Regulation and Control Endocrine System-is a series of hormone-producing glands throughout the body which are circulated through the blood and influence target cells

AP-Pertinent Endocrine Info Posterior Pituitary-stores ADH (antidiuretic hormone) and oxytocin, which are produced in the hypothalamus Anterior Pituitary-produces tropic hormones (hormones that target other glands) Regulated by releasing hormones produced by the hypothalamus Pancreas Islets of Langerhans have 2 cell types (producing antagonistic hormones) Alpha cells-secrete glucagon into the blood when blood sugar drops, stimulating the liver to release glucose Beta cells-secrete insulin, stimulating the liver to take up glucose and convert it to glycogen or fat

Figure 47-3-1 Hypothalamus Growth-hormone-releasing hormone: stimulates release of GH from pituitary gland Corticotropin-releasing hormone (CRH): stimulates release of ACTH from pituitary gland Thyroid-releasing hormone: stimulates release of TSH from thyroid gland Gonadotropin-releasing hormone: stimulates release of FSH and LH from pituitary gland Antidiuretic hormone (ADH): promotes reabsorption of H2O by kidneys Oxytocin: induces labor and milk release from mammary glands in females Polypeptides Amino acid derivatives Steroids

Figure 47-3-2 Polypeptides Amino acid derivatives Steroids Thyroid gland Thyroxine: increases metabolic rate and heart rate; promotes growth Adrenal glands Epinephrine: produces many effects related to short-term stress response Cortisol: produces many effects related to short-term and long-term stress responses Aldosterone: increases reabsorption of Na+ by kidneys Kidneys Erythropoietin (EPO): increases synthesis of red blood cells Vitamin D: decreases blood Ca2+ Testes (in males) Testosterone: regulates development and maintenance of secondary sex characteristics in males; other effects

Figure 47-3-3 Polypeptides Amino acid derivatives Steroids Pituitary gland Growth hormone (GH): stimulates growth Adrenocorticotropic hormone (ACTH): stimulates adrenal glands to secrete glucocorticoids Thyroid-stimulating hormone (TSH): stimulates thyroid gland to secrete thyroxine Follicle-stimulating hormone (FSH) and luteinizing hormone (LH): involved in production of sex hormones; regulate menstrual cycle in females Prolactin: stimulates mammary gland growth and milk production in females

Figure 47-3-4 Polypeptides Amino acid derivatives Steroids Parathyroid glands Parathyroid hormone (PTH): increases blood Ca2+ Pancreas (islets of Langerhans) Insulin: decreases blood glucose Glucagon: increases blood glucose Ovaries (in females) Estradiol: regulates development and maintenance of secondary sex characteristics in females; other effects Progesterone: prepares uterus for pregnancy

Follicle-stimulating Figure 47-16 The posterior pituitary The anterior pituitary Hypothalamus Neurosecretory cells of the hypothalamus Neurosecretory cells of the hypothalamus Hypothalamic hormones Hypothalamic hormones Blood vessels Posterior pituitary Anterior pituitary Blood vessels Pituitary hormones Hormone ADH Oxytocin Hormone ACTH Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) Growth hormone (GH) Prolactin (PRL) Thyroid- stimulating hormone (TSH) Target Kidney nephrons Mammary glands, uterine muscles Target Adrenal cortex Testes or ovaries Many tissues Mammary glands Thyroid Response Aquaporins activated; H2O reabsorbed Contraction during labor; ejection of milk during nursing Response Production of glucocorticoids Production of sex hormones; control of menstrual cycle Growth Mammary gland growth; milk production Production of thyroid hormones

How hormones work Method 1: (for steroid hormones) The hormone diffuses through the pm and heads for the nucleus. It binds to a receptor protein in the nucleus, which activates the DNA to turn on a specific gene Method 2: (for protein hormones) The hormone binds to a receptor on the plasma membrane (receptor-mediated endocytosis), which stimulates a second messenger 2nd messengers can be cAMP, which triggers an enzyme that makes cellular changes, or Inositol triphosphate (IP3) that triggers the release of calcium ion from the ER, that triggers enzymes to make cellular changes

STEROID HORMONE ACTION Figure 47-18 STEROID HORMONE ACTION Nucleus Hormone receptor mRNA Proteins DNA Steroid hormone Hormone- response element RNA polymerase Hormone-receptor complex 3. Hormone-receptor complex enters nucleus and binds to DNA, induces start of transcription. 4. Many mRNA transcripts are produced, amplifying the signal. Ribosome 1. Steroid hormone enters target cell. 2. Hormone binds to receptor, induces conformational change. 5. Each transcript is translated many times, further amplifying the signal.

4. Activation of cAMP-dependent protein Figure 47-21 MODEL FOR EPINEPHRINE ACTION 1. Epinephrine binds to receptor Epinephrine Adenylyl cyclase Receptor 2. Activation of G protein 3. Activated adenylyl cyclase catalyzes formation of cAMP Transmission of message from cell surface 4. Activation of cAMP-dependent protein kinase A 5. Activation of phosphorylase kinase 6. Activation of phosphorylase 7. Production of glucose from glycogen

Feedback Loops Positive Negative Increases an already present response. “good job, keep going” Oxytocin during labor increases contractions. As the baby’s head presses on the uterus the oxytocin increases. Negative Maintains balance by turning off a hormone when it is no longer needed. High levels of thyroxin “turn off” the hypothalamus and pituitary glands. They “turn on” when levels are low.

Endocrine Disorders and Environmental Effects Gigantism Infertility Issues Goiter Hyper-/ Hypothyroidism Diabetes Hormones in modified foods can affect the immune system. BPA found in plastics reacts in the body like estrogen.