Chapter 17/18 Flashcards
hormone
A substance secreted by a gland of the endocrine system.
Ligand
A molecule that binds to a receptor site or enzyme.`
Receptor
A structure that detects changes caused by a stimulus.
Negative Feedback System
A mechanism that responds to and corrects a homeostatic imbalance.
Hypothalamus
A gland that controls many physiological functions and regulates other endocrine glands.
Pituitary Gland
An endocrine gland that is connected to the hypothalamus; secretes hormones.
Anterior Pituitary
The front lobe of the pituitary gland.
Posterior Pituitary
the back lobe of the pituitary gland
Growth Hormone (GH)
a hormone that stimulates cells to grow and divide
Protein
An organic substance composed of linked amino acid molecules.
Amino Acid
A small molecule that makes up proteins.
Thyroid-stimulating hormone (TSH)
a hormone that controls the thyroid gland
When a hormone binds to a membrane–bound receptor and activates G proteins,
Select one:
a. ion channels could be opened.
b. IP3 may be activated.
c. cyclic AMP production may be increased.
d. DAG may be activated.
e. All of the choices may occur from activated G proteins.
e. All of the choices may occur from activated G proteins.
Which of the following events occurs last?
Select one:
a. IP3 (inositol triphosphate) is produced.
b. Epinephrine combines with membrane-bound receptor on smooth muscle cell.
c. Calmodulin binds to the enzyme that phosphorylates myosin and cross-bridges form.
d. IP3 stimulates Ca2+ release from the endoplasmic reticulum.
e. Ca2+ binds with calmodulin.
c. Calmodulin binds to the enzyme that phosphorylates myosin and cross-bridges form.
Which pattern of hormone secretion, often observed in steroid reproductive hormones, will fluctuate over a monthly cycle?
Select one:
a. acute hormone secretion
b. episodic hormone secretion
c. long-term hormone secretion
d. chronic hormone secretion
b. episodic hormone secretion
In general, the response of target cells to endocrine stimulation is _______ than their response to nervous stimulation.
Select one:
a. faster and briefer
b. slower and more prolonged
c. more accurate
d. more restricted to a small area of the body
e. more intense
b. slower and more prolonged
What type of chemical messenger stimulates the cell that originally secreted it?
Select one:
a. paracrine
b. neurotransmitter
c. autocrine
d. endocrine
c. autocrine
After a meal, blood glucose levels rise and stimulate the release of insulin. What type of stimulation is this example?
Select one:
a. humoral
b. neural
c. hormonal
d. hypothalamic
a. humoral
Emily is in labor with her first child. The amplitude-modulated system would show her oxytocin levels
Select one:
a. to have a weak signal.
b. to have a moderate signal.
c. to have a strong signal.
d. too weak to measure.
c. to have a strong signal.
Which intracellular mediator is directly activated by the binding of a water-soluble hormone to a membrane receptor?
Select one:
a. cGMP
b. cAMP
c. calmodulin
d. phospholipase C
a. cGMP
Most endocrine glands communicate with their target tissues using _____ signals.
Select one:
a. frequency-modulated
b. amplitude-modulated
c. pitch-modulated
d. resonance-modulated
b. amplitude-modulated
David has been feeling tired lately, and after having blood work completed, it shows elevated TSH, low iodine, and low thyroid hormone levels. Predict the possible cause from the choices below.
Select one:
a. David could possibly have a thyroid tumor.
b. David may have iodine deficiency that is causing his thyroid to produce too little thyroid hormone.
c. David could have a pituitary gland tumor.
d. Too little information is given to determine the cause.
b. David may have iodine deficiency that is causing his thyroid to produce too little thyroid hormone.
Compounds released from cells that influence the same cell are called _____________.
Select one:
a. paracrine chemical messengers
b. steroidal hormones
c. neuropeptides
d. tropic hormones
e. autocrine chemical messengers
e. autocrine chemical messengers
All of the following are regulatory functions of the endocrine system except
Select one:
a. labor contractions.
b. development of tissues.
c. immune functions.
d. metabolic rate.
e. thermoregulation.
e. thermoregulation.
Which of the following is NOT a regulatory function of the endocrine system?
Select one:
a. Regulates water balance by controlling the solute concentration of the blood.
b. Regulates skeletal muscle contraction strength.
c. Regulates satiation and the breakdown of food into individual nutrients.
d. Regulates the rate of metabolism.
e. Regulates the levels of nutrients such as glucose in the blood.
b. Regulates skeletal muscle contraction strength.
The connecting stalk between the hypothalamus and the pituitary gland is the
Select one:
a. tectum.
b. cerebral peduncle.
c. hippocampus.
d. infundibulum.
d. infundibulum.
Adrenal androgens
Select one:
a. are produced in the adrenal medulla.
b. stimulate growth of pubic hair in females.
c. reduce the inflammatory response.
d. cause reabsorption of potassium ions by the kidney.
e. decrease the sex drive.
b. stimulate growth of pubic hair in females.
Osmoreceptor cells in the hypothalamus are involved in the secretion of
Select one:
a. growth hormone.
b. aldosterone.
c. antidiuretic hormone.
d. adrenocorticotropic hormone.
e. parathyroid hormone.
c. antidiuretic hormone.
If both ACTH (adrenocorticotropic hormone) and cortisol levels increase, which of the following would occur?
Select one:
a. ACTH production is increased even more by positive feedback.
b. High cortisol levels will begin to cause ACTH levels to decline.
c. High ACTH levels will begin to cause cortisol levels to decline.
d. Aldosterone levels will increase.
e. None of these choices are correct.
b. High cortisol levels will begin to cause ACTH levels to decline.
The main hormone of the male reproductive system is
Select one:
a. luteinizing hormone.
b. testosterone.
c. progesterone.
d. follicle-stimulating hormone.
b. testosterone.
High blood glucose levels cause an increased secretion of
Select one:
a. insulin.
b. calcitonin.
c. erythropoietin.
d. glucagon.
e. growth hormone.
a. insulin.
All of the following are changes due to age-related decreases in endocrine secretions, except
Select one:
a. decrease in muscle mass.
b. decrease in bone mass.
c. change in sleeping patterns.
d. increased susceptibility to infection.
e. inability to regulate blood glucose levels.
e. inability to regulate blood glucose levels.
The pituitary gland…
a. develops from the floor of the brain.
b. develops from the roof of the mouth.
c. is stimulated by neurohormones produced in the midbrain.
d. secretes only three major hormones.
e. Both a and b are correct
e. Both a and b are correct
The hypothalamohypophysial portal system
a. contains one capillary bed.
b. carries hormones from the anterior pituitary to the body.
c. carries hormones from the posterior pituitary to the body.
d. carries hormones from the hypothalamus to the anterior pituitary.
e. carries hormones from the hypothalamus to the posterior pituitary.
d. carries hormones from the hypothalamus to the anterior pituitary.
Which of these hormones is not secreted into the hypothalamohypophysial portal system?
GHRH
TRH
PIH
GnRH
ACTH
ACTH
Which of these stimulates the secretion of ADH?
elevated blood osmolality
decreased blood osmolality
release of hormones from the hypothalamus
ACTH
increased blood pressure
elevated blood osmolality
Oxytocin is responsible for
preventing milk letdown from the mammary glands.
preventing goiter.
causing contraction of the uterus.
maintaining normal calcium levels.
increasing the metabolic rate.
causing contraction of the uterus.
Growth hormone
increases the usage of glucose.
increases the breakdown of lipids.
decreases the synthesis of proteins.
decreases the synthesis of glycogen.
All of these are correct.
increases the breakdown of lipids.
Which of these hormones stimulates somatomedin secretion?
FSH
GH
LH
Prolactin
TSH
GH
Hypersecretion of growth hormone…
results in gigantism if it occurs in children.
causes acromegaly in adults.
increases the probability that a person will develop diabetes.
can lead to severe atherosclerosis.
All of these are correct.
All of these are correct.
LH and FSH
are produced in the hypothalamus.
production is increased by TSH.
promote the production of gametes and reproductive hormones.
inhibit the production of prolactin.
All of these are correct.
promote the production of gametes and reproductive hormones
T3 and T4
require iodine for their production.
are made from the amino acid tyrosine.
are transported in the blood bound to thyroxine-binding globulin.
All of these are correct.
All of these are correct.
Which of these symptoms is associated with hyposecretion of thyroid hormones?
-hypertension
-nervousness
-diarrhea
-weight loss with either normal or increased food intake
-decreased metabolic rate
decreased metabolic rate
Choose the statement that most accurately predicts the long-term effect of exposure to a substance that prevents the active transport of iodide by the thyroid gland.
-Large amounts of T3 and T4 accumulate within the thyroid follicles, but little is released.
-The person exhibits hypothyroidism.
-The anterior pituitary secretes smaller amounts of TSH.
-The circulating levels of T3 and T4 increase.
The person exhibits hypothyroidism.
Calcitonin
-is secreted by the parathyroid glands.
-levels increase when blood calcium levels decrease.
-causes blood calcium levels to decrease.
-insufficiency results in weak bones and tetany.
causes blood calcium levels to decrease.
Parathyroid hormone secretion increases in response to
-a decrease in blood calcium levels.
-increased production of parathyroid-stimulating hormone from the anterior pituitary.
-increased secretion of parathyroid-releasing hormone from the hypothalamus.
-increased secretion of calcitonin.
decreased secretion of ACTH.
a decrease in blood calcium levels.
If parathyroid hormone levels increase, which of these conditions is expected?
-Osteoclast activity increases.
-Calcium absorption from the small intestine is inhibited.
-Calcium reabsorption from the urine is inhibited.
-Less active vitamin D forms in the kidneys.
-All of these are correct.
Osteoclast activity increases.
The adrenal medulla
-produces steroids.
-secretes cortisol as its major product.
-decreases its secretions during exercise.
-forms from a modified portion of the sympathetic division of the ANS.
-All of these are correct.
forms from a modified portion of the sympathetic division of the ANS.
In the condition in which a benign tumor results in hypersecretion of hormones from the adrenal medulla, expected symptoms include
-hypotension.
-bradycardia (slow heart rate).
-pallor (decreased blood flow to the skin).
-lethargy.
-hypoglycemia.
pallor (decreased blood flow to the skin).
Which of these is not a hormone secreted by the adrenal cortex?
-aldosterone
-androgens
-cortisol
-epinephrine
epinephrine
If aldosterone secretions increase,
-blood potassium levels increase.
-blood hydrogen levels increase.
acidosis results.
-blood sodium levels decrease.
-blood volume increases.
blood volume increases.
Glucocorticoids (cortisol)
-increase the breakdown of lipids.
-increase the breakdown of proteins.
-increase blood glucose levels.
-decrease inflammation.
-All of these are correct.
All of these are correct.
Which of these is (are) expected in Cushing syndrome (hypersecretion of adrenal cortex hormones)?
-loss of hair in women
-deposition of adipose tissue in the face, neck, and abdomen
-low blood glucose
-low blood pressure
-All of these are correct.
deposition of adipose tissue in the face, neck, and abdomen
Within the pancreas, the pancreatic islets produce
-insulin.
-glucagon.
-digestive enzymes.
-Both a and b are correct.
-All of these are correct.
Both a and b are correct. (insulin, glucagon)
Insulin increases
-the uptake of glucose by its target tissues.
-the breakdown of protein.
-the breakdown of lipids.
-glycogen breakdown in the liver.
-All of these are correct.
the uptake of glucose by its target tissues.
Glucagon
-primarily affects the liver.
-causes glycogen to be stored.
-causes blood glucose levels to decrease.
-decreases lipid metabolism.
-performs all of these functions.
primarily affects the liver.
When blood glucose levels increase, the secretion of which of these hormones increases?
-glucagon
-insulin
-GH
-cortisol
-epinephrine
insulin
If a person who has diabetes mellitus has forgotten to take an insulin injection, the symptoms that may soon appear include
-acidosis.
-hyperglycemia.
-increased urine production.
-lethargy and fatigue.
-All of these are correct.
All of these are correct.
Which of the following is not a hormone produced by the ovaries?
estrogen
progesterone
prolactin
inhibin
relaxin
Prolactin
Melatonin
is produced by the posterior pituitary.
production increases as day length increases.
inhibits the development of the reproductive system.
increases GnRH secretion from the hypothalamus.
decreases the tendency to sleep.
inhibits the development of the reproductive system.
Which of these substances, produced by many body tissues, can promote inflammation, pain, and vasodilation of blood vessels?
endorphins
enkephalins
thymosin
epidermal growth factor
prostaglandins
prostaglandins
Which of these secretions does not decrease with aging of the endocrine system?
-GH secretion
-melatonin secretion
-thyroid hormone secretion
-parathyroid hormone secretion
parathyroid hormone secretion
When comparing the endocrine system and the nervous system, the endocrine system generally
-is faster-acting than the nervous system.
-produces effects that are of shorter duration.
-uses blood-borne chemical messengers.
-produces more localized effects.
-relies less on chemical messengers.
-uses blood-borne chemical messengers.
Given this list of molecule types:
(1) nucleic acid derivatives
(2) fatty acid derivatives
(3) peptides
(4) proteins
(5) phospholipids
Which could be hormone molecules?
1,2,3
2,3,4
1,2,3,4
2,3,4,5
1,2,3,4,5
2,3,4 (fatty acid, peptides, proteins)
Which of these can regulate the secretion of a hormone from an endocrine tissue?
-other hormones
-negative-feedback mechanisms
-humoral substances in the blood
-the nervous system
-All of these are correct.
All of these are correct.
Hormones are released into the blood
-at relatively constant levels.
-in large amounts in response to a stimulus.
-in an episodic fashion.
-All of these are correct.
All of these are correct.
Lipid-soluble hormones readily diffuse through capillary walls, whereas water-soluble hormones, such as proteins, must
-pass through capillary cells.
-pass through pores in the capillary endothelium.
-be moved out of the capillary by active transport.
-remain in the blood.
-be broken down to amino acids before leaving the blood.
pass through pores in the capillary endothelium.
Concerning the half-life of hormones,
-lipid-soluble hormones generally have a longer half-life.
-hormones with a shorter half-life regulate activities with a slow onset and long duration.
-hormones with a shorter half-life are maintained at more constant levels in the blood.
-lipid-soluble hormones are degraded rapidly by enzymes in the circulatory system.
-water-soluble hormones usually combine with plasma proteins.
lipid-soluble hormones generally have a longer half-life.
Given these observations:
(1) A hormone affects only a specific tissue (not all tissues).
(2) A tissue can respond to more than one hormone.
(3) Some tissues respond rapidly to a hormone, whereas others take many hours to respond.
Which of these observations can be explained by the characteristics of hormone receptors?
1
1,2
2,3
1,3
1,2,3
1,2,3
Which of these is not a means by which hormones are eliminated from the circulatory system?
-excreted into urine or bile
-bound to binding proteins
-enzymatically degraded in the blood (metabolism)
-actively transported into cells
-conjugated with sulfate or glucuronic acid
bound to binding proteins
Down-regulation
-produces a decrease in the number of receptors in the target cells.
-produces an increase in target cells’ sensitivity to a hormone.
-is found in target cells that respond to hormones that are maintained at constant levels.
-occurs partly because of an increase in receptor synthesis by the target cell.
-All of these are correct.
produces a decrease in the number of receptors in the target cells.
Activated G proteins can
-cause ion channels to open or close.
-activate adenylate cyclase.
-inhibit the synthesis of cAMP.
-alter the activity of IP3.
-All of these are correct
All of these are correct
Given these events:
(1) GTP is converted to GDP.
(2) The subunit separates from the β and γ units.
(3) GDP is released from the α subunit.
List the order in which the events occur after a hormone binds to a membrane-bound receptor.
1,2,3
1,3,2
2,3,1
3,2,1
3,1,2
3,1,2
Which of these can limit a cell’s response to a hormone?
-phosphodiesterase
-converting GTP to GDP
-decreasing the number of receptors
-blocking binding sites
-All of these are correct.
All of these are correct.
Given these events:
(1) The α subunit of a G protein interacts with Ca2+ channels.
(2) Calcium ions diffuse into the cell.
(3) The α subunit of a G protein is activated.
Choose the arrangement that lists the events in the order they occur after a hormone binds to a receptor on a smooth muscle cell.
1,2,3
1,3,2
2,1,3
3,1,2
3,2,1
3,1,2
Given these events:
(1) cAMP is synthesized.
(2) The α subunit of G protein is activated.
(3) Phosphodiesterase breaks down cAMP.
Choose the arrangement that lists the events in the order they occur after a hormone binds to a receptor.
1,2,3
1,3,2
2,1,3
2,3,1
3,2,1
2,1,3
When a hormone binds to a nuclear receptor,
-DNA produces mRNA.
-G proteins are activated.
-the hormone-receptor complex causes ion channels to open or close.
-the cell’s response is faster than when a hormone binds to a membrane-bound receptor.
-the hormone is usually a large, water-soluble molecule.
DNA produces mRNA.
Given these events:
(1) activation of cAMP
(2) activation of genes
(3) alteration of enzyme activity
Which of these events can occur when a hormone binds to a nuclear hormone receptor?
1
1,2
2,3
1,2,3
2,3
