Chapter 26- Chemical Regulation

1. Adrenal cortex Adrenal glands Adrenal medulla Adrenocorticotropic hormone (ACTH) Androgens Antagonistic hormones Anterior pituitary Calcitonin Corticosteroids Diabetes Endocrine glands Endocrine system Endorphins Epinephrine Estrogen Follicle-stimulating hormone (FSH) Glucagon Glucocorticoids Goiter Gonads Growth hormone (GH) Hormone Hypoglycemia Hypothalamus Inhibiting hormones Insulin Islet cells Local regulators Luteinizing hormone (LH) Mineralocorticoids Neurosecretory cell Neurotransmitters Norepinephrine Pancreas Parathyroid glands Parathyroid hormone (PTH) Pineal gland Posterior pituitary Progestins Prolactin Prostaglandins Releasing hormones Steroid hormones Target cells Testosterone Thymus gland Thyroid-stimulating hormone (TSH) Thyroxine Triiodothyronine TSH-releasing hormone (TRH) Chapter 26- Chemical Regulation

2. Hormones • Regulatory chemicals that travel in blood from production site and affect other sites in the body • Coordinate activities in different parts of the body, enables organ systems to function cooperatively • Made and secreted by endocrine glands • Target cells- cells that respond to specific hormone • Neurosecretory cells- nerve cell that along with conducting nerve signals, makes and secretes hormones

4. Endocrine system • All hormone-secreting cells • Often collaborates with nervous system • Both rely on chemical messages • Small amount of hormones can govern activities in many cells • Nervous system- chemicals- neurotransmitters- carry information from one nerve cell to the other • Local regulator- secreted into interstitial fluid and affects nearby cells • Ex: interleukins, prostaglandins • Endocrine chemicals are transported in blood

6. Hormone attaches to receptor protein on membrane triggering a signal transduction pathway to activate a protein that carries out response Amine, peptide, protein hormones Ex: glycogen to glucose Steroid hormones- binds to receptors inside the cell (if it’s a target cell- binds to receptor and becomes and transcription factor) – transcription and translating of a gene follows Ex: testosterone, estrogen Lipids made from cholesterol Hormones affect target cells by 2 signaling mechanisms

10. Hypothalamus and Pituitary • Connect Nervous system with Endocrine system • They have multiple functions

11. Hypothalamus • Master control of endocrine system • Sends signals to pituitary which secretes hormones to body • Secretes TRH (TSH-releasing hormone), TRH makes anterior pituitary secrete TSH (thyroid stimulating hormone), thyroid secretes thyroxine which increases metabolism

12. Pituitary • Posterior pituitary- composed of nervous tissue (extension of hypothalamus), stores and secretes hormones made in hypothalamus • Anterior pituitary- glandular tissue- synthesizes hormones • Hypothalamus- regulates by secreting hormones into blood • Releasing hormones- make ant. pit. secrete • Inhibiting hormones- make ant. pit. stop secreting

14. Thyroid • Under voice box, affects many tissues • T3 and T3 hormones- major role in development and maturation • Maintain BP, heart rate, muscle tone, digestion and reproductive functions • Hyperthyroidism- too much T3 and T4 • Hypothyroidism- too little T3 and T4 • Goiter- defective gland or due to diet- thyroid enlargement

16. Parathyroid • 4 on surface of thyroid • Thyroid and parathyroid- maintains calcium homeostasis • Ca for nerve signals, clotting, transport, bones • Calcitonin and PTH (parathyroid hormone)- antagonistic hormones- elicit opposite effects • Calcitonin lowers Ca in blood, PTH raises Ca in blood

17. Pancreas • Hormones manage cellular fuel • Insulin- protein hormone- produced by beta cells • Glucagon- peptide hormone- produced in alpha cells • Blood sugar increases- insulin secreted- body cells take up glucose –it’s stored as glycogen and used for metabolic E • Blood sugar decreases- glucagon secreted- liver cells breakdown glycogen into glucose • Antagonistic- negative feedback- controls glucose level • Diabetes- hormonal disease, body cells are unable to absorb glucose from blood • Not enough insulin or cells don’t respond to insulin • Type I- insulin dependent- autoimmune disease- WBC’s attack beta cells • Type II- noninsulin dependent- body cells don’t respond to insulin –managed by controlled diet • Hypoglycemia- too much insulin- blood glucose too low

19. Adrenal Glands • Responses to stress- on top of kidneys • 2 portions- adrenal medulla and cortex • Medulla- flight or fight response • Responds to nerve signals • Amine hormones: epinephrine (Adrenaline) and norepinephrine (noradrenaline) • Liver cells release glucose, raise BP, raise breathing rate, metabolic rate, change blood flow patterns • Cortex- slower, longer lasting response • Responds to endocrine glands • ACTH- stimulates cortex to secrete steroid hormones- corticosteroids (2 types) • Mineralcorticoids- mainly affect salt and water balance- makes kidneys reabsorb = increase blood volume = increase BP • Glucocorticoids- mobilize cellular fuel, reinforce glucagon effect- promote synthesis of glucose from protein and fat • High levels can suppress body’s defenses ex: inflammation

20. Gonads • Secrete steroid sex hormones along with producing gametes • 3 categories are produced • Estrogens- higher in females- maintain female reproductive system, promote secondary sex characteristics • Progestins- higher in females- prepares uterus to support embryo ex: progesterone • Androgens- higher in males- maintain male reproductive system, produce “maleness”, promote secondary sex characteristics ex: testosterone