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CHAPTER 13 Lecture:

ENDOCRINE

HUMAN ANATOMY & PHYSIOLOGY II

BIO 212:

Illustrations courtesy of McGraw-Hill.

Dr. Lawrence G. Altman www.LawrenceGAltman.com

2 Endocrine glands release hormones into the internal environment (body fluids). Exocrine glands secrete to the outside environment, through ducts which lead to body surfaces.

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6 STEROID HORMONES

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passes through cell membrane > protein receptor (usually nucleus)> complex activates m-RNA synthesis Result: synthesis of protein Note: steroids in blood bound to protein. Unbound > cell.

STEROID HORMONES

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CONVERSION of ATP into c-AMP

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receptor sites (cell membrane) -activates adenylate cyclase: ATP > c-AMP c-AMP activates protein kinases which phosphorylate proteins causing cell changes.

NON - STEROID HORMONES

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gland A stimultates gland B Product of gland B inhibits activity of gland A.

NEGATIVE FEEDBACK

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CONSTANT FLUCTUATION but

NARROW RANGE

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HORMONES and their TARGET ORGANS

15 PITUITARY GLAND

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17 Hypothalamic control- of peripheral endocrine glands may utilize as many as 3 types of hormones; multiple negative feedback controls (- red circles)

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19 THYROID GLAND

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TRH from the hypothalamus stimulates the anterior pituitary gland to release TSH. TSH stimulates release of thyroid hormones (accompanied by negative feedback to the hypothalamus): reduces TSH & TRH.

REGULATION of THYROID HORMONE SECRETION

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4 small lobes Embedded in the thyroid gland.

PARATHYROID GLANDS

23 Mechanism by which PTH promotes calcium absorption in the small intestine.

24 ACTION of PTH

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ADRENAL GLAND

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ADRENAL CORTEX

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VERY SIMILAR MOLECULAR

STRUCTURES!!

30 Negative Feedback inhibits cortisol

secretion.

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ADRENAL MEDULLA

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INSULIN and GLUCAGON SECRETION

35 HYPOTHALAMUS and STRESS: flight or fight!

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LAST SLIDE