How can we help?

You can also find more resources in our Help Center.

254 terms

Endocrine Glands - Secretion & Action of Hormones

STUDY
PLAY
What are ductless & secrete hormones into bloodstream?
Endocrine glands
What do endocrine glands secrete into the bloodstream?
hormones
Where do hormones go?
target cells
What are secreted into blood by specialized neurons?
neurohormones
What are the 2 big categories of hormones?
Polar hormones & nonpolar hormones
What type of hormones are water soluble?
polar hormones
What type of hormones do not pass through the plasma membrane?
polar hormones
What type of hormones must be injected if used as a drug?
polar hormones
What type of hormones are insoluble in water (lipid soluble)?
nonpolar hormones
What type of hormones can enter target cells directly?
nonpolar hormones
What type of hormones include steroids & thyroid hormone?
nonpolar hormones
What type of hormones can be taken orally in pill form?
nonpolar hormones
What are lipids derived from cholesterol?
steroids
What are most water soluble hormones made from?
amino acids
What hormones are derived from tyrosine or tryptophan?
Amine
Amine hormones include:
Norepinephrine, Epinephrine, thyroxine, melatonin, triiodothyronine
What hormones are chains of amino acids?
polypeptide/protein
What are examples of polypeptide/protein hormones? gl
ADH, GH, insulin, oxytocin, glucagon, ACTH, PTH
What are LH, FSH, & TSH?
glycoproteins
What are precursors of hormones (inactive protein containing 1 or more copies of the hormone)?
Prohormones
What are examples of prohormones?
proinsulin & TRH (thyroid releasing hormone)
What are precursors of prohormones?
prehormones
What are examples of prehormones?
preproinsulin
What are examples of hormones that are inactive until activated by target cells?
Thyroxine (T4) is inactive until converted to T3 in target cells
What type of hormones are small enough to wiggle through membrane without the use of 2nd messenger system?
thyroid hormones
Both NS & endocrine system use ___________ to communicate.
chemicals
What is the difference between NTs & hormones?
transport in blood & more diversity of effects in hormone targets
Some ____________ are used as hormones & NTs.
chemicals
What do targets for both NTs & hormones have to have?
specific receptor proteins
2 hormones are ___________- if they work together to produce an effect?
synergistic
What works synergistically to stimulate a greater increase in cardiac heart rate than when working separately?
NE & E
A hormone has ___________ __________ if it enhances responsiveness of a target organ to 2nd hormone.
permissive effect
What is an example of a hormone with permissive effect?
Estrogen enhances the responsiveness of the uterus to progesterone
If the action of 1 hormone inhibits the effect of another, it is __________.
antagonistic
What is an example of hormones with antagonistic effect?
insulin impedes the action of glucagon
Target cell receptors show:
specificity, high affinity, & low capacity for a hormone
Are membrane receptors lipophilic or lipophobic for hormones?
lipophobic (water soluble)
What are examples of membrane receptors?
catecholamines, polypeptides, glycoproteins
Are cytoplasmic receptors lipophilic or lipophobic?
lipophilic (lipid soluble)
What is an example of cytoplasmic receptor?
some steroids
Are nuclear receptors lipophilic or lipophobic?
lipophilic (lipid soluble)
What are examples of nuclear receptors?
some steroids & thyroid hormones
What can diffuse through the lipid bilayer of the plasma membrane and bind to receptors within their target cells?
Lipid soluble hormones
________ _______ hormones detach from its transport protein in the bloodstream and later diffuse into the plasma membrane.
lipid-soluble
What type of hormone binds to and activates receptors within the cell?
lipid-soluble
The activated receptor-hormone complex then alters _____ ______: turns specific genes on or off.
gene expression
As ____ is transcribed, new messenger ____ forms, leaves the nucleus, and enters the cytoplasm where _______ synthesis can occur.
DNA; RNA; protein
The new proteins which are often _______, alter the cell's activity and cause responses to the specific hormone.
enzymes
Hormones that bind to nuclear receptor proteins are ______ hormones that travel in blood attached to ______ ________.
lipid; carrier proteins
The lipid hormones dissociate from ________ to pass thru plasma membrane of _______ cell.
carrier; target
_______ ________ receptors serve as transcription factors when bound to hormone ligands.
Nuclear hormone
Nuclear hormone receptors constitute a "superfamily" composed of ______ family & ______ hormone family.
steroid; thyroid
Nuclear hormone receptors superfamily includes ________ & _______ acid.
Vitamin D; retinoic
What catalyzes reactions?
amplifier enzymes
What is found on membrane & is activated by G protein and coverts ATP to cAMP?
Adenylate cylcase
What is found on membrane & ctyoplasm and is activated by receptor enzymes and NO & converts GTP- to cGMP?
Guanylate cyclase
What is found on membrane activated by G protein and converts membrane phospholipids to IP3?
Phospholipase C
What causes the activation of enzymes that produce the hormone's effect?
Second messengers
What are the second messengers?
Ions (Ca2+), Nucleotides (cAMP, cGMP), Lipids (IP3 inositol triphosphate, DAG diacylglycerol)
These hormones bind to receptors that protrude from the target cell surface since most are not lipid soluble and can't diffuse thru the lipid bilayer of plasma membrane.
amino-acid based hormones
When amino-acid based hormones bind to its receptor it acts as a ___ messenger.
1st
The 1st messenger (hormone) causes the production of a 2nd messenger inside the cell. A common 2nd messenger is ______ which is made from ATP.
cyclic AMP (cAMP)
How do water soluble hormones exert their effects?
1. The hormone (1st messenger) diffuses from blood and binds to its receptor in a target cell's plasma membrane.
2. As a result of binding, a reaction starts inside the cell that converts ATP into cyclic AMP.
3. Cyclic AMP (2nd messenger) causes the activation of several enzymes.
4. Activated enzymes catalyze reactions that produce physiological responses.
5. After a brief time, cAMP is inactivated and the cell's response is turned off.
What mediates effects of many polypeptide & glycoprotein hormones?
Adenylate Cyclase-cAMP
In Adenylate Cyclase-cAMP the hormone binds to receptor causing dissociation of a _______ subunit.
G-protein
G-protein subunit binds to & activates ________, which converts ___ into ____.
adenylate cyclase; ATP; cAMP
cAMP attaches to inhibitory subunit of _______ ______.
protein kinase
_______ ________- phosphorylates enzymes that produce hormone's effects.
protein kinase
cAMP is inactivated by:
phosphodiesterase
What serves as a 2nd messener system for some hormones?
Phospholipase-C-Ca2+
Hormone (____) binds to surface receptor, activates G-protein, which activates __________.
TSH; phospholipase C
Phospholipase C splits a membrane phospholipid into 2nd messengers ___ & ___.
IP3 & DAG
____ diffuses through cytoplasm to ER causing ___ channels to open.
IP3; Ca2+
Ca2+ diffuses into cytoplasm & binds to & activates:
...
What activates protein kinases which phosphorylate enzymes that produce hormone's effects?
Ca2+-Calmodulin
What is located beneath the hypothalamus at base of forebrain?
pituitary gland
The pituitary is structurally & functionally divided into what lobes?
Anterior & posterior lobes
The pituitary gland hangs below hypothalamus by:
...
Which lobe of pituitary produces own hormones controlled by hypothalamus & acts more like a gland?
Anterior lobe
Which lobe of pituitary stores & releases hormones made in hypothalamus?
Posterior
The Anterior pituitary is aka:
adenohypophysis
The posterior pituitary is aka:
neurohypophysis
This gland secretes hormones that act on other endocrine glands:
anterior pituitary
The anterior pituitary secretes ___ hormones that maintain size of targets.
6
High hormone blood levels in anterior pituitary cause target to _______.
hypertrophy
Low hormone blood levels in anterior pituitary cause target to _______.
atrophy
The anterior pituitary secretes hormones that regulate a wide range of bodily activities from _____ to _______.
growth to reproduction
___________ promotes growth, protein synthesis, & movement of amino acids into cells.
Growth hormone (GH)
__________ stimulates thyroid to produce & secrete T4 & T3.
Thyroid stimulating hormone (TSH)
__________ stimulates adrenal cortex to secrete cortisol, aldosterone.
Adrenocorticotrphic hormone (ACTH)
__________ stimulates growth of ovarian follicles & sperm production.
Follicle stimulating hormone (FSH)
_________ causes ovulation & secretion of testosterone in testes.
Luteinizing hormone (LH)
________ stimulates milk production by mammary glands.
Prolactin (PRL)
Axons of hypothalamic neurons called "________ ______" end near capillaries of hypothalamus where they release "_______" into the blood.
neurosecretory cells; neurohormones
Release of anterior pituitary hormones is controlled by hypothalamic _____ & ______ factors & by ________ from levels of target gland hormones.
releasing & inhibitory factors; - feedback
_____ & ______ hormones from hypothalamus are released from axon endings into capillary bed in response to -fb from glands & gonads.
releasing & inhibiting
Secretion of anterior pituitary hormones is stimulated by _______ hormones and suppressed by _______ hormones, both produced by the hypothalamus and by -fb from glands & gonads.
releasing; inhibiting
Hormones are carried by __________________ directly to another capillary bed in anterior pituitary.
hypothalamo-hypophyseal portal system
This direct route of __________________ allows hormones to act quickly on cells of anterior pituitary before they are diluted or destroyed in general circulation.
hypothalmo-hypophyseal portal system
This lobe of pituitary does not synthesize its own hormones just stores & releases.
posterior pituitary
This lobe has axons & axon terminals of more than 10,000 neurosecretory cells found in the hypothalamus.
posterior pituitary
______ _______ arrive at the axon terminal and trigger release of these hormones into the capillaries of the posterior pituitary.
nerve impulses
What 2 hormones are stored & released by posterior pituitary but produced by hypothalamus?
Antidiuretic hormone (ADH) & Oxytocin
What does ADH do?
promotes H2O conservation by kidneys (retain more water)
What does Oxytocin do?
stimulates contractions of uterus during parturition & contractions of mammary gland alveoli for milk-ejection reflex
What gland is found lying on top of each kidney?
adrenal
Each adrenal gland has regions that produce different hormones. What are they called?
the outer (adrenal cortex) & inner (adrenal medulla)
Which region of adrenal gland is controlled by ACTH?
Adrenal cortex
The _______ _______ is made of 3 zones; each of which makes and secretes different hormones.
adrenal cortex
Which zone of the adrenal cortex releases hormones that affect mineral homeostasis; mineralocorticoids.
Outer zone
What's an example of a mineralocorticoid found in outer zone which stimulates kidneys to reabsorb Na+ & secrete K+?
Aldosterone
The middle zone of the adrenal cortex releases hormones called _________ that affect glucose homeostasis.
glucocorticoids
What's an example of a glucocorticoid which inhibits glucose utilization & stimulates gluconeogenesis?
Cortisol
_________ is produced/released during stress.
Cortisol
The inner zone of the adrenal cortex releases ______ (___ ________).
androgens (sex hormones)
What's an example of an androgen?
supplementary sex steroids
What part of adrenal gland synthesizes & secretes 80% Epi & 20% NE?
Adrenal medulla
The adrenal medulla is controlled & activated by ____ (fight or flight).
Sympathetic Nervous System
The hormonal effects of ____ last 10x longer than ____.
Epi; NE
The adrenal medulla is innervated by ______ _____ ______ that are activated during "fight or flight" response.
preganglionic symp fibers
What does the activation of "fight or flight" cause?
Increased resp rate
Increased HR & cardiac output
General vasoconstriction which increases venous return
Glycogenolysis & lipolysis
What does glycogenolysis mean?
breakdown of glycogen stores
What does lipolysis mean?
breakdown of fat for energy
What is the large butterfly shaped gland that is composed of right & left lobes on either side of the trachea located just below larynx called?
thyroid gland
What makes up most of the thyroid gland?
thyroid follicles
Walls of these follicles are made of microscopic sized _______ cells that produce ____ & ____ which set ____ & are needed for growth,development.
follicular; T4 (thyroxine) & T3 (triiodothyronine); BMR (basal metabolic rate)
What are the special hormones of thyroid gland that are nonpolar and can pass through plasma membrane?
T4 & T3
____ is found inside nucleus & can alter genetic expression.
T3
In the absence of sufficient dietary ______, the thyroid cannot make adequate amounts of T4 & T3.
iodide
Low T4 & T3 don't provide -fb & ____ levels go up because ____ is a trophic hormone, high levels of it cause the thyroid gland to grow resulting in a _____.
TSH; TSH; goiter
People with inadequate secretion of T4 & T3 suffer from _________ - results from thyroid gland defect or insufficient ____.
hypothyroidism; TRH (thyroid releasing hormone)
What can ppl with hypothyroidism suffer from:
goiter, low BMR, weight gain, lethargy, cold interolerance, & myxedema (puffy face, hands, feet)
During fetal development hypothyroidism can cause ______ (severe mental retardation).
cretenism
Goiters are also produced by _____ ______.
Grave's Disease
________ is an autoimmune disease where antibodies act like TSH & stimulate thyroid gland to grow & oversecrete(esp T4) = hyperthyroidism.
Grave's Disease
What is characteristic of hyperthyroidism?
exopthalmos (bulging eyes), weight loss, heat intolerance, irritability, HBP & high BMR
What are the 4 glands embedded in lateral lobes of thyroid gland called?
parathyroid glands
PTHWhat do the parathyroid glands secrete?
Parathyroid hormone (PTH)
What is the most important hormone for control of blood Ca2+ levels?
Parathyroid hormones (PTH)
The release of parathyroid hormones is stimulated by _______ _____ ____.
decreased blood Ca2+
Parathyroid hormones act on _____, _____, & ______ to ________ ______ _____ levels.
bones, kidneys, intestines to increase blood Ca2+
The parathyroid hormone acts on bones to increase # & activity of the ________ which help with bone resorption.
osteoclasts
The parathyroid hormone acts on kidneys to slow rate that ___ & ___ are lost from the blood into the urine.
Ca & Mg
The parathyroid hormone acts on intestines to promote formation of hormone ______ that increases rate of Ca, PO, and Mg absorption.
calcitriol
What are the scattered clusters of endocrine cells in pancreas called?
Islets of Langerhans
The Islets of Langerhans contain _____ & _____ cells.
alpha & beta cells
Alpha cels of Islets of Langerhans secrete _______ in response to low blood glucose.
glucagon
Alpha cells of Islets of Langerhans stimulate __________ & _________.
glycogenolysis & lipolysis
The end result of glucagon secretion is to _____ _____ _____.
increase blood glucose
The beta cells of Islets of Langerhans secrete ______ in response to high blood glucose.
insulin
The beta cells of Islets of Langerhans promote entry of ______ into cells (esp ______ cells) by way of ________ transporters.
glucose; muscle; GLUT 4
Beta cells of Islets of Langerhans also convert glucose into _______ & _____.
glycogen; fat
The conversion of glucose into glycogen is aka:
glycogenesis
The conversion of glucose into fat is aka:
lipogenesis
The end result of glycogenesis & lipogenesis is to ______ _____ _______.
decrease blood glucose
What is the pine-cone shaped gland located in basal forebrain near thalamus called?
pineal gland
The pineal gland secretes _________ in response to activity of SCN (suprachiasmatic nucleus)of hypothalamus.
melatonin
_______ contributes to setting the body's biological clock (sleep/wake cycle).
Melatonin
More melatonin is released in _______ and during _____.
darkness; sleep
What is important for immunity & located around trachea below thyroid?
thymus
The thymus produces ______ of immune system & hormones that stimulate them.
T cells (lymphocytes)
What secretes steroid hormones testosterone, estrogen & progesterone?
Gonads (testes & ovaries)
What secretes estrogen, progesterone, hCG, and somatomammotropin?
Placenta
All hormones can be grouped into the following general chemical categories, except:
a. catecholamines (epinephrine 7 norepinephrine)
b. polypeptides and glycoproteins
c. nucleic acids
d. steroids
c. nucleic acids
The steroid hormones
a. are derived from cholesterol
b. are lipid molecules
c. are not water-soluble
d. include the sex hormones & corticosteroids
e. all of these describe steroid hormones
e. all describe steroid hormones
The hormones that contain the element iodine are:
a. triiodothyronine (T3) & tetraiodothyronine (T4)
b. catecholamines (Epi & NE)
c. sex steroids
d. corticosteroids
e. glycoproteins
a. triiodothyronine (T3) & tetraiodothyronine (T4)
Which of the following is not required for a particular chemical, such as a neurotransmitter or hormone to function as a physiological regulator in the body?
a. target cells with specific receptor proteins to which that chemical must bind
b. the chemical must open specific ion channels for the rapid diffusion of ions to occur
c. the chemical-receptor combination must cause a specific sequence of changes in the target cells
d. there must be a mechanism for quickly turning off the action of the chemical
b. the chemical must open specific ion channels for the rapid diffusion of ions to occur
Polypeptide hormones called prohormones:
a. are often derived from prehormones
b. include proinsulin from the endocrine beta cells of the pancreas
c. are usually less active "parent" or precursor molecules
d. are usually longer-chained molecules than those of the active hormone
e. all statements about prohormones are correct
e. all statements about prohormones are correct
Which of the following statements does not describe the synergistic effects of hormones?
a. two or more hormones working together to produce a particular result
b. effects that may be additive or complementary
c. enhancing the activity of a second hormone at a target cell
d. the action of epi & NE on the heart rate
c. enhancing the activity of a second hormone at a target cell
The interaction between which of the following hormone pairs is not an example of the permissive effect of a first hormone for a second hormone?
a. estrogen for prolactin on the mammary glands
b. PTH for vitamin D3 on blood Ca2+ levels
c. estrogen for progesterone on the utuerus
d. all hormone pairs display permissive effects
a. estrogen for prolactin on the mammary glands
The half-life period of most hormones ranges from:
a. seconds to minutes
b. minutes to hours
c. hours to days
d. days to weeks
e. weeks to months
b. minutes to hours
T/F: A list of endocrine glands should include the heart, liver, hypothalamus, kidneys, and adipose tissue
True
T/F: Although these hormones are not steroids, T3 & T4 are small and nonpolar; and thus can be taken orally without being inactivated by enzymes in the digestive tract.
True
T/F: In most respects, the actions of neurotransmitters and hormones on their respective target cells are distinctly different.
False: they are very similar
T/F: After stimulation of their target receptors, hormones do not generally remain the the area and accumulate in the blood.
True
T/F: To help excrete "old" steroid hormones in urine and in bile, the liver must first convert them into more polar, water-soluble metabolites.
True
T/F: A "pharmacological" dose is one that results in an abnormally high concentration of a substance; more than would normally be present in the bloodstream.
True
T/F: The priming effect of hormones may actually decrease the number of receptor proteins in their target cells, thereby causing a phenomenon called downregulation.
False: increase number of receptor proteins.....causing a phenom called upregulation
The receptors for most steroid hormones are found here.
a. within nucleus of target cell
b. within cytoplasm of target cell
c. on outer surface of target plasma membrane
a&b: within nucleus & cytoplasm of target cell
The receptors for thyroid hormone are found here.
a. within nucleus of target cell
b. within cytoplasm of target cell
c. on outer surface of target plasma membrane
a. within nucleus of target cell
The receptors for catecholamine & polypeptide hormones are found here.
a. within nucleus of target cell
b. within cytoplasm of target cell
c. on outer surface of target plasma membrane
c. on outer surface of target plasma membrane
Which statement about thyroxine is false?
a. it is the major hormone secreted by the thyroid gland; and also known as triiodothyronine, or T3
b. About 99.96% of thyroxine is attached to carrier proteins in the plasma and the rest is free or unbound
c. it's carrier protein in the blood is named thyroxine-binding globulin (TBG) with a high affinity for thyroxine
d. it is not the active thyroid hormone within the target cells
a. it is the major hormone secreted by the thyroid gland; and also known as triiodothyronine, or T3
The membrane enzyme that is activated by G-protein subunits to catalyze the synthesis of cAMP as the second messenger of target cells.
What intracellular enzyme is involved w/ 2nd messenger?
a. protein kinase
b. phosphodiesterase
c. adenylate cyclase
c. adenylate cyclase
The normally inactive enzyme that is activated by newly formed cAMP - acting to stimulate the phosphorylation of proteins.
What intracellular enzyme is involed w/ 2nd messenger?
a. protein kinase
b. phosphodiesterase
c. adenylate cyclase
a. protein kinase
The enzyme that inactivates the 2nd messenger cAMP by hydr.olyzing it into useless fragments.
What intracellular enzyme is involved w/ 2nd messenger?
a. protein kinase
b. phosphodiesterase
c. adenylate cyclase
b. phosphodiesterase
Which of the following does not describe calmodulin?
a. it is a protein found in the cytoplasm of specific target cells
b. it activates transcription and directs the formation of new proteins in the target cells
c. it is activated by Ca2+ entering the cytoplasm from the ER or from outside the cell
d. it activates specific protein kinase enzymes that phosphorylate other proteins to affect target cell activity
e. it is activated by the hormone insulin in adipose cells to direct the synthesis of fat
b. it activates transcription and directs the formation of new proteins in the target cells
T/F: Hormones are delivered by the circulation of blood to every cell in the body but only the target cells with receptor proteins specifically able to bind to that hormone are able to respond.
True
T/F: Hormones bind to receptor proteins with high capaciy (receptors per target cell) and low affinity (bond strength).
False: low capacity; high affinity
T/F: Because they are polar and thus water-soluble, most steroid and thyroid hormones are transproted in the blood stream bound to large plasma carrier proteins.
False: non-polar
T/F: Each nuclear hormone receptor molecule has a DNA-binding region or domain that must bind to a hormone-response element on the DNA molecule before the hormone response can occur.
True
T/F: The receptors for all lipophilic steroid & thyroid hormones are located in the cytoplasm and from there are translocated into the nucleus for expression of the hormone ligand.
False: some are already located in nucleus
T/F: Cyclic AMP activates previously inactive protein kinase enzymes to modulate the activity of other enzymes already present in the target cell.
True
T/F: Calcium ions (Ca2+) may act as second messengers inside the cell where active transport membrane pumps maintain very high intracellular calcium ion concentrations.
False: low intracellular calcium ion concentrations
T/F: Two different hormones can act on the same targer cell, in which one activates cAMP production as a second messenger while the other activates the phospholipase C-IP3-Ca2+-calmodulin system.
True
T/F: In the case of insulin and the many kinds of growth factors, the receptor protein is located in the plasma membrane and is itself a kind of enzyme known as tyrosine kinase.
True
T/F: Tyrosine kinase is both a receptor and an enzyme that adds a phosphate group to proteins and can thereby initiate a hormone response.
True
T/F: The synthesis of glycogen from glucse (glycogenesis) in liver cells is stimulated by cAMP second messengers whereas the opposite -- the breakdown of glycogen and secretion of glucose (glycogenolysis) -- is mediated by tyrosine kinase second messengers.
False: stimulated by tyrosine kinase; mediated by cAMP
Which of the following is not considered part of the adenohypophysis, or anterior pituitary gland?
a. pars distalis
b. pars nervos tuberalis
c. pars tuberalis
d. pars intermedia
e. all are parts of ant pit
b. pars nervosa
Which of the following is not a feature characteristic of the anterior pituitary?
a. it synthesizes and releases tropic hormones that can regulate other endocrine glands
b. it is controlled by releasing and inhibiting hormones from the hypothalamus
c. it serves as part of the hypothalamo-hypophyseal tract
d. its hormones may influce other endocrine glands
c. it serves as part of the hypothalamo-hypophyseal tract
A rare classic positive fb effect is demonstrated by:
a. increased TSH productin during goiter
b. increased estradiol, causing the LH "surge" in females
c. increased GnRH and FSH following castration in males
d. increased ACTH, causing increased cortisol secretion
b. increased estradiol, causing the LH "surge" in females
T/F: The anterior pituitary develops as a downgrowth of the brain (hypothalamus), while the posterior pituitary is derived from embryonic epithelium (Rathke's pouch)
False: posterior pit develops as downgrowth of brain; anterior pit derived from embryonic epithelium
T/F: The anteiror lobe of the pituitary is more a storage organ for hormones rather than a true gland.
False: posterior lobe
T/F: The hypothalamus rather than the anterior pituitary may be considered the true "master gland' in the body.
True
T/F: Anterior pituitary secretion of ACTH, TSH, and the gonadotropins (FSH & LH) is controlled by -fb loops from hormones produced and released by their target cells.
True
T/F: Tward the middle of the female menstrual cycle, rising levels of estradiol cause a temporary "surge" in the blood levels of LH that results in ovulation - a unique example of pos fb control of target gland secretion.
True
Which of the statements about the adrenal cortex is fase?
a. it is derived from mesoderm tissue in the embryo
b. it can be stimulated by the hormone ACTH (secreted by the anterior pit gland)
c. it secretes catecholamine hormones -- mostly epi
d. it is divided into 3 zones - outer, middle, inner -- that appear to have different functions
e. all statements about adrenal cortex are true
c. it secretes catecholamine hormones -- mostly epi
Which of the following hormones are not secreted by the adrenal cortex?
a. aldosterone & other minerlocorticoids
b. sex steroids: weak androgens and some estrogens
c. hydrocortisone and other glucocorticoids
d. epi & some NE catecholamines
e. all are secreted by adrenal cortex
d. epi & some NE catecholamines
Which statement about the hormone aldosterone is false?
a. it is the most potent adrenal glucocorticoid hormone
b. it is secreted by the zona glomerulosa region of adrenal cortex
c. its secretion is controlled by alterations in blood volume and electrolyte balance
d. its lack in addison's disease may lead to electrolyte imbalance, dehydration, and death, if not treated
e. all statements about aldosterone are true
a. it is the most potent adrenal glucocorticoid hormone
Which function of glucocorticoids (such as hydrocortisone), is best releated to the suggestion that prolonged stress results in an increased incidence of cancer and other diseases?
a. they stimulate an increase in heart rate and in cardiac output
b. they cause generalized vasoconstriction that elevates blood pressure
c. they stimulate the secretion of aldosterone hormones that regulates bld volume and electrolyte balance
d. they can inhibit the ability of the immune system to protect against disease
e. all statements are true
d. they can inhibit the ability of the immune system to protect against disease
T/F: The adrenal medulla is derived from embryonic mesoderm, whereas the adrena medulla is derived from embryonic ectoderm (neural) tissue.
False: cortex derived from emb mesoderm; medulla derived from emb ectoderm (neural)
T/F: The tree functional categories of steroid hormones secreted by the adrenal cortex are the sex steroids, the glucocorticoids, and the mineralcorticoids.
True
T/F: The anatomy of the adrenal medulla reveals 3 distinct zones that contain cells responsible for the synthesis of specific hormones.
False: cortex has 3 zones
T/F: Cortisol (hydrocortisone) in humans is the predominant glucocorticoid hormone secreted by the adrenal cortex.
True
T/F: Glucocorticoids are often taken as pills, inj's, sprays, & topical creams to suppress the immune response (asthma) and to inhibit inflammation (arthritis).
True
T/F: The adrenal medulla receives stimulation from preganglionic sympathetic axons resulting in the release of epi & NE hormones during "fight or flight" responses.
True
T/F: Under stressful conditions, there is increased secretion of ACTH and, thus, increased secretion of adrenal corticosteroids.
True
T/F: Many pleasant life changes such as marriage, graduation, or job promotin can be forms of "stress" -- activating the pituitary-adrenal axis and causing an increase in the secretions of ACTH & corticosteroids.
True
T/F: Hormones are secreted from the adrenal medulla are expected to increase cardiac rate and cardiac output, resp rate, & other major functions
True
T/F: Pheochromocytoma is a tumor of the adrenal cortex, releasing large quantities of epi & NE.
False: tumor of adrenal medulla
T/F: People under chronic stress release higher levels of cortisol that not only increases their risk ofillness but also appears to shrink memory areas of the brain (hippocampus) and may contribute to anxiety & depression.
True
Which statement about thyroid hormones is false?
a. thyroxine is synthesized by simple cuboidal epithelial cells called follicular cells
b. the name, thyroxine, includes both the hormones T4 & T3.
c. Calcitonin is a hormone produced by parafollicular cells located outside & between follicles
d. Thyroxine is ultimately formed from the precursor amino acid called tyrosine
e. Thyroxine is vital for normal CNS development & regulation of energy utilization by the body.
b. The name, thyroxine, includes both the hormones T4 & T3.
The abnormal growth of the thyroid gland, called goiter, is:
a. caused by the over secretion of thyroxine
b. by abnormally high levels of TSH secretion
c. successfully treated with radiactively labeled iodine
d. by abnormally low levels of TRH secretion
b. by abnormally high levels of TSH secretion
Which statement about the parathyroid glands is false?
a. they usually include 4 sm, paired glands
b. they are embedded in the post surfaces of the lat lobes of thyroid gland
c. they secrete only one hormones called PTH
d. PTH acts on tissues such as bone, kidney, & intestines to raise the levels of calcium in bld
e. all statements regarding parathyroid glands true
e. all statements true
T/F: They thyroid is the largest of the endocrine glands, weighing between 20-25 grams.
True
T/F: BMR can be defined as the minimum # of calories burned or expended by the body each hour just to stay alive.
True
T/F: Bld concentrations of calcium are lowered by the hormone calcitonin (thyrocalcitonin) secreted from parafollicular cells of the thyroid gland.
True
T/F: The nutrient required in the diet for the normal synthesis of the hormone thyroxine is iron.
False: iodine
T/F: One of thehallmark features of ppl suffering from hyperthyroidism is their intolerance to cold.
False: heat
T/F: Undersecretion of thyroxine (hypothyroidism) in infants results in myxedema, whereas hypothyroidism in adults causes cretinism.
False: adults myxedema; infants cretinism
T/F: Graves' disease, or toxic goiter, is an autoimmune disease in which antibodies are made that function like TSH, resulting in over stimulation of the thyroid gland.
True
T/F: The parafollicular cells of the thyroid gland secrete the hormone calcitonin.
True
T/F: There are usually four parathyroid glands embedded in the posterior surfaces of the lateral lobes of the thyroid gland.
True
Which statement about glucagon is false?
a. It is a hormone secreted by alpha cells within the islets of langerhans of the pancreas
b. it is a hormone secreted when bld glucose levels are low
c. as a hormone it stimulates both glycogen breakdown (glycogenolysis) and fat breakdown (lipolysis)
d. it is a hormone that is secreted during times of fasting
e. all statements are true
e. all statements true
Which statement about DM is false?
a. It is characterized by fasting hyperglycemia and the presence of glucose in theurine
b. Type I, or ins-dep diabetes is the more common form
c. Type II, or non-ins dep diabetes is caused by decreased tissue sensitivity to insulin so that more is required for normal effect
d. Type I diabetes is caused by the destruction of beta cells that produce insulin
e. both types of DM are associated with abnormally high levels of glucagon secretion from the alpha cells of the islets of langerhans
b.
The hormone, insulin
a. is secreted by alpha cells of the pancreas
b. promotes the entry of glucose and amino acids into tissue cells
c. promotes the breakdown of glycogen (glycogenolysis) and fat (lipolysis)
d. levels fall immediately after a meal is eaten
b. promotes the entry of glucose and amino acids into tissue cells
Which statement about melatonin is false?
a. it is secreted by the pineal gland, a small, cone-shaped gland located in the roof of the 3rd ventricle
b. its secretion is highest in children aged 1-7 yrs and decreases thereafter
c. it may have an important role in the onset of pubert
d. more melatonin is secreted in the daytime than at ight
d
Which statement about the testes is false?
a. the seminiferous tubules produce sperm, the male gamete
b. the interstitial tissue (leydig) cells secrete the primary androgen, testosterone
c. testosterone is needed for the development of the male sex accessory organs, that include the prostate, seminal vesicles, epididymis, and ductus deferns
d. testosterone is required for the development of male secondary sexual characteristics
e. all statements true
e. all true
During the menstrual cycle in females
a. the hormone, progesterone is secreted by ovarian follicles
b. many follicles within the ovary will undergo ovulation each month
c. luteinizing hormone converts the empty follicle into a corpus luteum, which secretes progesterone and estradiol
d. that critical even, ovulation, occurs near the end of the cycle
c. LH converts empty follicle into a corpus luteum, which secretes progesterone and estradiol
Which hormone is not secreted by the endocrine tissues of the human placenta?
a. prolactin
b. estrogens
c. progesterone
d. human chorionic gonadotropin (hCG)
e. somatommotropin
a. prolactin
T/F: After a meal, glucagon secretion is increased and insulin secretion is decreased -- an example of antagonistic action between these two hormones.
False: insulin secrettion increased; glucagon decreased
T/F: The pineal gland is both an endocrine and an exocrine gland.
False: pancreas
T/F: After the age of 7, the pineal gland begins to shrink and in an adult appears as a thickened strand of firous tissue.
True
T/F: During the daytime, light stimulates the release of a newly found pigment in the regina called melanopsin that activates neurons to the suprachiasmatic nucleus (SCN) of the hypothalamus that in turn reduces sympathetic stimulation of the pineal gland and thereby reduces melatonin secretion.
True
T/F: The hormone melatonin may inhibit the pituitary-gonad axis in some species, and perhaps, be associated with a delay in the onset of reproductive maturity.
True
T/F: After puberty, the thymus gland continues to shrink in size and reduce its secretions.
True
T/F: The thymus gland serves as the site for production of B-type lymphocytes (B-cell) that are involved in cell-mediated immunity.
False: T-type lymphocytes (T-cells)
T/F: Both the stomach and sm intestine secrete a number of hormones that act both locally on the GI tract itself and remotely on tissues of the pancreas and GB.
True
T/F: Somatommatropin is a hormone secreted by the placenta that is similar in its action to both growth hormone and prolactin.
True
Many hormones become active only after conversion from less active precursors called ____(pre/pro) hormones; whereas ____(pre/pro) hormones are inactive until activated by the target cells. The overall effects of hormones depend on their ________ where pharmacological doses are abnormally ____(high/low).
pro; pre; concentration; high
Interaction between different hormones are described as __________, _________, or ________.
permissive, synergestic, antagonistic
Steroid and thyroid hormones ___(do/don't) enter their target cells, whereas amine, polypeptide, and ________ hormones ____(do/don't) enter the target cells. Receptors for thyroid hormones are located in the _____, steroid hormone receptors are usually located in the _____ or the nucleus with protein-derived hormone receptors located in the __________.
do; glycoprotein; don't; nucleus; cytoplasm; membrane
Many protein-derived hormones activate second messengers such as _____, _____, _____, or _____ to carry out the action of the hormone.
cyclicAMP, cyclic GMP, or Ca2+
List the 8 pituitary hormones:
GH, TSH, ACTH, FSH, LH, Prolactin, ADH, & Oxytocin
6 of the 8 are from the ______ pituitary and are controlled by releasing hormones from the ______, which flow along the hypothalamo-hypophyseal ______ system.
anterior; hypothalamus; portal