Male Genital System
Author: Dr.R.Menaka
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The male genital system consists of
i. Testis
ii. Epididymis
iii. Vas deferens
iv. Penis/ male -urethra
v. Accessory sexual glands
i. Testis:
- Produces-spermatozoa (live germ cells)
- Secretes- male sex hormone (testosterone)
- Compound tubular glands
- Testis surrounded by connective tissue -i.e. tunica albugenia (outer dense fiberous tissue) and smooth muscle fibers.
- The capsule rich in blood vessels (septum vasculare)
- The glandular parenchyma divided into number of pyramidal or cone-shaped testis septuli (or lobuli testis).
-Each lobule is occupied by seminiferous tubules.
- Seminiferous tubules have an extremely tortous course and rarely branched. They are called convoluted seminiferous tubules.
- Sperms are formed in the convoluted seminiferous tubules.
- The lobuli recti and rete testis are lined by cuboidal or squamous epithelium. These tubular structure receives the sperm produced by seminiferous epithelium.
Seminiferous Tubules:
- Wall composed of collagenous connective tissue and containing elastic fibers.
- The seminiferous epithelium comprised of two kinds of cells
a. Spermatogenic cells
b. Sertoli cells
a. Spermatogenic Cells:
- Make up the basal layer.
- Gives rise to many generations of spermatogonia
- Spermatogonia- primary spermatocytes- secondary spermatocytes- spermatids- spermatozoa.
- The spermatids remain attached to the cytoplasm of sertoli cells.
Note: Spermatogonia -have dark stained spheroid nuclei.
Spermatids don't divide but by transformation forms the specialized cells known as spermatozoa.
b. Sertoli Cells:
- They are tall columnar cells
- Situated perpendicular to the basement membrane to which they are attached.
- They are projected into the seminiferous tubule.
- Vesicular oval nucleus is present on the basal portion of the tall columnar cells.
Leydig Cells:
- Present in the interstitial tissue.
- The interstitial tissue. i.e. the thin collagenous tissue between the seminiferous tubules.
- Leydig cells are polyhydral
- Nuclei are large and spherical with a distinct nucleolus.
- Cytoplasm stains lightly
-Secretes- testosterone.
Epididymis:
- It is highly convoluted
- Tunica mucosa shows no folds
- Epithelium - Pseudo stratified ciliated columnar (sterocilia or non-motile cilia)
- The lumen accommodates clumps of spermatozoa.
Note: Spermatozoa are stored within the epididymis while they undergo maturation to become mature sperm.
Vas Deferens:
A. Tunica Mucosa
i. Epithelium- Pseudo stratified columnar epithelium.
ii. Lamina propria- Areolar connective tissue.
iii. Lamina muscularis- Absent
B. Tunica Submucosa- Typical form of areolar connective tissue
C. Tunica Muscularis- Very thick
D. Tunica Serosa- is present and typical.
Urethra:
- Male urethra consists of two portions
i. Pelvic urethra and
ii. Penile urethra
- Both pelvic urethra and penile urethra lined with transitional epithelium.
- Below the epithelium, the tunica muscularis (smooth muscle fibers) and cavernous (corpus cavernosum muscles) tissue is present.
- In the penile urethra, the corpus cavernosum penis (spongy bone) is also present.
- In the pelvic urethra, the smooth muscle fibers replaced by the striated urethral muscle.
- Tunica adventitia- typical form (areolar connective tissue).
Penis:
- The histology of the penis varies from species to species and from region to region within the same species.
- In general, the body of the penis consists of
i. the urethra
ii. erectile tissue- corpora cavernosa penis and corpora cavernosum urethra
iii. Smooth and skeletal muscles
iv. Touch and pressure receptors i.e. (pacinian corpuscles).
v. A dense connective tissue capsule (tunica albugenia).