (BMR)?

A) insulin
B) adrenocorticotropic hormone
C) glucagon
D) thyroid hormone

Question 42

Hypothyroidism during adulthood can produce which of the following symptoms?

A) acromegaly
B) Graves' disease
C) hypoglycemia
D) myxedema

Question 43

Iodine is necessary for the formation of

A) TSH
B) thyroxin binding globulin
C) thyroxine
D) calcitonin

Question 44

What levels of TSH in blood would you expect in a person after a total thyroidectomy (removal of thyroid) before hormone therapy has started?

A) high
B) low
C) normal
D) zero

Question 45

One of the symptoms of excessive secretion of thyroid hormones is the increased heart rate. The mechanism of this is

A) permissive effect of thyroid hormones on epinephrine
B) synergistic effect between thyroid hormones and epinephrine
C) antagonistic effect between thyroid hormones and epinephrine
D) tropic effect of epinephrine on thyroid hormones

Question 46

One of the effects of thyroid hormones is the increase of BMR (basic metabolic rate). This effect is achieved through

A) increase of gluconeognesis
B) increase of aerobic oxidation
C) shifting metabolism to fermentation
D) accumulation of pyruvate

Question 47

Parathyroid hormone is secreted when

A) when bones are low in calcium
B) calcium levels in blood are too low
C) when calcium "shows up" in urine
D) when vitamin D in blood is low

Question 48

Deficiency of thyroid hormones can result in

A) an increase in metabolic rate
B) growth retardation
C) increase in heart rate
D) prepubertal growth spurt

Question 49

You might have noticed that much of the table salt sold in the U.S. is iodized. What is the reason for the fortification of salt with iodide?

A) iodide has permissive effect on thyroid receptor activity
B) iodine is an essential substrate in thyroid hormone production
C) iodide is necessary for TSH synthesis and secretion
D) iodide is just the extra ingredient in salt that can't be removed

Question 50

Which of the following statements regarding T₃ is FALSE?

A) Most T₃ is produced by monodeiodination of T₄ in peripheral tissues.
B) T₃ is the primary iodothyronine secreted by the thyroid gland.
C) T₃ has several times the potency of T₄.
D) The conversion of T₄ to T₃ occurs only in the kidney and liver.

Question 51

The adrenal cortex

A) is surrounded by the adrenal medulla
B) has two histologically distinct zones
C) produces steroid hormones
D) secretes angiotensin

Question 52

Low levels of parathyroid hormone will manifest itself as

A) low levels of calcium in blood
B) lower absorption of calcium from food
C) higher level of calcium loss in urine
D) decrease of bone reabsorption

Question 53

Which of the following hormones is NOT secreted by the thyroid gland?

A) calcitonin
B) T₃
C) T₄
D) TSH

Question 54

Glucocorticoids such as cortisol

A) increase glucose synthesis from amino acids
B) increase glycogen synthesis
C) decrease glucose synthesis in the liver
D) increase protein synthesis

Question 55

Goiter may result from

A) lack of iodine in the diet
B) hypothyroidism
C) hyperthyroidism
D) All of the choices are correct.

Question 56

Thyroid hormones are transported in the blood bound to a plasma protein known as thyroxine-binding globulin.

Question 57

Parathyroid hormone works by several mechanisms to maintain an adequate level of calcium in the blood. Which of the following is a mechanism of parathyroid hormone action?

A) stimulates release of calcitriol
B) increases deposition of hydroxyapatite in the bone
C) mobilizes Ca²⁺ from sarcoplasmic reticulum
D) increases loss of calcium in urine

Question 58

The inhibition of TRH secretion by an increased blood concentration of thyroid hormones is an example of

A) positive feedback
B) negative feedback
C) accentuation
D) sensitization

Question 59

TSH stimulates thyroid function in many ways, but it does NOT increase

A) iodination of tyrosine
B) iodine uptake from the blood
C) rate of synthesis of thyroglobulin
D) synthesis of thyroxine binding globulin

Question 60

The secretion of parathyroid hormone is controlled by the concentration of

A) calcium bound to citrate anions
B) calcium in the diet
C) calcium inside of the bone matrix
D) ionized calcium in the blood

Question 61

The major secretory product of the zona glomerulosa of adrenals are

A) glucocorticoids
B) mineralcorticoids
C) androgens
D) catecholamines

Question 62

Calcitriol, an active form of vitamin D is a hormone that

A) is necessary for collagen formation in the bones
B) increases absorption of calcium in the gastrointestinal tract
C) reduces osteoblast activity
D) increases calcium loss in urine

Question 63

How is the secretion of melatonin influenced by light?

A) light does not affect secretion
B) light enhances secretion
C) light suppresses secretion

Question 64

High levels of aldosterone would tend to

A) increase in the retention of potassium ions
B) increase blood pressure
C) lower the blood volume
D) increase the level of sodium in the urine

Question 65

Melatonin is correctly described by all the following statements EXCEPT

A) it is derived from serotonin
B) it regulates skin pigmentation in humans
C) its secretion is increased by darkness
D) its secretion is stimulated by the sympathetic nervous system

Question 66

Cortisol, a hormone secreted from the adrenal cortex during resistance phase of stress, plays a role in

A) maintaining blood glucose levels
B) retention of K⁺ in kidneys
C) calcium ion excretion through kidneys
D) bone maturation

Question 67

Chronic adrenocortical insufficiency is most often caused by an autoimmune disorder and is also known as

A) Cushing's disease
B) Addison's disease
C) Conn's disease
D) Diabetes mellitus

Question 68

The heart is a part of circulatory system but it is also a part of endocrine system because it secretes hormone(s).

Question 69

Cortisol binds to

A) cell surface receptors and stimulates production of cyclic amp
B) cell surface receptors and then activates intracellular processes by an increase in intracellular calcium levels
C) intracellular receptors and initiates protein synthesis
D) receptor tyrosine kinases and opens ion channels

Question 70

The production of aldosterone

A) is usually associated with increased plasma renin activity
B) is mainly under the control of the adenohypophysis
C) increases when the sodium ion concentration rises by more than 10 mmol/L
D) is inhibited by angiotensin II

Question 71

An important hormone precursor that is formed in the skin when it is exposed to sunlight is

A) cholesterol
B) melatonin
C) melanin
D) cholecalciferol

Question 72

Cholecalciferol aka vitamin D3 can be synthesized in the body, and does not necessarily have to be consumed.

Question 73

Which of the following hormones is implicated in the dark skin of Addison's patients?

A) ACTH
B) cortisol
C) aldosterone
D) LH

Question 74

Which of the following conditions would result from hyposecretion of aldosterone?

A) decreased heart rate
B) decreased airway dilation
C) dehydration
D) increased basal metabolic rate

Question 75

Cortisol is produced in response to

A) LH
B) TRH
C) CRH
D) ACTH

Question 76

Testosterone

A) is a water soluble hormone
B) is produced from cholesterol
C) binds to receptor tyrosine kinases
D) works through production of second messengers

Question 77

Cholecystokinin causes all of the following EXCEPT

A) contraction of the gallbladder and release of bile
B) stimulation of pancreatic enzyme secretion
C) inhibition of gastric emptying
D) initiates a feeling of fullness

Question 78

The class of hormones that have potent anti-inflammatory and immunosuppressive properties are

A) mineralcorticoids
B) estrogens
C) glucocorticoids
D) catecholamines

Question 79

The renin-angiotensin- aldosterone pathways is activated in which of the following conditions?

A) dehydration
B) increase in blood pressure
C) decrease of K⁺ in extracellular fluid
D) increase in blood volume

Question 80

The effect of estrogen on the secretion of GnRH is an example of

A) negative feedback
B) metabolism of the hormone
C) positive feedback
D) synergistic effect