Reproductive System Flashcards
What is reproduction?
- sexual reproduction produces new individuals
- fertilization results in one cell with 23 chromosomes from each parent
- gonad primary sex organ
- testis in male
- ovary in female
- produce gametes, sex hormones
- gamete - sex cell
- sperm in males
- 2nd oocyte in females
- sex hormones
- testosterone in males
- estrogens, progesterone, etc. in females
what is the scrotum?
- sac of skin, fascia, smooth muscle suspended from perineum
- divided internally by septum
- supporting structure for testes
what are testes?
- paired oval glands
- 4 cm X 2.5 cm, 10 -15 grams
- develop near kidneys, descend to scrotum via inguinal canal during 7th month of gestation
- maintained 3 degrees Celsius below core temp.
testis - tunica vaginalis?
- outer covering of serous membrane
- extension of peritoneum
- partially covers testis
testis - tunica albuginea?
- dense fibrous capsule internal to tunica vaginalis
- extends inward as septa
testis - septa?
- divide testis into 200 - 300 lobules
- lobules contain seminiferous tubules and interstitial cells
structure of testis - sustentacular cells
- extend from basement membrane to lumen
- support developing sperm cells
- produce fluid, control release of sperm into lumen
- secrete inhibin (slows down sperm production)
what is spermatogenesis?
- production of sperm in wall of seminiferous tubules
- begins at puberty and continues until old age
- takes 65-75 days
sperm morphology?
- adapted for reaching, penetrating a secondary oocyte
- head contains acrosomes, DNA, enzymes
- midpiece contains mitochondria (make ATP)
- tail is flagellum for motility
hormonal control of spermatogenesis?
- at puberty:
- increase gonadotropin-RH from the hypothalamus
- increase LH, FSH from the anterior pituitary
- LH stimulates interstitial cells to secrete testosterone
- FSH acts with testosterone to stimulate spermatogenesis
what are hormonal effects of testosterone?
- testosterone binds to receptors in the cell nucleus, changes genetic activity
- prenatal surge > masculinization of the fetus
- increase at puberty > development of secondary sexual characteristics, adult reproductive system
what makes ul the duct system?
- seminiferous tubules
- epididymis
- vas deferens
- ejaculatory duct
- urethra
- penis
what is the epididymis?
- coiled tube, 6m long
- stores sperm
- sperm mature (~20 days)
- storage 1-2 months
what is the vas (ductus) deferens?
- smooth muscle tube
- extends from scrotum to pelvic cavity via the inguinal canal
- stores sperm
- propels sperm by peristalsis
- connects with the seminal vesicle to form the ejaculatory duct
what is the ejaculatory duct?
- passes through the prostate gland
- joins the urethra
- secretes fluid to the urethra just before ejaculation
- contracts to propel sperm
what is the urethra?
- smooth muscle tube
- conveys both urine and semen
what is the seminal vesicle?
- sac-like structure posterior to the bladder
- produce seminal vesicle
what is seminal fluid?
- viscous alkaline secretion
- neutralizes acidic pH of vagina, male urethra
- prostaglandins stimulate sperm motility, viability
- fructose for ATP production
- clotting proteins for coagulation of semen
what is the prostate gland?
- doughnut-shaped
- surrounds the urethra, inferior to the bladder
- produces fluid that contains citric acid, proteolytic enzymes, antibiotics
what are bulbourethral glands?
- paired, pea-sized glands
- secrete watery, alkaline mucus
- lubricates the urethra, neutralizes the acidity of the urethra
what is semen?
- a milky mixture of sperm, secretions from accessory organs
- fructose, citric acid provides energy
- alkaline pH neutralizes acids
- prostaglandins stimulate motility
- antibiotic inhibits microorganisms
- 2 - 5 mL/ejaculation
- 50 - 150 million sperm/mL
- sperm count of <20 million/mL infertility
- coagulates within 5 min, reliquifies in 15 min due to proteolytic enzymes from prostate
what is the penis?
- passageway for semen, urine
- body composed of 3 erectile tissue masses that fill with blood > erection
- corpora cavernosa
- upper paired, erectile tissue masses
- corpus spongiosum
- lower erectile mass
- surrounds urethra
- ends as glans penis
what is an erection and how does it happen?
- parasympathetic impulses from the sacral spinal cord via pelvic nerves
- arteries to the penis dilate
- blood flow to erectile tissue increases
- erectile tissue becomes engorged with blood
what is ejaculation?
- sympathetic impulses from the lumbar spinal cord
- sperm, prostatic secretions, and fluid from seminal vesicles enter the internal urethra (emission)
- fluid in internal urethra > sensory impulses to sacral spinal cord > rhythmic contractions of muscles which force semen from the urethra
what are ovaries?
- almond-shaped; 2-3.5 cm x 1-1.5 cm
- contain primordial ova
- 5 million before birth
- ~300,000 at birth
- ~400 will mature
- produce, expel ova; secrete estrogen and progesterone
histology of ovary?
- cortex
- just deep to tunica
- contains follicles
- medulla
- deeper region
- composed of CT, blood vessels, lymphatic vessels
what are the reproductive ligaments in females?
- mesovarium
- part of parietal peritoneum
- anchors ovary to the broad ligament
- ovarian ligament
- anchors the ovary to the uterus
- suspensory ligament
- anchors ovary to the pelvic wall
- round ligament
- inerts into inguinal canal
- broad ligament
- part of parietal peritoneum
- suspends uterus from sidewall of the pelvis
what are fallopian (uterine) tubes?
- 10 cm long
- convey ova to uterus
- 3 layers - serosa, muscularis, mucosa (ciliated columnar epithelium)
- site of fertilization
what is the uterus?
- pear-shaped
- 7.5 cm x 5 cm x 2 cm
- superior, posterior to urinary bladder
- suspended by ligaments
- site of implantation
how is the uterus oriented?
- anteflexed, anteverted
- 90 degrees to the vaginal canal
anatomy of uterus
- fallopian tube
- ovary
- uterine cavity
- fundus
- body
- cervix
- internal os
- external os
- vagina
layers of the uterine wall?
- perimetrium
- myometrium
- endometrium
what makes up the endometrium?
3 components:
- simple columnar epithelium
- stroma
- stratum functionalis (shed during menstruation)
- stratum basalis (replaces stratum functionalis)
- endometrial glands
what makes up the myometrium?
- 3 layers of smooth muscle
- contracts during labour to expel fetus
what makes up the perimetrium?
the outer layer of serous membrane (visceral peritoneum)
how is blood supplied to the uterus?
radial aa. >
arcuate aa. >
uterine aa. >
internal iliac aa. >
just prior to entering the endometrium, radial aa. branch into:
- straight arteriole (supply stratum basalis)
- spiral arterioles (supply stratum functionalis)
what is the vagina?
- fibromuscular tube ~10 cm long
- posterior to urinary bladder, urethra
- anterior to the rectum
- passageway for birth, menstrual flow, intercourse
what is the vulva (pudendum)?
- female external genitals
- the region between labia minora is the vestibule
- includes:
- mons pubis (fatty pad over symphysis pubis)
- clitoris
- labia majora
- labia minora
- external urethral orifice
- vaginal orifice
- anus
what is the perineum?
- a diamond-shaped region between thighs of both sexes
- contains external genitals, anus
- 3 openings in female (U,V,A), 2 in male (U, A)
what are mammary glands?
- modified sweat glands
include:
- nipple
- areola
- lactiferous ducts
- alveolar glands
- adipose tissue (determines the size of the breast)
- thoracic cage
what is the female reproductive system?
- > cycle of changes in ovary and uterus
- controlled by the hypothalamic, anterior pituitary, ovarian hormones
what makes up the ovary?
- primordial follicles
- primary follicle
- secondary follicle
- mature follicle
- ovulated oocyte
- corpus luteum
what are the reproductive hormones in females?
pituitary hormones:
- FSH stimulates follicle development
- LH (luteinizing) causes ovulation
ovarian hormones:
- estrogen is produced by the developing follicle
- progesterone produced by the corpus luteum
what is the purpose of estrogen?
stimulates:
- development of endometrial glands, blood vessels
- development of female secondary characteristics (fat distribution to hips, breasts, buttocks; axillary and pubic hair; broadening of the hips)
- promote proliferation of the endometrial cells (and to a lesser degree myometrial cells)
- causes uterine tissue to become more sensitive to progesterone
what is the purpose of progesterone?
stimulates the thickening of the endometrium
- endometrial gland development, secretion
- further development of blood vessels
- acts with estrogens to thicken the endometrium for implantation
- causes myometrial thickening
- high levels inhibit FSH and LH secretion
what are the female reproductive cycles?
ovarian cycle:
- changes in the ovary during and after maturation of the oocyte
uterine cycle:
- preparation of the uterus to receive a fertilized ovum
- the stratum functionalis is shed if implantation does not occur
menstrual phase
- days 1 - 5
- endometrium sloughs off exposing endometrial spiral arteries > blood loss
ovulation
- day 14
- FSH and LH surge stimulates:
- ovulation
- formation of the corpus luteum from the cells of the mature follicle
what is the corpus luteum?
secretes ovarian hormones:
- estrogens
- progesterone
- relaxin (relaxed uterus)
- inhibin (inhibits FSH)
what is the route for sperm passage?
- seminiferous tubules
- epididymis
- vas deferens
- ejaculatory duct
- urethra
what is the route of ovum passage?
- ovary
- pelvic cavity
- fallopian tube
- uterus
what is fertilization?
- normally happens in the infundibulum of the fallopian tube (usually within 24 hours after ovulation)
- a sperm penetrates an ovum to form a zygote
what is the period of cleavage?
- mitotic divisions that occur in the first 3 days following fertilization
- results in formation of a morula (solid ball of cells) by day 3
when does implantation happen?
- by day 4-5, morula develops into a hollow ball of cells called a blastocyst
- blastocyst moves along the fallopian tube towards the uterus and implants in the endometrium
terminology of development
- gestation period
- from fertilization to birth (38 weeks)
- prenatal period (before birth)
- embryonic period (first 8 weeks after fertilization)
- fetal period (week 9 until birth)
- neonatal period (first 42 days after birth)
