M6(1) Common Features of the Male and Female Reproductive Systems

Reproductive System Purposes

There are 4 main functions the reproductive system (in both males and females) carries out:

• Gamete Production

• Game Transport and Union

• Fertilization

• Development and Birth

Gamete

A reproductive sex cell

• Carries half (23) the normal number of chromosomes in humans (46)

Gamete Production

Reproductive organs produce gametes

• Males produce sperm

• Females produce ova (eggs)

Gamete Transport and Union

The reproductive system allows sperm and egg to meet

• This typically occurs through sexual intercourse (copulation)

Fertilization

The combining of genetic information contained within the male and female gametes occurs here

• Male and female gametes fuse

• Zygote is produced

Development and Birth

Reproductive system

1. Supports the development of the fetus (gestation)

2. Enables birth of the baby (parturition)

Reproductive System Note

Both the male and female reproductive systems are equal partners in the events leading up to fertilization

• However, the last 2 tasks (fertilization, pregnancy) occur entirely within the female

Reproductive System Common Features

1. Gonads

2. Accessory Reproductive Organs

3. Reproductive Hormone Secretion

4. Meiosis

Gonads

Reproductive organs that produce gametes and secrete sex hormones

• Males: testes

• Females: ovaries

Sex Hormones

Includes hormones like testosterone, estrogen, progesterone

Homologous Structures

Structures that share a common origin during development

• Often have functions in common

• e.g. male testes and female ovaries, male penis and female clitoris

Accessory Reproductive Organs

Reproductive organs that support, transport, and protect gametes

• Includes ducts, glands, external genitalia

Reproductive Hormone Secretion

Controlled by interaction between

• Hypothalamus

• Anterior pituitary gland

• Gonads

Hypothalamic Pituitary Gonadal Axis

The relationship between the hypothalamus, anterior pituitary, and gonads

• Between each level of axis, hormones regulate the secretion of other hormones

HPG Axis Steps

1. Hypothalamus releases GnRH (gonadotropin-releasing hormone)

2. Anterior pituitary responds to GnRH and releases LH (luteinizing hormone) and FSH (follicle-stimulating hormone)

3. Gonads respond to LH and FSH and produce gametes + sex hormones + inhibin

4. Sex hormones exert negative feedback on the hypothalamus + anterior pituitary which inhibits GnRH, LH, FSH secretion

5. Inhibin exerts negative feedback on the anterior pituitary which inhibits FSH secretion

Meiosis

Both systems produce gametes using meiosis