Endocrine Glands - Secretion & Action of Hormones

254 terms by prissyella

Create a new folder

Advertisement Upgrade to remove ads

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

See More

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

Star this term

You can study starred terms together

NEW! Voice Recording

Create Set