Question

Where are seminiferous tubules? Where are Sertoli cells and what is there function? Where are the interstitial cells (of Leydig) found and what do they produce?

Explain the negative feedback control of the hypothalamus and pituitary gland on the testes.

What are the primary sex organs of males? What are the accessory organs, tubes and glands? What are the external genitalia?

What is the function of the epididymis? Where is the vas deferens (ductus deferens) located?

What is secreted from the seminal vesicle?

Answer 1

1. a Seminiferous tubules are found within the testes, and are the specific site of meiosis resulting in spermatogenesis.

b. A Sertoli cell is called the "nurse" cell of the testes that is found in the epithelium, of the convoluted seminiferous tubule. Function: Helps in the process of spermatogenesis and is very essential for testis formation.It creates hemato-testicular barrier and the nourishes the spermatozoa.

C.Interstitial cells of Leydig, are found  in the interstitial spaces/connective tissue spaces of the seminiferous tubules.  They produce androgens like testosterone, androstenidione and dihydroepiandrosterone in the presence of luteinizing hormone (LH).

2. Negative feedback control of the hypothalamus and pituitary gland on the testes

Pituitary hormone effects: LH and FSH stimulate spermatogenesis and testosterone secretion by the testes. Hypothalamus GnRH Gonadot Releasing Hormgne Anterior pituitary of GnRH stops the release GnRH produces+ positive effect releasing FSH and LH LH Inhibin Testes Testosterone FSH Sertoli cells facilitate Testes hormone effects: Testosterone and inhibin inhibit the secretion of GnRH by the hypothalamus and LH and FSH by the pituitary. Leydig cells
From the diagram, it is found that GnRH is produced by hypothalamus which positively stimulate the release of LH and FSH by pituitary gland which help sperm development in Testis. This ultimately helps in the release of inhibin which inhibit the production of GnRH. This is the negative feedback.

3.

The primary male sex organs are a pair of testes which is lying outside the abdominal cavity. It is enclosed in a sac- like scrotum.

Secondary male sex organs are seminiferous tubules, seminal vesicles, prostate gland,epididymis, sperm duct Cowper's gland and penis.

The external male genitalia include the penis, urethra, and scrotum.

4. .The epididymis is a tube -like connection which connects a testicle to a vas deferens.Epididymis plays an important role in storage of sperm and ejaculantion of sperm.

Vas deferens usually start as a continuation of the epididymis tail, as a partially coiled tube which ascends/passes into the abdomen through the inguinal canal.

5. The secretion of the seminal vesicles is called seminal fluid (semen). It is a thick fluid that consist of sugar (fructose), proteins, citric acid, potassium, inorganic phosphorus, and prostaglandins.