Term
| The second most important control system that regulates the body's functions is the endocrine system. What is the MOST important? |
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Definition
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Term
| What are the 3 main functions of hormones? |
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Definition
1. regulate rate of chemical reactions
2. Transport of substances through the membrane
3. cellular growth and secretion |
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Term
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Definition
| a chemical substance secreted into the internal body fluids by one cell or a group of cells and having a physiological control effect on other cells in the body |
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Term
| There are many interrelations between the nervous and endocrine systems. There are at least two glands that secrete their hormones almost entirely in response to neural stimuli. What are they? |
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Definition
| Adrenal medulla and pituitary gland |
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Term
| The _______ is made up of almost all neurons, but is still considered part of the endocrine system. |
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Definition
| Posterior hypophysis (neurohypophysis) |
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Term
| The whole endocrine system is regulated by the ___________, which is part of the _________ (part of the nervous system). |
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Definition
| hypothalamus; diencephalon |
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Term
| Some hormones are local hormones. The important ones are: |
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Definition
| acetylcholine, secretin, and cholecystokinin |
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Term
| What is the center of all cholinergic receptors in the body? |
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Definition
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Term
| What is the function of secretin? |
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Definition
| Released by the duodenal wall and transported in the blood to the pancreas in response to high acidity (chime) in small intestine---> pancreas secretes a HCO3 rich fluid to buffer the acidic environment in the small intestine and liver to secrete bile. |
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Term
| What is the function of cholecystokinin? |
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Definition
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Term
| What is the function of cholecystokinin? |
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Definition
| In the presence of chyme it is released in small intestine and transported to gallbladder (to release bile) and pancreas (to secrete digestive enzymes) |
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Term
| What 2 general hormones affect all, or almost all, of the cells of the body? |
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Definition
| growth hormone and thyroid hormone (t3 & t4) |
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Term
| What 2 general hormones affect all, or almost all, of the cells of the body? |
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Definition
| growth hormone and thyroid hormone |
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Term
A) What controls most of the endocrine glands?
B) What controls the pituitary? |
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Definition
A) The hypophysis (pituitary)
B) The hypothalamus (via feedback mechanisms) |
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Term
| How is hormonal secretion maintained within physiologic range? |
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Definition
| via feedback mechanisms (mainly negative) |
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Term
| What are the 2 parts of the pituitary |
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Definition
| anterior pituitary (adenohypophysis) and posterior pituitary (neurohypophysis) |
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Term
| What hormones does the neurohypophysis release? |
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Definition
| ADH (vasopressin) and oxytocin |
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Term
| What is the function of ADH? |
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Definition
| secreted based on the necessity to maintain homeostatic osmolarity of ~ 300 mOsmol/L. Works on distal tubule and cortical portion of the collecting duct to reabsorb water. |
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Term
| What is the function of oxytocin? |
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Definition
| positive feedback mechanism. Upon uterine contractions oxytocin is released which causes more contractions during labor. Also sucking by the infant during breastfeeding causes spinal nerves to relay message to hypothalamus--> neurohypophysis--> milk "letdown" into subareolar tissue |
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Term
| How is the anterior pituitary (adenohypophysis) connected to the hypothalamus? |
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Definition
| via the hypophyseal portal system |
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Term
| communication b/w the hypothalamus and ______ pituitary is mainly via chemical/hormonal means and communication b/w hypothalamus and ________ pituitary is mainly via nervous system stimulation. |
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Definition
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Term
| the adenohypophysis regulates other glands through the ______ hormones, which are released after stimulation by the _______ hormones |
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Definition
| tropic (tropin); releasing |
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Term
| what hormones does the anterior pituitary release? |
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Definition
TROPIN HORMONES:
ACTH, TSH, FSH, LH
Also hormones that act directly on tissues: GH, prolactin, and melanocyte stimulating hormone) |
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Term
| FSH and LH are known as the ______ hormones. |
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Definition
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Term
| What are tropin hormones? |
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Definition
| hormones that regulate the activity of various other endocrine glands. The release of tropic hormones is controlled by a class of hypothalamic hormones called releasing hormones, produced in the hypothalamus |
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Term
| Where does ACTH (corticotropin) act and what does it do? What hormone is it controlled by? |
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Definition
Acts on adrenal glands (suprarenal) to secrete glucocorticoids (cortisol) and mineralcorticoids (aldosterone)known as corticosteroids.
ACTH is controlled by CRH (corticotropin releasing hormone) |
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Term
| Where does TSH (thyrotropin) act and what does it do? What hormone is it controlled by? |
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Definition
Acts at the thyroid to release T3 and T4.
TSH is controlled by TRH (thyrotropin releasing hormone) |
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Term
| Where does FSH act, what does it do, and what hormone controls it? |
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Definition
| FSH acts at the ovaries to stimulate growth and recruitment of immature follices/eggs. Acts in the testes to stimulate maturation of seminiferous tubules and spermatogenesis. It is controlled by GnRH (gonadotropin releasing hormone) |
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Term
| Where does LH acts, what does it do, what hormone controls it? |
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Definition
| LH acts at the ovaries to secrete estrogen and progesterone. Works at the cells of Leydig in the testes to secrete testosterone. It is controlled by GnRH (gonadotropin releasing hormone) |
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Term
| LH and FSH MUST work together in ___________. |
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Definition
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Term
| what are "releasing hormones" |
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Definition
| A class of hormones produced by the hypothalamus that control the release of tropic hormones |
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Term
| Name the "releasing hormones" |
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Definition
| thyrotropin releasing hormone (TRH), corticotropin releasing hormone (CRH), growth hormone releasing hormone (GHRH), gonadotropin releasing hormone (GnRH), growth hormone inhibitory hormone (GHIH), prolactin inhibitory hormone (PIH) |
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Term
| For most hormones the RELEASING factors are most important, but in the case of _________ the inhibitory factor exerts more control. |
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Definition
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Term
A) Does the hypothalamus control the releasing/inhibitory hormones or the tropic hormones?
B) What about the posterior pituitary? |
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Definition
A) releasing/inhibitory hormones
B)NEITHER, the posterior pituitary releases ADH & oxytocin. The ANTERIOR pituitary releases the tropic hormones |
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Term
A) Does the hypothalamus control the releasing/inhibitory hormones or the tropic hormones?
B) What about the posterior pituitary? |
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Definition
A) releasing/inhibitory hormones
B)NEITHER, the posterior pituitary releases ADH & oxytocin. The ANTERIOR pituitary releases the tropic hormones |
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Term
| between the ant & post. pituitary, which would be more accurately called "glandular"? |
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Definition
The anterior pituitary.
The posterior pituitary is not a gland, per se, it is more of a collection of axons extending from the hypothalamus |
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Term
growth hormone is also known as _________.
What does GH do? |
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Definition
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Term
| What is the function of GH? |
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Definition
1. causes growth of almost ALL tissues in the body capable of growing except brain. After adolescence GH levels diminish.
2. lipolysis (utilization of fat for energy)
3. increase in protein synthesis
4. decreases liver uptake of glucose
5. promotes gluconeogenesis |
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Term
| What controls the rate of secretion of GH (not GHRH or GHIH). |
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Definition
| levels of protein and glucose |
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Term
| what is the most potent stimulator of GH in acute conditions? |
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Definition
| Hypoglycemia. causes decreased uptake of glucose by liver and promotes formation of glucose from non-carbohydrate carbon substrates (gluconeogenesis) |
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Term
| What is the most potent stimulator of GH in chronic conditions? |
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Definition
| decreased protein in cells. causes protein synthesis. |
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Term
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Definition
| An increase in GH levels AFTER epiphyseal plate closure. |
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Term
| How do GH levels in elderly people compare to those of adolescents? |
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Definition
| GH levels are ~25% of that during adolescence |
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Term
| What is the function of Prolactin? |
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Definition
| Stimulate the secretion of milk by the mammary glands (lactation) |
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Term
| What is the function of melanocyte stimulating hormone (MSH)? |
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Definition
| Acts on the proliferation, growth, and maturation of melanocytes in the skin. |
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Term
| T/F. The catecholamines (epinephrine & norepinephrine) are secreted by the adrenal cortex. |
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Definition
| FALSE. They are secreted by the adrenal medulla |
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Term
A) in the CNS, is norepinephrine or epinephrine more commonly released?
B) How about in the adrenal medulla? |
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Definition
A) norepinephrine
B) epinephrine |
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Term
| What causes the adrenal medulla to secrete catecholamines? |
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Definition
| DIRECT neural/nervous stimulation induced by a stressor |
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Term
| What stimulates the adrenal cortex to release its components? |
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Definition
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Term
| Once stimulated by ACTH, What does the adrenal cortex release? |
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Definition
| mineralcorticoids (aldosterone), glucocorticoids (cortisol), and androgens |
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Term
| What is the function of aldosterone? |
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Definition
| reabsorption of Na+ and H2O and excretion of K+ in the distal convoluted tubule. |
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Term
| What is the function of cortisol? |
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Definition
| Depression of immune and inflammatory response, increase release of glucose from cells, also inc. reabsorption of H2O. |
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Term
| What is the function of androgens? |
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Definition
| stimulates testosterone and increases sex drive |
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Term
| What hormones does the thyroid gland secrete? |
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Definition
| thyroid hormones (thyroxine & triiodothyronin), and calcitonin |
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Term
| What is the function of calcitonin? |
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Definition
SMALL role in regulation of calcium. It decreases calcemia by:
inhibition of osteoclast activity in bones and also decreases GI tract absorption of Ca++ |
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Term
| T/F. Thyroid hormone acts on MOST tissues and cells of the body |
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Definition
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Term
| what is the function of thyroid hormone? |
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Definition
1. increase metabolism of fat, protein, and carbs
2. Increases heat production and body temp.
3. Regulates metabolic rate of ALL cells
4. Allows GH to act properly during fetal period |
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Term
| What are the functions of estrogen? |
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Definition
| formation of female sex characteristics, proliferation of endometrium, in high levels will inhibit ovulation-- contraceptives contain estrogen |
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Term
| What is the function of progesterone? |
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Definition
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Term
| gametes are the ______ and ______ |
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Definition
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Term
| T/F. the placenta secretes estrogen and progesterone to maintain pregnancy |
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Definition
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Term
| In the early stages, the placenta secretes _____, which stimulates the secretion of estrogen and progesterone |
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Definition
| human chorionic gonadotropin (HCG) |
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Term
| What is the single most important factor in the regulation of Ca++ in the blood? |
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Definition
| secretion of PTH by the parathyroid gland |
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Term
| What the 3 mechanisms does PTH use to increase calcemia? |
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Definition
1. increases the activity of osteoclasts (destroys bone and releases Ca++ into blood)
2. Increases the reabsortion of Ca++ in the digestive tract
3. Decreases the excretion of Ca++ in the urine |
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Term
| What the 3 mechanisms does PTH use to increase calcemia? |
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Definition
1. increases the activity of osteoclasts (destroys bone and releases Ca++ into blood)
2. Increases the reabsortion of Ca++ in the digestive tract
3. Decreases the excretion of Ca++ in the urine |
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Term
| What 3 things is Ca++ very important for in the body? |
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Definition
| muscle contraction, cardiac function, nerve impulse transmission |
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Term
| T/F. The pancreas involves both endocrine and exocrine functions. |
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Definition
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Term
| What are the exocrine functions of the pancreas? |
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Definition
| Secretion of bicarbonate fluid into duodenum and secretion of digestive enzymes for proteins, carbs, and fats. |
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Term
| Where is the endocrine portion of the pancreas and what is its purpose? |
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Definition
Islets of langerhans. Consists of alpha and beta cells.
Alpha--> glucagon
Beta--> Insulin |
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Term
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Definition
hyperglycemia causes release of insulin by the pancreas. The insulin increases cell permeability to glucose so it can be taken up and also causes the liver to turn excess glucose into glycogen to be stored.
Inhibits gluconeogenesis by inhibiting release of glucagon
Also enhances active transport of amino acids into tissue cells resulting in protein synthesis |
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Term
| Does insulin increase the permeability of ALL cells to glucose? |
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Definition
| No. Neurons and muscle cells during exercise are not dependent on insulin to absorb glucose. |
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Term
| T/F. Insulin is lipogenic. What does this mean? |
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Definition
| TRUE. It causes high cholesterol |
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Term
| where does the body store glycogen? |
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Definition
| In the liver and skeletal muscle (mostly liver) |
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Term
| What happens to excess glucose that can't be stored as glycogen? |
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Definition
| It is stored as fat in the adipose tissue |
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Term
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Definition
It causes conversion of glycogen to glucose in the liver
Increases gluconeogenesis
Activates adipose cell lipase--> increases # of fatty acids available--> inhibits storage of triglycerides in liver. |
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