MALE REPRODUCTIVE SYSTEM

Testes

The male gonad produces both testosterone (male sex hormone) and spermatogonia (male germ cell that differentiates into sperm)

testes, epididymis, deferent duct, urethra, penis and accessory sex gland

The parts of the male reproductive system

Scrotum

The testes are contained in the __ and vary considerably in size and shape among species.

Scrotum

pouch of skin where the testes are located.

1. Skin

2. Tunica dartos

3. Spermatic fascia

4. Cremaster muscle

Layers of the scrotum

Skin

Part of scrotum that usually hairless

Tunica dartos

Part of scrotum that is fibromuscular subcutaneous layer

Cremaster muscle

a detachment of the internal abdominal oblique muscle

1. Tunica albuginea (white tunic)

2. Mediastinum testis

3. Lobules

Connective tissue component of testis

Tunica albuginea (white tunic)

the strong, white fibrous capsule enveloping the testes

Mediastinum testis

the cord of fibrous tissue running through the middle of the testicle, containing the rete testis

Lobules

units of testicles which contains few seminiferous tubules.

Septa

Lobules are separated by __

1. Seminiferous tubules

2. Rete testis

3. Efferent duct

4. Epididymis

Parenchyma of the testis

Seminiferous tubules

hollow structures in which male germ cells differentiate to spermatozoa.

Convoluted seminiferous

Major part of the tubule where sperm production occurs

Straight seminiferous tubules

the short, straight part are near the mediastinum and they do not produce sperm

Rete testis

network of irregular, interconnecting channels continuing as the straight seminiferous tubules through the mediastinum to the efferent duct

Efferent duct

8 – 15 channels leading into the head of the epididymis. They unite to form the epididymis

Epididymis

the structure adjacent to the testes.

Head

Part of epididymis that consist of efferent ducts

Body

The central part of the epididymis, consists of highly coiled epididymal duct connecting the head and the tail

Tail

The bulbous end of the epididymis, continues on as the ductus deferens.

Seminiferous tubules – Rete testis – Efferent duct - Epididymis – Ductus deferens – Vas deferens –Urethra

The route of the sperm in chronological order

Ligaments associated w/ the testis and epididymis

1. Proper ligament of the testis

2. Ligament of the tail of the epididymis and scrotal ligament

Proper ligament of the testis

connects the tail of the epididymis to the ventral extremity of the testis

Ligament of the tail of the epididymis and scrotal ligament

connects the tail of the epididymis to the tunica vagina parietalis

Spermatid cord

The structure extending from the testicle through the inguinal canal; consisting of the ductus deferens, testicular vessels and nerves and the lymphatics and their serous coverings.

Vaginal tunic

double wall of serous membrane (visceral and parietal) around the spermatic cord and testicle in the male and the round ligament of the uterus in female.

Parietal vaginal tunic

continuation of the abdominal parietal peritoneum through the inguinal canal. It surrounds the visceral vaginal tunic-covered spermatic cord and testicle.

Mesorchium

serosal fold connecting the visceral tunic with the parietal vaginal tunic.

Mesoductus

fold of connecting vaginal tunic between the mesorchium and ductus deferens

Mesofuniculus

part of mesorchium between the parietal vaginal tunic and where the mesoductus arise

Vaginal cavity

the potential space between the two vaginal tunic layers. It is continuous with the peritoneal cavity at the vaginal ring.

Vaginal ring

the crescent-shaped opening located on the abdominal side of the deep inguinal ring.

Pampiniform plexus

coils of testicular veins around testicular artery, making the bulk of the spermatic cord. It functions to draw heat from the testicular artery, cooling the blood before it reaches the testes.

Venous blood

Which is cooler, Venous blood or Arterial blood?

Accessory sex glands

Glands associated with the urethra that add liquid portion to the ejaculate.

95-98%

How many percent is the total ejaculate volume provided by the accessory sex glands

Prostate gland

• completely envelops the proximal portion of the male pelvic urethra at the neck of the bladder.

• It is the only accessory sex gland present in the male dog (except for ampullary gland)

1. rectum

2. symphysis pubis

3. abdominal wall

The prostate is bounded dorsally by the _ and ventrally by the __ and ventral _

1. Ampullary gland

2. Vesicular gland

3. Bulbourethral gland (Cowper’s gland)

Other male accessory sex gland present in other animals

Ampullary gland

paired; found at the ampulla (proximal dilatation of the urethra)

Vesicular gland

absent in dogs. Paired; secretes fructose - energy source for sperm; in the form of pouch (seminal vesicle)

Bulbourethral gland (Cowper’s gland)

absent in dogs. paired; cleanse and neutralize urethra

Penis

• Copulatory organ of male, extending from the ischiatic arch cranially (except cats) between the thighs.

• It provides a passageway for semen and urine to the outside of the body, thus part of both urinary and reproductive system.

Root of the penis

The penis originates as two cruca that converge to form the __, which continues as the body penis to the glans of the penis

Musculocavernous type

The penis of dog is of what type?

Corpora cavernosa

paired, blood filled; made up the dorsal column of the penis

Corpus spongiosum

unpaired spongy body; provides the ventral column; more delicate with larger blood spaces.

Prepuce

cutaneous sheath around the free part of the penis in the non-erect state.

Inner lamina

The part of the prepuce continuous with the skin over the glans penis

Outer lamina

The part of the prepuce continuous with the skin on the abdomen

Preputial orifice

is the opening of the prepuce to the outside

Os penis (baculum)

is found on the penises of carnivores.

Prospector’s toothpick

The os penis of coyotes is sometimes called __

Bulbus glandis

part of the glans penis surrounding the proximal os penis.

Vestibular bulb

Bulbus glandis together with the bitch’s __, it is responsible for the “tie” or coital lock in dogs.

1. Retractor penis muscle

2. Ischiocavernous muscle

3. Bulbospongiosus muscle

Muscles of the penis

Retractor penis muscle

paired smooth muscle originating from the first caudal vertebra. They travel laterally around the rectum and then continue side by side over the urethral surface if the penis to attach distally.

Ischiocavernous muscle

short skeletal muscle covering the crus of the penis, arising from the ischiatic arch and inserting on the cavernous body.

Bulbospongiosus muscle

paired skeletal muscle covering the bulb of the penis