The Reproductive System, etc. Flashcards
Testes
The organs that produce spermatozoa, They’re paired and lie in a sac called a scrotum, which keeps the spermatozoa at a constant temperature.
Tunica Albuginea of the Testes
A connective tissue capsule which surrounds each testis.
Septa of the Testes
Inward extensions which divide the testis into different compartments
Seminiferous Tubules
The sperm factory. Highly convoluted tubules inside the septal compartments, the site of spermatogenesis.
Rete Testis
A network of tubes where the seminiferous tubules join. They empty into the efferent ductules. The sperm then leaves through these.
Interstitial Cells of Leydig
Produce androgens, mostly testosterone.
Spermatic Cord
Encloses the nerve fivers, blood vessels, and lymphatics.
Epididymis
A structure that sits on top of each testis. It’s full of highly convoluted tubules which reice secretions from the testes via the efferent ductule. It has some smooth muscle that surround the tubules.
Functions of the Epididymis
- Monitors and adjusts the composition of tubular fluid
- Recycles damaged spermatozoa
- Stores spermatozoa and facilitates their maturation.
Vas Deferens
A continuation of the epididymis, lined by ciliated columnar epithelium. The cord swings over the urinary bladder and joins the duct of the seminal vesicle forming an ejaculatory duct that passes through the prostate gland and joins the urethra. The sperm moves along this due to peristaltic contractions. Functions to move the sperm from storage and into the urethra.
Seminal Vesicles
Produce about 60% of semen. It’s yellow, and very rich in fructose, which nourishes sperm, ascorbic acid, amino acids, and prostaglandins.
Prostate
Produces an alkaline fluid, rich in enzymes. It’s function isn’t completely clear. The alkalinity of the prostate fluid neutralizes the acidity of the female tract. It accounts for about 1/3 of semen.
Bulbourethral Glands
Small glands, lie at the bast of the penis. Produce a fluid which lubricates the urethra and neutralizes any uric acid present. Also called Cowpers glands.
Urethra
The common urogenital tract of the male. It carries both the semen and urine.
Penis
The copulatory organ of the male. It has an elongated shaft and an enlarged end, the glans.
Connective Tissue of the Penis
- The corpora cavernosa is the paired cylindrical bodies which contain the erectile tissue in the penis
- The corpora spongiosum is the single ventral column which surrounds the urethra
Erection
This process may be initiated by both psychic and tactile stimuli. Parasympathetic stimulation causes dilation of the arterioles that supply the erectile tissue. The increasing volume of erectile tissue compresses the veins which drain the penis so the blood stays.
Ejaculation
Caused by a sympathetic reflex causing rhythmic contractions of the epididymis, vas deferens, seminal vesicles, and the prostate gland. Normally between 2-6 mL are ejaculated. Following ejaculation, the arterioles to the penis constrict and pressure is taken off the veins. The blood leaves the penis and it returns to the flaccid state.
Impotence
The failure to attain or maintain an erection. It can be psychological, due to an ANS malfunction, a congenital problem with the shunt arterioles, or due to alcohol.
Hormonal Regulation in Males
FSH, LH, and testosterone are responsible for the hormonal regulation of reproductive processes.
FSH Stimulation in Males
FSH stimulates the production of sperm my acting on the sustentacular cells of the seminiferous tubules. Sustentacular cells act as nurse cells to sperm producing cells. FSH causes the sustentacular cells to release androgen binding protein which causes the cells to bind to testosterone. Testosterone then stimulates spermatogenesis.
Inhibin
Inhibits FSH
LH Stimulation in Males
LH stimulates the Leydig cells to produce testosterone. The Leydig cells are the interstitial cells between the seminiferous tubules. Since testosterone is required for sperm production, LH indirectly stimulates sperm production.
Testosterone
A steroid hormone, produced under the influence of LH. It initiates sexual differentiation in the fetus at about 5-6 weeks of gestation, and the descent of the testes from the body cavity into the scrotum.