Endocrine System I. Introduction A. Hormone - (to arouse or spur on) - defined B. Endocrine vs. exocrine gland C. Difference in this system as compared to others D. Communication system E. Terms: Hypo vs. Hyper F. Blood level - constant (destruction equals production) G. Regulatory action is superimposed on basal genetic metabolic rate H. Chemical nature: steroids and others II. Methods of Study A. Gland removal or X-ray B. Clinical observation of disease followed by autopsy and observation C. Hormone injection followed by observation D. Radioisotope tracings E. Chemical analysis of blood F. Electrode stimulation/inhibition of gland III. Endocrine glands Pituitary Hypothalamus Pineal Thyroid Parathyroid Adrenals Pancreas Ovaries Testes Placenta Stomach (gastrin) Duodenum (Secretin, cholecystokinin) Kidney (renin) IV. Pituitary (hypophysis) A. Introduction 1. Called the "master" gland because it controls other endocrine glands: thyroid, adrenal cortex, gonads 2. Is regulated in turn by hypothalamus by neurosecretions 3. Location: sella turcica 4. Size: 1/2 inch in diameter 5 Embryological origin: anterior lobe - from endoderm in roof of mouth, posterior lobe - from neural ectoderm B. Anterior pituitary (adenohypophysis) controlled by neurosecretions from the hypothalamus, makes neuro-secretory substances or releasing factors
C. Hormones of anterior pituitary 1. Growth Hormone - GH, somatotropin a. Stimulates growth of bone, muscle, organs b. Increase protein synthesis c. Increase fat utilization for energy (keto-genesis) d. (Release of GH under hypothalamic control. SRF (somatotropin releasing factor) via pituitary portal system, stimulus - deletion of cellular proteins) 2. Thyroid Stimulating Hormone - TSH, thyrotrophin a. regulates thyroid function b. (TSH controlled by blood level of thyroid hormone and formation of TRF (thyrotrophin releasing factor) of hypothalamus) 3. Adrenocorticotrophin - ACTH a. controls growth, secretions of adrenal cortex b. (release of ACTH under control of blood level of cortical hormones, these influence CRF (corticotrophin releasing factors) of hypothalamus) 4. Gonadotrophins - control growth and function of gonads a. FSH - development / maturation of tubules and follicles in female, maturation of sperm in males b. LH (females) and ICSH (males) - promotes formation of testosterone in male from interstitial cells, final maturation of
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- Fall '14
- Endocrine System, secondary sex characteristics, Adrenal cortex, blood calcium levels