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100 Cards in this Set
- Front
- Back
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What cells produce Growth hormone and where are they located?
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Somatotrophs in the anterior pituitary
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Does growth hormone act on target cells directly?
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Yes
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What organ does Growth Hormone to stimulate?
What does that organ produce. |
The Pancreas which produces Insulin-like Growth Factors 1 and 2
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What causes the release of Growth Hormone?
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The anterior pituitary receives the signal from the hypothalamus in the form of Growth Hormone Releasing hormone (GHRH)
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What hormone inhibits GH?
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Somatostatsin
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Where is somatostasin produces and what does it counterbalance?
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In the periventricular region of the hypothalamus.
It counter balances GHRH |
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What type of pattern is GH release?
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Pulsatile
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When is the frequency at its highest for GH release?
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During slow wave (Non REM) cycle of sleep
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What are 2 other names for the Non REM cycle?
What happens during this portion of sleep? |
Restorative Sleep and Delta sleep
THe body repairs and stores tissues. "If this party of sleep is missed it gives the greatest feeling of not being well rested." |
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What two aspects of Growth Hormone release are increased during Non REM sleep?
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Both frequency and amplitude of GH concentration increases.
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What is the predominant direct effect of GH?
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To RAISE blood glucose by decreasing the uptake of glucose by tissue types in the body like muscles, fat and the liver.
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How does GH act on the liver to increase blood glucose? (2 ways)
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It stimulates glucose production by promoting the breakdown of glycogen.
It also produces new glucose by gluconeogenesis. |
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How does Growth Hormone act INDIRECTLY in the body?
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Through the regulation of the release of 2 more hormones. IGF 1 and 2
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What are the cells called that produce IGFs 1 and 2?
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Somatomedins in the LIver
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Why were the hormones IGFs 1 and 2 named "insulin-like growth factors?"
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Because they act like insulin to reduce glucose levels in the blood.
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What are the general effects of IGFs on the body?
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-They increase production of visceral tissue.
-They increase production of lean body mass (skeletal tissue) -They increase the linear growth of long bones. |
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How does GH's direct and indirect effects contradict?
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Direct actions are to increase blood glucose levels.
Indirect actions cause a decrease in blood glucose level through IGFs. |
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What effect does GH, IGF-1 and IGF-2 have on the anterior pituitary?
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All three provide negative feedback regulation on the Anterior Pituitary.
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Where is the Thyroid gland located and what is its shape?
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Sits at the base of the neck and shaped like a bow tie.
Composed of 2 lobes with a connecting piece. |
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What comprises the functional unit of the Thyroid Gland?
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Follicular cells and follicles
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What cells synthesize Thyroid Hormone?
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Follicular cells
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Describe the functional unit of the thyroid hormone.
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Follicles.
Lobes of endocrine cells that are surrounding an acellular material. The center of the lobe holds the colloid material. |
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What surrounds the follicular cells of the thyroid gland?
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Capillaries!
The follicles are highly vascularized. |
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What is the function of the colloid?
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Stores thyroid hormones in the midst of a proteinous matrix.
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What is thyroid hormone composed of?
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Tyrosine an Iodine
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What component of thyroid hormone cannot be produced in the body?
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Iodine.
We only get it through our food: SALT!! |
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How does iodine enter the follicular cell? The colloid?
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Iodine is actively pumped into the follicle.
Once inside it moves directly/passively into the colloid. |
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What is tyrosine attached to in the first stages of TH production?
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THYROGLOBULIN
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How does tyrosine get into the colloid?
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exocytosis
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How is tyrosine attached to iodine and where does this happen?
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Iodine attaches to THYROGLOBULIN, which houses the tyrosine.
It takes place in the colloid. |
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Why does iodine stay attached to they thyroglobulin inside the colloid?
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So that it will not diffuse out prematurely.
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What signals for T3 and T4 to be released?
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The thyroid will receive a signal from TSH, which binds to a TSH receptor on the thyroid follicular cell.
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When TSH attaches to receptors on follicular cells, what is the first response?
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The follicular cell will start to endocytose a chunk of the colloid matrix which houses the big TGB proteins.
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How does the follicular cell free up the endocytosed TGB in the vesicles?
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It fuses the vesicles with lysosomes which break the peptide bonds and liberates the contents including T3 and T4
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How does T3 and T4 released from the vesicle get out of the follicular cell?
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T3 and T4 are lipid soluble and they simply float across the membrane.
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Explain to overall production of TH.
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Give 2 examples of conditions that stimulate the release of or inhibit T3 and T4
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-When infants feel cold they increase their amounts of T4 and T3
-Chronic stress will inhibit the production of T3 and T4 |
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What enzyme must a target tissue have to use T4 or T3?
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monoiodinase
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Where is the T3 receptor in the cell?
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It is a nuclear receptor that sits on the promoter region of gene.
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Name some examples of proteins created from T3 acting on the gene.
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-Na/K ATPase pumps
-Gluconeogenic enzymes: -Respiratory enzymes (those in aerobic metabolism) -B adrenergic enzymes -Enhances hepatic glucose production -The breakdown of stored fat and muscle tissue -Metabolic related enzymes and structural proteins -It is PRIMARY determinant of basal metabolic rate |
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What hormone is the primary determinant of basal metabolic rate?
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Thyroid Hormone (T4 and T3)
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Where is Thyroid Hormone absolutely critical?
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Fetal development
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What condition occurs as a result of thyroid hormone deficiency?
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Cretinism: mental retardation, growth delays, short stature, protuberant abdomen, coarse hair, many structural abnormalities and developmental delays
Iodine deficiency in pregnancy. |
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Where are the adrenal glands located?
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On top of the kidneys
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What is the outer layer of the adrenal gland called?
What type of hormones does it produce? |
Adrenal Cortex
Steroid Hormone |
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What is the outermost layer of the adrenal cortex called?
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Zona Glomerulosa
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Where is the Zona Fasciculate?
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The middle layer of the Adrenal Cortex
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What is the innermost layer of the Adrenal cortex called?
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Zona Reticularis
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What are the sex hormones and how much of them are produced in the cortex?
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Testosterone, estrogen, progesteron and different intermediates in the production of these sex hormones
-Only a very small amount is made in the cortex |
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Where are glucocorticoids made?
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In the cortex
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What is the primary glucocorticoid?
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Cortisol, and similar in structure is Cortisone
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What pattern does cortisol follow for activation?
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It follows a diurnal pattern
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How is cortisol released?
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Increases in production of CRH to act on the AP to release ACTH to act on the cortex to release cortisol.
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Where does high levels of cortisol place negative feedback?
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On the hypothalamus and the anterior pituitary
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What is a second condition that causes the release of cortisol?
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Stress
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What affect does cortisol have that can be useful in a stress response?
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Increase blood glucose
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How does cortisol raise blood sugar?
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-Reduces uptake of glucose by the cells
-Decrease uptake of glucose by insulin sensitive tissues -Antagonizes insulin receptors -Acts on the liver to stimulate the production of glucose (gluconeogenesis) -Can break down muscle INHIBITS UPTAKE AND STIMULATES THE LIVER |
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What regions of the body does cortisol not break down subcutaneous fat?
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Face and abdomen
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What is Cushion Syndrome?
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High levels of cortisol
-See moon face a lot of fat on the waist, less on the arms and legs |
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What effects does cortisol have on bone?
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-Interferes with the laying down of new bone
-Interferes with absorption of Ca in GI tract -Excess levels can demineralize and weaken bones and cause osteoporosis like conditions. |
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What effect does cortisol have on NE?
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It helps to set baseline vascular tone so NE can regulate after that.
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How does cortisol effect the immune system?
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It acts as an immuno suppressant and a potent anti-imflammatory
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What is Cushing?
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giving high doses of cortisol
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How does cortisol effect the CNS?
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In appropriate levels it enhances mental acuity. If the levels get to high it can turn acuity to agitation and limited mental acuity.
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what is the primary mineralcorticoid?
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Aldosterone
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Why did mineralcorticoids get their name?
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Named after their effects on sodium and potassium levels
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Where is aldosterone produced?
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Only one place, Zona Glomerulosa!
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What is the effect of aldosterone?
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Tends to increase sodium levels and decrease potassium levels.
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Where is aldosterone's site of action?
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In the kidneys for renal excretion.
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What does the adrenal medulla secrete>?
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Catecholamines
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What is the exocrine function of the pancreas?
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Produces digestive enzymes and releases them on the surface of the duodenum (SI)
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What is the endocrine function of the pancreas?
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to produce 2 hormones, insulin and glucagon.
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Where does the endocrine portion of the pancreas take place?
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Islets of Langerhans
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Which cells secrete glucagon and what is its function?
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Alpha Cells
-Antagonistic to insulin -Maintain the blood glucose level during a fasting state |
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Where is insulin produced and what is its function?
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Beta Cells
-Antagonistic to glucagon -Released at an onset of a meal and when blood glucose starts to rise. -Known as the absorptive state |
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What happens to insulin during fasting?
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We stop producing insulin and we are not taking in glucose
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What do the delta cells secrete?
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Somatostatin
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What is the safe range of Ca++ in the ECF?
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6.6-10.6
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List some possible outputs for CA++
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-Feces, kidney excretion
-taken out of circulation and used to make new bone |
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How does Ca++ get inputed into the system?
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-Absorbed through the gut
-Retained in the kidneys -Resorb or breakdown bone to get a little bit of Ca++ back in the blood |
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What other ionic compound does Ca++ have an affinity for?
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Phosphate
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How does Phosphate interact with Ca++?
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It will bind with Ca++ in plasma and reduce the free Ca++
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What will a rise in phosphate concentration do in the body?
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It will cause a rise in PTH because it will predict that there will be a DROP in Ca plasma conentration.
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What two hormones are responsible for regulating Ca++ in the body?
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-Parathyroid hormone PTH
-Calcitonin |
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Does PTH or Calcitonin have a more profound effect on blood Ca++ levels?
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PTH
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What is PTH's relationship with Calcitonin?
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antagonistic
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The sum of PTHs effect on the body will result in what?
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ELEVATE blood Ca++ levels
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What two mechanisms does bone use to effect Ca++ levels in the body?
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-Osteoblast: break down bone to release Ca++ into the blood
-Osteoclast: build up bone to remove excess calcium in the blood |
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What substance surrounds bone and contributes to plasma Ca++ levels?
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Acellular Matrix surrounds the bone and has Ca Occitate within Ca in the plasma.
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What lies next to the bone cells that acts as a source of Ca for bone or a deposit for Ca once bone has broken down?
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Blood vessels
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List two ways that our body increases its Vitamin D concentration.
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-Through direct sunlight (UV) exposure
-Or consumed dietarily |
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When we consume or produce Vitamin D is it active or inactive?
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Inactive
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How does the body activate Vitamin D?
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First done in the liver and then sent to the kidney.
The PTH regulates the release of Vitamin D in the plasma |
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Does phosphate act directly on the kidneys?
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No, it acts through PTH, which can then act on the kidney.
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What produces and releases Calcitonin?
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Thyroid gland, specifically the Thyroid C cells (parafollicular)
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What is the effect of Calcitonin on the blood?
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It will REDUCE blood Ca++
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How many mechanisms does Calcitonin use to reduce blood Ca++ levels?
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ONE ONLY
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A source of inhibition for calcitonin directly relates to what for the PTH?
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A source of Stimulation for PTH.
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What effect does a rise in phosphate have on PTH and activated Vit D?
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It will activate PTH and cause a rise in activated Vit D in the Kidneys.
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When Ca++ drops, what results can be seen in the body?
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-May see a rise in Phosphate
-A rise in PTH -A drop in Calcitonin _ |
