Male Reproductive Biology and Anatomy

Vocabulary practice flashcards covering male reproductive anatomy, spermatogenesis, species differences, and testicular thermoregulation.

Tunica albuginea

The white connective tissue covering (meaning "white coat") that encapsulates and holds the lobules of the testes in place.

Mediastinum

The central core or middle region of the testis into which the seminiferous tubules drain.

Caput

The head of the epididymis where the maturation process of spermatozoa begins as their cytoplasm and supporting structures begin to shrink.

Cauda epididymis

The tail of the epididymis that functions as the long-term storage site where spermatozoa are fully mobile and mature enough for fertility.

Vas deferens

The muscular transport duct exiting the epididymis that carries spermatozoa toward the urethra.

Vasectomy

The surgical separation or severance of the vas deferens.

Thermosensitive neurons

Sensory neurons located in the scrotal skin that detect ambient temperatures and prompt physiological and behavioral responses such as panting, shivering, or scrotal constriction.

Leydig cells

Endocrine cells located within the testicular lobules outside of the seminiferous tubules that produce testosterone.

Basement membrane

The structural boundary that surrounds and separates individual seminiferous tubules, shielding them from external blood vessels.

Sertoli cells

Supporting cells located within the seminiferous tubules that originate near the basement membrane and facilitate spermatogenesis toward the lumen.

Spermatogonia

The germinal stem cells situated at the outer edge along the basement membrane of the seminiferous tubule that undergo mitosis and meiosis.

Seminal vesicles

Accessory sex glands that secrete the bulk of the volume of seminal fluid, contributing nutrients, electrolytes, and protective compounds.

Cowper's gland

One of the four male accessory sex glands, also known as the bulbourethral gland, that contributes secretions to seminal fluid.

Sigmoid flexure

The S-shaped bend found in fibroelastic penises that straightens out to allow penile extension upon relaxation of the retractor muscle.

Retractor muscle

The muscle that maintains the sigmoid flexure in a retracted state and relaxes during stimulation to permit elongation and extension.

Glans

The specialized tip of the penis whose anatomical shape varies across species (e.g., corkscrew-shaped in boars, bell-shaped in stallions, pointed in bulls).

Fibroelastic penis

A penis type contained within a fibrous sheath that does not expand in diameter and extends via the relaxation of the sigmoid flexure.

Vascular penis

A penile type found in stallions, humans, and nonhuman primates that extends and enlarges in diameter due to an influx of blood flow.

Flehmen response

A mating behavior characterized by curling of the upper lip to expose the nasopalatine duct for detecting pheromones and estrogen in receptive females.

Nasopalatine duct

A specialized opening located in the upper palate and gum exposed during the Flehmen response to direct fluid-borne chemical signals to the vomeronasal organ.

Filiform appendage

A thin, thread-like projection on the glans of a ram that allows precise deposition of low-volume ejaculate directly into the cervix.

Cryptorchidism

The failure of one or both testes to descend into the scrotum during development, potentially resulting in impaired thermoregulation and reduced fertility or sterility.

Pampiniform plexus

The intricate network of cooler veins surrounding the testicular artery that extracts heat from incoming arterial blood.

Countercurrent heat exchange

The thermoregulatory mechanism where heat transfers from the warmer testicular artery to the cooler surrounding pampiniform venous network to reduce blood temperature entering the testes.