Reprductive System Flashcards
“Each cell” in your body contains ..
46 chromosomes (23 homologous pairs)*
Each cell has the exact same chromosomes
Homologous pair members
- ) look like the other
2. ) carries the same type of genes
23 pairs of chromosomes
Diploid chromosome number (2n)
Reproduction - Gonad
Gonad (2n cells)
—-meiosis—-> Sperm cell
—> Oocyte
Sperm cell & oocyte = Gametes
—> 23 unpaired chromosomes (1n)
Haploid chromosome number (1n)
23 unpaired chromosomes
Reproductive organs (primary)
Primary reproductive gonads
—> ovaries
-> gametes = oocytes
-> hormones = - estrogen
- progestins
—> testes
- > gametes = spermatozoa
- > hormones = androgens (test.)
Gonads
- Make gametes (sex cells)
2. Secrete sex hormones
Reproductive organs (accessory)
Accessory reproductive organs
- > nourish, transport, and store gametes
- > allow copulation (sex)
- > allow gestation
Male reproductive system
Glands:
- testes (2)
- seminal vesicles (2)
- prostate (1)
- bulbourethal (cowper’s) gland (2)
Ducts:
- epididymis (2)
- vas deferens (2)
- ejaculatory ducts (2)
- urethra (1)
Supporting Structures:
- spermatic cords (2)
- scrotum
- penis
Development of the Testes - descent of the testes
Testes begin development within the abdominal-pelvic cavity -> anchored to the pelvic floor by DFCT
*Gubernaculum - anchors testes to the pelvic floor
Fetus grows - Gubernaculum stays the same length - *accounts for testes descending
At 7 months - Gubernaculum shortens - pulls testes into the scrotum along with tubes + wires
When Testes pulled through.. they drag with them..
- Fibers of the internal oblique muscle -> Cremaster muscle
- CT of body wall -> spermatic facia
- Testicular blood vessels
- Vas Deferens
- Testicular Nerves - regulate temp. of blood
ALL FORM —> Spermatic Cord
Cremaster muscle
Regulates temperature
Cryptorchidism
Failure of the testes/testis to descend
If not corrected
- > sterility of the non descended testis
- > big increases risk of testicular cancer
Testis Structure
Wall - outer layer
-> serious membrane called Tunica Vaginalis (outer layer of testicles)
Underneath*
DFCT -> Tunica Albuginea
Tunica Albuginea:
Inward radiating walls (septa)
-> part testes into 250-300 lobules
Lobules -> smallest functional unit of the testicle
-> each contain 1-4 coiled Seminiferous Tubules* (“sperm factories”)
Spermatogenesis (see pic)
Spermatogonium (46)
- pre mitosis (duplicates chromosomes)—>
- Spermatogonium now has 92 chromatids—mitosis—>
Primary Spermatocyte (46)
*Other spermatogonium (remains behind attached to wall
Primary Spermatocyte
- pre meiosis (duplicates chromosomes)—>
- now has 92 chromatids
—Meiosis 1–>
Secondary Spermatocytes (46) (x2)
—Meiosis 2–>
Spermatids (23) (x4)
—Spermiogensis—>
Spermatozoa (23) (x4)
Spermiogensis
Process where spermatids are transformed into spermatozoa
Spermiogensis
Loss of most of the cytoplasm of the Spermatid
Formation of:
- acrosome -> hyaluronic acid - acid that digests the “egg shell”
- mid piece -> mitochondria - ATP - used to power “run” flagellum
- flagellum (tail)
Errors in Meiosis
Non Disjunction (females)
- > failure of chromosomes to segregate during Meiosis
- > results in gametes that have a faulty chromosome number (Down syndrome “Trisomy 21”
Females
XX
Males
XY
Development of gender
Females -> Oogenesis
50% oocytes carry X
50% oocytes carry X
Males -> Spermatogenesis
50% carry X
50% carry Y
*sperm determines gender of child
Further gender development
- All embryos contain duct precursors for both male and female reproductive organs
- male duct precursors - Wolffion ducts
- female duct precursors - Müllerian ducts
- Up to 6 weeks gestation, males and females are indistinguishable (have ducts for both)
- The automatic pattern of development is Müllerian development -> female fetus, and this will occur in the absence of hormonal modification
XY
Causes the embryo to produce Testes
- become active at 7 weeks
- produce the hormones
- testosterone
- MIF (Müllerian duct inhibiting factor)
- stimulates Wolffion development
- > produces male
- MIF -> stops female development *
Control of Testosterone secretion + Spermatogenesis
Brain - Testicular axis
See diagram in notes *
Hypothalamus
—secretes GNRH on—>
Anterior pituitary gland
—secretes FSH on—> Sustentacular cells
—secretes LH on—> Interstitial cells
Sustentacular cells
—secrete inhibin on—> Anterior P. Gland
(Inhibits FSH output from Anterior P.)
—secrete ABP (androgen bonding protein)
*ABP allows testosterone to bind to
spermatogonia -> stimulates
Spermatogenesis
Interstitial cells
—secrete testosterone -> stimulates
Spermatogenesis
Testosterone - all systemic effects
- high concentrations of
testosterone inhibit GNRH
output from hypothalamus
Sperm count
Ejaculatory volume (mL) (2-5mL)
x
Concentration (number of sperm cells/mL)
(20-100 million/mL)
Up to 500 million per ejaculation
Minimum requirement for fertility
- count at least 60 million/ejaculation
- at least 60% should swim
- at least 60% should be normal morphology (looks right, right shape)
Sperm can live up to 48 hours in the female reproductive tract
Oocyte lives for 24 hours if not fertilized
Seminal vesicles
Seminal fluid
-> 60% of semen volume
- > basic (alkaline) - neutralizes acid in female reproductive tract
- > fructose “sperm food” gives sperm energy
- > fibrinogen - semen clot
Prostate gland
Prostatic fluid
-> 30% of semen volume
- > seminalplasmin (kills bacteria)
- > fibrinolysin - liquefies clot
BPH - Bennie Prostatic Hypertrophy
- enlarged prostate
- older men (>50)
- treated with drugs -> decreases androgens to shrink prostate
- TURP - transurethraldisectomy (surgery)
Prostatic Carcinoa - #1 male cancer
Cowper’s Gland
Cowper’s fluid
-> 5% of semen
-> secreted during erection
-> alkaline mucus
- neutralizes acid urine in males urethra
because sperm don’t like an acidic
environment
*both lubrication for copulation
Epididymis
Long coiled tube (21 inches)
Functions:
- stores sperm
- adjusts Testicular fluid
- absorbs dead sperm
- sperm mature here
Vas Deferens
18 inches long
Smooth muscle
- peristalsis of Testicular fluid to ejaculatory
duct
- vasectomy - cut and tie off vas deferens
Ejaculatory duct? Urethra?
Scrotum
Sac of skin + facia
Facia -> holds testes
Scrotum -> dartos muscle
-> when cold.. muscle contracts
-tightens scrotal skin
-decrease of surface area
which conserves heat
Penis
Regions
- root
- body (shaft)
- glans
Glans - covered by *prepuce:
- sebacious glands (smegma)
- foreskin
—> circumcission
Erectile Tissue
Spongy, vascular CT
-> corpora cavernosa (2)
- > corpus spongiosum
- urethra
- forms bulb (proximal)
- forms glans (distal)
Erection reflex
Autonomic Nervous System (ANS)
- parasympathetic*
Sacral spine - dump nitric oxide on anterioles of erectile tissue - dilate - blood to cells - erection
Sacral spine also activates Cowper’s glands
Ejaculation reflex
Sympathetic
Emission : L1 L2
-> stimulate peristalsis in
epididymis tail and vas
deferens
-> seminal vesicles - send seminal fluid
into urethra
-> prostate- send prostatic fluid into
urethra
Seminal vesicles and prostate contract **
Contraction of skeletal muscles about the bulb of penis —> ejaculation
Ejaculation effects
Increased heart rate
Increased blood pressure
Increased sweating
Increased respiration
Pupils dilate
Endorphins - make you feel good
Female reproductive system
Glands:
- Ovaries (2)
- Bartholins glands (2)
- Uterine glands
Ducts:
- Fallopian tubes (2)
- uterus
- vagina
External genitalia (vulva)
- mons pubis
- labia majora
- labia minora
- clitoris
- vaginal + urethral openings
Breasts:
- breasts
Ovary
Outer layers
-> germinal epithelium
(simple cuboidal)
-> tunica albuginea - DFCT
Outer region
- > ovarian cortex
- vascular CT
- contains ovarian follicles
Ovarian follicles
- release oocytes
- release sex hormones
Core - medulla
- vascular CT
- large blood vessels
Ovarian Follicles (pre ovulatory)
Central Oocyte
Epithelial cells -> secrete female
sex hormones
Primordial
- oocyte surrounded by one layer of squamous cells (follicle cells) -> inactive
Primary
- oocyte surrounded by one or a few layers of cuboidal cells -> granulosa cells -> secrete estrogens*
Secondary
- oocyte surrounded by many layers of cuboidal cells (increased estrogen)
Graafian
- oocyte surrounded by many layers of cuboidal cells and large antrums
Oogenesis - pre natal
Oogonia (2n)
—mitosis—>
Primary oocytes
-> begin meiosis 1
-are arrested in prophase of meiosis
1 (2n x 2) 92 chromatids
- at birth, ovaries hold 1-2 million
primary oocytes
- by puberty -> about 400,000
remain
Oogenesis
Day 1 - ovarian cycle
See diagram
Fallopian tubes
About 5 inches long
- infundibulum with fimbriae
- ampulla
- isthmus
- uterine
Histology:
Outer layer - visceral peritoneum (simple squamous)
Middle layer - muscularis
- smooth muscle
- peristalsis
Inner layer - mucosa
- vascular CT - lamina propia
- simple columnar epithelium
with ciliated and non ciliated
cells
PID
1 cause of sterility
Pelvic inflammatory disease
- bacterial infection of female reproductive tract
- chronic
-> inflammation
-> collagen fibers (scar tissue)
build up and clog fallopian
tube
The Uterus
Regions
- Fundus -> superior rounded
- body -> surrounds uterine cavity
- Isthmus -> surrounds cervical canal
- > cervix
Histology/layers:
Outer - visceral peritoneum -> Perimetrium
Middle - myometrium - smooth muscle
-90% of uterine wall
Inner - endometrium - thick mucosa
- lamina propia - vascular CT
- simple columnar
- 10% of uterine wall
*endometrium -> uterine glands -> secrete glycogen
Endometrium
Stratum Basalis
- > contracts myometrium - > thinner, permanent
Stratum Functionalis
- > faces lumen - > thicker, shed + regrown once per month
Stratum basalis
Fed by straight arteries
-> always open
Stratum functionalis
Fed by spiral arteries
-> constrict/dilate in response to changing ovarian hormones
Spiral arteries
- when there is an increase in estrogen, stratum functionalis and it’s spiral arteries grow - proliferate
- when there is an increase in progestins, stratum functionalis and spiral arteries dilate
- when levels of progestins decrease, stratum functionalis and spiral arteries constrict -> stratum functionalis dies, sloughed off
Ovarian + menstrual cycle
Concurrent, 28 day cycles in which changing levels of ovarian hormones cause uterine stratum functionalis to be alternately shed and regrown
Ovarian cycle —causes—> uterine cycle
Ovarian cycle *see diagram
Hypothalamus
-secretes GNRH on->
(Day 1 - 1 spurt/60-90 min)
Anterior Pituitary Gland
-secretes FSH on->
Primordial follicles
-secretes LH on Graafian follicle
(stimulates ovulation**)
Primordial cells after FSH
-turn into—>
Primary follicles
-secrete inhibin on anterior pituitary g.
(inhibits FSH output)
- secretes estrogen
(est. stimulates more follicular growth)
Primary follicle —> secondary follicles
Secondary follicle
-secrete more estrogen
(more follicular growth)
Secondary follicle —> Graafian follicle (day 13)
Graafian follicle
-secretes tons o estrogen->
-increased estrogen causes
hypothalamus to increase frequency
of GNRH to (1 spurt/30 min) (day 13)
Increased estrogen also causes a blast of LH from the anterior pituitary gland on to the Graafian follicle which stimulates ovulation
->
Corpus Luteum forms
-> secretes progestins
-increased progestin output
inhibits GNRH release from the
hypothalamus
Corpus Luteum lives two weeks, if not conception, it dies and becomes -> Corpus Albicans
.. next cycle
***when Corpus Luteum dies, it stops producing progestins, so inhibition of hypothalamus stops and it releases GNRH again
Ovarian cycle phases
Day 1-14 -> Follicular Phase
-> increased estrogen
-ovulation-
Day 14-28 -> Luteal phase
-> increased progesterone
If conception happens:
Oocyte —> embryo
embryo —> secretes human chorionic
gonadotropin
-> keeps the corpus luteum
alive + secretes progestins
for 2-3 months.. after ->
placenta produces progestins
Menstrual cycle *see diagram in notes
Uterine cycle
Mensis-> /7 days/ -> proliferative
—> ovulation -> secretory
Ovarian cycle
Follicular phases -> /ovulation (day 14) —
—> luteal
Mensis (1/2 of follicular)
- decreases estrogen
- decreases progestins
- spiral arteries constrict
- > stratum functionalis dies/sloughed off
Proliferative (1/2 of follicular)
- increased estrogen
- s functionalis regrows
- uterine glands increase in number
- cervical mucus thins out
Ovulation - day 14
Secretory phase (luteal phase)
- increased progestins
- spiral arteries dilate
- stratum functionalis thickens
- uterine glands secrete glycogen
- cervical mucus plug forms
Vagina
Histology
- outer -> Aventitia - DFCT
- mid -> smooth muscle - muscularis
- inner -> mucosa
- vascular CT - lamina propia
- stratified squamous
Functions:
- female copulatory organ
- birth canal
- outlet for menstrual flow
Vulva - see other notes*
- mons pubis - adipose tissue
