Endocrinology Final

produce testosterone and sperm

functions of testes

epididymis

site where sperm matures and develops the ability to be mobile; stores mature sperm

vas deferens

long tube which conducts sperm from the testes to the prostate

seminal vesicle

secretes fluid containing fructose, mucus, and prostaglandin

prostate gland

secretes an alkaline fluid to neutralize vaginal acids

Urethra

conducts sperm/semen from the prostate gland to the outside of the body

seminiferous tubules

where sperm are produced

rete testis

where tubules converge, empties into the epididymis

Leydig cell

where production of testosterone takes place

Sertoli cells

where gametogenesis occurs

smooth muscle

what type of cell wraps around seminiferous tubules

Sertoli cell

cell type that lines the tubules

tight junctions

hold Sertoli cells together

basal compartment

extends from the smooth muscle to the tight junction

lumenal compartment

extends from the light junction to the lumen of the tubule

Leydig cells

cell type that surround the seminiferous tubule/are found in between them

GnRH

released by the hypothalamus, signals release of LH and FSH

LH and FSH

released by the anterior pituitary, signal release of steroid hormone/gamete production

peptide

GnRH type of hormone

glycoprotein

FSH and LH type of protein

GPCR on Leydig cell, AC, cAMP, PKA

LH signaling mechanism

steroid

testosterone type of hormone

primary and secondary sex characteristics, skeletal muscle growth, sex drive, increased bone density

functions of testosterone

androgen-binding protein

testosterone in bloodstream circulates bound to…

unbound

only _____ testosterone is biologically active

diffuses into cell, binds to androgen receptor, dissociates from HSP, translocates to nucleus, dimerizes, binds to HRE, regulates gene expression

testosterone signaling mechanism

dihydrotestosterone (DHT)

most potent androgen

liver

where are testosterone/derivates degraded

5a-reductase

converts testosterone into DHT

anabolic steroids

synthetic testosterone

delayed puberty, muscle atrophy

testosterone can be clinically used to treat…

acne, aggression, hair loss, heart attack, high BP, infertility, liver damage, breast pain and enlargement

negative effects of anabolic steroids

spermatogonia

diploid germ cells, undergo mitosis to produce primary spermatocytes

primary spermatocyte

diploid cell, undergoes meiosis I

secondary spermatocyte

haploid cell, undergoes meiosis II

spermatids

haploid cells that undergo spermiogenesis (maturation) to produce sperm

spermatozoa

sperm cells

70

how many days does spermatogenesis take

GPCR on sertoli cell, cAMP, ABP binds, maintains high levels of testosterone

FSH signaling mechanism

100,000,000

how many sperm are produced per day

2-5

how many days can sperm live

acrosome

head of sperm, contains enzymes to penetrate egg

negative feedback on hypothalamus (GnRH) and pituitary (LH)

how is testosterone regulated

inhibin

inhibits secretion of FSH

peptide

inhibin type of hormone

high levels of FSH

stimulates production of inhibin by sertoli cells

ovary

where oocytes mature prior to the release, estrogen and progesterone secretion

fimbria

fringe of tissue adjacent to an ovary that sweep an oocyte into the oviduct

fallopian tube

transports the oocyte to the uterus, where fertilization occurs

uterus

organ where a fertilized egg will implant and develop

endometrium

mucous membrane lining of the uterus, thickens in preparation for implantation or is lost via menstruation

cervix

muscular opening protecting the uterus

vagina

passage leading to the uterus by which the penis and sperm can enter

produce estrogen and progesterone, develop and store eggs

function of ovaries

estrogen

produced during first half of menstrual cycle, increases thickness of endometrium

Progesterone

produced during second half of menstrual cycle, maintains endometrium

breasts, body hair, fat distribution

characteristics regulated by progesterone

endometrium

inner layer lining the uterus

myometrium

middle layer of smooth muscle

perimetrium

outer layer of serous tissue

FSH

stimulates granulosa cells to provide nourishment for developing follicle and egg

LH

stimulates hormone synthesis in theca cells and stimulates ovulation

progesterone

produced by corpus luteum

prepare uterus for implantation, regulates monthly menstrual cycle

functions of progesterone

steroid

progesterone type of hormone

estrogens

group of steroid hormones that promote and maintain female body characteristics

E1

estrone

E2

estradiol

E3

estriol

LH binds to GPCR on theca cells, stimulates synthesis of androstenedione

LH role in estrogen production

FSH binds to GPCR on granulosa cells and stimulates conversion of androgens to estrodiol

FSH role in estrogen production

intracellular and membrane-bound

types of receptors estrogen can bind to

oogenesis

process by which female gametes are produced in ovaries

Oogonium

diploid precursor cell, undergoes mitosis to produce primary oocytes

primary oocyte

diploid cell that undergoes meiosis I to produce secondary oocyte

secondary oocyte

haploid cell that is frozen in metaphase II until fertilization occurs

ovum

haploid female gamete

24 hours

how long do eggs live for

follicular phase

ovarian follicle develops, menstruation to ovulation, day 1-14

ovulation

egg is released, day 14

luteal phase

corpus luteum generates progesterone, ovulation to before menstruation, day 14-28

menstrual phase

uterine lining shed

proliferative phase

uterine lining develops

secretory phase

glands secrete products

ovarian follicle

fluid-filled structure containing a developing oocyte and supporting cells

primary follicle develops into a secondary follicle, secondary oocyte released into fallopian tube during ovulation, rest of secondary follicle develops into corpus luteum

follicular phase events

primordial follicle

contains primary oocyte surrounded by granulosa cell, remains in arrested state

primary follicle

contains primary oocyte surrounded by zona pellucida and granulosa cells

secondary follicle

stratified granulosa cells, theca cells, oocyte is arrested in late prophase of meiosis I

graafian follicle

mature follicle containing secondary oocyte, contains antrum (fluid-filled space)

oogenesis

primary oocytes complete first meiotic division, first polar body produced, secondary oocyte is produced and enters meiosis II, but is arrested in metaphase

upon fertilization

second round of meiosis completed, second polar body extruded

luteal phase

mature follicle fills with blood, forming corpus hemorrhagicum, theca and granulosa cells divide, cholesterol levels rise, corpus luteum is formed

FSH levels

elevated at beginning of cycle and diminish through early and middle follicular phases

LH levels

remain low during follicular phase, then surges after mid-cycle

estrogen

peaks at mid-cycle

1-5

days of menstruation phase

6-14

days of proliferative phase

15-28

days of secretory phase

menstruation

estrogen and progesterone levels are low