endocrine system mcq Flashcards
(106 cards)
1
Q
A
2
Q
Which of the following correctly describes a key difference between the endocrine and nervous systems?
A
A. The endocrine system’s effects are typically slower to initiate but longer-lasting than those of the nervous system.
3
Q
The endocrine system works closely with which other body system to regulate and maintain homeostasis?
A
C. Nervous system
4
Q
Which structure in the brain serves as the link between the nervous system and the endocrine system?
A
B. Hypothalamus
5
Q
Which of the following is NOT characteristic of endocrine system communication?
A
C. Hormonal responses are immediate and short-lived.
6
Q
How do endocrine glands differ from exocrine glands?
A
A. Endocrine glands are ductless and release hormones directly into the bloodstream.
7
Q
Which of the following is not an endocrine gland?
A
D. Sweat gland
8
Q
Which gland has both endocrine and exocrine functions?
A
A. Pancreas
9
Q
The primary target organ of the hypothalamic releasing and inhibiting hormones is the:
A
B. Anterior pituitary gland
10
Q
All of the following hormones are secreted by the anterior pituitary except:
A
D. Parathyroid hormone (PTH)
11
Q
Which hormone is released from the posterior pituitary?
A
A. Antidiuretic hormone (ADH)
12
Q
Which endocrine gland primarily regulates the body’s basal metabolic rate (BMR)?
A
A. Thyroid gland
13
Q
Which of the following correctly describes the roles of calcitonin and parathyroid hormone (PTH) in calcium homeostasis?
A
A. Calcitonin lowers blood calcium levels, whereas PTH raises blood calcium levels.
14
Q
Which hormones are responsible for the “fight-or-flight” response?
A
A. Epinephrine and norepinephrine
15
Q
Which pituitary hormone stimulates sperm production in males and follicle development in females?
A
D. Follicle-stimulating hormone (FSH)
16
Q
A surge of which hormone triggers ovulation in the middle of the menstrual cycle?
A
B. Luteinizing hormone (LH)
17
Q
All of the following hormones are produced by the adrenal cortex except:
A
C. Epinephrine
18
Q
The hormone-producing cell clusters in the pancreas are known as:
A
B. Islets of Langerhans
19
Q
In the pancreatic islets, the β (beta) cells secrete:
A
C. Insulin
20
Q
What is a primary effect of the hormone glucagon?
A
A. It stimulates the breakdown of glycogen to raise blood glucose levels.
21
Q
Which of the following is not an action of insulin?
A
C. Stimulating gluconeogenesis (new glucose production) in the liver.
22
Q
Which endocrine gland secretes melatonin and helps regulate circadian rhythms (sleep–wake cycles)?
A
A. Pineal gland
23
Q
Which gland is large and active in children (supporting immune development) but shrinks after puberty?
A
A. Thymus
24
Q
The secretions of which endocrine glands differ between males and females?
A
C. Gonads (ovaries vs. testes)
25
Which organ, though not primarily endocrine, secretes erythropoietin (EPO) to stimulate red blood cell production?
A. Kidney
26
What is the main effect of the hormone aldosterone?
A. It increases sodium reabsorption (and potassium excretion) by the kidneys, leading to water retention and higher blood pressure.
27
Which anterior pituitary hormone is not a tropic hormone (i.e. does not primarily act on another endocrine gland)?
C. Growth hormone (GH)
28
Where are the hormones oxytocin and antidiuretic hormone (ADH) actually produced?
A. In the hypothalamus
29
Which hormone stimulates uterine contractions during childbirth and causes milk ejection during breastfeeding?
A. Oxytocin
30
Which hormone stimulates milk production in the mammary glands?
A. Prolactin
31
Which of the following stimuli would cause the pancreas to secrete insulin?
A. A high blood glucose level (for example, after a carbohydrate-rich meal)
32
Parathyroid hormone (PTH) is secreted in response to:
A. Low blood calcium levels
33
What is the primary trigger for insulin release?
Elevated blood glucose after a carbohydrate-rich meal
## Footnote
Insulin is secreted to promote glucose uptake by cells.
34
What stimulates the secretion of parathyroid hormone (PTH)?
Low blood calcium levels
## Footnote
PTH raises blood calcium by mobilizing calcium from bone and increasing calcium reabsorption in kidneys.
35
What stimulates the secretion of antidiuretic hormone (ADH)?
Increased blood osmolarity
## Footnote
ADH causes the kidneys to conserve water.
36
Which hormone raises blood glucose and suppresses the immune system during stress?
Cortisol
## Footnote
Cortisol is a glucocorticoid released in response to ACTH.
37
Thyroid-stimulating hormone (TSH) primarily acts on which gland?
Thyroid gland
## Footnote
TSH stimulates the thyroid to produce and release thyroid hormones.
38
What does adrenocorticotropic hormone (ACTH) stimulate?
Adrenal cortex to secrete cortisol
## Footnote
ACTH triggers the release of glucocorticoids like cortisol.
39
In males, what does luteinizing hormone (LH) directly stimulate?
Testosterone production by the testes
## Footnote
LH acts on Leydig cells in the testes.
40
Which hormone is detected by common pregnancy tests?
Human chorionic gonadotropin (hCG)
## Footnote
hCG is secreted by the early embryo/placenta.
41
What is the primary role of progesterone in the female reproductive system?
Preparing and maintaining the uterine lining for possible pregnancy
## Footnote
Progesterone acts on the endometrium to make it receptive for implantation.
42
Which hormone is responsible for the development of female secondary sexual characteristics?
Estrogen
## Footnote
Estrogens from the ovaries are responsible for pubertal changes.
43
Which hormone is primarily responsible for male secondary sexual characteristics?
Testosterone
## Footnote
Testosterone induces male traits during puberty.
44
Which hormone is a steroid (lipid-derived) hormone?
Cortisol
## Footnote
Cortisol is derived from cholesterol.
45
Which hormone is derived from amino acids?
Epinephrine
## Footnote
Amine hormones are modified from single amino acids.
46
Where are the receptors for steroid hormones typically located?
Inside the target cell
## Footnote
Steroid hormones bind to intracellular receptors.
47
How do peptide hormones generally exert their effects on target cells?
By binding to cell-surface receptors
## Footnote
This triggers second-messenger cascades inside the cell.
48
Which class of hormone generally requires a transport protein in the bloodstream?
Steroid hormones
## Footnote
Steroid hormones are hydrophobic and travel in blood bound to carrier proteins.
49
Thyroid hormones (T₃ and T₄) are synthesized from which amino acid?
Tyrosine
## Footnote
Thyroid hormones are iodinated derivatives of tyrosine.
50
Steroid hormones are derived from which precursor molecule?
Cholesterol
## Footnote
All steroid hormones share a four-ring core structure derived from cholesterol.
51
What is true regarding the synthesis and storage of steroid hormones?
Steroid hormones are synthesized on demand
## Footnote
They are not stored in vesicles.
52
What enzyme does the second messenger cAMP directly activate?
Protein kinase A (PKA)
## Footnote
cAMP activates PKA to alter cell activity.
53
Activation of phospholipase C (PLC) leads to an increase in which second messengers?
Inositol trisphosphate (IP₃) and diacylglycerol (DAG)
## Footnote
IP₃ causes release of Ca²⁺ from the endoplasmic reticulum.
54
Insulin binds to which type of receptor on target cells?
A receptor tyrosine kinase
## Footnote
The insulin receptor triggers a cascade leading to increased glucose uptake.
55
Thyroid hormones exert their effects by binding to which receptors?
Intracellular receptors
## Footnote
They alter gene transcription in the nucleus.
56
What is down-regulation in the context of hormone action?
A decrease in the number of receptors on target cells
## Footnote
This occurs in response to chronically high hormone levels.
57
What is a chemical signal that acts on the same cell that secreted it called?
Autocrine signaling
## Footnote
Autocrine signals affect the secreting cell itself.
58
Growth hormone and prolactin exert their effects via which signaling pathway?
JAK/STAT kinase pathway
## Footnote
This pathway leads to transcription of specific genes.
59
Hormones that act on neighboring cells without entering the bloodstream are described as?
Paracrine signals
## Footnote
Paracrine signaling involves local mediators affecting nearby cells.
60
Most hormone secretion is regulated by?
Negative feedback mechanisms
## Footnote
This is the primary method used by nearly all endocrine glands.
61
What is paracrine signaling?
Paracrine signaling involves local mediators affecting nearby cells, such as nitric oxide or prostaglandins. They diffuse through interstitial fluid, not blood.
## Footnote
Autocrine signals affect the same cell that secreted them, and endocrine signals travel through blood to distant targets.
62
Most hormone secretion is regulated by which mechanism?
Negative feedback mechanisms.
## Footnote
Nearly all endocrine glands use negative feedback to maintain homeostasis, inhibiting further hormone release as effects rise.
63
Which hormone is an example of a positive feedback mechanism in the endocrine system?
Oxytocin release during childbirth intensifies uterine contractions, stimulating more oxytocin release.
## Footnote
This positive feedback loop continues until birth.
64
If thyroid hormone levels (T₃/T₄) are elevated, what happens to TSH secretion?
TSH secretion would decrease.
## Footnote
Excess T₃/T₄ suppresses TRH and TSH release.
65
The surge of luteinizing hormone (LH) before ovulation is an example of what type of feedback?
Positive feedback.
## Footnote
High estrogen levels stimulate LH release, leading to ovulation.
66
What characterizes Type I diabetes mellitus?
Autoimmune destruction of pancreatic β-cells leading to little or no insulin production.
## Footnote
This condition typically begins in childhood and requires insulin therapy.
67
Which of the following is often associated with Type II diabetes mellitus?
Insulin resistance in target cells.
## Footnote
Type II diabetes is often associated with obesity and may be managed initially with diet and exercise.
68
Which symptom is NOT common in uncontrolled diabetes mellitus?
Oliguria – low urine output.
## Footnote
Uncontrolled diabetes leads to polyuria, not oliguria.
69
What is a characteristic symptom of hyperthyroidism?
Unexplained weight loss despite increased appetite.
## Footnote
Hyperthyroidism increases metabolism, leading to weight loss.
70
Which of the following is NOT a feature of hypothyroidism?
Frequent diarrhea and abdominal cramping.
## Footnote
Hypothyroidism typically causes constipation, not diarrhea.
71
Which condition is associated with excessive cortisol?
Cushing’s syndrome.
## Footnote
This condition leads to symptoms like weight gain, hypertension, and a rounded face.
72
Which condition leads to weight gain and central obesity?
Cushing’s syndrome.
## Footnote
This is the opposite of Addison’s disease, which causes weight loss.
73
What results from excessive growth hormone secretion in a child?
Gigantism.
## Footnote
This occurs before the epiphyseal growth plates close.
74
Excess growth hormone in adults leads to what condition?
Acromegaly.
## Footnote
Acromegaly results in thickening of bones and soft tissues.
75
What does a deficiency of growth hormone in childhood result in?
Pituitary dwarfism.
## Footnote
This condition features short stature with normal body proportions.
76
Severe hypothyroidism in infancy is known as what?
Cretinism.
## Footnote
Cretinism results from congenital hypothyroidism, leading to developmental delays.
77
A deficiency of iodine can lead to what condition?
Goiter.
## Footnote
Lack of iodine leads to an enlarged thyroid due to elevated TSH.
78
A deficiency of antidiuretic hormone (ADH) results in which condition?
Diabetes insipidus.
## Footnote
This condition involves excessive dilute urine production.
79
What does hyperparathyroidism cause?
Elevated blood calcium and bone demineralization.
## Footnote
This condition leads to osteopenia and may cause kidney stones.
80
What is a major symptom of acute hypoparathyroidism?
Muscle cramps or spasms (tetany) due to low blood calcium.
## Footnote
Hypocalcemia increases nerve and muscle excitability.
81
What physical sign is often associated with Graves’ disease?
Exophthalmos (bulging eyeballs).
## Footnote
This sign results from autoimmune inflammation behind the eyes.
82
What is a pheochromocytoma?
A tumor of the adrenal medulla causing excessive secretion of epinephrine and norepinephrine.
## Footnote
This leads to episodic high blood pressure and other symptoms.
83
Excessive secretion of ADH leads to which condition?
Syndrome of inappropriate ADH (SIADH).
## Footnote
SIADH results in water retention and low blood sodium.
84
What is up-regulation in terms of hormone receptors?
An increase in target-cell receptor numbers in response to low hormone levels.
## Footnote
This makes the target cells more sensitive to the hormone.
85
What is up-regulation in hormonal response?
Up-regulation is when a target cell produces more receptors, becoming more sensitive to a hormone.
## Footnote
This often occurs when hormone levels have been lower than normal, such as low circulating thyroid hormone leading to increased thyroid hormone receptors.
86
Which element is essential for the production of thyroid hormones T₃ and T₄?
Iodine
## Footnote
Each T₃ molecule contains three iodine atoms and T₄ contains four. Iodine deficiency impairs thyroid hormone synthesis and can cause goiter.
87
What is the pituitary gland commonly referred to as?
Master gland
## Footnote
The pituitary is called the 'master gland' because it regulates many other endocrine glands by secreting tropic hormones.
88
What is the most abundant hormone produced by the anterior pituitary?
Growth hormone (GH)
## Footnote
GH constitutes a large percentage of the gland’s cells and plays widespread roles in growth and metabolism.
89
Which hormone is NOT secreted by the hypothalamus?
Adrenocorticotropic hormone (ACTH)
## Footnote
ACTH is produced by the anterior pituitary and is stimulated by hypothalamic CRH.
90
What pancreatic hormone inhibits the release of both insulin and glucagon?
Somatostatin
## Footnote
Somatostatin is secreted by delta cells of the pancreas and helps fine-tune blood glucose regulation.
91
Which endocrine gland is located just below the Adam’s apple?
Thyroid gland
## Footnote
The thyroid gland is butterfly-shaped and located in the anterior neck.
92
What are the glands located superior to the kidneys called?
Adrenal glands (suprarenal glands)
## Footnote
Each adrenal gland has an outer cortex and inner medulla that produce different hormones.
93
Which hormone produced by the kidneys helps increase calcium absorption from the intestine?
Calcitriol (active vitamin D)
## Footnote
Calcitriol increases calcium absorption in the gut and is formed from calcidiol in the kidneys.
94
What effect does atrial natriuretic peptide (ANP) have on blood pressure?
Lowers blood pressure by promoting sodium and water excretion in the kidneys
## Footnote
ANP counteracts the renin-angiotensin-aldosterone system to lower blood pressure.
95
Insulin and glucagon have ________ effects on blood glucose levels.
opposing (antagonistic)
## Footnote
Insulin lowers blood glucose, while glucagon raises it.
96
Antidiuretic hormone (ADH) is also known as?
Vasopressin
## Footnote
The term 'vasopressin' highlights ADH's vasoconstrictor effect at high concentrations.
97
Diabetic ketoacidosis (DKA) is most commonly associated with which type of diabetes?
Untreated Type 1 diabetes mellitus
## Footnote
DKA occurs when insulin is very low or absent, leading to fat breakdown and ketone production.
98
Which hormone acts via the cAMP second-messenger system?
Glucagon
## Footnote
Glucagon activates adenylyl cyclase, raising cAMP levels to increase blood glucose.
99
What enzyme converts ATP to cyclic AMP (cAMP) upon hormone stimulation?
Adenylyl cyclase
## Footnote
This enzyme cyclizes ATP to form cAMP, the second messenger in various hormonal pathways.
100
What enzyme terminates the cAMP second-messenger signal?
Phosphodiesterase
## Footnote
Phosphodiesterase breaks down cAMP into AMP, stopping the signaling pathway.
101
Which hormone stimulates acid secretion by the stomach?
Gastrin
## Footnote
Gastrin is produced in response to food and stimulates gastric parietal cells to secrete hydrochloric acid.
102
Which hormone stimulates the pancreas to release bicarbonate-rich fluid?
Secretin
## Footnote
Secretin is released from the duodenum in response to acidic chyme from the stomach.
103
What effect does antidiuretic hormone (ADH) have on urine output?
It decreases urine output by causing the kidneys to reabsorb more water
## Footnote
ADH increases water reabsorption in the kidneys, leading to smaller, more concentrated urine volume.
104
Which form of thyroid hormone is more biologically active at target tissues?
T₃ (triiodothyronine)
## Footnote
T₃ is about 3–5 times more potent than T₄ and is derived from the conversion of T₄ in target tissues.
105
The adrenal medulla secretes which hormones?
Epinephrine and norepinephrine
## Footnote
These catecholamines are produced in response to sympathetic stimulation.
106
What hormone do the parafollicular 'C cells' of the thyroid gland secrete?
Calcitonin
## Footnote
Calcitonin helps lower elevated blood calcium by inhibiting bone resorption.
