Major endocrine glands: Figure 45.4 Major endocrine glands: Hypothalamus Pineal gland Pituitary gland Organs containing endocrine cells: Thyroid gland Thymus Parathyroid glands (behind thyroid) Heart Liver Adrenal glands (atop kidneys) Stomach Pancreas Kidneys Small intestine Figure 45.4 Major human endocrine glands. Ovaries (female) Testes (male)

Water-soluble (hydrophilic) Lipid-soluble (hydrophobic) Figure 45.5 Water-soluble (hydrophilic) Lipid-soluble (hydrophobic) Polypeptides Steroids 0.8 nm Insulin Cortisol Amines Figure 45.5 Hormones differ in structure and solubility. Epinephrine Thyroxine

Water- soluble hormone Lipid- soluble hormone Figure 45.6-2 SECRETORY CELL Water- soluble hormone Lipid- soluble hormone VIA BLOOD Transport protein Signal receptor TARGET CELL OR Signal receptor Figure 45.6 Receptor location varies with hormone type. Cytoplasmic response Gene regulation Cytoplasmic response Gene regulation NUCLEUS (a) (b)

Estradiol (estrogen) receptor Figure 45.8-2 Hormone (estradiol) EXTRACELLULAR FLUID Estradiol (estrogen) receptor Plasma membrane Hormone-receptor complex NUCLEUS CYTOPLASM Figure 45.8 Steroid hormone receptors directly regulate gene expression. DNA Vitellogenin mRNA for vitellogenin

S cells of duodenum secrete the hormone secretin ( ). Figure 45.11 Pathway Example  Stimulus Low pH in duodenum S cells of duodenum secrete the hormone secretin ( ). Endocrine cell Hormone Negative feedback Figure 45.11 A simple endocrine pathway. Blood vessel Target cells Pancreas Response Bicarbonate release

Hypothalamus/ posterior pituitary Figure 45.12 Pathway Example  Stimulus Suckling Sensory neuron Hypothalamus/ posterior pituitary Posterior pituitary secretes the neurohormone oxytocin ( ). Neurosecretory cell Positive feedback Neurohormone Blood vessel Figure 45.12 A simple neuroendocrine pathway. Target cells Smooth muscle in breasts Response Milk release

Body cells take up more glucose. Insulin Figure 45.13 Body cells take up more glucose. Insulin Beta cells of pancreas release insulin into the blood. Liver takes up glucose and stores it as glycogen. STIMULUS: Blood glucose level rises (for instance, after eating a carbohydrate-rich meal). Blood glucose level declines. Homeostasis: Blood glucose level (70–110 mg/m100mL) STIMULUS: Blood glucose level falls (for instance, after skipping a meal). Figure 45.13 Maintenance of glucose homeostasis by insulin and glucagon. Blood glucose level rises. Liver breaks down glycogen and releases glucose into the blood. Alpha cells of pancreas release glucagon into the blood. Glucagon

Cerebrum Pineal gland Thalamus Hypothalamus Cerebellum Pituitary gland Figure 45.14 Cerebrum Pineal gland Thalamus Hypothalamus Cerebellum Pituitary gland Spinal cord Hypothalamus Figure 45.14 Endocrine glands in the human brain. Involvement of brain = CONTROL and COORDINATION Posterior pituitary Anterior pituitary

Mammary glands, uterine muscles Figure 45.15 Hypothalamus Neurosecretory cells of the hypothalamus Neurohormone Axons Posterior pituitary Anterior pituitary Figure 45.15 Production and release of posterior pituitary hormones. HORMONE ADH Oxytocin TARGET Kidney tubules Mammary glands, uterine muscles

Liver, bones, other tissues Figure 45.16 Tropic effects only: FSH LH TSH ACTH Neurosecretory cells of the hypothalamus Nontropic effects only: Prolactin MSH Nontropic and tropic effects: GH Hypothalamic releasing and inhibiting hormones Portal vessels Endocrine cells of the anterior pituitary Posterior pituitary Pituitary hormones Figure 45.16 Production and release of anterior pituitary hormones. TROPIC HORMONES from anterior pituitary target other endocrine organs HORMONE FSH and LH TSH ACTH Prolactin MSH GH TARGET Testes or ovaries Thyroid Adrenal cortex Mammary glands Melanocytes Liver, bones, other tissues

Table 45.1 Table 45.1 Major Human Endocrine Glands and Some of Their Hormones

Increases Ca2 uptake in intestines Active vitamin D Figure 45.20-2 Increases Ca2 uptake in intestines Active vitamin D Stimulates Ca2 uptake in kidneys PTH Parathyroid gland (behind thyroid) Stimulates Ca2 release from bones Figure 45.20 The roles of parathyroid hormone (PTH) in regulating blood calcium levels in mammals. STIMULUS: Falling blood Ca2 level Blood Ca2 level rises. Homeostasis: Blood Ca2 level (about 10 mg/100 mL)

Short-term stress response and the adrenal medulla (b) Figure 45.21 (a) Short-term stress response and the adrenal medulla (b) Long-term stress response and the adrenal cortex Stress Nerve signals Hypothalamus Spinal cord (cross section) Releasing hormone Nerve cell Anterior pituitary Blood vessel Nerve cell ACTH Adrenal medulla secretes epinephrine and norepinephrine. Adrenal cortex secretes mineralo- corticoids and glucocorticoids. Adrenal gland Kidney Figure 45.21 Stress and the adrenal gland. Effects of epinephrine and norepinephrine: Effects of mineralocorticoids: Effects of glucocorticoids: Glycogen broken down to glucose; increased blood glucose • Retention of sodium ions and water by kidneys • Proteins and fats broken down and converted to glucose, leading to increased blood glucose Increased blood pressure Increased breathing rate Increased metabolic rate • Increased blood volume and blood pressure Change in blood flow patterns, leading to increased alertness and decreased digestive, excretory, and reproductive system activity • Partial suppression of immune system

Parasympathetic division Sympathetic division Figure 49.8 Parasympathetic division Sympathetic division Action on target organs: Action on target organs: Constricts pupil of eye Dilates pupil of eye Inhibits salivary gland secretion Stimulates salivary gland secretion Sympathetic ganglia Constricts bronchi in lungs Relaxes bronchi in lungs Cervical Slows heart Accelerates heart Stimulates activity of stomach and intestines Inhibits activity of stomach and intestines Thoracic Stimulates activity of pancreas Inhibits activity of pancreas Stimulates gallbladder Stimulates glucose release from liver; inhibits gallbladder Figure 49.8 The parasympathetic and sympathetic divisions of the autonomic nervous system. Lumbar Stimulates adrenal medulla Promotes emptying of bladder Inhibits emptying of bladder Promotes erection of genitalia Sacral Promotes ejaculation and vaginal contractions Synapse