Endocrine System II

Endocrine System II - Endocrine System II Anatomy Adrenal...

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Endocrine System II: Anatomy, Adrenal Glands 2 sections to the Adrenal Glands – adrenal cortex (blood flows into this first through the arteries) and medulla (centrally located, blood comes here next so hormones produced in the cortex and carried into the medulla and leave the adrenal glands thru the adrenal vein that drains the medulla) Cortex – 3 zones, the two inner zones (Zona reticularis and Zona fasciculata) produce cortisol and androgens in bulk o The outer zone – Zona glomerulosa produces aldosterone in response to low BP Medulla – produces amines – epinephrine, norephinephrine Steroid Production Pathway Cholesterol Progesterone Aldosterone/Cortisol (in Adrenal Cortex) OR Testosterone/Estradiol (in gonads) Slide 3 – structure of diff steroid structures (be able to differentiate) Steriods are lipid soluble – move through plasma on carrier proteins – detach fr carriers when they reach target cell and cross membrane to enter cell Latch onto receptors either in cytoplasm or nucleus (if receptor is cytoplasmic, it translocates to nucleus, so receptors end up there anyway) Steroid-receptor complex binds to specific area of DNA and activates specific genes. o Receptor protein has ligand binding domain ad DNA-binding domain. o When ligand binds, receptor dimerizes and binds to hormone response element on DNA – activates RNA synthesis. Glucocorticoid Synthesis first stimulated by hypothalamus via stress/circadian rhythms Glucocorticoids cause Gluconeogenesis in liver – creates new glucose from building block of food o Needs to call upon fat reserves – from fat cells o Needs AA reserves – from muscle cells (AA loss from muscle cells – goes to liver to be used in gluconeogenesis Results in increase of blood glucose and liver glycogen. Feedback mechanism inhibits pituitary and hypothalamus – so limits ACTH release Other effects of cortisol in addition to gluconeogenesis Decrease in muscle mass – b/c of loss of AA to liver for gluconeogenesis Decrease in bone formation – b/c Ca2+ and phosphate are stored Decrease in connective tissue – b/c of AA loss to liver o Decreases in muscle, bone, and connective tissue combat growth Facilitates maturation of fetus
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Endocrine System II - Endocrine System II Anatomy Adrenal...

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