Endocrine (other stuff not just hormones) Flashcards
Explain hypothalamus role in endocrine function.
- Neurons in the hypothalamus make ADH and oxytocin.
- neurons in the hypothalamus produce tropic hormones that regulate anterior pituitary hormones
- neurons in the hypothalamus stimulate adrenal medulla ( sympathetic neurons stimulate cells in adrenal medulla to release EP and NEP).
Which hormones are water soluble?
-Amino acid derivatives
-peptide hormones (small glycoprotein)
(basically everything but steroids, sex hormones and thyroxine and triiodothyronine)
Which hormones are lipid soluble?
-steroid hormones (made from cholesterol)
sex hormones, end in -oid or -one, ad thyroxine and triiodothyronine
Explain the mechanism of water soluble hormones
Membrane bound receptor
1) Bind to receptor on cell membrane (doesn’t enter cell)
2) activates G protein
3) turns on signalling cascade
4) activates many secondary messenger molecules
5) the secondary messengers activate kinases
6) the kinases activate:
- Many of the same enzyme (magnified cellular response - increased production of protein)
- activate many copies of different enzymes (multiple different cellular responses)
- Open and close channels
* *already knows how to make something, just telling it to make it or bring to surface.
Explain the mechanism of lipid soluble hormones (intracellular receptor)
1) Hormone passes through the membrane (simple diffusion) and binds to receptor on nucleus
2) Hormone receptor complex binds to DNA/ gene and triggers transcription
3) produces copy of DNA called mRNA
4) mRNA leaves nucleus to provide instructions for protein synthesis
5) ribosomes translate genetic code in mRNA into strange of new amino acids (proteins)
6) cell has a new structure or can perform a new function
Do hormone carry info?
No they trigger a programmed event
Hormone interaction depends on
Level of circulating hormone, receptor affinity for hormone, # of receptors.
What is down regulation
When hormone levels are high, receptors decrease and cells are less sensitive.
What is up regulation
when hormone levels are low, receptors increase and are more sensitive.
What controls the release?
1) humoral stimuli 2) neural stimuli 3) hormonal stimulation
What is humeral stimuli
Change in blood levels of a nutrient (eg. Hi calcium triggers calcitonin) `
What is neural stimuli
Hypothalamus stimulates release of E/NE, ADH and oxytocin
What is hormonal stimulation
in response to other hormones. eg. Tropic hormones
