MCAT Biology Lecture 5
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- calcitonin
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made: thyroid
effects: decreases blood calcium level - Progesterone
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made: ovaries
effect: prepares and maintaines uterus for pregnancy - Placenta hormones
- HCG, (Estrogens, Progesterone... in addition to ovaries).
- estrogen
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made: ovaries
effect: growth of mother sex organs, causes LH surge - testosterone
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made: testes
effect: secondary sex characteristics, closing of epiphyseal plates - Difference between endocrine and exocrine glands.
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exocrine release enzymes to external environment through ducts, ie sweat, oil, digestive stuff.
endocrine releases directly into body fluid. - Three types of hormones
- peptide, steroid, tyrosine derivatives
- effector
- target cell of hormone
- peptide hormone properties
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peptide derivative, water soluable.
have hard time diffusing through effector cell membrane. - specific peptide hormones
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1. anterior pituitary: FSH, LH, ACTH, hGH, TSH, Prolactin
2. posterior pituitary: ADH, oxytocin
3. parathyroid: PTH
4. pancreatic: glucagon, insulin - specific second messengers
- cAMP, cGMP, calmodulin -- often lead to cascade
- steroid hormone properties
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cholesterol derived, similar.
formed in smooth ER & Mito.
lipids, so require protein transport in blood.
can diffuse through effector membrane.
tends to increase protein production - specific steroid hormones
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1. glucocorticoids and mineral corticoids of adrenal cortex: cortisol, aldosterone
2. gonadal hormones: estrogen, progesterone, testosterone - specific tyrosine derivatives
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1. thyroid hormones: T3, T4
2. catecholamines adrenal medulla: epinephrine and norepinephrine - thyroid hormone properties
- lipid soluable, use plasma protein carriers. Bind to receptors in nucleus. Latent response, longer duration.
- epinephrine and norepinephrine properties
- water soluable, bind to receptors on target tissue, act through 2nd messenger cAMP
- negative feedback
- gland lags behind effector... high hormone concentrations are not feeding back. gland responds to BODY not body to GLAND. glands try to normalize body.
- anterior pituitary
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beneath hypothalmus in brain.
releases prolactin, hGH, ACTH, TSH, FSH and LH - human growth hormone (hGH)
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made: anterior pituitary
effects: all body cells
action: stimulates growth, increasing protein production - ACTH
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made: anterior pituitary, stress response
effects: adrenal cortex
action: adrenal cortex releases glucocorticoids - TSH
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made: anterior pituitary
effects: thyroid
action: thyroid releases T3 and T4, thyroid cells grow - Prolactin
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made: anterior pituitary
effects: breasts
action: stimulates milk production - posterior pituitary
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support tissue for hypothalamus.
hypothalmus makes oxytocin and ADH, which are released by post. pituitary - oxytocin
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made: hypothalamus
effects:
action: uterine contractions and milk ejection - ADH
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made: hypothalamus
effects: kidney collecting ducts
action: concentrates urine, retains water. - adrenal cortex
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on top of kidney, cortex is outside part.
releases Aldosterone, Cortisol, ie minteral corticoids and glucocorticoids. - aldosterone
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made: adrenal cortex
effects: Na+ absorption, K+ secretion in tubule of kidney, also increases blood pressure - cortisol
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made: adrenal cortex
effects: stimulates gluconeogenesis in liver, degrades adipose tissue for energy, diminishes immune response - catecholamines - epinephrine, norepinephrine
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made: adrenal medulla
effects: 'fight or flight', like in sympathetic NS, but longer lasting. - thyroid
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gland located along trachea in front of larynx
releases T3, T4 and calcitonin - T3 & T4
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made: thyroid
difference is 3 vs 4 iodine atoms
effects: increase basal metabolic rate.
release regulated by TSH - pancreas
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located near kidney
both endo and exocrine gland.
releases insulin and glucagon. - insulin
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made: pancreas
effects: lowers blood glucose levels, by increasing membrane permeability to glucose (except in brain) - glucagon
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made: pancreas
effects: raise blood glucose levels, by promoting gluconeogenesis and glycogenolysis in liver. Also breaks down adipose tissue. (fat) - parathyroid
- small glands attached to back of thyroid, releases PTH
- PTH, parathyroid hormone
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made: parathyroid
effects: increase blood calcium, regulated by calcium ion concentration in plasma - seminiferous tubules
- sperm production occurs there
- FSH - follicle stim. hormone
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made: anterior pituitary
effects: growth of follicles in female, sperm production in male - LH
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made: anterior pituitary
effects: causes ovulation, stimulates estrogen and testosterone secretion - HCG
- stimulates corpus luteum to grow and release estrogen and progesterone
- androgen
- male sex hormone, primary is testosterone. Also responsible for secondary sex characteristics.
- sperm growth phases
- epithelial tissue, spermatogonia, spermatocytes, spermatids, spermatozoa.
- zygote
- egg and sperm fuse to form
- cleavage
- zygote undergoes many mitosis resulting in ball of cells called morula
- blastocyst
- hallow ball of cells derived from morula implanted in wall of uterus
- induction
- once cell type affects the direction of differentiation of another cell type. differentiation "determines" cell fate.