Sunday, April 12, 2009

Hormones cont'd

Insulin lowers glucose level by:
--promoting cellular uptake of glucose
--slowing glycogen breakdown in liver
--promoting fat storage

Glucagon increases blood glucose levels by:
--stimulating conversion from glycogen to glucose in the liver
--stimulating breakdown of fat and protein into glucose

The hypothalamus receives information from the nervous system and initiates response through the endocrine system.

Attached to the hypothalamus is the pituitary gland composed of the posterior and anterior

Oxytocin induces uterine contractions and the release of milk
--Suckling sends a message to the hypothalamus via the nervous system to release oxytocin, which further stimulates the milk glands
--This is an example of positive feedback, where the stimulus leads to an even greater response
--Antidiuretic hormone enhances water reabsorption in the kidneys

--A hormone can stimulate the release of a series of other hormones, the last of which activates a nonendocrine target cell; this is called a hormone cascade pathway

--A tropic hormone regulates the function of endocrine cells or glands
  • Follicle-stimulating hormone (FSH)
--Nontropic hormones target nonendocrine issues

--Two antagonistic hormones regulate the homeostasis of calcium (Ca2+) in the blood of mammals
  • Parathyroid hormone (PTH) is released by the parathyroid glands
  • Calcitonin is released by the thyroid gland
PTH increases the level of blood Ca
Calcitonin decreases the level of blood Ca

These notes are from Wednesday, April 8th

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