Male Reproductive System

Testes

male gonads, produce sperm & hormones (mostly testosterone)

Gonads

Sex organs: ovaries in females, testes in males.

seminiferous tubules

Narrow, coiled tubules that produce sperm in the testes.

rete testis

network of tubules between the seminiferous tubules and the epididymis, concentrate & mix sperm

epididymus

structure in the male reproductive system in which sperm are fully matured and are stored (can be 6m long!)

vas deferens

tube that carries sperm from the epididymis to the urethra

bulbourethral glands

the two glands below the prostate that secrete a sticky fluid that becomes a component of semen

prostate

a gland surrounding the neck of the bladder in male mammals and releasing prostatic fluid.

seminal vesicles

two small glands that secrete a fluid rich in sugar that nourishes and helps sperm move

Urethra

tube leading from the urinary bladder to the outside of the body

glans

head of the penis

prepuce

foreskin; loose casing that covers the glans penis; removed by circumcision

Scrotum

a pouch of skin containing the testicles.

tunica albuginea

white fibrous capsule on testes

urinary bladder

muscular sac in the pelvis that stores and releases urine through the urethra

Testosterone

the most important of the male sex hormones. Both males and females have it, but the additional testosterone in males stimulates the growth of the male sex organs in the fetus and the development of the male sex characteristics during puberty

luteinizing hormone (LH)

secreted by the pituitary gland to stimulate interstital cells to produce testosterone

Follicle-stimulating hormone (FSH)

secreted by the pituitary gland to stimulate spermatogonia to undergo mitosis

interstitial cells

small specialized cells in the testes (near the seminiferous tubules) that secrete the male sex hormone, testosterone

Sperm

the male gametes (reproductive cells)

acrosome

A region at the head of a sperm cell that contains digestive enzymes to help the sperm penetrate into the oocyte (within B on the diagram)

midpiece of sperm

generates ATP from fructose and contains many mitochondria (C on the diagram)

Flagellum

A long, hairlike structure that grows out of a cell and enables the cell to move. (D on the diagram)

Spermatogenesis

production of sperm

Spermiogenesis

transformation of spermatids to spermatozoa during spermatogenesis

secondary sex characteristics

male voice quality, body hair, enlargement of muscles, increased bone density

vasectomy

ligation of a segment of the vas deferens to produce sterility in the male

Hypothalamus

a neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion

Gonadotropin-releasing hormone (GnRH)

A hormone released from the hypothalamus that triggers the anterior pituitary to secrete FSH and LH.

Mitosis

cell division in which the nucleus divides into nuclei containing the same number of chromosomes

Meiosis

Cell division that produces reproductive cells in sexually reproducing organisms

spermatogonia

Stem cells in a testis that can give rise to primary spermatocytes.

lumen

space within a tubular part or organ, such as the space within the seminiferous tubules (6 on this diagram)

spermatid

an immature male sex cell formed from a spermatocyte that can develop into a spermatozoan without further division.

erectile tissue

Specialized tissue with a lot of space that can fill with blood upon proper stimulation, causing the tissue to become firm. Found in the penis, the clitoris, the labia, and the nipples.