9C - Human Male Reproductive System - Structure and Function

What are the main internal parts in the male reproductive system?

Main internal parts consists of

1. Gonads (testes which produce sperm and reproductive hormones)

2. Epididymis (which store mature sperm)

3. Accessory glands that secrete products required for sperm movement

4. Ducts that transport the mature sperm and glandular secretions

What are the main external organs in the male reproductive system?

The scrotum and penis

What are the accessory glands in the male reproductive system?

1. seminal vesicles
2. prostate gland
3. bulbourethral glands

What are the different kinds of ducts found in the male reproductive system?

1.Vas deferens

2. Urethra
3. Ejaculatory duct

What is the structure of Scrotum?

A pouch formed by a fold of the body wall.
Divided into two compartments
Each compartment contains one testis, one epididymis and part of the spermatic cross which suspend the testis in the scrotum

Where are the testis found?

within the scrotum

Why is the testis located in the scrotum?

This allows the testis to maintain a temperature that is 2°C below the core body temperature

What is the function of scrotum?

keep the testes at the best temperature for sperm production

Why is it important testis are maintained at the right temperature?

Sperms are produced only when the testis are cooler than the rest of the body

What is known as seminiferous tubules?

Many lobules are found inside the testis
Within each lobule there are highly coiled (convulated) loops these are called seminiferous tubules

Where is sperm produced?

seminiferous tubules of the testes

What are Sertoli cells?

Supporting cells which surround and connect to the different cells that are undergoing spermatogenesis

Structure of Sertoli cells

They extend from the wall of seminiferous tubules to the lumen.

Function of Sertoli cells

These cells secrete the hormone "Inhibin"
and nourish and provide attachment for cells that are in different stages of spermatogenesis

Different development stages of spermatogenesis found from periphery to the lumen of seminiferous tubules are in order of:

1. Geminal epithelial cell (2n)
2. Spermatogonial stem cell (2n)
3. Spermatogonia (2n)
4. Primary spermatocyte (2n)
5. Secondary spermatocyte (2n)
6. Spermatids (n)
7. Sperm

Function of Leydig Cells

Secrete the hormone testosterone and
other androgens after puberty which promote spermatogenesis

Structure of Epididymis

Tightly packed mass that is formed by the repeatedly folded long duct originated from combined seminiferous tubules in the testis.

Where does spermatogenesis occur?

seminiferous tubules

How long does sperms take to travel the length of epididymis?

About 3 weeks which is about the same time taken for a sperm to become mature and motile

Function of epididymis

Maturation of Sperm
Storage of matured sperm until ejaculation

What are known as Erectile Tissues?

The modified veins and capillaries found in the penis

vas deferens

Long, narrow tube carrying sperm
that extends around and behind the urinary bladder where it joins a duct from seminal vesicle forming a short ejaculatory duct

functions of male urethra

Urinary excretion
Deliver of sperm in semen into the female reproductive tract

(Both can't happen at the same time)