Term
| what is the difference between helper and regulator T-cells?W |
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Definition
| helper T-cells activate macrophages and B-cells; regulators prevent auto-immunity |
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Term
| What is the ratio of mature-naive to non mature-naive lymph cells in circulation? |
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Definition
|
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Term
| what is the role of a dendritic cell? |
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Definition
| Presents antigens to T cells |
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Term
| What is the difference between follicular and regular dendritic cells? |
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Definition
| Though these are all antigen-presenting cells, they have different lineages (follicular=mesenchymal vs. hematopoietic). Folliculars are found in follicles of lymphatic tissue (including spleen), regulars are not. |
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Term
| True or false: B cells, microglia, follicular dendritic cells, and epithelioreticular cells are antigen-presenting cells. |
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Definition
| True in that they can process and display antigens, false in that they are not of the same lineage as macrophages/dendritic cells. |
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Term
| What are the two possible products of a hematopoietic stem cell? |
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Definition
| Common myeloid or common lymphoid progenitors |
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Term
| What is the mechanism of B/T cell education? |
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Definition
| If the cell responds to antigen during its education, it undergoes apoptosis. This prevents any cells that would be auto-immune from developing. |
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Term
| What are the subsets of the acid hormones? |
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Definition
1) amino acids - thyroid hormones are aa's (derivatives) but are the exception to the rule that aa hormones are H2O soluble
2) arachidonic acid derivatives (prostaglandins) |
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Term
| what is the alternate name of the pituitary gland? |
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Definition
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Term
| What is the name of the unusual deposits in the pineal gland? |
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Definition
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Term
| What are the names of the cells that release T3/T4 and the names of the cells that release calcitonin in the thyroid? |
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Definition
T3/T4 - principle cells
calcitonin - parafollicular cells |
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Term
| What do D cells of pancreatic islets secret? |
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Definition
|
|
Term
| What are the three zones of the adrenal cortex? |
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Definition
| Zona glomerulosa, zona fasiculata, zona reticularis |
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Term
| What is the function of ganglion cells in the adrenal medulla? |
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Definition
| They modulate the blood vessels of the cortex, to give a neural control over cortex cortisol secretions. |
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Term
| What is the significance of the portal system in the pancreas? |
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Definition
| It allows islet endocrine secretion to influence exocrine secretions |
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Term
| What signal do pancreatic B-islet cells respond to (think molecular) when they release insulin? |
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Definition
| Increased [ATP], caused by energy influx - eg. glucose going through GLUT2 into cell. |
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Term
| What are the primary two cellular reasons a particular cell may develop insulin resistance? |
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Definition
1) diminishing receptor number
2) Defects in post-receptor signalling |
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Term
| why does losing insulin receptors cause a shift in the Km but not the Vmax of the receptors dose-response? |
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Definition
| The cell can reach maximum stimulation when only 10% of its insulin receptors are stimulated. |
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Term
| What must develop for insulin resistance to progress to diabetes type 2? |
|
Definition
|
|
Term
|
Definition
| a gut hormone - causes insulin release! |
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|
Term
| What are the targets of metformin/biguanides? |
|
Definition
| Insulin sensitivity of the liver |
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|
Term
| What are the targets of sulonylureas/meglitinides/incretin mimetics? |
|
Definition
| Insulin secretion of the pancreas |
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|
Term
| What is the target of thiazolidinediones/roglitizone? |
|
Definition
| PPARy - changes insulin sensitivity of the muscles/adipose tissue. |
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|
Term
| Why is lispro absorbed more readily than normal insulin? |
|
Definition
| It is constructed such that it doesn't dimerize, and the monomeric form is absorbed most readily. |
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Term
| What determines the time frame over which an H1c measures blood sugar average levels? |
|
Definition
| The duration of an RBC - about 120 days |
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|
Term
| What are the main mechanisms of diabetes-caused tissue damage? |
|
Definition
| glycosylation (AGE's and cross-links), sorbitol accumulation (eg peripheral neuropathies), oxidative stress, inflammation |
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Term
What are the effects of:
GHRH
TRH
Dopamine
GnRH
Somatostatin
CRH
PRF |
|
Definition
GHRH -> (+) somatotropin (GH)
TRH -> (+) TSH, (+) prolactin
PRF -> (+) prolactin
Dopamine -> (-) prolactin
somatostain -> (-) GH, (-) TSH
GnRH -> (+) LH, (+) FSH
CRH -> (+) ACTH |
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Term
| Why don't starving people produce IGF-1 if GH is anti-insulin? |
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Definition
| insulin stimulates secretion of IGF-1 when GH is present. |
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|
Term
| Which hormones increase GH secretion? |
|
Definition
|
|
Term
| What are two ways to clinically stimulate GH secretion? |
|
Definition
1. exercise
2. insulin-hypoglycemia
NOT GHRH - because the hypothalamus could be non-functional, and you'd get a false negative test! |
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|
Term
|
Definition
| cells lack GH receptors, and thus don't produce IGF-1. |
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|
Term
| Which pituitary hormone would increase concentration if stalk was cut? |
|
Definition
| prolactin - dopamine is major regulator through inhibitory effects |
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Term
|
Definition
|
|
Term
| what is the most common tumor of the pituitary? |
|
Definition
|
|
Term
| Which enzyme forms T3 from T4? Forms reverse T3 from T4? |
|
Definition
| 5'-deiodinase forms T3, 5-deiodinase forms reverse T3. |
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|
Term
| Which T4 deiodinase enzyme is more active during illness, fasting? |
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Definition
| 5-deiodinase; so most T4 is inactivated into reverse T3 instead of being activated to T3 |
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Term
|
Definition
| Antibodies are produced against the TSH receptors - stimulating the thyroid gland to make T3/T4 |
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Term
| What are the main steroid hormones of the zona glomerulosa, fasiculta, reticularis? |
|
Definition
glomerulosa - aldosterone
fasiculata - cortisol (and some corticosterone)
reticularis - DHEA, androstenedione
Note that fasiculata, reticularis have overlapping products |
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Term
| Which hormone causes pubic/axillary hair development? |
|
Definition
|
|
Term
| What is the biochemical/cellular affect of hyperthyroidism? |
|
Definition
| Increased B-adrenergic receptors (greater effects of catecholamines) |
|
|
Term
| what is the target of metyrapone? |
|
Definition
| the final step (11-hydroxylation) of cortisol production -causes acute cortisol deficiency |
|
|
Term
| what is the most important action of cortisol? |
|
Definition
| convert protein -> glycogen |
|
|
Term
| how does cortisol cause increased glycogen storage if it is anti-insulin? |
|
Definition
| It conditions the body to store extra glycogen in times of plenty to be ready for times of stress |
|
|
Term
| how does cortisol decrease insulin sensitivity? |
|
Definition
| Causes insulin receptors to be removed from cell surface |
|
|
Term
| What is the effect of angiotensin II physiologically? |
|
Definition
| It is a vasoconstrictor - increases BP |
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|
Term
| What is the rate-limited step of aldosterone synthesis? |
|
Definition
| cholesterol -> mitochondria, pregnenolone |
|
|
Term
| What three stimuli increase aldosterone secretion? |
|
Definition
1) angiotensin II
2) high [K+]
3) sympathetic nervous system |
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|
Term
| Which steps of aldosterone synthesis are in the mitochondria? |
|
Definition
1) cholesterol (from lipid droplet) to pregnenolone
2) corticosterone to aldosterone |
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|
Term
| What are the three stimuli for renin secretion? What is the main negative stimulus for renin secretion? |
|
Definition
Stimuli - juxtaglomerular cells sense low blood pressure
-macula densa cells (in distal tubule) sense low Na+ because too much reabsorption because low bp
- sympathetic nerve stimulation
Negative - aldosterone |
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|
Term
| What are the two possible blood ion effects of aldosterone? |
|
Definition
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|
Term
What are the effects of cortisol on blood volume?
How are these effects minimized |
|
Definition
At high concentration, it can bind to mineralocorticoid receptors.
Minimized by renal use of 11-B-hydroxysteroid dehydrogenase (converts to cortisone) |
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|
Term
| what will indicate the hypo-pit-adrenal axis is working correctly following metyrapone administration |
|
Definition
| increase in 11-deoxycortisol (precursor to cortisol that accumulates when 11-hydroxylation is blocked and there's no feedback to hypothal, pituitary) |
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|
Term
| Which steroid hormone has the highest fraction of unbound hormone (that we have studied to date)? |
|
Definition
| aldosterone - only ~50% bound |
|
|
Term
| What is the best way to measure active cortisol? |
|
Definition
| Measure urinary cortisol - this will be proportional to UNBOUND cortisol |
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