Hornones Flashcards
Males
Testes->testosterone-> wolffian ducts develop into the seminal vesicles, vascular deferens, prostate
Males 1.2
Testes-> MIS-> atrophy of Müllerian ducts
Females
Ovaries-> no testosterone-> wolffian ducts atrophy
Females 1.2
Ovaries-> no MIF-> Müllerian ducts develop into the uterus, vagina, fallopian tubes
Requires presence of 5 a-reductace in embryonic genital skin for genital fusion and development of male genitalia
Testosterone converted to DHR (5 a-dihydrotestosterone)
Males
Testosterone-> penis, urethra, scrotum
Females
No testosterone->clitoris and external labia
Direct gene activation
-lipid soluble, steroid hormones
-diffuse through cell membranes
-bind to intracellular receptor
-activated hormone receptor/complex binds with gene, turning it on
-gene transcribes mRNA
-ribosomes use mRNA to synthesize enzymes to stimulate cell activity or synthesize structural proteins to be excreted or used within the cell
Second messenger systems
-amino acid and protein based
-cannot pass through cell membranes
-bind to cell membrane receptors
-activate G protein in membrane to produce cyclic AMP in cytoplasm
-cyclic AMP acts as second messenger inside cell activating protein kinases
-protein kinases trigger cellular responses
Gonadotropin-releasing hormone (GnRH)
Source: hypothalamus
Targets and functions: anterior pituitary
-stimulates the production of follicle stimulating hormone (FSH) and leutinizing hormone (LH)
-regulates the release of FSH and LH by the anterior pituitary gland
Follicle stimulating hormone
Source: anterior pituitary
Follicle stimulating hormone in females
Ovaries
-Stimulates folic growth and maturation
-Stimulates estrogen production
Follicle stimulating hormone in males
Seminiferous tubules
-promotes sperm production (spermatogenesis) by establishing testosterone receptors on tubules
Leutenizing hormone
Source:anterior pituitary
Leutenizng hormone females
Females- ovaries
-stimulates primary oocyte to complete first neurotic divison to become secondary oocyte
-triggers ovulation of secondary oocyte
-transforms ruptured follicle into corpus luteum
-stimulates production of progesterone by corpus luteum
Leutenizing hormone in males
Males-semnferous tubules
-stimulates sperm production (spermstogenis) by causing intestinal cells in testes to secrete testosterone
Estrogen
Sources: maturing follicles and corpus luteum
Estrogen (body in general)
Stimulates the development of female secondary sexual characteristics
Estrogen (uterus)
Stimulates proliferative phase of uterine cycle
Estrogen (ovaries)
Promotes oogenesis
Estrogen (breasts)
Stimulates development of milk ducts and sinuses (ampullae)
Estrogen (anterior pituitary)
Stimulates burst-like release of LH
Progesterone
Source: corpus luteum and placenta
Progesterone uterus
-maintains thickened endometrium
-stimulates nutrient release
-quiets myometrium
Progesterone breasts
Stimates development of alveoli for milk production
Progesterone anterior pituitary
Inhibits production and release of FSH and LH
Testosterone
Source: interstitial cells in testes
Testosterone (body in general)
Stimulates the development of male secondary sexual characteristics including
-development of male genitalia
-male skeleton and muscle development
-male patterns for hair growth
-increased RBC production and higher metabolic rate
Testosterone (seminiferous tubules)
Necessary for the completion of spermatogenesis
Testosterone (anterior pituitary)
Moderate inhibition of pituitary and hypothalamus
Oxytocin
Sources: manufactured by hypothalamus
Stored and relaxed by posterior pituitary
-positive feedback mechanisms:
1.childbirth-stretching of uterus and cervix
2. Suckling- milk letdown reflex
Oxytocin (uterus)
Stimulates contraction of uterine myometrium causing lowering of fetus and labor
Oxytocin (Breasts)
-stimalest contraction of milk ducts and sinuses, releasing milk
Prolactin
Source: anterior pituitary
Targets: breasts-stimulates alveoli of breasts to produce milk
Regulation-release of prolactin by anterior pituitary is regulated by hypothalamus production of prolactin releasing hormone(PRH) and prolactin inhibiting hormone (PIH)
Human chorionic gonadotopin
Source: trophoblasts of blastocyst and chorion
Targets: corpus luteum
-maintains corpus luteum and causes it to continue producing progesterone in the absence of LH through first four months of pregnancy till placenta produces sufficient estrogen and progesterone to maintain the pregnancy
