Human Reproduction

Notes

Human Reproduction

Reproduction is the ability of living organisms to produce a new generation of living individuals similar to themselves.

Reproductive Events in Humans

1. Gametogenesis
2. Insemination
3. Fertilisation
4. Implantation
5. Gestation
6. Parturition

• Formation of gametes, i.e. sperm in male and ovum in female, is known as gametogenesis.
• Transfer of sperm into the female reproductive tract is known as insemination.
• Fusion of male and female gametes is known as fertilisation.
• Formation, development and attachment of blastocyst to the uterine wall is known as implantation.
• Embryonic development is known as gestation.
• Delivery of the baby is known as parturition.

Puberty

Puberty is the period when an individual becomes capable of reproducing sexually. It is brought about by hormones and maturation of reproductive organs such as testes and ovaries.

• The age at which puberty occurs is generally around 14 years in boys and 12 years in girls, as given in the supplied notes.
• Changes occurring in the body during puberty are caused by hormones.
• Hormones are chemical substances produced in the body.

Changes During Puberty in Females

• During puberty the female body produces hormones such as oestrogen and progesterone.
• Oestrogen causes the breasts to grow.
• Oestrogen and progesterone control the menstrual cycle.
• Hair grows under the armpits and in the genital region.
• Changes in voice also occur.

Changes During Puberty in Males

• Testosterone is the major male sex hormone.
• It is produced in the testes.
• Testosterone starts the production of sperm.
• It causes the chest and shoulders to broaden.
• It also causes facial hair to grow.

Male Reproductive System

The male reproductive system consists of primary sex organs, accessory ducts, accessory glands and external genitalia.

Primary Sex Organ – Testes

• Testes are the primary sex organs in man.
• Testis is the site where male gametes or sperms are produced.
• The testes are situated outside the abdominal cavity within a pouch called the scrotum.
• In adults, each testis is oval in shape and is about 4–5 cm in length and 2–3 cm in width.
• The outermost covering of the testis is a dense fibrous membrane called tunica albuginea.
• Each testis has about 200–300 compartments called testicular lobules.
• These lobules contain highly coiled tubules called seminiferous tubules.
• Each testicular lobule contains about 1–3 seminiferous tubules in which sperms are produced.