Chapter 4 Flashcards & Key Terms

acrosome
A structure at the front of a sperm that contains enzymes and receptors required for penetration of the zona pellucida of an ovum.
balanitis
Inflammation of the glans of the penis.
bulbospongiosus muscle
A muscle that attaches to the base of the penis or clitoris and assists with erection and (in men) ejaculation. In women, the internal portion of the muscle surrounds the introitus.
bulbourethral glands
Two small glands near the root of the penis whose secretions (“pre-cum”) may appear at the urethral opening during sexual arousal prior to ejaculation. Also known as Cowper’s glands.
corona
The rim of the glans of the penis.
corpus cavernosum (pl. corpora cavernosa)
Either of two elongated erectile structures within the penis or clitoris, which also extend backward into the pelvic floor.
corpus spongiosum
A single midline erectile structure. In both sexes it fills the glans; in males it extends backward along the underside of the penis, surrounding the urethra.
cremaster muscle
A striated muscle that wraps around the spermatic cord and the testis.
dartos
A sheet of smooth muscle underlying the skin of the scrotum, which when contracted causes the skin to become thick and wrinkled.
ejaculatory duct
Either of the two bilateral ducts formed by the junction of the vas deferens and the duct of the seminal vesicle. The ejaculatory ducts empty into the urethra within the prostate.
emission
The loading of the constituents of semen into the posterior urethra immediately before ejaculation.
epididymis (pl. epididymides)
A structure, attached to each testis, through which sperm must pass before entering the vas deferens.
fascia
A tough sheet or sheath of connective tissue.
flagellum
A whiplike fiber, extending from a spermatozoon or other cell, that confers motility.
foreskin
The loose skin that partially or completely covers the glans in males who have not been circumcised.
frenulum
A strip of loose skin on the underside of the penis, running between the glans and the shaft.
fructose
A simple sugar (monosaccharide) present in semen.
genital end-bulbs
Specialized nerve endings, found in the genital area, that probably detect the tactile stimulation associated with sexual activity.
glans
The terminal knob of the clitoris or penis.
inguinal canal
A short canal passing through the abdominal wall in the region of the groin in males.
ischiocavernosus muscle
One of the muscles that attaches to the internal portions of the penis and clitoris. It assists with erection and (in men) ejaculation.
Leydig cells
Cells located between the seminiferous tubules in the testis that secrete steroids. Also called interstitial cells.
locus coeruleus
A nerve center in the pons that helps regulate the state of consciousness.
midpiece
The portion of the tail of a sperm that is closest to the head, containing mitochondria.
nitric oxide
A dissolved gas that functions as a neurotransmitter in erectile tissue.
nocturnal orgasm
Orgasm during sleep.
Onuf’s nucleus
A sexually dimorphic group of motor neurons in the sacral segments of the spinal cord that innervates striated muscles associated with the penis and clitoris.
paraphimosis
Entrapment of the retracted foreskin behind the corona.
pelvic nerves
Nerves that convey parasympathetic signals from the lower spinal cord to the genitalia and other organs.
penile bulb
An expansion of the corpus spongiosum at the root of the penis.
penis
The erectile, erotically sensitive genital organ in males.
Peyronie’s disease
Pathological curvature of the penis.
phimosis
A tightening of the foreskin, preventing its retraction from the glans.
prostate gland
A single gland at the base of the bladder, surrounding the urethra; its secretions are a component of semen.
pudendal nerves
Peripheral nerves supplying the external genitalia.
rete testis
A network of spaces, between the testis and epididymis, through which sperm must pass.
scrotum
The sac behind the penis that contains the testicles.
semen
The fluid, containing sperm and a variety of chemical compounds, that is ejaculated from the penis at male sexual climax.
semenogelin
A protein secreted by the seminal vesicles that coagulates after ejaculation.
seminal plasma
The noncellular constituents of semen.
seminal vesicles
Two glands situated to either side of the prostate; their secretions are a component of semen.
seminiferous tubules
Convoluted microscopic tubes within the testis; the site of spermatogenesis.
Sertoli cell
A type of cell within the seminiferous tubules that nurtures developing sperm and secretes hormones.
sexual dimorphism
An anatomical difference between the sexes.
sinusoids
A vascular space, such as within erectile tissue, capable of being expanded by filling with blood.
sperm
A male gamete, produced in the testis.
spermatic cord
Either of two bilateral bundles of structures, including the vas deferens, blood vessels, and the cremaster muscle, that pass through the inguinal canal to the testis.
spermatogenesis
The production of sperm.
spinal reflex
A reflex mediated by neurons in the spinal cord, requiring no participation by the brain.
subincision
A form of male circumcision in which a cut is made along the underside of the penis, exposing the urethra.
superincision
An unusual form of male circumcision in which the upper part of the foreskin is incised but not removed.
suspensory ligament
A ligament that connects the root of the penis to the pubic symphysis.
testicle or testis (pl. testes)
The male gonad: one of the two glands within the scrotum that produce sperm and secrete sex steroids.
trabeculae
Connective tissue partitions separating the sinusoids of erectile tissue.
tunica albuginea
A fibrous capsule surrounding the corpora cavernosa.
urethral meatus
The opening at the tip of the penis (in males) or in front of the vagina (in females).
vas deferens (pl. vasa deferentia)
Either of the two bilateral ducts that convey sperm from the epididymis to the ejaculatory duct.
Go