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Endocrine Physiology and Control Mechanisms
Test 4
117
Physiology
Graduate
07/30/2011

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Term
A communication system which consists of glands that secrete hormones.
Definition
Endocrine System
Term
Name 3 things that make up endocrine glands.
Definition
-Ductless
-Secrete hormones directly into blood
-Signal each other in sequence to form axis
Term
Generally thought of as chemical messengers
Definition
hormones
Term
Highly speciaized organic molecules produced by endocrine organs that exert their actions on specific target cells.
Definition
Hormones
Term
Can a single hormone exert its effects on different tissues or only one?
Definition
Different tissues
Term
Can a single functionbe regulated by more than one hormone?
Definition
Yes
Term
Released by glands or specialized cells into circulating blood and influence the function of target cells at other locations in the body.
Definition
endocrine hormones
Term
Give 3 examples of endocrine hormones
Definition
1. Growth Hormone
2. TSH
3. ACTH
Term
Hormones secreted by neurons in the circulating blood and influence the function of target cells at other locations in the body.
Definition
Neuroendocrine Hormones
Term
Give 3 examples of Neuroendocrine Hormones.
Definition
1. ADH
2. NE
3. Epi
Term
Secreted by cells into the ECF and affect neighboring cells of a different type.
Definition
Paracrines
Term
Give an example of a paracrine hormone
Definition
Sex steroids on the ovary
Term
Secreted by cells into the ECF and affect the function of the same ells that produced them.
Definition
Autocrines
Term
Give an example of an autocrine
Definition
Release of insulin from pancreatic beta cells can inhibit its release from the same cells
Term
Secreted by cells into the ECF and can function as autocrines, paracrines, or endocrine hormones.
Definition
Cytokines
Term
Name 2 cytokines
Definition
Interleukins
Leptin
Term
Name 4 major chemical classes of hormones.
Definition
1. Polypeptides
2. Proteins
3. Steroids
4. Amines
Term
Includes hormones secreted by the hypothalamus, anterior and posterior pituitary gland, the pancreas, thyroid and parathyroid glands, placenta, kidney, heart, stomach, and small intestine and adipocytes.
Definition
Polypeptides and Proteins
Term
Make up most of the hormones in the body and range in size from 3 to 200 amino acids.
Definition
Polypeptides and Proteins
Term
Most are initially synthesized on the ribosomes of the endocrine cells as preprohormones, then cleaved into prohormones in the RER. The prohormones are packaged in the Golgi and converted to hormones.
Definition
Polypeptides and proteins
Term
Can be produced and stored in secretory vesicles and released as needed.
Definition
Polypeptides and proteins
Term
Secreted by the adrenal cortex, testes, ovaries, placenta, and kidneys
Definition
Steroids
Term
Primarily synthesized in the SER of the adrenal cortex cells and gonads
Definition
Steroids
Term
Functions may vary from organic metabolism, to stress response, to sex drive and reproductive development, and Na/K balance.
Definition
Steroids
Term
Can some steroids be a precursor for the production of other hormones?
Definition
yes
Term
All are derived from cholesterold (mostly LDL's) which means they are lipid soluble.
Definition
Steroids
Term
Are steroids stored in the cytosol?
Definition
NO - the diffuse thru the lipid membrane into the intersitial fluid and circulation
Term
Amines are all derivatives of the amino acid what?
Definition
Tyrosine
Term
Includes thyroid hormones, epi, NE, and dopamine
Definition
Amines
Term
Secreted by the adrenal medulla (modified symp ganglion w/no axons) and serve as neurotransmitters for the SNS.
Definition
NE and Epi
Term
Name 3 functions of NE and Epi
Definition
Organic metabolism
Cardiovascular functions
Response to stress
Term
Humans secrete 4X more _ than _ because the adrenal medulla has high levels of PNMT.
Definition
Epi than NE
Term
What does PNMT do?
Definition
Catalyzs conversion of NE to Epi
Term
__ neurons do not express PNMT and only secrete NE
Definition
Sympathetic
Term
Synthesized by the hypothalamus and regulates certain activities of the pituitary gland.
Definition
Dopamine
Term
Name 2 hormones that are produced within seconds of the gland being stimulated and develop full action within another few seconds.
Definition
NE and Epi
Term
Name 2 hormones that may require a few months to get their full effect.
Definition
Thyroxine
GH
Term
Are circulating concentrations that are required to control most metabolic and endocrine functions small or large?
Definition
Incredibly Small
Term
Are the rates of excretion of various hormones small or large?
Definition
Extremely Small
Term
Causes a surge of hormone such as in oxytocin.
Definition
Positive feedback
Term
Prevents overacivity of the hormone systems and are the most common.
Definition
negative feedback
Term
In most instances, precise control of hormone secretion is exerted thru what?
Definition
Negative feedback loops
Term
After a stimulus causes a release of a hormone, conditions or products of its actions tend to suppress the further release of the hormone. This prevents the oversecretion of the hormone or overactivity of the target tissue.
Definition
Negative Feedback
Term
__ __ such as circadian rhythms, seasonal changes, developmental changes, etc. are superimposed on the positive and negative feedback systems.
Definition
Cyclical Variations
Term
Peptides and Catecholamines are __ soluble
Definition
Water
Term
__ __ hormones are dissolved in the plasma and transported to their target tssues, where they diffuse out of the capillaries, into the ECF and ultimately into the cells.
Definition
Water soluble
Term
__ and __ hormones circulate in the blood mainly bound to plasma proteins and remain biologically inactive until they dissociate from the proteins. They serve as a reservoir of hormone.
Definition
Steroid and Thyroid
Term
Name 2 factors that affect the concentration of hormone in the blood
Definition
1. Rate of secretion
2. Metabolic clearance rate
Term
Name 4 ways in which hormones are cleared from the plasma
Definition
1. Metabolically destroyed in blood and tissues
2. Binding with tissue
3. Excretion by liver into bile
4. Excretion by kidneys into urine
Term
The ability of a cell to respond to a hormone depends upon the presence of receptors for that hormone on or in the what?
Definition
Target cell
Term
__ are usually located on the surface of the cell membrane, in the cell cytoplasm, or in the cell nucleus
Definition
Receptors
Term
Do the number of active receptors remain constance from day to day or minute to minute?
Definition
No
Term
__ can be inactivated or destroyed, or they can be reactivated or synthesized from new.
Definition
Receptors
Term
A decrease in the number of receptors for a hormone
Definition
Down-Regulation
Term
An increase in the number of receptors for a hormone
Definition
Up-Regulation
Term
Can results from increased hormone concentration and increased binding with its target cell receptors
Definition
Down-Regulation
Term
Name 5 causes of down-regulation
Definition
1. Inactivation of some receptors
2. Inactivation of some of the intracellular protein signaling molecules
3. Temporary sequestering of the receptor into the cell
4. Destruction of the receptor by lysosomes
5. Decreased production of the receptor
Term
The stimulating hormone induces greater than normal formation of the receptor or intracellular signaling molecules, or greater availability of the receptor for interaction with the hormone
Definition
Up-Regulation
Term
Increases the sensitivity of the tissue to the hormone.
Definition
Up-Regulation
Term
__ hormones increase protein synthesis
Definition
Steroid
Term
__ hormones increase gene transcription
Definition
Thyroid
Term
The adrenal cortex forms the bulk of the endocrine gland and secretes what 3 things?
Definition
Glucocorticoids
Mineralcorticoids
Adrenal Sex hormones
Term
The adrenal cortical function is essential for life. Loss of function is fatal in __ days if untreated.
Definition
4-14
Term
The secretion of glucocorticoids and androgens is controlled by what?
Definition
ACTH
Term
The site of metabolism of the adrenal cortical hormones
Definition
Liver (excreted in urine and bile)
Term
These play an essential role in regulating K and Na levels and water balance.
Definition
Mineralocorticoids
Term
Where are the mineralocorticoids produced within the adrenal cortex?
Definition
Zona glomerulosa (thin layer of cells just under the capsule)
Term
Name 2 mineralocorticoids
Definition
Aldosterone
Corticosterone
Term
This hormone is tightly regulated by the renin-angiotensin mechanism and by blood K levels
Definition
Aldosterone
Term
Where are glucocorticoids synthesized in the adrenal cortex?
Definition
Zona fasciculata
Term
These exhibit important effects that increase blood glucose concentration.
Definition
Glucocorticoids
Term
Blood levels of glucocorticoids are regulated by __ __ mechanisms of the HPA axis.
Definition
Negative feedback
Term
Name a glucocorticoid
Definition
Cortisol
Term
A very potent hormone; has primary action of glucose, protein and fat metabolism, anti-inflammatory actions, psychic effects, and permissive effects.
Definition
Cortisol
Term
Name 5 things that cortisol does.
Definition
1. Stimulation of gluconeogenesis
2. Decreases glucose utilization by cells
3. Reduces protein stores in all body cells but liver
4. Mobilizes fatty acids from adipose tissue
5. Large anti-inflammatory role
Term
How does cortisol stimulate gluconeogenesis?
Definition
Increases the enzymes required to convert amino acids into glucose in liver and causes mobilization of amino acids from the extrahepatic tissues mainly from muscle
Term
How does cortisol reduce protein stores in all body parts but liver?
Definition
Increased catabolism and decreased synthesis
Term
__ is much less potent than corisol
Definition
Corticosterone
Term
__ is almost as potent as cortisol
Definition
Cortisone
Term
__ is synthetic and 4X as potent as cortisol
Definition
Prednisone
Term
__ is stimulated by ACTH from the ant. pit. gland
Definition
Glucocorticoids
Term
Where in the adrenal cortex are androgens synthesized?
Definition
Zona reticularis
Term
Contribute to pubertal growth of body hair, mainly in women.
Definition
Androgens
Term
By the age of 60, levels of this in men decline 1/6 and of 20 y/o
Definition
Androgens
Term
Adrenocortical hormones are degraded mainly where?
Definition
Liver
Term
About 25% of degraded adrenocortical hormones are exreted in what? The remaining are filtered by what?
Definition
Bile and Feces
Kidneys
Term
Name 2 adrenal medullary hormones
Definition
NE
Epi
Term
Name 3 inputs that control hormone secretion
Definition
1. Ions or nutrients
2. Neurotransmitters
3. Hormones
Term
A hormone that controls the secretion of another hormone
Definition
Tropic
Term
The sequence of hormone-hormone signaling
Definition
Axis
Term
Increased ECF K+ ___ aldosterone secretion
Definition
Increases
Term
Increased ECF angiotensin II __ aldosterone secretion
Definition
Increases
Term
Inceased ECF Na slightly __ aldosterone secretion
Definition
Decreases
Term
___ is necessary for aldosterone secretion, but has little effect on the rate of secretion.
Definition
ACTH
Term
Cortisol is stimulated by __
Definition
ACTH
Term
Where does ACTH come from?
Definition
Anterior Pituitary Gland
Term
ACTH is stimulated by what?
Definition
CRH
Term
Where does CRH (cortiotropin releasing hormone) come from?
Definition
Hypothalamus
Term
Walk through the Hypothalamic Pituitary Adrenal (HPA) Axis
Definition
Hypothalamus secretes CRH - This stimulates pituitary to secrete ACTH - This stimulates adrenals to secrete cortisol - Cortisol inhibits CRH and ACTH production (negative feedback)
Term
The secretion of too little hormone
Definition
Hyposecretion
Term
The secretion of too much hormone
Definition
Hypersecretion
Term
Name 2 things that Hypoaldosteronism causes.
Definition
Hyperkalemia
Cardiac Toxicity
Term
Name 3 things that Hyperaldosteronism causes.
Definition
1. Increases ECF volume and arterial pressure
2. Hypokalemia and ms weakness
3. Increases tubular H+ secretion and causes alkalosis
Term
Occurs when the target cells do not respond properly to a hormone (2)
Definition
Hypo/Hyperresponsiveness
Term
Where the primary defect is of the gland; produces too much/little of the hormone
Definition
Primary disorder
Term
Where the primary defect is due to excessive/insufficient stimulation of the gland.
Definition
Secondary disorder
Term
Name 3 ways in which you could have excess cortisol secretion.
Definition
1. Excess secretion from adrenal cortex
2. Excess secretion of ACTH - which increases cortisol secretion
3. Excess secretion of CRH - which increases ACTH secretion - which increases cortisol secretion
Term
The inability of the adrenals to produce sufficient adrenocortical hormones.
Definition
Addison's dz
Term
80% involves autoimmune diorders; Most frequently caused by primary atrophy or injury to the adrenal cortices.
Definition
Addison's dz
Term
Hypersecretion of the adrenal cortex; most of the abnormalities are assoiated with abnormal amounts of cortisol, although excess androgens may also have an effect.
Definition
Cushing's Syndrome
Term
Can be due to adenomas of the anterior pituitary
Definition
Cushing's dz
Term
Can be due to abnoral function of the hypothalamus, ectopic excretion of ACTH from tumor in the body, or adenoma of the adrenal cortex.
Definition
Cushing's syndrome
Term
Primary aldosteronism; where there is overproduction of aldosterone
Definition
Conn's Syndrome
Term
Where you ave excessive quantities of androgens; primarily effects kids; increases development of genitalia.
Definition
Adrenogenital Syndrome
Term
Name 5 ways in which you can test for endocrine disorders.
Definition
1. Blood test
2. Urine test
3. Genetics test
4. Imaging
5. Stimulation and suppresion tests
Term
What would be the primary disorder and secondary disorder in Addison's disease?
Definition
1 - Adrenal Cortex
2 - Pituitary or hypothalamus
Term
Results in adrenal insufficiency and a hyposecretion of cortisol
Definition
Addison's dz
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