Introduction to the Endocrine System 7

Simple Endocrine Reflex: Parathyroid Hormone Figure 7-10

Neurohormones: Major Groups Adrenal medulla Catecholamines Hypothalamus Anterior pituitary Posterior pituitary

The Pituitary Gland Anatomy Figure 7-11

The Pituitary Gland: Two Fused Posterior pituitary Vasopressin Oxytocin Figure 7-12 (1 of 4)

The Pituitary Gland: Two Fused Figure 7-12 (2 of 4)

The Pituitary Gland: Two Fused Figure 7-12 (3 of 4)

The Pituitary Gland: Two Fused Figure 7-12 (4 of 4)

The Pituitary Gland: Two Fused Figure 7-12

The Pituitary Gland: Two Fused Hormones of the hypothalamic-anterior pituitary pathway Figure 7-13

Endocrine Control Three levels Hypothalamic stimulation—from CNS Pituitary stimulation—from hypothalamic trophic hormones Endocrine gland stimulation—from pituitary trophic hormones

Negative Feedback Controls Long-loop feedback Short-loop feedback Figure 7-14

Control Pathway for Cortisol Secretion Figure 7-15

The Hypothalamic-Hypophyseal Portal System Figure 7-16

A Complex Endocrine Pathway PLAY Animation: Endocrine System: The Hypothalamic-Pituitary Axis Figure 7-17

Hormone Interactions Synergism Permissiveness Antagonism Multiple stimuli—more than additive Permissiveness Need second hormone to get full expression Antagonism Glucagons opposes insulin

Example of Synergism Figure 7-18

Endocrine Pathologies Exogenous medication Replaces and exceeds normal Cause atrophy of gland Figure 7-19

Endocrine Pathologies Hypersecretion: excess hormone Tumors or cancer Grave’s disease—thyroxin Hyposecretion: deficient hormone Goiter—thyroxin Diabetes—insulin

Pathologies: Due to Receptors Downregulation Hyperinsulinemia Transduction abnormalities Testicular feminization syndrome Pseudohypothyroidism Abnormalities of control mechanisms

Primary and Secondary Pathologies PLAY Animation: Endocrine System: Response to Stress Figure 7-20

Hormone Evolution Evolutionary conservation of hormone function Comparative endocrinology Pineal gland and melatonin example

Pineal Gland and Melatonin Influences body clock and antioxidant activity Other roles need research SAAD and sexual behavior

Pineal Gland and Melatonin Figure 7-22 (1 of 3)

Pineal Gland and Melatonin Figure 7-22 (2 of 3)

Pineal Gland and Melatonin Figure 7-22 (3 of 3)

Summary Introduction to hormones Classifications and features of hormones Regulation controlled by the endocrine and nervous systems Interactions of hormones with other hormones Endocrine pathologies Hormone evolution