Chapter 27: Reproductive System Flashcards
Gonads
testes and ovaries; develop from the same embryonic tissues (gonadal ridges) during 5th week of gestation
Gonads produce same types of products…
gametes via meiosis; steroid sex hormones (estrogen, progesterone and testosterone)
What regulates the production of gametes?
hypothalamic pituitary gonadal axis (HPG)
Hypothalamic Pituitary Axis
functions to regulate production of gametes and sex hormones
Inhibin
inhibits FSH ONLY
Scrotum
external sac enclosing testes; internal temp ~3 C lower than body temp;
Pampariform Venous Plexus
absorbs heat from the testicular artery
Cremaster Muscles
elevate testes; when it is cold
Duortes Muscle
wrinkles scrotal skin; when its cold
Testes
descend from abdomen into scortum thru inguinal canals; each one surrounded by 2 tunics
Spermatic Cords
connective tissue sheath; convey blood vessels, lymphatics, nerves and ducuts deferens to each testis
Tunica Vaginalis
outermost layer derived from the peritoneum
Tunica Albuanea
fibrous layer that forms septa, divising testis into lobules
Each lobule (of testis)…
contains 1-4 seminiferous tubules to straight tubule to rete testis to efferent duct to epididymis
Epididymis
comma shaped organ cupping the testis; contains a long, highly coiled duct; lined with pseudostratified epithelium; non motile stereocilia extend into lumen; sperm gain ability to swim and are stored until ejacualtion
Ductus Deferens
transports sperm from epididymis into pelvic cavity during ejaculation; ampulla (expanded end) merges with seminal vesicle duct to form ejaculatory duct
Urethra
transports both sperm and urine; subdivided into prostatic, mebranous and spongy regions
Penis
deposits sperm in female vagina; consists of root, shaft, and glans penis; prepuse (foreskin): loose skin covering the glans penis; contains 3 erectile tissues- 2 corpora lavernosa (dorsal) and 1 corpus spongiosum (ventral) (surrounds urethra)
Seminal Glands
2; contract during ejaculation to secrete thick, yellowish, alkaline fluid (contains fructose, ciltrate, clotting factors and protaglandins); contribute 70% of semen volume
Prostate Gland
1; donut shaped gland encirculing the urethra; contracts during ejaculation to secrete a milky, slightly acidic fluid (plays role in activating sperm); contributes ~30% semen vol
Bulbourethral Glands
2; pea sized glands embedded in the urogenital diaphragm; contracts during ejaculationto secrete a thick, clear mucus (functions to neutralize acid in male urethra and lubricates teh glans; <1% of semen vol
Semen
combination of sperm and accessory gland secretions; prostaglandin reduce viscosity of cervical mucus and stimulates reverse peristalsis in uterus; relaxin (hormone) enhances sperm motility; citrate and fructose provde sperm with energy source to make ATP; antibiotic chemicals; clotting factors and liquifying enzyems; pH 7.2-8 (helps neutralize acid in vagina); 2-5 ml per ejaculation; 20-150 million sperm/ml
Erection
enlargement and stiffening of penis; sexual excitement triggers parasympathetic reflex which stimules local release of nitrix oxide (NO) which vasodilates penile arterioles which leads to corpora caveronas filling with blood
Ejaculation
erectile impulses trigger sympathetic spinal reflex which constricts internal urethral sphincter and stimulates contraction of ductus deferens, prostate and seminal galnds; which leads to semen in urethra triggering somatic spinal refex which stimulates rythmic contractions of penile muscle resulting in ejaculation
Resolution
period of muscular and psychological relaxxation; follows ejaculation; initiated when SNS vasoconstricts penile arterioles, causing penis to become flaccid again
Spermatogenesis
process of sperm formation; begins at puberty; occurs in seminifrous tubules; occurs from puberty to death
Embryonic/Fetal Development- Males
primordial germ cells (PGCs) form in the yolk sac during 3rd week of embryonic development; PGCs prolifertae and migrate to gonadall ridges (weeks 5-9); gonadal ridges develop into testes (under influecne of SRY gene on Y chromosome); PGC differentitae into spermatogonia (2n stem cells) which divide continuously by mitoses to produce additional spermatogonia until puberty;
Sustenocytes
form blood testis barrier; provide nutrients; phagocytize defective cells; secrete testicular fluid; produce androgen binding protein (stimulates spermatogenesis) and inhibin (inhibits FSH release)
Spermatogenic Cells
sperm forming cells (spermatagonia, primary and secondary spermatocytes, spermatids)
Interstitial Endocrine Cells
(aka leydig cells); secrete testosterone; between seminiferous tubules
Myoid Cells
smooth muscle like cells; move materials along tubule
Events of Spermatogenesis
1) spermatogonia (2n) stem cells that divide mitotically to form 2 types of daughter cells; 2) Primary spermatocytes (2n) divide via meiosis to form spermatids 3) spermiogenesis occurs
Type A Cell
2n; remains spermatognia and maintains pop; does not move down to become spermatids
Type B Cells
move toward lumen to form primary spermatocytes; 2n; programmed to undergo meiosis
Primary Spermatocytes to…
meiosis I to become (2) secondary spermatocytes (n) and then meiosis 2 to become 4 spermatids (n)
Spermiogenesis
spermatids modified to form sperm; golgi apparatus packages acrosome enzymes; acrosome forms at anterior end; microtubules extend from centrioles to form flagellum; mitochondria multiply and cluster at base of flagella; excess cytoplasm sheds
How long does it take to go from primary spermatocyte to spermatozoa
64-72 days
Effects of Testosterone
stimulates formation of male ducts, glands, and external genitalia; masculinizes the brain and promotes descent of testes; stimulates growth spurt and development of male secondary sex characteristics at puberty; maintains adult size and function of genitalia; required for spermatogenesis;influences and libido; increases bone density and skeletal muscle mass
Ovaries
suspended in peritoneal cavity by suspensory, ovarian and broad ligament
Layers/Parts of the Ovary
layer of cuboidal cells (surface epithelium); Tunica albuginea (fibrous tunic); cortex (contains ovarian follicles); medulla (contains blood vessels and nerves)
Uterine Tubes
not connected to ovaries; consists of three regions- infundibulum, ampulla, isthmus; wall contains smooth muscle; mucosa highly folded with 2 cell types;
Infundibulum
funnel shaped region that bears ciliated fimbria; receives ovulated oocyte
Ampulla
widened region; usual site of fertilization
Isthmus
constricted region attached to uterus
Ciliated Cells
help transport ovulated oocyte toward uterus
Nonciliated Cells
have microvilli that produce noursihing secretion
Ectopic Pregnancy
implantation occurs somewhree besides uterus (normally oviduct)
PID
pelvic inflammatory disase
Uterus
receives and nourishes developing embryo; consists of fundus, body and cervix (contains cervical glands)
Pap Smear
scraps cells from cervix and look for abnormal cells; papillomavirus
Prolapsed Uterus
uterus can drop cervix into vagina
Wall of the Uterus consists of:
perimetrium, myometrium, endometrium
Perimetrium
visceral peritoneum
Myometrium
bundles of smooth muscle
Endometrium
innermost; receives implanted embryo if fertilization occurs
Stratum Functionalis
sheds during menstruation
Stratum Basalis
forms a new functional layer after menstruation ends
Spiral Arteries
serve functional layer and repeatedly degenerate and regenerate
Straight Arteries
serve basal layer and do not degenerate
Vagina
sanwhiched between bladder and rectum; passageway for menstrual flow and delivery of infant
Wall of Vagina consists of…
adventitia (fibroelastic outer layer); muscularis (smooth muscle); mucosaa (innermost, stratified squamous with rugae
What lubricates the vagina?
cervical mucous glands and mucosal fluid from vaginal epithelium
pH of Vagina
acidic; alkaline in adolescents
Mons Pubis
fatty rounded area over pubic sympysis
Labia
skin folds; labia majora (Lg, hair covered fatty folds); labia minora (thin, hairless folds)
Vestibule
recess enclosing the urethral and vaginal orifices
Greater Vestibular Glands
release mucus into vestibule
Clitoris
richly innervated erectile tissue; contains copora cavernosa
Mammary Glands
modified sweat glands found in both sexes; develop ability to produce milk under influence of pregnancy hormones
Breast Cancer
2nd most common type of cancer among females in the US; usually arises in epithelial cells of small ducts; 70% of women have no known risk factors; most are discovered by mammograms; 5yr survival rate >90%
Oogenesis
process of egg formation; begins before birth and continues till menopause
Embryonic/Fetal Development of Eggs
primordial germ cells (PGCs) form in the yolk sac during 3rd week of embryonic development; PGCs proliferate and migrate to gonadal ridges (week 5-9); gonadal ridges develop into ovaries (SRY gene absent); PGCs differentiate into oogonia (2n stem cells) which divide by mitososis and enlarge to form primary oocytes (2n)
Oogenesis Steps
Primary oocytes begin meiosis I but arrest in prophase I (in womb/before birth); by 5th week 7 million oocytes formed ; ~20 dormant primary oocytes are recruited (activataed) each month (complete meisosis I); only one moves on to be ovulated (depends on estrogen levels); secondary oocyte begins meiosis II but arrests in metaphase II and is ovulated; secondary oocyte completes meiosis II ONLY if fertilization occurs (1st and 2nd polar bodies degenerate)
Primordial Follicle
primary oocyte surrounded by 1 layer of flattened follicle cells
Primary Follicle
primary oocyte surrounded by single layer of cuboidal follicle cells
Secondary Follicle
primary oocyte surrounded by 2 or more layers of granulosa cells
Vesicular Follicle
or antral/tertiary; contains a fluuid filled cavity (antrum)
Grafian Follicle
large, mature follicle; secondary oocyte within hours of being ovulated
Ovarian Cycle
monthly series of events associated with ovum (egg) maturation; avg cycle about 28 days (but can range from 21-40); regulated by fluctuating levels of FSH and LH (affect vesicular follicles ONLY); consists of follicular phase and luteal
Follicular Phase
14 days but varies from 7-26; falling FSH levels trigger atreasia of all non dominant vesicular follicles ; primary oocyte of dominant follicle completes MI forming secondary oocyte (begins but does not complete M2) and first polar body; secondary oocyte ovulated
Fraternal Twins
resutls from 2 sperm fertilizng 2 separate eggs
Identical Twins
result from the splitting of an early stage embryo
Luteal Phase
ALWAYS 14 days after ovulation; initiated by ovulation; ruptured follicle collapses and antrum fills with clotted blood forming a corpus hermorrhagium; clot is resorbed and remaining granulosa and thecca cells form corpous luteum (secretes progesterone and some estrogen)
If implantation of embryo does not occur…
corpus luteum degenerates forming a scar (the corupus albicans)
If implanata of embryo does occur…
corpus luteum persists until placenta is able to take over hormone producing duties of corpus luteum (~3 months)
Regulation of female reproductive function at onset of puberty
linked to fat content of body (adipose produces the protein hormone liptin); if fat content is adequate hypothalamus becomes less sensitive to estrogen; if fat content and leptin low, puberty is delayed
Female REproductino Function: Adult Pattern Steps
1) GnRH stimulates ant pituitary to secrete FSH and LH; 2) LH initially stimulates thecal cells to release androgens; FSH stimulates granulosa cells to convert androgens to estrogens and secrete inhibin; 3) slightly elevated estrogen levels and rising inhibin exert negative feedback inhibiting release of FSH 4) mature dominant follicle produces large amounts of estrogens which exerts postivie feedback and triggering LH surge; 5) LH surge triggers- primary oocyte to complete meiosis I (and begin II), ovulation and transition of ruptured follicle into a corpus luteum ; 6) elveated progesterone, estrogens and inhibin exert negative feedback inhibiing release of LH and FSH
Uterine (Menstrual) Cycle
monthly changes in the endometrium; regulated by estrogens and progesterone; consists of menstrual, proliferative and secretory phase
Proliferative Phase
5-14 days; basal layer of endometrium form new functional layer; formation of progesterone receptors on endothelial cells; thinning of cervical mucus
Amenorrhea
not menstruating
Secretory Phase
15-28 days; endometrium prepares for implantation; rising progesterone levels stimualte spiral arteries to increase blood supply to endo metrium, endothelial glands enlarge and secrete glycogen into uterine cavity, cervical mucus thickens to form cervical plus
Effects of Estrogen
mostly estradiol; promotes oogenesis, follicle growth, and ovulation; stimulates growth spurt and development of secondary sex characterisitics at puberty; stimulates closure of epiphyseal plates at puberty in both males and females; maintains adult size and function of genetalia; stimulates production of watery cervical mucus; in conjunction with DHEA influecnes libido; inhibits diuresis (releasing lg amts of water)
Effects of Progesterone
after ovulation, enhances beting of cilia in uterine tubes to facilitate sperm momvement toward ovulated oocyte; promotes secretoy phase of uterine cycle; acts with estrogens to stimulate breast development; stimulates production of viscous cervical mucous; promotes diuresis
Female Erection
clitodirs, vaginal mucosa, and breasts engorge with blood; greater vestibular glands incresae secretion to lubricate vagina
Female Orgasm
intense pleasure followed by relaxation; unlike male is not accompanied by ejaculation or a refractory period; female orgasm not required for contraception
Trichomornasis
parasitic inf; more common in females than males; 70% of women asymptomatic; yellow green vaginal discharge with strong odor is most common symptom
Chlamydia
most common STI in the US; most infection are symptomatic; symptoms include urethrisi, vaginal or penile discharge, painful intercourse and irregular menses; in females responsible for 25-50% PID and major cause of sterility ; new borns affected during bith develop conjunctivites and respiratory tract infection
Gonorrhea
caused by the bacterium, neisseria gonorrhea; most infections asymptomatic; most common symptom in males is uretheritis; if untreated- in males urethral constriction and inflammation of ducts; in females PID and sterility
Syphilis
caused by bacterium treparema pallidum; primary symphilis- painless sore develops ~3 weeks post infection, disappears within a few weeks; secondary - body rash develops several weeks later; may exhibit fever and joint pain, enters latent period; tertiary- destructive lesions of CNS, blood vessels, bones and skin
Human Papillomavirus
most common STI in US; causes congenital warts; linked to 80% of all cases of invasive cervical cancer as well as penile, anal and oropharyngeal cancers; gardasil vaccine recommnede dfor both sexes before being sexually active
Genital Herpes
caused by herpes simplex virus; usually asymptomatic, however painful blister like lesion flareup repeatedly over time ; antiviral drugs reduce duration and intensity of flare ups; congenital herpes casues sever fetla malformations
