Reproductive SystemMark Jay V. Peña BSED 1

Organs and tissues involved in the production and maturation of

gametes and in their union and subsequent development as

offspring.

Functions of Reproductive

System

• Production of

gametes

• Fertilization

• Development and

nourishment of a

new individual

• Production of sex

hormones

Formation of Gametes

The formation of

gametes in males

and females occurs

by a cell division

called meiosis

Male Reproductive

System

• Produces and

transfers sperm cells

to the female and

produces hormones

that influence sexual

functions and

behaviors. Consists of

testes, accessory

structures, ducts, and

penis

Scrotum

Sac-like structure

containing the testes

• Dartos Muscle -

Layer of loose

connective tissue

and a layer of

smooth muscle

• Cremaster Muscles

– extensions of

abdominal muscles

into the scrotum

Testes

• Also called Male gonads

• Oval organs, 4-5 cm long, within the scrotum

• Seminiferous tubules –sperm cells develop

• Germ cells – embedded in the sustentacularcells

• Sustentacular cells or Sertoli – large and extended from the periphery to the lumen of seminiferous tubule

• Interstisial cells or LeydigCells – secretes testosterone

Spermatogenesis

Formation of sperm

cells

Spermatogonia –

most peripheral

germ cell

Sperm cell –

contains head,

midpiece, and

flagellum

Ducts

After their production, sperm cells are transported through the seminiferous tubules and series of ducts to the exterior of the body

Rete testis – tubular network where in seminiferous tubule of each testis empties

Efferent ductules – carry sperm cells from the testis to a tightly coiled series of threadlike tubules that form a comma shaped structure on the posterior side of the testis called epididymis

Epididymis – sperm cells continue to mature until the time it can swim and bind to oocytes

Capacitation – occur after ejaculation of semen into the vagina prior to fertilization

Ductus Deferens

Also called vas deferens

45 cm

Contains smooth muscle which contracts in peristaltic waves to propel sperm cells from the epididymis through the ductus deferens

emerges from the epididymis and ascends along the posterior side of the testis to become associated with the blood vessels and nerves that supply the testis which forms the spermatic cord

Seminal vesicle and

ejaculatory duct

Seminal Vesicle – sac shaped gland

Ejaculatory duct – short duct extends from the seminal vesicle to the ampulla of the ductusdeferens join

Urethra – passageway for urine and male reproductive fluids

• Urinary bladder to distal end of the penis• Prostatic urethra

• Membranous urethra

• Spongy urethra

Penis

Male organ of copulation and functions in the transfer of sperm cells from the male to the female

Three columns of erectile tissue:

• Two columns forms the dorsal portion and the sides of the penis and are called corpora cavenosa

• Third column – smaller and occupies the ventral portion of penis and is called corpus spongiosum

• Glans penis – expands over the distal end of the penis to form a cap

• Prepuce – loose fold of skin that covers the glans penis

Glands

The seminal vesicles are glands consisting of many saclike structures located next to the ampulla of the ductus deferens.

Two glands

1. Prostate gland • consists of both glandular and

muscular tissue

• Size and shape of walnut

• Surrounds the urethra and two ejaculatory ducts

• Consists of capsule and numerous partitions

• 10-20 short ducts that carry the secretions of the prostate gland to the prostatic urethra

2. Bulbourethrel glands• Also called as cowper’s

gland

• Pair of small, mucus secreting glands located near the base of the penis

• Size of a pea but they decrease in size with age

• A single duct from each gland enters the urethra

Puberty

• Sequence of events by which a child is transformed into a young adult

• Begins at ages 12-14

• Completed at the age of 18

• Testosterone • Major male hormone secreted

by the testes

• Necessary for spermatogenesis

• Secondary male characteristics• Hair distribution and growth

• Skin texture

• Fat distribution

• Skeletal muscle growth

• Changes in the larynx

Male sexual behavior and

the male sex act

Testosterone is

required for normal

sexual behavior

• Male sex act

• Emission

• Ejaculation

• Orgasm (Climax

• Resolution

Sensory Impulses and

Integration

• Rhythmic massage

of the penis

• Psychic stimuli

• Ejaculation while

sleeping ( Wet

dreaming )

Disorders

(Causes and Treatment)

Erectile Dysfunction (ED)

• Also called Impotence

• Inability to achieve erections

• Caused by reduced testosterone secretion resulting from hypothalamic, pituitary, or testicular complications

• Due to defective stimulation of that erectile tissue by nerve fibers or reduced response of the blood vessels to neutral stimulation

• Can be corrected by taking oral medications such as sildenafil(Viagra), tadalafil (Cialis), or verdanafil (Livitra), or by having specific drugs injected to the base of the penis

• These drugs increases blood flow into the erectile tissue of the penis, resulting in erection for many minutes

Infertility

• Reduced or diminished fertility

• Caused by low sperm cell count due to damage in the testes as a result of trauma, radiation, cryptorchidism or infections such as mumps, which blocks the ducts in the epididymis

• Also caused by inadequate secretion of luteinizing hormone and follicle-stimulating hormone

• Fertility can be achieved by collecting several ejaculations, concentrating the sperm cells and inserting them into the female’s reproductive tract, a process called artificial insemination

Reference: Seeley’s Essentials of Anatomy and Physiology, Eight Edition