Endocrine Flashcards
Hypothalamus and Pituitary secretions
Post pituitary - secretes directly to post pit which flows directly to blood (ADH and Oxy)
Ant Pit - Hypothalamus to Hypothalmic - hypophyseal portal veins to tropic cells which stim release of hormones to blood
Draw Overall hormone flow chart
On paper
What controls concentration of Free hormone
Rate of secretion is primary determinant
Degradation is at constant rate and is not regulated nor responsible for normal fluctuations
Dose threshold curve
SD50 is concentration of hormone that elicits half maximal response
Threshold is the minimum amount of hormone that produces a response
Sensitivity and effect on dosage curve
Decreased sensitivity shifts curve to the right, this effect can be overcome with concentration. Due to decreased receptors, affinity, increased degradation
Capacity and dosage curve
Decreased capacity will decrease maximal response and cannot be overcome with more H.
This is caused by a decrease in reacting cells or substrate available
Somatotrophs
Secretes GH
Thyrotrophs
Secrete TSH
Corticotrophs
Secrete ACTH
Lactotropes
Secretes PRL
Gonadotrophs
Secrete FSH and LH
Glycoprotein family
2 subunits: alpha is conserved and beta unique
FSH, LH, TSH
Somatomammotropin family
GH and PRL
POMC family
Single gene and CRH cleaves product to what is needed
ACTH
Hypo-Pit GH axis
GH stim by GHRH and in turn stims IGF 1
GH and IGF-1 stim Somatostatin to inhib GH secretion. They also neg feedback on GHRH and GH
Direct effects of GH
Increases IGF-1
Increases lipolysis by adipocytes
Inhibits glucose uptake
Indirect effects of GH
Through IGF 1, Induces skl growth through proliferation of chondrocytes and osteoblast proginator
Increases AA uptake and protein synth
Insulin like activity
Which zone of adrenal gland produces what hormones
ZG - mineralcorticoids (Aldosterone)
ZF - glucocorticoids (cortisol)
ZR - Androgens (DHEA and androstenedione)
Medulla - Epi
Blood flow of adrenal glands
Cortisol is secreted in artery in cortex which then flows to medulla to influence chromaffin cells and therefore epi secretion
Draw Steroidgenic adrenal pathway
On paper
Role of star
Steroidgenic acute regulatory protein transports chol to inner mito membrane to be altered by P450 scc
Actions of ACTH on adrenocorticol cells
Binds to receptor activating cAMP pathway
Increases hydrolysis of chol esters, increases star protein, increases growth and proliferation of ZF and ZR, increases steroidgenic enzymes (LDL-R and p450s)
Biological effects of Cortisol
- Carbohydrate, protein, and fat intermediary metabolism ie increases their blood levels by appropriate mechanisms
- Protective during acute stress: increases raw materials for correct response
- Anti-inflamm and immunosuppressive - via glucocorticoids and blocks all steps in inflamm pathway
- Permissive for other hormones by enhancing their effects
Chromaffin cells
Modified SNS ganglion