Notes

Slide Show

Outline

1	Chemical signals in animals
2	Keywords Reading Ch. 45 Endocrine system Hormone Target cell Neurosecretory cell Steroid Amino acid derived hormone Surface receptors Internal receptors Action of steroids Glucose homeostasis Insulin Glucagon Epinephrine Norepinephrine ACTH
3	Chemical signals outside of organisms Pheromones Prey tracking by rattlesnakes
4	Pheromone A small volatile chemical signal that functions in communication between animals Often in mate attraction
5	Will focus on chemical signals inside organisms Two regulatory systems coordinate internal body functions Nervous system (will deal with in a later lecture) Endocrine system (focus of today’s lecture)
6	Endocrine system definition The internal chemical communication system involving hormones Hormone Chemical signal secreted into body fluids (usually blood) Effective in minute amounts
7	Hormones act on specific target cells in two ways Surface receptors Within target cells (internal receptor)
8	Surface receptor - often amino acid derived hormone
9	Internal receptor - often steroid hormones
10	Action of steroids
11	Two specific examples of hormone action Glucose homeostasis Stress and the adrenal gland
12	Glucose homeostasis Homeostasis = The steady-state physiological condition of the body Glucose = major fuel of cellular respiration Normal blood glucose level = 900 mg/L How is this regulated? First look at when glucose levels are too high
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14	"High blood glucose causes beta..." High blood glucose causes beta cells to release insulin
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17	Summary Beta cells release insulin Insulin causes body cells and liver to take up glucose Glucose levels restored
18	What happens if you need to increase blood glucose?
19	"Low blood glucose causes alpha..." Low blood glucose causes alpha cells to release the hormone glucagon
20	"Glucogon stimulates the liver to..." Glucogon stimulates the liver to break down glycogen releasing glucose
21	Summary Low blood glucose causes alpha cells to release the hormone glucagon Glucogon stimulates the liver to break down glycogen releasing glucose
22	Glucose homeostasis Example of use of amino-acid derived hormones: insulin and glucagon are peptides Surface receptors on target cells
23	Diabetes mellitus Greek = copious urine, honey Type I - autoimmune disorder - cells of pancreas are targeted - no ability to produce insulin - usually occurs during childhood Type II (90%) - reduced responsiveness of target cells or insulin deficiency-usually occurs after age 40
24	Stress and the adrenal gland Short-term response - Epinephrine (adrenaline) and norepinephrine Long-term response - ACTH and corticosteroids
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26	Short-term stress: medulla of the adrenal gland
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28	Some effects of epinephrine and norepinephrine Glycogen broken down to glucose Increased blood pressure, breathing, metabolic rate
29	Example of: Use of neurosecretory cells Amino acid-derived hormones
30	Long-term stress: cortex of the adrenal gland
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32	Corticosteroids (mineral- and gluco- corticoids) released by adrenal cortex Some effects: increased blood volume and blood pressure, breakdown of protein and fats
33	Example of: Interaction between nervous and endocrine systems Use of steroid hormones