Homeostasis and Endocrine Signaling 32 Homeostasis and Endocrine Signaling

Figure 32.1 Figure 32.1 How do long legs help this scavenger survive in the scorching desert heat? 2

Skeletal muscle tissue Figure 32.2 Lumen 10 m Apical surface Nervous tissue Epithelial tissue Axons of neurons Basal surface Epithelial tissue (Confocal LM) Blood vessel Glia 20 m Blood Loose connective tissue Plasma White blood cells Figure 32.2 Exploring structure and function in animal tissues 50 m Skeletal muscle tissue Nuclei Red blood cells Muscle cell Collagenous fiber Elastic fiber 100 m 100 m 3

(a) A walrus, an endotherm Figure 32.5a Figure 32.5a Endothermy and ectothermy (part 1: endotherm) (a) A walrus, an endotherm 4

(b) A lizard, an ectotherm Figure 32.5b Figure 32.5b Endothermy and ectothermy (part 2: ectotherm) (b) A lizard, an ectotherm 5

Hormones - Endocrine Signaling molecules - May effect a single location or throughout the body - Only effect cells with correct receptors 6

Endocrine cell Cell body of neuron Figure 32.9 (a) Signaling by hormones (b) Signaling by neurons Stimulus Stimulus Endocrine cell Cell body of neuron Nerve impulse Axon Hormone Signal travels everywhere. Signal travels to a specific location. Blood vessel Nerve impulse Figure 32.9 Signaling in the endocrine and nervous systems Axons Response Response 7

Major Endocrine Glands and Their Hormones Hypothalamus Figure 32.11a Major Endocrine Glands and Their Hormones Hypothalamus Pituitary gland Anterior pituitary Pineal gland Melatonin Posterior pituitary Oxytocin Vasopressin (antidiuretic hormone, ADH) Thyroid gland Thyroid hormone (T3 and T4) Calcitonin Adrenal glands (atop kidneys) Parathyroid glands Parathyroid hormone (PTH) Adrenal medulla Epinephrine and norepinephrine Ovaries (in females) Estrogens Progestins Figure 32.11a Exploring the human endocrine system (part 1: glands and hormones) Adrenal cortex Glucocorticoids Mineralocorticoids Testes (in males) Androgens Pancreas Insulin Glucagon 8

Hypothalamus Anterior pituitary Neurosecretory cells of the Figure 32.11b Hypothalamus Neurosecretory cells of the hypothalamus Portal vessels Hypothalamic hormones HORMONE Posterior pituitary Anterior pituitary Endocrine cells TARGET Pituitary hormones Figure 32.11b Exploring the human endocrine system (part 2: hypothalamus and pituitary) FSH TSH ACTH Prolactin MSH GH Mammary glands Testes or ovaries Thyroid gland Adrenal cortex Melanocytes Liver, bones, other tissues 9

Stimulus TSH circulation throughout body Sensory neuron Thyroid gland Figure 32.11c Stimulus TSH circulation throughout body Sensory neuron − Hypothalamus Thyroid gland Neurosecretory cell TRH Negative feedback Thyroid hormone Thyroid hormone circulation throughout body Figure 32.11c Exploring the human endocrine system (part 3: hormone cascade) − Anterior pituitary TSH Response 10

Pathways of Water-Soluble and Lipid-Soluble Hormones Water-Soluble (Peptide) hormones bind to cell-surface receptors The intracellular response is called signal transduction and often includes cyclic AMP 11

Lipid-soluble (Steroid) hormones have receptors inside cells When bound by the hormone, the hormone-receptor complex moves into the nucleus and alters transcription 12

Same receptors but different intracellular proteins (not shown) Figure 32.13 Same receptors but different intracellular proteins (not shown) Different receptors Different cellular responses Different cellular responses Epinephrine Epinephrine Epinephrine  receptor  receptor  receptor Glycogen deposits Figure 32.13 One hormone, different effects Vessel dilates. Vessel constricts. Glycogen breaks down and glucose is released from cell. (a) Liver cell (b) Skeletal muscle blood vessel (c) Intestinal blood vessel 13

Tadpole Adult frog Figure 32.14 Figure 32.14 Specialized role of a hormone in frog metamorphosis Adult frog 14