Endocrine System Flashcards
- contribute to the setting of the body’s biological clock, controlled by the suprachiasmatic nucleus of the hypothalamus
- increased secretion during darkness
- promotes sleepiness
melatonin
- synthesize & secrete insulin-like growth factors
- promote growth of body cells, protein synthesis, tissue repair, lipolysis, and evaluation of blood glucose concentration
- target tissues: liver, muscles, cartilage, bone, and other tissues
Human Growth Hormone or Somatotropin
- stimulates synthesis and secretion of thyroid hormones by thyroid gland
- Target tissues: thyroid gland
thyroid-stimulating hormone/thyrotropin
- female - initiates development of oocytes & induces ovarian secretion of estrogens
- males - stimulates testes to produce sperm
- Target tissues: ovaries or testis
follicle-stimulating hormone
- females - stimulates secretion of estrogens and progesterone, ovulation, and formation of corpus luteum
- males - stimulates testes to produce testosterone
- Target tissues: ovaries or testis
luteinizing hormone
- together with other hormones, promotes milk production by mammary glands
- Target tissues: mammary glands
prolactin
- stimulates secretion of glucocorticoids (mainly cortisol) by adrenal cortex
- Target tissues: adrenal cortex
adrenocorticotropic hormone/corticotropin
- exact role in humans is unknown but may influence brain activity; when present in excess, can cause darkening of skin
- Target tissues: brain
melanocyte-stimulating hormone
- stimulates contraction of smooth muscle cells of uterus during childbirth
- stimulates contraction of myoepithelial cells in mammary glands to cause milk ejection
- Target tissues: uterus & mammary glands
oxytocin
- conserves body water by decreasing urine volume
- decreases water loss through perspiration
- raises blood pressure by constricting arterioles
- Target tissues: kidneys, sudoriferous/sweat glands, arterioles
antidiuretic hormone/vasopressin
- increase basal metabolic rate; stimulate synthesis of proteins
- increase use of glucose and fatty acids for ATP production
- increase lipolysis; enhance cholesterol excretion
- accelerate body growth
- contribute to development of nervous system
T3 (triiodothyronine) and T4 (thyroxine)
- lowers blood levels of Ca2 and HPO42 by inhibiting bone resorption by osteoclasts and by accelerating uptake of calcium and phosphates into bone extracellular matrix
calcitonin
- increases blood Ca2 and Mg2 levels and decreases blood HPO42
- increases bone resorption by osteoclasts
- increases Ca2 reabsorption and HPO42 excretion by kidneys
- promotes formation of calcitriol (active form of vit. D), which increases rate of dietary Ca2 and Mg2 absorption
Parathyroid hormone
- increase blood levels of Na and water
- decrease blood level of K
mineralocorticoids (aldosterone)
- increase protein breakdown (except in liver), stimulate gluconeogenesis and lipolysis, provide resistance to stress, dampen inflammation, depress immune responses
glucocorticoids (cortisol)
- assist in early growth of axillary and pubic hair in both sexes
- in females, contribute to libido and are source of estrogen after menopause
androgens (dehydroepiandrosterone)
- raises blood glucose level by accelerating breakdown of glycogen into glucose in liver (glycogenolysis), converting other nutrients into glucose in liver (gluconeogenesis), and releasing glucose into blood
glucagon
- lowers blood glucose level by accelerating transport of glucose into cells, converting glucose intro glycogen (glycogenesis), and decreasing glycogenolysis and gluconeogenesis
insulin
- inhibits secretion of insulin and glucagon
- slows absorption of nutrients from gastrointestinal tract
somatostatin
- inhibits somatostatin secretion, gallbladder contraction and secretion of pancreatic digestive enzymes
pancreatic polypeptide
Together with gonadotropic hormones of anterior pituitary, regulate female reproductive cycle, maintain pregnancy, prepare mammary glands for lactation, and promote development and maintenance of female secondary sex characteristics
estrogen and progesterone
- Increases flexibility of pubic symphysis during pregnancy
- Helps dilate uterine cervix during labor and delivery
relaxin
Inhibits secretion of FSH from anterior pituitary
inhibin
- Stimulates descent of testes before birth; regulates sperm production
- Promotes development and maintenance of male secondary sex characteristics
Testosterone
Inhibits secretion of FSH from anterior pituitary
Inhibin