Anatomy & Physiology Reproductive & Urinary Systems; Fluid, Electrolytes, Acid-Base Balance

Functions of the Reproductive System

Production of gametes, fertilization, development and nourishment of a new individual, production of reproductive hormones

Gametes

Haploid sex cells produced by gonads

Oocytes

female gametes

Spermatazoa

sperm cells/male gametes

Ovum

in females; egg (secondary oocyte), haploid nucleus + 1 haploid polar body prior to fertilization

Fertilization

fusion of the haploid sperm nucleus with the secondary oocyte haploid nucleus

Zygote

diploid, single cell product of fertilization

Acrosome

“head” of sperm cells, contain hydrolytic enzymes that breakdown the glycoprotein matrix of the zona pellucida

zona pellucida

a structure that surrounds egg cells where sperm cells bind to receptors, becomes impermeable upon fertilization, preventing the entry of further sperm.

exocytosis of cortical granules

drives the structural chanes in the zona pellucida upon fertilization, secreted by the cells of the corona radiata.

Ductus (Vas) Deferens

transports sperm from the epididymus to the seminal vesicle. walls have smooth muscle that exhibits peristalsis during ejaculation.

seminal vesicle

produces approx 60% of the contents of semen, empties into the ejaculatory duct

prostate gland

produces approx. 30% of the contents of semen and secretes contents into the prostatic urethra.

bulbourethral gland

produces approximately 5% of the contents of semen, mostly mucus for lubrication of the urethra and neutralization of the vaginal environment (normally around pH 4.5; too acidic for sperm cells to survive)

Testis / Testes pl. / Testicle(s)

act as both endocrine (secretion of the hormone testosterone) and exocrine glands (production, some maturation of, and expulsion of sperm cells)

capacitation

final maturation of sperm cells, occurs in females.

Hypothalamus

at puberty, produces gonadotropin releasing hormone (GnRH), which travels to the anterior pituitary gland which produces luteinizing hormone (LH) and follicle stimulating hormone (FSH) as a response.

scrotum

2 chambered sac that contains the testes; contraction and relaxation of 2 muscles: dartos and cremaster muscles help regulation temperature

Spermatogenesis

Sperm production

Spermiogenisis

Sperm maturation

93.2F

the temperature in which sperm production occurs, 5F below normal body temperature

Perineum

diamond shaped area between thighs on males and females.

Tunica Vaginalisis

derived from serous membrane of the peritoneum, but not continuous with the peritoneum to keep sperm cells separated from interstitial fluids and blood, part of the “immune privilege of the testes”

Tunica Albunginea

thick connective tissue that penetrates the testis into lobules

Lobules

contain convoluted coils of densely packed sperm-producing structures called seminiferous tubules. also contain, outside of the seminiferous tubules, interstitial cells called Leydig cells

Effent ductules

lead out of testes

epididymis

site of sperm cell maturation (spermiogenesis; takes minimum of 1-2 days)

Stereocilia

actin-based protrusions that are also present on auditory and vestibular sensory cells, required for hearing and balance. found in pseudostratified columnar epithelium. increase surface area to facilitate absorption of fluid from the lumen of the seminiferous tubules and epididymis for transport of sperm cells outside of the body.

Ejaculatory duct

joining of ductus deferens and seminal vesicle, ends at urethra within prostate gland

urethra (male)

extends from urinary bladder to distal end of penis, passageway for urine and semen; 3 mains parts + a fourth minor portion

prostatic urethra

connected to the bladder, passes through the prostate gland

membranous urethra

extends through perineum to penis

spongy or penile urethra

passes through the penis

Penis

urinary organ, serves as copulatory organ for transport of sperm in semen to vagina

Erection

three columns of erectile tissue engorge with blood due to vasodilation of afferent arterioles and vasoconstriction of venules and veins in the penis - due to compression of these vessels as the penis becomes engorged with blood. the relaxtion of smooth muscles surrounding blood vessels in the penis promotes vasodilation.

Nitric Oxide (NO)

produced and acts as a neurotransmitter of parasympathetic neurons in the penis; promotes smooth muscle relaxation and vasodilation

Corpus Cavernosa

2 columns of tissue. run longitudinally along lateral aspects; expanded at base near the bulb at the base of the penis.

corpus spongiosum

1 column of tissue. surrounding spongy urethra

glans penis

enlargement of corpus spongiosum; anatomically, but not functionally, homologous to the glans clitoris of female reproductive system

prepuce or foreskin

covers the glans penis

circumcision

surgical removal of the foreskin

external urethra orifice

outer opening of the urethra

seminal vesicle

accessory gland; empties into the ejaculatory duct. produces about 60% of semen. secretion contains fibrinogen- making semen initially viscous and hydrophobic. high pH- neutralizes the low pH (approx 4.5) of the vagina otherwise sperm cells would die.

prostate gland

accessory gland; produces about 30% of semen. thin, milky secretion, high pH. contains clotting facots and fibrinolysin; initially semen is very viscous and then fibrinolysin results in less viscosity, semen becomes watery and hydrophillic. sperm cells become more motile and more metabolically active (capacitation)

bulbourethral gland

accessory gland; contributes to 5% of semen. mucous secretion. just before ejaculation, also helps neutralize pH of vagina.

accessory glands (male)

prostate gland, bulbourethral gland, seminal vesicle

semen

secretions of seminal fluid (from prostate gland, bulbourethral gland, and seminal vesicle) + semen

emission

discharge of semen into prostatic urethra

ejaculation

forceful expulsion of semen from urethra caused by peristalsis.

capacitation

sperm cells become more active as the final stages of flagella maturation takes place in the vagina, approx 15-20 min later liquefication frees the sperm to swim to the ovum for fertilization, usually in the fallopian tube.

female reproductive organs

ovaries, uterine tubes, uterus, vagina, external genital organs, mammary glands

ovaries

female gonads; production of gametes (ova / secondary oocytes) and hormones. both endocrine and exocrine functions.

uterine tubes

AKA Fallopian tubes or salpinges

uterus

3 main regions, body, isthmus, (cervix), and fundus. composed of 3 layers; peritoneum, myometrium, endometrium

fundus

bottom or foundation of uterus

perimetrium

serous membrane, outer part of uterus

myometrium

smooth muscle, middle part of uterus

endometrium

mucous membrane, inner part of uterus. simple tubular glands that build up and maintenance of the endometrium: form lacunae that will coalesce when the blastocyst implants; secrete glycogen as an energy source for the embryo, promotes increased vascularization in preparation for possible blastocyst implantation.

functional layer

innermost layer of uterus, replaced monthly during menstrual cycle

basal layer

deepest layer of uterus- maintains regenerative epithelial stem cell population and tubular gland formation

Cervix

more rigid and less contracile than rest of uterus

Cervical canal

lined with mucous glands; mucous plug except near ovulation

vagina

female organ of copulation, allows menstrual flow and childbirth, muscular walls with mucous membrane lining (moist stratified squamous epithelium)

hymen

covers the vaginal opening or orifice

fornix

superior domed portion attached to sides of cervix

ovarian germinal epithelium

outermost covering of ovary

tunica albuginea

capsule of dense fibrous connective tissue in ovary

ovary cortex

outer layer, dense, contains follicles with oocytes.

ovary medulla

inner layer, looser. contains blood vessels, nerves, and lymphatic vessels

ovary stroma

connective tissue of an ovary

vulva

collectively refers to the external female genitalia

labia minora

forms borders on both sides of the vagina

clitoris

female erectile structure.

corpus cavernosum (female)

of the clitoris; relatively large columns that become engorged with blood when erect.

corpus spongiosum

of the clitoris; small amount of spongy tissue extending anterior to make up the glans clitoris

labia majora

rounded folds of skin on either side of labia minora. unite to form mons pubis. medial surfaces covered with numerous sebaceous and sweat glands.

vaginal orifice

in lateral margins; erectile tissue called the bulb of vestibule (homologous to corpus spongiosum in males)

pudenal cleft

space between labia majora

mons pubis

anteriorly labia majora merge in an elevated area over the symphysis pubis

mammary glands

organs of milk production located within the breasts. consist of glandular lobes and adipose tissue. modified sweat glands, most closely related to apocrine sweat glands.

gametogenesis

formation of gametes. spermatogenesis in males (seminiferous tubules) oogenesis in females (ovaries)

details of spermatogenesis

leydig cells secrete testosterone, stimulates secondary sex traits and spermatogenesis. at puberty, GnRH from the hypothalamus stimulates the pituitary lobe to release LH and FSH. LH promotes sperm production by stimulating Leydig cells to release testosterone.

spermatogonia

sperm stem cells; diploid cells in seminiferous tubules. near sertoli cells deep in testicular tissues divided by mitosis.

sertoli cells

form tight intercellular junctions forming the blood-testicular-barrier: isolates sperm cells from the immune system to prevent formation of antibodies against sperm cells. AKA nurse cells, nourish the sperm cell and prevent infection.

spermiogenesis

completion of sperm differentiation and migration to the lumen of the seminiferous tubule. loss of superfluous cytoplasm, development of acrosome

acrosome

shield like structure on the head of a sperm cell which secretes hydrolytic enzymes that facilitate fertilization of the egg

oogenesis

production of secondary oocytes in the ovaries.

stages of follicle maturation

1. primordial follicle (only one layer of cells)

2. primary follicle (two layers of cells

3. secondary follicle (fluid filled space)

4. vesicular/ mature (graafian) follicle: bulges

5. corpus luteum: the ruptured follicle

primordial follicles

develop from oogonial cells (oocyte stem cells) + squamous epithelial cells

primary follicles

primary oocytes (diploid) stem cells divide by meiosis (no mitosis as in males)

meiosis 1 (females)

starts during fetal development, then stops and resumes during puberty

secondary follicle

partial completion of secondary oocyte development (started, but hasnt completed meiosis II)

graafian (mature) follicle

contains the ovum (secondary oocyte that has yet to complete meiosis). usually only one ovulated at a time. vesicles signal the completion of development.

corpus luteum

remnants of the ruptured follicle after the release of an ovum. yellow body is from presence of lipids and lipid-soluble carotenoids. produces progesterone for a while to ensure maintenance of the endometrium and prevention of next ovarian cycle if necessary. degenerates into corpus albicans (white body)

ovulation

rupture of the mature follicle and release of the ovum and supportive cells.

corona radiata

cells that surround the egg “shiny crown”

zona pellucida

clear glycoprotein matrix located between egg and corona radiate. contains sperm receptors which a sperm will attach too after the acrosome had digested the corona radiata

syngamy

single sperm cell fertilization of ovum

fertilization results in

1. fusion of haploid gamete nuclei

2. completion of meiosis II

3. formation of third polar body (haploid, non gametic cells of meiosis)

4. formation of a diploid zygote

placenta

usually formed by 18-20 weeks, takes over progesterone production from corpus luteum.