ANHB1102 Lecture 16: Endocrine notes
29 May 2018
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ANHB1102: Endocrine Notes
- Physiological mechanisms allow us to change
constantly to counteract changes in body, to maintain
a constant environment
2 ways:
1) Neural – nerve impulse activates other
neurons/NTs to target cells
2) Endocrine – secrete hormone which
communicate/activate target cells. Endocrine system is
surrounded by blood vessels
Negative feedback = achieve homeostasis
- Hormones bind to receptors on target organ = elicit a response.
- Thus, this achieves level of specificity
- Steroids: bind to intracellular receptors because: steroid hormones can pass through csm and
nuclear membrane
- Peptides: bind to membrane receptors because it cannot pass through csm. Requires 2nd
messengers!!
find more resources at oneclass.com
find more resources at oneclass.com
1) Hormone binds to
receptor
2) 2nd messenger mediation
3) Done by G proteins
RELAY
4) Elicit a response
Eg. G proteins changes Ca2+
concentration, affects function
of enzymes/proteins = elicit a
response
- Steroids can cross biological
membrane easily
- Derived from cholesterol
Eg. Testosterone, cortisol
- Highly lipiphilic thus can pass
csm easily
- NO 2nd MESSENGER REQUIRED
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Physiological mechanisms allow us to change constantly to counteract changes in body, to maintain a constant environment. 2 ways: neurons/nts to target cells communicate/activate target cells. Hormones bind to receptors on target organ = elicit a response. Steroids: bind to intracellular receptors because: steroid hormones can pass through csm and nuclear membrane. Peptides: bind to membrane receptors because it cannot pass through csm. G proteins changes ca2+ concentration, affects function of enzymes/proteins = elicit a response. Highly lipiphilic thus can pass csm easily. Hypothalamus = most important endocrine organ as it controls majority of glands. Hypothalamus release peptide factor which stimulates pituitary gla(cid:374)d (cid:894)(cid:862)(cid:373)aster gla(cid:374)d(cid:863)(cid:895) Anterior and posterior lobes develop from different origins. Neurons (paraventricular and supraoptic nucleus) = magnocellular because it is big. Big because it send axonal projections directly to posterior lobe, and secret hormones from hypothalamus, down projections, directly into bloodstream of posterior pituitary gland. Of hormones in this method = oxytocin and adh.
