Endocine Flashcards
GH/ growth Hormone
Stimulates the growth of all tissues and organs.
Especially Bone, cartilage and skeletal muscle
Stimulates the transport of amino acids in to cells and the synthesis of glucose during periods of fasting.
Prolactin/lactogenic hormone
Stimulates breast milk production
Stimulates breast development
Tropic Hormones
Part of the anterior pituitary
Thyrotropin- (TSH) targets the thyroid gland, stimulating it to secrete 2 thyroid hormones.
Adrenocorticotropic Hormone- (ACTH) targets the adrenal cortex, stimulating it to secrete steroids.
Gonadotropic hormone- targets gonads FSH- stimulates dev. Of ovums and sperm. LH- stimulates ICHS to secrete testosterone
Posterior pituitary gland
Extension of hypothalamus-
Smaller lobe AKA neurohypophysis
1. Antidiuretic Hormone ( ADH) or arginine vasopressin: causes reabsorption of water from renal turbulence of kidneys.
2. Oxytocin: causes contraction of uterus during labor and the release of breast milk
Antidiuretic Hormone (ADH)
Stimulates water reabsorption by the kidneys, also constricts blood vessels
Oxytocin
Causes contraction of uterine muscle during labor
Releases milk from mammary glands during breastfeeding ( milk let down)
Thyroid and parathyroid gland
- Thyroid hormones ( T3 and T4)
- triiodothyronine ( T3)
- tetraiodothyronine (T4)
- calcitonin
- parathyroid Hormone ( PTH)
Thyroid Hormone T3 and T4
Triiodothyronine t3
Tetraiodothyronine t4 or thyroxine
Controls metabolic rate and regulates physical and neurological growth and development.
Regulation of secretion
Thyroid gland activity regulated by hypothalamus
- Hypothalamus releases hypothalamus releasing hormone
- HRH stimulates the anterior pituitary gland to secrete TSH
- TSH stimulates the thyroid to secrete T3 and T4
Negative feedback prevents further secretion of TSH when plasma increases sufficiently
Calcitonin
Secreted by the thyroid gland
Regulates calcium and phosphate
Decreases plasma levels of calcium and phosphate
Parathyroid glands
Small group located behind thyroid
Most ppl have 4
Targets Digestive tract, kidneys and bones
Secretes PTH
Regulates calcium level/controls calcitonin secretion
Stimulates kidneys to absorb calcium from urine
Excretes phosphate (phosphaturic)
PTH Deficiency
Hypocalcemic Tetany
PTH def. decline in blood calcium causing hypocalcemia
Hypocalcemia: nerve and muscle membranes become unstable & fire electrical signals causing muscle contracture.
May also contract larynx muscle (larynospasm) inability to relax: causes asphyxiation and death. Hypocalcemia is life threatening!!
Adrenal Glands
Small pair, highly vascularized, triangular shaped. Located in retroperitoneal cavity above kidneys.
Outer part called the cortex, inner part the medulla.
Medulla: made of ganglia (nerves) secretes catecholamines- epinephrine and norepinephrine.
Cortex: secretes steroids, mineralocorticoids, glucocorticoids, androgens and estrogen.
Glucocorticoids
Regulates sugar
Converts amino acids into glucose
Steroids
Secreted by the adrenal cortex:
Cortisol: glucocorticoid helps regulate glucose, fat and protein metabolism. Part of stress response. Increases blood glucose.
Aldosterone: mineralcorticoid that causes kidneys to reabsorb sodium, water and excrete potassium. Helps regulate extra cellular fluids, electrolytes (na and K)
Sex hormone: the androgens esp. testosterone, helps develop the 2nd sex characteristics
