Transcript Bio 257
Bio 257 Day 24 Today’s topics Thyroid Gland Parathyroid Glands Thymus Adrenal Glands Pancreas Gonads Thyroid Gland • Homones- thyroxine-T4 & triiodothyronine-T3 – increases basal metabolic rate need for growth & maturation –Target: most organs Thyroid Gland • Hormone-calcitonin – decreases blood calcium levels by decreasing bone breakdown –Target: bone (inhibit osteoclasts), kidneys Parathyroid Gland • 4 pea –sized lobes • embedded in the posterior portion of thyroid gland • 1 hormone = PTH (parathyroid hormone) – increases blood calcium levels – Target: bone, kidneys Relative Location of Thymus Trachea Thymus Lung Heart Ribs Thymus Gland • Anterior & superior to heart • Decreases in size with age • 1 hormone = thymosin – stimulates t-cell (WBC, lymphocyte) development & maturation – Target: Immune tissue - t-cells, bone marrow, lymphatic tissue, thymus Adrenal Glands diaphragm left adrenal gland left kidney ureter urinary bladder Posterior view Adrenal Glands • Sit atop of each kidney • Consist of two major tissue layers –Adrenal cortex = outer portion –Adrenal medulla = inner portion Adrenal Glands • Adrenal Medulla –2 major hormones = epinephrine & to a small extent norepinephrine • Same effects as sympathetic division of the nervous system Regulation of Adrenal Medullary Secretions Adrenal Glands • Adrenal cortex –3 major classes of hormones • 1) Glucocorticoids • 2) Mineralocorticoids • 3) Androgens Adrenal Glands • Adrenal cortex –Glucocorticoid Hormones • mainly Cortisol • increases the synthesis of glucose from proteins & fats to increase glucose reserve and antinflammatory effects • target many organs Adrenal Glands • Adrenal cortex – Mineralocorticoid Hormones • mainly Aldosterone • regulates Na+ & K+ blood levels by increasing Na+ & decreasing K+ • target: primarily kidneys, small extent intestines and sweat glands Regulation of Aldosterone Secretion Adrenal Glands • Adrenal cortex – Androgens • male sex hormones • in females stimulate pubic & axillary hair grow and sex drive, in males negligible effects • over secretion in females results in masculinization Structure of Pancreas Regulation of Blood Glucose Levels Pancreas Gland • Lies behind the stomach and 1st portion of small intestines (duodenum) • Contains clusters of endocrine cells called Islets of Langerhans Pancreas Gland • 2 primary hormones = glucagon and insulin • Insulin (Beta-cells) –Lowers blood glucose levels by increasing the uptake of blood glucose by liver & muscles –Targets: primarily liver and skeletal muscles Pancreas Gland • Glucagon (alpha-cells) –Increases blood glucose levels by increasing the breakdown of glycogen by liver –Target: Primarily liver Gonads (ovaries & testes) Ovaries, located in the pelvic cavity of the female. remain functionless,until puberty, when secretion of FSH & LH stimulates them. Ovarian Hormones progesterone & estrogen stimulates uterine lining growth for menstrual cycle or pregnancy development development of ovaries, & female secondary sex characteristics. Testes (male) suspended in a sac called the scrotum, outside the male pelvic cavity produce hormones called androgens -testosterone is the most important. Testosterone stimulates growth & maturation of male reproductive organs development of male secondary sex characteristics aids in production of sperm stimulation of the male sex drive