Chemical Signals in Animals Chapter 45 Chemical Signals in Animals

I. Basics Hormone – chemical signal secreted into body fluids that communicates directly with target cell Endocrine Gland – secretes hormones into blood Endocrine systems work very closely with the nervous system - neurosecretory cells / hormones and signals for n.s. Basic regulation in insects / BH – ecdysone - JH

Local Regulators Mechanisms of Cell Signaling II. Chemical Signals Local Regulators Mechanisms of Cell Signaling

A. Local Regulators Growth Factors – stimulate cell proliferation NO – neurotransmitter, kill cells, dilate vessels Prostaglandins – induce fever and pain, reproductive system

B. Mechanisms of Cell Signaling Receptor – STP – Response Receptor in the plasma membrane / activates an enzyme, etc Receptor in the nucleus / make a certain protein

III. Vertebrate Endocrine System Tropic Hormone – have other endocrine glands as targets Hypothalamus - region of lower brain - secretions of hypothalamus are stored in or regulate the pituitary gland - posterior pituitary stores oxytocin and ADH made by hypothalamus - creates releasing and inhibiting hormones to control the anterior pituitary

Posterior Pituitary

Anterior Pituitary

Endocrine Gland Locations

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