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139 Cards in this Set

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  • Back
Name the peripheral endocrine glands?
1. Thyroid
2. Adrenal Glands
3. Endocrine Pancreas
4. Parathyroid Glands
Is the Thyroid gland essential? Why or why not?
it is
b/c it controls the body's basal metabolic rate
Function of the Adrenal Glands?
Important for metabolizing nutrients, adapting to stress, maintaining salt balance, some androgens
Function of the Endocrine Pancreas?
Important in metabolizing nutrients
Function of Parathyroid Glands?
Important for Calcium metabolism
Where is the Thyroid gland located?
over the trachea, below the larynx
What is the general structure of the Thyroid gland?
2 lobes of endocrine tissue
How many kinds of cells involved in thyroid? Name them.
1. Follicular cells
2. C cells
Describe, generally, the follicular cells of thyroid gland?
-MAJOR secretory cells
-ring of them encloses inner lumen filled with colloid
Describe, generally, the Colloid of the thyroid gland?
-serves as extracellular storage site of TH (b/c amines and lipophilic, needs to be stored)
-colloid fills inner lumen surrounded by follicular cells
What is TGB?
-a protein
What is the main constituent of the colloid?
thyroglobulin (TGB)
-with TH incorporated into TGB
What do the Follicular cells in thyroid gl. produce?
-T4 and T3, which are collectively known as TH
What is T4?
-tetraiodothyronine or thyroxine
-one of the components of TH
What is T3?
-one of the components of TH
What does TH regulate?
Overall basal metabolic rate
Where are the C cells of the thyroid gland located?
in interstitial space between the follicular cells
What do the C cells secrete and what do they have a role in?
-secrete calcitonin and play a role in calcium metabolism
Name the basic ingredients of Thyroid hormone synthesis?
Tyrosine and Iodine
How is tyrosine obtained for TH synthesis?
synthesized in sufficient amounts in body
How is Iodine obtained for TH synthesis?
-must be obtained by diet
ex) seafood, iodized salt
What does Iodine deficiency cause?
Goiter b/c Thyroid gl. tries to compensate
Where specifically does TH synthesis occur?
On thyroglobulin molecules in the colloid
Describe steps (1-7b) of TH synthesis? (see p. 703 in sherwood)
1. Tyrosine containing TGB produced w/n the thyroid follicular cells is transported into the colloid by exocytosis
2. Iodine is actively transported from the blood into the colloid by the follicular cells
3a. attachment of one I to tyrosine within the TGB mol. yields MIT
3b. Attachment of iodines to tyrosine yields DIT
4a. Coupling of two DITs yields T4
4b. Coupling of one MIT and one DIT yields T3
5. Upon stimulation, the thyroid follicular cells engulf a portion of TGB-containing colloid by phagocytosis
6. Lysosomes attack the engulfed vesicle and split the iodinated products from the TGB
7a. T3 and T4 diffuse into the blood
7b. MIT and DIT are deiodinated, and the freed I is recycled for synthesizing more hormone
Compare T4 to T3?
90% of secreted product is T4
BUT T3 is 4 times more potent
How does T4 become T3?
-most of it is converted OUTSIDE of the thyroid
-T4 loses one of it's iodines in the liver and becomes T3
TH has what kind of effects? What does it essentially oversee?
-metabolic effects
-essentially oversees Oxygen consumption and heat expenditure
What does TH do to the body's overall metabolic rate?
it increases it
What does TH do to the body's use of oxygen?
regulates it
Is TH heat producing or using?
Heat producing (calorigenic)
What tissues are effected by TH?
almost all of them either directly or indirectly
How long does it take to see response and effect of TH?
-it is extremely slow
-long time for response
-even longer before maximum effect is seen
-but sticks around for awhile
Large amounts of secreted TH convert ? into ? and stimulate ??. What kind of effect are these.
-converts glycogen into glucose
-stim.s protein degradation
-they are both metabolic effects and both produce energy
What is a sympathomimetic effect in general?
-one that mimics the SNS
What are the sympathomimetic effects of TH?
TH increases target cells responsiveness to epinephrine and norepinephrine
The sympathomimetic effects of TH (inc. in cell resp. to E and NE) cause what?
-increases in heart rate and the force of heart contraction
-this is the "fight response"
TH stimulates the secretion of what else?
Stimulates GH secretion and promotes the effect that this hormone has on increased protein synthesis
When you think of TH what should you think?
What system regulates the secretion of TH?
the hypothalamus-pituitary-thyroid axis
What is TSH?
Thyroid stimulating hormone
Where is TSH derived from? What does it stimulate?
the anterior pituitary, it stim. the release of TH
Besides stimulating the release of TH what else does TSH do?
-maintains the structural integrity of the thyroid gland.
Describe negative feedback as it involves TH and TSH?
-increased TH feeds back to anterior pituitary to decrease TSH
Okay, TSH stim.s TH...but what stim.s the release of TSH?
TRH from the hypothalamus
Okay, TRH stim.s TSH...but what stim.s the release of TRH?
The ONLY KNOWN factor to increase TRH secretion is exposure to cold in infants.
Quick breakdown of the regulation of TH secretion.
1. Hypothal. activated by cold in infants- releases TRH
2. Anterior pit. stim. by TRH - Releases TSH
3. Thyroid gl. stim. by TSH - releases TH
One of the most common endocrine disorders is what?
Abnormal thyroid function
Two major categories of abnormal thyroid functions?
1. hypothyroidism : deficiency
2. hyperthyroidism: excessive
What does an imbalance in the thyroid hormone cause?
Changes in development
Hypothyroidism in Adults produces what? Explain.
-produces myxedema
-it is an edematous (swelling) condition, resulting in puffy appearance, especially noticeable in the face
Hypothyroidism from birth causes what?
-causes cretinism, characterized by dwarfism and mental retardation
What could cause hypothyroidism?
-too little TH
1. deficiency of TRH, TSH, or TH
2. Deficiency of Iodine in diet
Some general symptoms of hypothyroidism?
1. lowered basal metabolic rate
2. excessive weight gain
3. quick onset of fatigue
Treatment for hypothyroidism?
Replacement therapy with exogenous hormone (or iodine in diet if needed)
What causes Hyperthyroidism?
Grave's Disease usually (autoimmune disease), Causes TSI (thyroid stim. immunoglob.) to be continually stim.
---a tumor could also cause hyperthyroidism
Can thyroid gl. be removed?
4 symptoms of Hyperthyroidism?
1. Elev. metabolic rate (excessive perspiration and poor heat tolerance)
2. Decreased body weight, despite increased appetite and consumption
3. Increased HR
4. Exopthalmos (in Grave's Dis)
What is Exopthalmos?
Bulging eyes seen in Graves Disease
When you think Grave's, you should think of what?
Thyroid Hormone feeds back to where? what does it not feed back to?
feeds back to anterior pit.
but not to thyroid itself
What is a Goiter?
An enlarged thyroid gland
When does a goiter develop?
When the thyroid gland is overstimulated, either by TSI or TSH
Goiter develops when thyroid is overstimulated? Describe the two ways this can happen?
1. Hypothyroidism
2. Hyperthyroidism
How does Hypothyroidism lead to goiter?
b/c it leads to high levels of TSH (which stim.s and maintains the thy. gl)
-TSH acts on the follicular cells to increase their size and number
How does hyperthyroidism lead to goiter?
-ex. grave's disease
-cause TSI (thy. stim. immunoglob.) to bind with TSH receptors and cause continual stimulation
How many adrenal glands do you have?
Where are the Adrenal glands located?
each one is embedded in a capsule of fat on top of each kidney
To have deficiencies what has to be done to the Adrenal glands?
You would have to remove both or have a lack of enzymes in both.
Each Adrenal gland has what two distinct portions?
1. Steroid-secreting Cortex
(outer portion)

2. Catecholamine Secreting Medulla (NE and E)
(Inner portion)
What are Catecholamines?
Norepinephrine and Epinephrine
Adrenal CORTEX has how many different Zones?
Each of the 3 different zones of the adrenal CORTEX secretes what? Name them.
a different family of hormones
1. Mineralocorticoids
2. Glucocorticoids
3. Sex Hormones
Why are Mineralocorticoids essential to life?
Without them you die from shock b/c they maintain plasma levels
Give an example of a Mineralocorticoid?
What do mineralocorticoids influence?
mineral (electrolyte) balance
How does aldosterones secretion (a mineralocorticoid) differ from that of other secretion systems?
it is not a 3 gland chain of command
How do the mineralocorticoids influence mineral (electrolyte) balance?
1. Signal the kidneys (distal tubule and collecting duct) to RETAIN SODIUM (and H2O) and ELIMINATE POTASSIUM
2. Aldosterone secretion is increased by activation of the RENIN-ANGIOTENSIN-ALDOSTERONE system
When the mineralocorticoids cause the kidneys to retain sodium what does this cause?
increases blood volume and pressure
What system secretes the mineralocorticoid aldosterone?
What is the main Glucocorticoid?
What does cortisol secretion by the adrenal cortex stimulate? Give example.
Where does this occur mostly?
ex. the conversion of AAs into Carbohydrates
-occurs mostly in the liver
How do glucocorticoids effect glucose? proteins? lipolysis?
-inhibits glucose uptake
-stimulates protein degradation
-promotes lipolysis

Glucocorticoids play a major role in what?
the adaptation to stress
What is the body's main response to stress? How is it induced?
The body's main response is to increase the conc. of glucose in the blood.
It is induced by noxious stimuli, including physical, chemical, physiologic, psychological, emotional, and social sources.
What kind of system regulates the secretion of cortisol? Name it.
A 3 gland chain of command

Describe briefly the 3 gland chain of command for the secretion of cortisol?
1. Stress/Diurnal rhythm stim. Hypothal - releases CRH
2. CRH stim. anterior pit. - releases ACTH
3. ACTH stim. adrenal cortex - releases cortisol
What is ACTH?
adrenocorticotropic hormone
What is CRH?
corticotropin-releasing hormone
What 2 sex hormones are released by the adrenal cortex?
1. androgens (male)
2. estrogens (female)

(but both produced in both genders)
Main production site of sex hormones is where?
Gonads, NOT the adrenal cortex

(this is why males and females differ on what sex hormone predominates)
Normally, the amount of sex hormone produced by the adrenal cortex is what?
Not enough to produce masculine or feminine features
What is DHEA?
-only androgen secreted by adrenal cortex with any biological importance
-can affect females, but in males it is just overwhelmed by testosterone
How is DHEA important to women?
-if given supplementally it increases lean muscle mass, decreases fat, increases psych. well being and decreases stress
-BUT it also decreases good cholesterol (HDL)
The secretion of DHEA by the ADRENAL CORTEX begins when and peaks when?
begins at puberty and peaks at 25-30
DHEA is what kind of hormone?
DHEA is responsible for what?
-pubic and axillary hair
-enhancing growth spurt
-dev. and maintenance of female sex drive
What controls Androgen secretion?
Abnormal adrenal cortex function could be the result of what two general things?
could be secreting too much or too little of its 3 categories of hormones.
Name a syndrome that is a Primary Hyperaldosteronism?
(assoc. with adrenal cortex)
Conn's Syndrome
What causes Primary hyperaldosteronism?
(Conn's Syndrome)
Its caused by a hypersecreting adrenal tumor made up of aldosterone secreting cells
What are aldosterone secreting cells?
a specific cell in the adrenal cortex
What causes Secondary hyperaldosteronism?
High activity of the renin-angiotensin mechanism (which is due to chronic reduction in blood flow to the kidneys; which may be caused by a narrowing of the renal arteries)
The term difference between primary vs. secondary?
secondary=indirect, some change in a sequence of events
The symptoms for Primary and Secondary Hyperaldosteronism are what?
1. Excessive sodium retention
2. Potassium depletion
3. High blood pressure
What is hypernatremia?
excessive sodium retention
-symptom of hyperaldosteronism
What is hypokalemia?
potassium depletion
-symptom of hyperaldosteronism
In general what is hyperaldosteronism associated with?
adrenal cortex secreting too many aldosterones (ie. mineralocorticoids) (one of the 3 different familys of hormones adrenal cortex secretes)
Name syndrome associated with Excessive Cortisol secretion which occurs when there is an abnormal adrenal cortex function?
Cushing's disease
What causes Cushing's Syndrome? (Excessive Cortisol secretion)
-any of the following
1. increased amounts of CRH or ACTH
2. Adrenal tumors
3. ACTH-secreting tumors elsewhere
What are the main symptoms of excessive cortisol secretion?
excessive gluconeogenesis, resulting from the exaggerated effects of the glucocorticoid
What is gluconeogenesis?
production of glucose
What is CRH?
Cortisol releasing hormone
What is ACTH?
Adrenocorticotropic hormone
Describe 6 symptoms of Cushing Syndrome? (which is associated with excessive cortisol secretion)
1. increased blood glucose at expense of protein breakdown
2. Excess glucose deposited in abdomen, face ("moon face"), shoulder blades ("buffalo hump")
3. Loss of protein leads to muscle wasting and fatigue
4. Blood vessels weaken, due to lack of structural proteins
5. Poor wound healing, due to lack of collagen, a major structural protein
6. weakened skeleton, due to collagen loss
Adrenal androgen hypersecretion is caused by abnormal function of what?
Adrenal cortex
Adrenal androgen hypersecretion produces what?
adrenogenital syndrome
In adrenal androgen hypersecretion what inparicularly is the androgen?
How does adrenal androgen hypersecretion manifests its different effects?
-it depends upon the age and biological sex of the subject
If a question refers to too much DHEA what is it referring too?
Adrenal androgen hypersecretion (which produce adrenogenital syndrome)

ALL interchangeable
How does adrenal androgen hypersecretion (adrenogenital syndrome) manifests in ADULT females?
1. develop male characteristics
2. pattern of body hair, (hirsutism)
3. deepening voice
4. muscular arms and legs
4. smaller breasts
What is hirsutism?
pattern of body hair
How does adrenogenital syndrome manifest itself in NEWBORN females?
1. Male-type external genitalia
2. clitoris enlarges and resembles penis
3. major cause of pseudohermaphroditism condition in which the ovaries are present but external genitalia resembles male
How does adrenogenital syndrome manifest itself in Prepubertal males?
1. Premature development of secondary sexual characteristics
2. deep voice
3. enlarged penis
4. sex drive
5. beard
Progesterone, Aldosterone, Cortisol, DHEA, Testosterone, Estrone, Estradiol, Estriol, Estrogens. What are all of these?
All are steroid hormones
Where are all steroid hormones derived from?
Can a cell produce aldosterone, cortisol, and DHEA?
1. a cell that produces aldosterone cannot produce cortisol or DHEA
2. BUT a cell can produce both cortisol and DHEA
If a cell produces both DHEA and cortisol but has a deficiency in cortisol production what occurs?
the cholesterol in the cell flow moves in the direction of the DHEA
-so increases the DHEA production
If there is a cortisol deficiency causing an increase in DHEA how could you treat it?
-Give exogenous cortisol
-this would give you the needed negative feedback loop
Cortisol's negative feedback loop feeds back to what? What does this cause?
1. Anterior pituitary - so it secretes less ACTH to the adrenal cortex
2. Hypothalamus - so it secretes less CRH to the anterior pituitary
If cortisol is deficient, it causes a surplus of androgen, what does this surplus cause? How can you treat it?
1. the androgen feeds back only to the hypothal. so it inhibits CRH and GnRH, and the lack of GnRH could cause a deficiency in gonad secretion
2. treat with exogenous cortisol
In terms of feedback what does an increase in androgen cause?
-increased neg. feedback to the hypothalamus
-this causes a decrease in GnRH and CRH
-but it also causes an increase in ACTH if there is no cortisol present to give a neg. feedback to ant. pit.
Addison's disease is caused by what?
PRIMARY adrenocortical insufficiency
A primary adrenocortical insufficiency (Addison's disease) is usually what kind of disease? What does it effect?
-It is usually an autoimmune disease
-it affects the whole adrenal cortex
What is deficient in a primary adrenocortical insufficiency?
Aldosterone and Cortisol
Some symptoms of Primary adrenocortical insufficiency (Addison's disease)?
1. potassium retention and sodium depletion
2. poor response to stress
3. hypoglycemia (from the decreased glucose)
4. may be life threatening, b/c aldosterone is essential
Why could addison's disease be life threatening?
Because Aldosterone is essential
When you don't have aldosterone (like in a primary adrenocortical deficiency) what happens?
1. decreased blood pressure
2. decreased bl. vol.
3. hypertension
4. could die w/n weeks if not treated
What does SECONDARY adrenocortical insufficiency result from?
From abnormality of the pituitary or hypothalamus, with insufficient ACTH the result
What is deficient in SECONDARY adrenocortical insufficiency?
ONLY cortisol
-not aldosterone like in primary b/c it is not dependent upon ACTH stimulation
-so you don't have to worry about hypertension