Human Growth and Development

Lesson 1 – The Reproductive System

Vocabulary• hormones – chemicals made in one part of

the body that is released into the blood, that is carried through the bloodstream, and that causes a change in another part of the body; controls growth and development and many other body functions.

• gonads – reproductive organs that make reproductive cells and hormones – 1. Testosterone (testis) – growth and function of

men’s bodies – ex. Facial hair, muscle growth– 2. Estrogen (ovary) – controls growth and function

of a women’s body – ex. Breast growth, curves

• Chromosomes – long strands of matter located in cell nuclei; contain codes for all your inherited traits – 46 total chromosomes – 23

from mother (egg), 23 from father (sperm)

– a. A sperm and egg joining makes a complete cell with 23 pairs or 46 chromosomes

– b. Every new egg and sperm combination is completely different than another

• What makes you a boy or girl?• 1. Egg/ovum always = X Sperm = X or Y – a. Males determine whether you are a boy or girl– b. X chromosome and Y chromosome

• 2. XX = girl XY = boy

• Genes – tiny bits of information on chromosomes; influence heredity. Genes carry the codes or directions for a trait

• Dominant – describes the stronger gene of a pair; this gene’s codes keep codes on the recessive gene from being carried out

• Recessive – describes the weaker gene of the pair; its codes are “hidden” by the codes on the dominant gene – codes on the recessive genes are carried out only when 2 recessive

genes are paired together Inherited traits are called sex-linked traits – carried by the chromosomes that determine a person’s sex– Ex: color blindness is carried on the Y chromosome

Male Reproductive System

• Sperm – contains 23 chromosomes• Testes (testicles) – produce sperm• Scrotum – houses the testes• Vas deferens – sperm delivery tube• Penis – male reproductive organ• Testosterone – male sex hormone

Female Reproductive System

• Egg – contains 23 chromosomes• Ovary – produces eggs• Uterus – houses the fertilized egg• Fallopian Tube – egg delivery tube• Vagina – female reproductive canal• Progesterone and Estrogen – female sex

hormones

Reproductive System Facts

• The male reproductive system makes and stores sperm

• The female reproductive system makes and stores eggs and carries out pregnancies

• It is important to keep the reproductive area clean and dry because many diseases are caused by bacteria and fungus that like to live in warm, moist environments

More Reproductive System Facts

• The ovaries are like the testes in that they both produce sex cells and hormones. These hormones are responsible for much of the growth and function of the female and male body.

• A healthy adult male make several million sperm each day. Each sperm cell takes about 70 days to mature.

• A female’s ovaries contain about 2 million immature eggs at birth. At puberty, one egg matures each month.

Male Reproductive System

• Parts and pieces:• Testes, scrotum, and penis• Testes - produce sperm; also

produce the hormone, testosterone.

• Scrotum: external pouch that hold testes

• Vas deferens – tube sperm travel through to get to urethra

• Prostrate – gland encircling the urethra; plays part in semen production

• Penis: external organ

Female reproductive system

• Role is to produce eggs and if fertilized, nourish young until birth.

• Parts and pieces: ovaries, uterus and vagina

• Ovaries produce eggs• Fallopian Tubes pathway

to the Uterus for eggs• Uterus: hollow muscular

organ the size of a pear• Vagina: muscular

passageway; birth canal