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Endocrine System. Overall Functions. Regulatory System Maintains homeostasis internally Responds to environmental changes Growth and development Reproduction. Glands. Exocrine e.g. salivary glands Endocrine e.g. Thyroid gland. Hormone.
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Overall Functions • Regulatory System • Maintains homeostasis internally • Responds to environmental changes • Growth and development • Reproduction
Glands • Exocrine e.g. salivary glands • Endocrine e.g. Thyroid gland
Hormone • Definition: A chemical messenger carried by bloodstream and made by endocrine glands. • Structure • Transport in body
Action of hormones • Target cell • Receptors • Plasma membrane • Within target cell • Second messenger (cAMP) • Activation of genes
Relationships • To other hormones • To nervous system
Controls • Negative Feedback • Releasing hormones and Inhibiting hormones from Hypothalamus
PITUITARY GLAND (Hypophysis) • Location – in sella turcica of sphenoid bone
Hormones of the Adenohypophysis • Gonadotropins • FSH = Follicle Stimulating Hormone • LH/ICSH = Luteinizing hormone in female, Interstitial cell stimulating hormone in male
Adenohypophysis • TSH = Thyroid stimulating hormone • ACTH = Adrenocorticotropic hormone • GH = Growth hormone • Prolactin • MSH = Melanocyte stimulating hormone • (endorphins)
Adenohypophysis • Controls • Inhibiting hormones and Releasing hormones • Brain • Negative feedback
Neurohypophysis • Infundibulum (hypothalamic-hypophyseal tract) • ADH = Antidiuretic hormone = Vasopressin • Oxytocin
Thyroid Gland • Location • Histology • Follicles, colloid • Thyroid hormones
Thyroid hormone • Iodine • T4 (thyroxine – 90%) • T3 (thriiodothyronine – 10%) • TBG (thyroid binding globulin) • Function • Controls
Thyroid Hormone Synthesis • Tyrosine + Iodine Monoiodotyrosine • + Iodine Diiodotyrosine • 2 Diiodotyrosine Tetraiodothyronine = T4 = Thyroxine
Thyroid Hormone Synthesis • 1 Diiodotyrosine + 1 mono… Triiodothyronine = T3
Thyroid gland • Calcitonin • Parafollicular (C) Cells • Decreases Ca and P • Controls
Parathyroid glands • Location • PTH (Parathromone) • Increases Ca and decreases P • Controls
Adrenal gland • Location • Adrenal Medulla • Chromaffin cells • Epinephrine (80%) • Norepinephrine (20%) • Action • Release
Adrenal gland • Adrenal Cortex • Mineralocorticoids • Zona glomerulosa • Aldosterone (90%) • Na reabsorption, K excretion in kidneys
Aldosterone • Release/Controls • Renin, Angiotensin • K/Na levels • ACTH, CRH
Adrenal cortex • Glucocorticoids • Zona fasciculata • Conserves and supplements energy • Anti-inflammatory • Release/Controls • ACTH, CRH, • Stress
Adrenal cortex • Sex hormones • Zona reticularis
Pancreas • Location • Endocrine AND Exocrine • Pancreatic islets = Islets of Langerhans