Reproductive system

Lab-9

Body and Sex cells

• Body cells: – Each body cell has 46 chromosomes (23 pairs) within the

nucleus • Sex cells:

– Gametes (egg and sperm) have only 23 chromosomes (1 of each pair) in their nuclei

• Meiosis: – Is a type of reduction division in which a cell halves the

number of chromosomes

– This process is used to form eggs and sperm

– Occurs in the gonads

• Gonads form a part of the endocrine system and are the primary reproductive organs of both male and female.

• Gonads are generally considered mixed glands in both sexes because they manufacture both cells and hormones. The hormones and cells they produce are

vital to reproduction.

• Both sexes have:

1. primary sex organs

2. secondary sex organs

The primary sex organs

(gonads) are those that produce gametes (sperm and eggs)

The gonads in males are the testes and the gonads

in females are the ovaries

Female: ovaries Male: testes

The secondary sex organs

- Essential for reproduction

Male:

ducts, glands, penis

Female:

uterine tubes, uterus, vagina

Testes

ovaries

Male sex organs Female sex organs

The Male Reproductive System Delivers Sperm

• Testes produce sperm – Scrotum: sac of skin and smooth muscle that

holds the testes • Maintains testes at a slightly lower temperature

– Seminiferous tubules within testes: produce sperm

• Epididymis : sperm become motile and are stored here

• Ductus deferens: transports sperm to where it becomes the ejaculatory duct

Ductus

deferens

Penis

Erectile

tissue

Testis Scrotum

Urethra

Epididymis

Bulbourethral

gland

Prostate gland

Ejaculatory duct

Seminal

vesicle

Ureter Ductus

deferens

Testis Penis Uncoiled semi-

niferous tubule

Urethra

Bulbourethral

gland

Prostate gland

Seminal vesicle

A sagittal cutaway view. A posterior view of the reproductive organs and bladder.

• Route of sperm through male reproductive structures

– Seminiferous tubules

– Epididymis

– Ductus deferens

– Ejaculatory duct

– Penis

• Semen: mixture of sperm and secretions of accessory glands which help sperm survive

The Female Reproductive System Produces Eggs and Supports Pregnancy

• Ovaries

– Release oocytes (immature eggs) and secrete the hormones estrogen and progesterone

• Oviduct (fallopian tube)

– Leads from the ovary to the uterus

– Fertilization occurs in the upper third of the oviduct

• Uterus: the hollow, pear-shaped organ where fertilized egg grows and develops

• Cervix: the narrow opening in the lower part of the uterus

• Vagina: birth canal

Oviduct

Ovary

Uterus

Vagina

Cervix Uterus

Ovary

Oviduct

Cervical canal

Sagittal section showing the components of the system in relation to other structures.

Anterior view of internal organs.

Low magnification view of the human ovary

Human ovary cross section with developing follicles (right)/ Corpus luteum (left)

Human Fallopian tube cross section.

Magnification 40X

Cross section in Fallopian tube (oviduct)

Low and High magnification in human testis

showing the Seminiferous tubules

Structure of human sperm

Human sperm under microscope