Sexual Reproduction in the Human
From ZuluNotes - Free Leaving Cert Notes
| This is a Biology Article | |
| |
| Sexual Reproduction in the Human | |
|---|---|
| Subject | Biology |
| Section | The Organism |
| Note | |
Contents |
Human Reproductive System
Reproduction is the formation of new individuals of the same species.Sexual reproduction involves the fusion of specialised haploid sex cells. Unlike many of the other anatomical systems in the body, the organs in this system differ completely in men and women.
In men they include;
- Prostate Gland
- Testes
- Testicular Vessels
- Penis
- Scrotum
In women, they include;
- Ovaries
- Fallopian Tubes
- Uterus
- Cervix
- Vagina
- Labia
In both sexes, the Pelvic Girdle is the bony cavity which protects these organs.
Fertilisation
is the fusion of 2 Haploid gametes to form a Diploid zygote
Male Reproductive System
Functions;
- Production of sperm (male gametes)
- Transfer of sperm into the female (insemination)
Testes
Are the male gonads or glands.
Structure:
- 2 Glands contained within a sac of skin and muscle called the scrotum.
- They develop in the abdomen before descending into the scrotum just before birth.
Functions;
- Produce sperm
- Produce Testosterone
Prostate Gland
Structure:
- A small gland situated between the bladder and the rectum.
- It surrounds the beginning of the urethra.
Function:
- Produces 2 secretions carried in semen
- 1 secretion helps keep the lining of the urethra moist
- 2nd secretion is part of the seminal fluids which help semen to travel along the urethra and into the female
Testicular Vessels
Are the Epididymis and the Vas Deferens, two tubes which form the passageway from the testes to the urethra.
Epididymis
Structure;
- A tightly coiled tube
- Opens from the top of each testis, continues down along the side of the gland then straightens out along into the Vas Deferens
Function:
- To store sperm
- To transport sperm
- Immature sperm mature here
Vas Deferens
Also known as the sperm duct
Structure:
- A duct with muscular walls leading from the epididymis to the urethra
Functions:
- Acts as a passageway for the transfer of sperm from the storage site of the epididymis to the urethra and eventually to the penis
Scrotum
One of 2 external sex organs in the male, it is a sac which contains the testes, epididymis and vas deferens. It hands under the penis.
Structure;
- A sac made of an outer layer of skin and an inner layer of muscle
- A membrane divides it into 2 halves, one for each testes
Functions:
- To support the testes
- To protect the testes
- Maintains correct temperature for the testes
'Bold text'Failed to parse (Missing texvc executable;
please see math/README to configure.): <math>Insert formula here
</math>===Penis===
The main external sex organ of the male. It has 3 important parts;
- Erectile Tissue Bodies
- Foreskin
- Urethra
Structure:
- 3 layers of spongy erectile tissue all running lengthways,when engorged with blood, cause the penis to stiffen and become erect.
- Foreskin is a loose double fold of skin which protects the glans
Function;
- Excretion - carries urine from the bladder
- Reproduction - when erect this allows for the penis to become rigid which allows penetration into the vagina of the female and safe delivery of the semen during intercourse
Sperm
Structure;
- Sperm look like microscopic tadpoles
- Each one consists of
- a head
- a middle section
- a tail (which helps propel the sperm along the vagina and into the uterus)
- The head is a nucleus that contains 23 chromosomes
- The tail is a flagellum, a projection resembling a thread, which moves backwards & forwards enabling the sperm to "swim" to its destination
Function;
- Fertilisation - Sperm fertilises the Ova that the female reproductive system produces
Semen
Is the fluid discharged from the penis during sexual intercourse. It contains sperm and secretions from the prostate gland and seminal vesicle.
