HORMONES ENDOCRINE SYSTEM Hormone substances produced in cells in one part of the body that exert specific effects on other organs or structures Made by endocrine glands organs specialized for secretion into blood vs exocrine which secrete into ducts are not signaling molecules 50 different hormones made by vertebrates effects metabolic rate growth maturation reproduction Hormones broad target different effects on different targets heart speeds up liver increases glycogen breakdown glucose release in liver sexual dilates blood vessels Hormones help maintain stability homeostasis Examples low calcium OR high phosphorus calcium release from bone water balance sugar balance Two types of hormone Lipid Soluble Steroid hormones Receptor Location intracellular bind to receptors inside cell which then bind to DNA which triggers transcription e g testosterone turns on genes in Y chromosome Amino acid derived hormones amino acids peptides proteins Receptor Location Membrane Surface don t enter cell they bind to receptors trigger intracellular transduction pathways Most amino acid and protein hormones do not cross cell membrane They bind first with receptors Generalized Scheme for Cell Signaling signal molecule ligand 1st messenger signal Transduction Pathway Transcription factor activated response transcription new protein Translation Hierarchy of Endocrine Control Hypothalamus in brain is top of hierarchy as such it receives signals from all over the body Pituitary controlled by hormones released by hypothalamus 1 Posterior pituitaru is nervous tissue stores secretes hormones made by hypothalamus 2 Anterior pituitary is glandular tissue makes its own hormones which control other endocrine glands also releases two hormones synthesized in hypothalamus Kidneys ADH increases water re absorption and prevents dehydration Example of Anterior Pituitary function growth hormones influences mostly muscle and skeleton can now produced by bacteria via genetic engineering Thyroid and Parathyroid Glands are important to calcium balance located in neck under larynx increases oxygen consumption and metabolic rate of cells maturation of bone and nerve cells some of its hormones contain iodine can therefore be influenced by diet too little iodine hypothyroidism goiter Parathydroid LOOK AT SLIDE regulates calcium balance which is important to nerve signal transmission muscle contraction blood clotting membrane transport Calcitonin lowers calcium level in blood Parathyroid hormone raises calcium level in blood Pancreas LOOK AT SLIDE produces insulin and glucagon are antagonistic because they have opposite effects both involved in glucose balance use vs storage Insulin stimulated by presence of blood glucose helps cells take up glucose liver and muscle take up glucose and then make glycogen Diabetes mellitus body cells cannot absorb glucose Type I insulin dependent not enough insulin is produced Type II adult on set associated with obesity body produces enough insulin but cells do not respond to it without glucose cells burn fats and protein glucose accumulates in blood over time can cause dehydration cardiovascular disease nerve damage Adrenal Gland sits on top of kidney produced in response to stress negative OR positive produces epinephrine adrenaline connection to hypothalamus stimulates liver to release glucose LOOK AT SLIDE Gonads sex hormones ovaries testes Female high ratio of estrogens to androgens estrogens promote high voice breasts wide hips progestins prepares uterus for embryo Male androgens testosterone stimulates male reproductive system produced in seventh week of embryo makes it male turns on Y chromosome lower voice muscles facial hair
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