Exam 5 Practice Quiz Flashcards
A hormone is defined as a chemical substance produced by an endocrine cell in response to certain stimuli to cause an effect on a target cell, which in turn causes a change or adjustment in various organ systems in the body.
true
The endocrine system has little to do with homeostasis for processes involved in growth and development, blood pressure, or regulation of ions.
false
There are 4 endocrine signaling pathways that exist. In telecrine signaling, a hormone:
a. Exerts an effect by diffusing to a nearby cell
b. Exerts an effect on the same cell that secreted it
c. Exerts an effect over a long distance via the bloodstream
c
Hormones can be classified according to structure and are synthesized from different parent compounds. Amines are specifically derived from the amino acid:
a. Threonine
b. Tryptophan
c. Tyrosine
d. Phenylalanine
c
For peptide hormones, the structure is usually very similar across species
true
Within a species, peptide hormones have very similar structures and may only differ in a side chain, thus allowing them to weakly act on several types of receptors.
true
For a peptide hormone to be synthesized, the mRNA is translated on ribosomes to form a:
a. Pre-Pro-hormone
b. Pre-hormone
c. Pro-hormone
d. Hormone
a
For steroid, amine and eicosanoid hormones, secretion from a cell is:
a. Fast and occurs through secretory vesicles
b. Fast and occurs through simple transfer through the cell membrane
c. Slow and occurs through secretory vesicles
B
Examples of amine hormones include:
a. Catecholamines, dopamine, and growth hormone
b. Oxytocin, dopamine, and growth hormone
c. Catecholamines, dopamine, and thyroid hormones
d. Oxytocin, dopamine, and prostaglandin
C
Feedback loops can be long, short or ultra-short. An example of a long feedback loop would be feedback from target tissue back to the pituitary/hypothalamus.
t
When a hormone interacts with its target cell, there are several factors that determine the level of response achieved in the target tissue. One of these factors would be number and/or affinity of receptors for that hormone.
t
If less hormone can achieve 50% of the maximal response, then it can be said that sensitivity has:
a. Increased
b. Decreased
c. Stayed the same
A
In up-regulation of a hormone, the number or affinity of receptors increases. Therefore, it can be said that sensitivity of the hormone has:
a. Increased
b. Decreased
c. Stayed the same
A
There are several ways in which a hormone-receptor complex can generate a response in the target cell. In a classic cell membrane receptor system:
a. The response is typically rapid and uses an enzyme system with kinases
b. The response is typically slow and uses an enzyme system with kinases
c. The response is typically rapid and uses a second messenger system
C
Second messenger systems may be coupled to G-proteins and may use the adenylyl cyclase-cAMP system.
t
An example of a hormone response that uses cAMP as its second messenger system is:
a. Thyrotropin-releasing hormone (TRH)
b. Thyroid-stimulating hormone (TSH)
c. Oxytocin
d. Growth-hormone releasing hormone (GHRH)
B
An example of a catalytic hormone receptor system is:
a. Tyrosine kinase
b. Phospholipase C
c. Phospholipase E
A
Insulin and insulin-like-growth-factors (IGF) use this type of tyrosine kinase system:
a. Tyrosine-kinase associated receptor
b. Monomer-type
c. Dimer-type
C
Steroid hormones use intracellular receptor systems and must find their receptor in the cytoplasm or nucleus. Additionally, they must bind:
a. Steroid-binding element (SBE)
b. Steroid-responsive element (SRE)
c. Steroid-like element (SLE)
B
The anterior and posterior lobes of the pituitary gland are derived from different tissue and are functionally different.
t
Examples of neurotransmitters that influence the hypothalamus include dopamine, serotonin and GABA.
t
Control of the adenohypophysis and neurohypophysis occurs via the hypothalamus. For the adenohypophysis, hormones are produced in the hypothalamus, travel down axons, and are released at the end of the neurons.
There are several releasing-hormones produced by the hypothalamus that in turn, cause release of hormones from the anterior lobe of the pituitary. Name 3 of these hormones.
- THYROTROPIN RELEASING HORMONE (TRH)
- CORTICOTROPIN RELEASING HORMONE (CRH)
- GONADOTROPIN RELEASING HORMONE (GnRH)
In response to pulsatile secretions of releasing-hormones from the hypothalamus, these types of cells in the anterior pituitary secrete hormones episodically:
a. Trophic
b. Autocrine
c. Paracrine
d. Pars
A
Name three hormones released by the anterior pituitary.
- GROWTH HORMONE (GH)
- ADENOCROTICOTROPIC HORMONES (ACTH)
- PROLACTIN
Two stimulators of TSH secretion include:
a. Increase in triiodothyronine (T3) and thyroxine (T4)
b. Somatostatin and growth hormone
c. TRH and a decrease in T3
C
ACTH is secreted as a large pre-pro-hormone called:
a. POMC
b. Β-lipotropin
c. Β-endorphin
A
An inhibitor of ACTH secretion can be:
a. A decrease in cortisol
b. Stress
c. TRH
d. ACTH
A
Secretion of FSH and LH are stimulated by:
a. Melatonin
b. Prolactin
c. Pheromones
d. Testosterone
D
A tonic inhibitor of prolactin is:
a. Suckling
b. Dopamine
c. TRH
B
GH secretion peaks:
a. Nocturnally
b. Diurnally
A
The following two factors will stimulate release of GH:
a. Increased glucose, GH
b. Increased FFA, somatostatin
c. Decreased glucose, increased amino acids (AA)
C
Somatomedins are produced in the liver and an example is:
a. Ketones
b. Insulin-like growth factor 1 (IGF-1)
c. Leptin
B
The direct anabolic effects of growth hormone are mediated by somatomedins
t
In addition to the anabolic effects of GH, it also has catabolic effects. An example of a catabolic effect of GH is:
a. Increased lipolysis and release of free fatty acids (FFA)
b. Decreased gluconeogenesis
c. Increased glucose uptake in muscle
d. Increased protein synthesis in muscle
A
Dwarfism can be due to lack of GH.
t
Oxytocin is primarily produced in this portion of the hypothalamus:
a. Supraoptic nuclei
b. Paraventricular nuclei
c. Preoptic nuclei
d. Medial nuclei
B
Hormones produced by the hypothalamus are synthesized as pre-pro-hormones, packaged into vesicles as pro-hormones, and this compound is cleaved off as it travels down the axon to the posterior pituitary:
a. Synaptophysin
b. Pantophysin
c. Nanophysin
d. Neurophysin
D
Oxytocin not only has effects in the female, but also has effects in the male on sperm movement and ejaculation.
t
A stimulator of anti-diuretic hormone (ADH) secretion is:
a. Increased blood pressure
b. Decreased plasma osmolality
c. Increased plasma osmolality
d. Increased blood volume
C
ADH has effects on both the kidney and vascular smooth muscle. In the kidney, ADH will:
a. Cause Na+ reabsorption
b. Decrease water reabsorption
c. Allow expression of aquaporin proteins in the distal convoluted tubules and collecting ducts for reabsorption of water
C
ADH causes dilation in vascular smooth muscle.
false, it causes constriction of blood vessels, meaning it leads to vasoconstriction
The predominant hormone secreted by the follicles of the thyroid gland is:
a. Reverse T3
b. Triiodothyronine (T3)
c. Thyroxine (T4)
C
In the synthesis of thyroid hormones, a tyrosine amino acid attaches to this structure within the follicular cell:
a. Iodine
b. Thyroglobulin
c. Peroxidase
B
How is iodine transported into the follicular cell of the thyroid?
a. Symport
b. Antiport
c. Na+/K+ ATPase
A
Which hormone causes release of thyroid hormones from the thyroid gland?
a. TRH
b. T3
c. T4
d. TSH
D
When a follicular cell is stimulated to release thyroid hormones (T3, T4), these hormones are cleaved from what compound?
a. Monoiodotyrosine
b. Diiodotyrosine
c. Thyroglobulin
d. Peroxidase
C
The biologically active form of thyroid hormone is:
a. T3
b. T4
c. rT3
A
This enzyme is present in many tissues and converts T4 to T3:
a. 5’ deiodinase
b. 5 deiodinase
c. Deiodinase
A
During what condition does rT3 increase?
a. Well-fed state
b. Illness
c. Growth
B
Leptin is produced by adipocytes and helps to:
a. Regulate energy intake by increasing appetite
b. Regulate energy intake by stabilizing appetite
c. Regulate energy intake by decreasing appetite
C
T3 and T4 can circulate as either free hormones (active/available) or bound hormones (not active/not available).
t
Name three of the binding proteins for thyroid hormones.
THYROXINE BINDING GLOBULIN (TBG)
TRANSTHYRETIN
ALBUMIN
Once T3 is produced inside a target cell, it binds to a:
a. Nuclear receptor
b. Cytoplasmic receptor
c. Membrane receptor
A
A major effect of thyroid hormones on metabolism includes:
a. Decreased gut absorption and motility
b. Decreased glucose and protein turnover
c. Decreased lipolysis
d. Increased mobilization of carbohydrates, fat, protein
D
Hyperthyroidism is most commonly seen in:
a. Dogs
b. Horses
c. Cats
C
Glucocorticoid hormones are secreted from this zone of the adrenal cortex:
a. Zona glomerulosa
b. Zona fasciculata
c. Zona reticularis
B
Mineralocorticoid hormones are secreted from this zone of the adrenal cortex:
a. Zona glomerulosa
b. Zona fasciculata
c. Zona reticularis
A
Androgen hormones are released from the adrenal medulla.
An example of an androgen precursor that can be converted to testosterone or estrogen is:
a. Corticosterone
b. Deoxycortisol
c. Dehydroepiandrosterone (DHEA)
C
The precursor for any hormone synthesized in the adrenal cortex is:
a. Corticosterone
b. Pregnenolone
c. Androstenedione
d. Cholesterol
D
This enzyme is under the influence of ACTH in the formation of pregnenolone:
a. Aldosterone synthase
b. 11β-hydroxylase
c. Cholesterol desmolase
d. 21β-hydroxylase
C
Giving exogenous glucocorticoids will suppress production of CRH and ACTH and this suppression will continue for several days even after stopping exogenous administration.
t
Once ACTH binds target cells in the adrenal cortex, this second messenger system is activated:
a. cAMP
b. cGMP
c. Phospholipase C
d. Tyrosine kinase
A
A factor that stimulates cortisol secretion is:
a. Opioids
b. Hypoglycemia
c. Dopamine
d. Exogenous glucocorticoids
B
This protein can bind and transport either cortisol or aldosterone in the blood:
a. Globulin
b. Albumin
c. Transcortin
C
The receptors for glucocorticoids are:
a. On the cell membrane
b. In the cytoplasm
c. In the nucleus
B
A major effect of cortisol on energy metabolism is to:
a. Increase blood glucose concentrations
b. Decrease blood glucose concentrations
c. Decrease appetite
A
The main effect of cortisol on the musculoskeletal system is to increase protein catabolism, bone resorption, and inhibit collagen synthesis.
t
Cortisol will have the following effect on neutrophils:
a. No change
b. Decrease
c. Increase
C
Cortisol will have the following effect on lymphocytes:
a. No change
b. Decrease
c. Increase
B
In the regulation of aldosterone, a decrease in renal perfusion will stimulate release of this enzyme from the kidney:
a. Renin
b. Angiotensin converting enzyme (ACE)
c. Aldosterone synthase
A
Aldosterone targets these areas of the nephron in the kidneys to stimulate reabsorption of Na+:
a. Proximal convoluted tubules and distal convoluted tubules
b. Proximal convoluted tubules and collecting ducts
c. Distal convoluted tubules and collecting ducts
C
Pituitary dependent hyperadrenocorticism very commonly occurs in cats.
no, It occurs more frequently in dogs. In cats, hyperadrenocorticism, also known as Cushing’s syndrome, is relatively rare, and when it does occur, it is more often associated with diabetes mellitus. In cats that do develop hyperadrenocorticism, adrenal-dependent hyperadrenocorticism (caused by an adrenal tumor) is more common than pituitary-dependent forms.
The adrenal medulla is an enlarged specialized sympathetic ganglion that uses what type of receptors?
a. Cholinergic receptors
b. Adrenergic receptors
c. Muscarinic receptors
B
The predominant catecholamine released from the adrenal medulla is norepinephrine.
The predominant catecholamine released from the adrenal medulla is epinephrine (approximately 80%), with a smaller amount of norepinephrine (about 20%).
Epinephrine acts on distant target cells while norepinephrine acts on target cells at point of release.
t
The actions of epinephrine are catabolic; that is, to cause release of glucose and free fatty acids for energy.
t
These cells in the pancreas secrete insulin:
a. Alpha
b. Beta
c. Gamma
d. Delta
B
These cells in the pancreas secrete somatostatin:
a. Alpha
b. Beta
c. Gamma
d. Delta
D
Which type of glucose transporter exists in the pancreas?
a. GLUT 1
b. GLUT 2
c. GLUT 3
d. GLUT 4
B
Oral and intravenous administration of glucose causes a similar response in release of insulin.
False.
Oral administration of glucose causes a greater insulin response than intravenous administration. This is due to the incretin effect, where hormones like GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide) are released from the gut in response to oral glucose, enhancing insulin secretion from the pancreas. This effect is absent with intravenous glucose.
Insulin secretion is decreased by:
a. Amino acids
b. Glucose
c. Fasting
d. Calcium
C
Insulin uses a catalytic receptor system. Specifically, it uses this type:
a. Tyrosine kinase, dimer type
b. Tyrosine kinase, monomer type
c. Tyrosine kinase-associated receptors
d. Guanylyl cyclase
A
The following glucose transporter is insulin-dependent and transports glucose into muscle and fat cells:
a. GLUT 1
b. GLUT 2
c. GLUT 3
d. GLUT 4
D
Insulin causes uptake of AA into muscle (thus decreasing blood AA concentrations) and inhibits breakdown of AA.
t
The overall effect of insulin on the liver is to:
a. Decrease both gluconeogenesis and glycogenolysis
b. Decrease gluconeogenesis and increase glycogenolysis
c. Increase both gluconeogenesis and glycogenolysis
d. Increase gluconeogenesis and decrease glycogenolysis
A
In adipose tissue, insulin will:
a. Promote FFA storage and promote lipolysis
b. Promote FFA storage and inhibit lipolysis
c. Inhibit FFA storage and promote lipolysis
d. Inhibit FFA storage and inhibit lipolysis
B
Insulin has no effect on uptake of minerals such as K+, Mg++, and phosphate.
false
Potassium (K⁺): Insulin stimulates the Na⁺/K⁺-ATPase pump, driving potassium into cells.
Magnesium (Mg²⁺): Insulin facilitates magnesium uptake, although the mechanism is less well understood.
Phosphate: Insulin enhances phosphate transport into cells, often linked with glucose metabolism.
Insulin resistance can be caused by:
a. Increased affinity of insulin for receptors
b. Increased number of insulin receptors
c. Changes in the intracellular action of insulin
C
Insulin resistance can also be caused by other hormones such as epinephrine.
t
A lack of insulin will result in:
a. Hypoglycemia
b. Hyperlipidemia
c. Protein anabolism
d. Weight gain
B
Excess insulin secretion occurs in Type I Diabetes Mellitus.
The following will stimulate glucagon secretion:
a. Hyperglycemia
b. Protein meal
c. Insulin
B
Glucagon uses this receptor system:
a. cAMP
b. cGMP
c. Phospholipase C
d. Tyrosine kinase
A
The overall effect of glucagon is to:
a. Increase blood glucose and decrease blood lipids
b. Decrease blood glucose and increase blood lipids
c. Increase blood glucose and increase blood lipids
d. Decrease blood glucose and decrease blood lipids
C
Glucagon has little to no effect on glucose utilization by peripheral tissues.
t
Somatostatin inhibits both insulin and glucagon.
t
A hormone secreted by adipocytes is:
a. Cholecystokinin
b. Serotonin
c. Cortisol
d. Leptin
D
A role of adiponectin is to:
a. Stimulate glucagon
b. Inhibit leptin
c. Improve insulin sensitivity
C
Of the total Ca in the blood, the majority circulates in this form:
a. Ionized Ca
b. Bound to albumin
c. Complexed to anions
A
Acid-base disturbances can alter the amount of ionized Ca circulating in the bloodstream. In conditions of acidosis:
a. There will be LESS ionized Ca and more Ca bound to albumin
b. There will be MORE ionized Ca and less Ca bound to albumin
B
Absorption of Ca in the intestines is DIRECTLY stimulated by:
a. Calcitonin
b. Parathyroid hormone
c. Vitamin D
C
Both Parathyroid hormone and Vitamin D stimulate Ca reabsorption in the renal tubules of the kidneys.
t
The following hormones will stimulate bone resorption of Ca and P:
a. Calcitonin and Parathyroid hormone
b. Parathyroid hormone and Vitamin D
c. Calcitonin and Vitamin D
B
Phosphate is not only an important component of bones and teeth, but also serves an important role in nutrient metabolism (cAMP, ATP).
t
The most important mechanism of phosphate balance is:
a. Soft tissue storage in muscle
b. Bone remodeling
c. Intestinal absorption
d. Renal tubular excretion
D
A cause of hyperphosphatemia is:
a. Renal failure
b. Excess dietary P with sufficient dietary Ca
c. Hyperparathyroidism
A
While parathyroid hormone stimulates synthesis and release of vitamin D by the kidney, vitamin D feeds back and inhibits release of PTH.
t
PTH uses this receptor system:
a. Phospholipase C
b. cGMP
c. cAMP
d. Tyrosine kinase
C
PTH will have this effect on P reabsorption in the proximal convoluted tubules of the kidney:
a. Stimulate
b. Inhibit
B
Secondary hyperparathyroidism can be caused by:
a. Renal failure
b. Tumor of the parathyroid gland
c. Renal calculi
A
The following is an action of calcitonin:
a. Increase urinary P excretion
b. Stimulate bone resorption
c. Inhibit bone deposition
A
Vitamin D can only increase bone resorption in the presence of PTH.
t
Eicosapentaenoic acid (EPA) is a precursor for eicosanoid synthesis and it is an omega-3 fatty acid.
t
Eicosanoids are synthesized as needed and the fatty acids (EPA or arachidonic acid) are cleaved from the phospholipid membrane by:
a. Phospholipase C
b. Phospholipase A
c. Phospholipase A2
C
Prostaglandins, prostacyclins and thromboxanes are synthesized via this pathway:
a. Lipoxygenase pathway
b. Cyclooxygenase pathway
B
Eicosanoids synthesized from arachidonic acid (omega 6) are pro-inflammatory.
t
Melatonin is produced by the:
a. Pineal gland
b. Pituitary gland
c. Thyroid gland
A
Melatonin is derived from:
a. Dopamine
b. Tyrosine
c. Threonine
d. Tryptophan
D
The secretion of melatonin is stimulated by darkness. Retinal photoreceptors release this compound:
a. Epinephrine
b. Norepinephrine
c. Dopamine
d. Serotonin
B
