Male Reproductive System Flashcards
What are the functions of the male reproductive system?
- make and support male gametes(sperm)
- transfer sperm to female genital tract
- produces hormones
What are the components of the male reproductive system?
Testes—> makes sperm
Penis—> transfer of sperm and urinary functions
Genital ducts: epididymis, ductus deferens, efferent ducts, ejaculatory ducts —> transport semen
Glands: prostate, seminal vesicles, bulbourethral glands—> make seminal fluid
Describe the root of the penis
Attached to perineal membrane
Unattached parts of the corpus cavernousa and spongiosum
- Right and left Crus
- bulb
Describe the body of the penis
Not attached
- Two corpora cavernosa (dorsal)
- One corpus spongiosum(ventral)
- forms glans penis
- contains the penile (spongy) urethra
The muscles of the perineum …
Surrounds the erectile tissues and openings in the perineum
What is the scrotum?
-supporting structure for the Testes
- Dartos muscle
- subcutaneous layer of smooth muscle
- contraction tightens the scrotum
Describe the spermatic cord
-fascia
- Cremaster muscle
- Skeletal muscle from internal oblique
- Contraction moves Testes closer to the body
- Skeletal muscle from internal oblique
- Nerve; a branch of genitofemoral
- esticular artery
- Pampiniform plexus of testicular veins
- Ductus deferens
- transports spermatozoa from epididymis to ejaculatory duct
What are the Testes?
Paired oval glands
-approximately 2 inch long x 1 inch diameter
Develop in the posterior abdomen & descend into the scrotum through the inguinal canals @ 7-8 months
Describe the structure of Testes
Tunica vaginalis
- serous membrane derived from peritoneum during descent of Testes
Tunica albuginea
- thick connective tissue capsule
- extends inward to form septa
Lobules
- 200-300 internal compartments
- each lobule contains 1-4 seminiferous tubules
Seminiferous tubules
- seminiferous epithelium
- produce spermatozoa
Seminiferous tubules has two cell populations…
- Sertoli cells are supporting cells
2. Spermatogonic cells replicate & differentiate into mature sperm
Explain the structure and function of Sertoli cells
- supporting cells
- extend from basement membrane to lumen
- tight junctions join adjacent Sertoli cells
- blood-testis barrier
- secrete inhibin
- hormone that inhibits FSH secretion
- secrete androgen-binding protein
- binds testosterone to keep concentration high
What are the types of spermatogonia cells?
- spermatogonia(2n)
- stem cells
- primary spermatocytes(2n,4d)
- secondary spermatpcytes (1n, 2d)
- spermatides( 1n, 1D)
- spermatozoa( 1n, 1d)
What are the Leydig cells?
Also known as interstitial cells
- located in spaces between adjacent seminiferous tubules
- secrete testosterone
Summarize spermatogenesis
Development of spermatogonia into sperm
-Include meiosis and spermiogenesis
Lasts 65-75 days
Spermatogonia
Stem cells
2n,2d
Primary spermatocyte
2n,4d
Secondary spermatocyte
1n, 2d
4 spermatids
1n, 1d
4 spermatozoa
- 1n,1d
- mature sperm
Describe sperm
Head
- acrosome
- vesicle contains enzymes required for penetration of the zona pelucida of the oocyte
- nucleus
- 23 condensed chromosomes (22, X or Y)
Tail (flagellum)
1. Neck
- Middle piece
- mitochondria provide ATP for sperm motility
- Principal piece
- End piece
- core of microtubules & dynein motor proteins
What is Cryptorchidism?
Condition when Testes do not descend into the scrotum
- 3% full-term infants
- 30% premature infants
- Most (80%) will descend spontaneously during the first year of life
- Untreated & bilateral results in sterility
- 30-50x greater risk of testicular cancer
What are the types of ducts in the reproductive system?
Intra-testicular ducts & excurrent ducts
What are the intra-testicular ducts?
- seminiferous tubules
- seminiferous epithelium
Straight tubules (tubuli recti) -short terminal portion of the seminiferous tubule
Rete testis
- network of channnels
- simple cuboidal to low columnar
What are the excurrent ducts?
- efferent ducts
- epididymis
- Ductus deferens
- pseudostratified columnar epithelium with stereocilia
- Ejaculatory ducts
- union of the duct of seminal vesicle and ampulla of Ductus deferens
What are the efferent ducts made of ?
Pseudostratified columnar epithelium
What are the parts of epididymis ?
Head, body, tail
Psuedostratified columnar epithelium with stereocilia
What are the Ductus deferens made of?
Ductus deferens have a pseudostratified columnar epithelium with stereocilia and a thick muscular wall
What is a vasectomy?
Is the interruption of the Ductus deferens usually at the scrotum
What are the accessory sex glands?
- Seminal vesicles
- Prostate
- Bulbourethral glands
What is the function of a prostate?
- Single gland inferior to bladder
- typically the size of a golf ball
- surrounds the prostatic urethra
Secretes a milky, slightly acidic fluid into the prostatic urethra
- Citric acid
- ATP production
- Proteolytic enzymes
- prostate-specific antigen(PSA)
- Acid phosphatase
- Seminalplasmin
- antibiotic
Produces about 25% of volume of semen
Describe the Bulbourethral glands(Cowper’s glands)
- Paired glands inferior to prostate on either side of the membranous urethra
- Ducts open into the penile (spongy) urethra
-Secrete clear, mucus-like fluid into the urethra
Describe the ejaculatory ducts
Union of the duct of seminal vesicle and ampulla of Ductus deferens
Give the function of seminal vesicle
Paired glands posterior to bladder duct joins Ductus deferens to form ejaculatory duct
Secrete an alkaline, viscous fluid
- Fructose needed for ATP production by sperm - Prostaglandins & clotting proteins
Describe the structure-function of prostate
Single gland inferior to bladder and surrounds the prostatic urethra
Produces about 25% of volume of semen
Secretes a milky, slightly acidic fluid
- citric acid for ATP production - prostate-specific antigen (PSA) - enzymes - acid phosphatase - seminalplasmin —> antibiotic
What are the symptoms of benign prostatic hypertrophy ?
- enlarged prostate gland
- relatively common in men by age 80
- numerous nodules compress the prostatic urethra
- weak urination
- difficulty starting & stopping
- urge or feeling to urinate
How does semen get to the female genital tract?
- Semen is a mixture of sperm cells and glandular secretions
- Volume of 2.5-3 ml
- 50-150 million sperm per ml
- low sperm count : 20 million or less sperm per ml
- higher risk of infertility
What is erection? What Causes it?
-enlargement & stiffening of the penis
How?- parasympathetic fibers initiate and maintain the erection
- Nitrous oxide(NO) released - smooth muscle of arterioles relax - blood vessels dilate - large amounts of blood enter the erectile tissues - veins become compressed blocking outflow.
What is ejaculation? What causes it?
Release of semen
Caused by the sympathetic reflex
Peristaltic contractions propel semen into the urethra
- Contraction of smooth muscle
- decrease blood flow and blood pressure
- Veins open and drain blood
