Chapter 25- Reproductive System Flashcards
Scrotum
Skin and superficial fascia surrounding testes
Testes divided by septum
Positioned outside pelvic cavity to optimal sperm temperature
Dartos muscle
Smooth muscle that contracts to raise the testes
Cremaster muscle
Skeletal muscle that contracts to raise the testes
Spermatic cord
Vessels exiting scrotum and entering pelvic cavity
Vas deferens, testicular artery, and pampiniform plexus (venous)
Tunica vaginalis
Serous sac that surrounds testes
Extension of peritoneum
Tunica albuginea
Fibrous capsule of the testes
Projection divide testes into 250-300 lobules with 1-4 seminiferous tubules each
Seminiferous tubules
Site of sperm production
Separated by areolar connective tissue
Contain spermatogenic, columnar sustentacular, myoid, and interstitial cells
Spermatogenic cells
Cells in the seminiferous tubules that divide to produce sperm
Columnar sustentacular cells
Support cells that surround spermatogenic cells
Tight junctions form blood-testis barrier, keeping immune system out
Extend from basal lamina to lumen of seminiferous tubules
Myoid cells
Surrounds seminiferous tubules and move sperm
Similar to muscle cells
Interstitial (Leydig) cells
Secrete testosterone
Stages of spermatogenesis
Stage 1- Stem cell divides into basal cells and spermatocytes
Stage 2- Meiosis
Stage 3- Spermatogenesis- Differentiate into spermatozoa
Process produces 4 viable sperm
Epididymis
Coiled duct connecting testes to vas deferens
Site of sperm maturation and storage until ejaculation
Composed of pseudostratified columnar epithelium with stereocilia
Sperm maturation
Gain ability to swim and fertilize egg
Occurs in the epididymis
Vas (Ductus) Deferens
Passageway for sperm during ejaculation
Wraps around urinary bladder and joins seminal vesicle in prostate
Seminal vesicles
Gland posterior to urinary bladder that joins ductus deferens to form ejaculatory duct
Secretes 60% of semen volume:
Fructose for sperm nutrition
Other substances
Functions of seminal fluid
Stimulate uterine contraction
Suppress immune responses
Enhance sperm motility
Clot and liquify semen
Prostate gland
Gland that encircles prostatic urethra
Contains 20-30 tuboalveolar glands that secrete 25-30% of semen
Function to enhance sperm motility and semen clotting
Bulbourethral glands
Small gland inferior to prostate
Secretes mucus into spongy urethra during arousal that cleanses, regulates pH, and lubricates urethra
Path of sperm
Seminiferous tubules
Epididymis
Ductus deferens
Junction with seminal vesicles
Enters prostate
Ejaculatory duct
Junction with prostatic urethra
Membranous urethra
Spongy urethra
Female Reproductive System Functions
Produce gametes
Prepare for pregnancy to support embryo
Undergo changes based on menstrual cycle
Ovaries
Almond-shaped organs that serve as site of follicle maturation and ovulation
Held in place by ligaments and mesenteries
Ovarian Cycle
Follicular phase
Ovulation- Day 14
Luteal phase
Follicular phase
Ovarian phase pre-ovulation
Oocyte undergoes meiosis and secretes hormones
Primary follicle contains oocyte and begin making estrogen
Oocyte divides, producing secondary follicle which produces estrogen and progesterone
Vesicular follicle develops with mature secondary oocyte
Ovulation
Occurs on day 14 of ovarian and uterine cycles
Secondary oocyte is released into peritoneal cavity and is swept into the uterine tube by fimbriae
Luteal phase
Ovarian cycle post-ovulation
Remaining follicle becomes corpus luteum which produces progesterone and some estrogen to control menstrual cycle
Corpus luteum degenerates
Oogenesis
Primary oocytes are made during fetal period and arrested until puberty
Primary oocyte undergoes meiosis and becomes primary follicle
Only produces one viable oocyte, only completes meiosis II if fertilized
Uterine tubes
Connect ovaries and uterus
End in fimbriae
Fertilization occurs in lateral third of uterine tube
Fimbriae
Fingerlike projections at the end of uterine tubes that guide oocyte into uterine tubes
Uterus
Pear-shaped organs intermediate to bladder and rectum
Ends inferior in cervix
Layers-
Myometrium (muscular layer)
Basal endometrium- Long lasting blood vessels
Functional endometrium- Highly vascular portion that builds and sheds during menstruation
Uterine Cycle
Cycle of building and shedding endometrium that coordinates with ovarian cycle
Directed by pituitary hormones FSH and LH
Uterine cycle Phases
Menstrual phase- Days 1-5: Stratum functionalis is shed
Proliferative phase- Days 6-14; Endometrial growth
Day 14- Ovulation occurs
Secretory phase- Days 15-28, endometrial growth continues
Vagina
Entrance to female reproductive system
Serves as the birth canal
Intermediate to urethra and anus
Mamillary glands
Breasts are modified sweat glands
Composed of adipose tissue and glandular structures that secrete milk after childbirth
Glandular structures are underdeveloped in non-pregnant people
Events leading to fertilization
Sperm binds to zona pellucida on egg
Acrosomal reaction
Cortical reaction
Fertilization
Acrosomal reaction
Fusion of oocyte and sperm plasma membranes
Cortical reaction
Enzymes secreted by oocyte prevent further sperm entry
Fertilization
Fusion of gametes from sperm and egg
Implantation
Occurs during days 7-16 after fertilization
Performed by syncytiotrophoblast- Secretes substances to regulate pregnancy that suppress T lymphocytes and other hormones
Placenta
Site of exchange between fetal and maternal blood
Blood vessels come into close contact
Chorionic villi layers form barriers to diffusion of harmful molecules
Parturition
Childbirth
Occurs 266 days after fertilization
Labor events expel infant from uterus
Phases of parturition
Dilation- expansion of the cervix
Expulsion by contractions of uterine muscles
Placental phase- Placenta detaches and is expelled
Testicular cancer
Impacts 1/50000 males; common in young and old
Arises from early-stage spermatogenic cells
Highly treatable by testis removal
Prostate cancer
Slow-growing from peripheral glands
Risk factors include fatty diet and genetics
Ovarian cancer
Arises from germinal epithelium
Increased risk with increased number of ovulation
Cervical cancers
Caused by HPV
Slow growing from epithelium on the tip of cervix
Breast cancers
Risk of long exposure to hormones
Treated with surgical removal of cancerous tissue or other therapies
May elect for hormone replacement
Menstruation across the lifetime
Reproductive peak- Late 20s
Follicle degeneration increases around 35, shortens reproductive cycles
Age 46-54- Menopause
Menopause
Ovulation and menstruation cease
Ovaries stop secreting estrogen
Reproductive organs and breasts begin to atrophy without hormones, reducing secondary sex characteristics
