The Reproductive System
Reproduction (def):
sexual reproduction involves the production of the egg by the female and sperm by the male-----the egg and sperm join together during fertilization
In humans, the reproductive system produces, stores, nourishes, and releases specialized cells known as sex cells.
Sex cells are known by the scientific name of gametes.
· the male sex cell, or gamete, is called the sperm.
· the female sex cell, or gamete, is called the egg or ovum/ova.
Fertilization (def):
joining of sperm and egg
The nucleus of both the male and female sex cells, or gametes contain chromosomes, which are responsible for passing on inherited traits of characteristics.
· sex cells contain 23 chromosomes, while non-sex cells contain 46 chromosomes, or 23 pairs
· upon the union of the egg and sperm, their 23 chromosomes pair to make 46 total, and they contain all the information needed to make a complete being
Prior to the 7th week after an egg has been fertilized, male and female embryos are indistinguishable. During the 7th week, gender is determined when either male or female hormones are released and give the embryo the message to develop into a male or female.
Sometime 10-15 years after birth, the reproductive system of both the male and female matures by receiving the same hormone messages of those received before birth.
The Male Reproductive System
sperm—male sex gamete; contains ½ the information needed to make a complete being; made up of 3 section---head (nucleus), middle piece, and tail
testes—male sex or reproductive organs; made of tightly coiled tubes where sperm is produced
scrotum—sac surrounding and protecting the testes
epididymus—crescent shaped structures attached to the testes; sperm is stored here
seminal vesicles—glands producing sugars to help nourish sperm
prostate gland—gland producing milky fluid that helps sperm mobility
Cowper’s glands—glands secreting a mucus like substance to help neutralize acids in urine
semen—name given to the fluid containing sperm that is produced from the glands
vas deferens—the tubes leading from the testes to the penis (vasectomy)
urethra—tubes carrying sperm and fluid out of the body by way of the penis
testerone—male sex hormone that triggers male sexual maturation and the development of secondary sex characteristics
1) production of sperm 3) deepening of voice
2) broadening of shoulders 4) facial and body hair
The Female Reproductive System
ovum—the female sex cell or gamete; females are born with all the ovum they’ll ever have; each ovary contains eggs
ovaries—female reproductive organ where eggs/ovum are produced; contain approximately 200, 000 ovum in each; lifetime release is approximately 500
fallopian tube—tube or duct located near each ovary that will carry the ovum to the uterus; also called the oviduct or egg tube
uterus—hollow, muscular organ, or womb; where the fertilized egg develops or grows
cervix—area between the uterus and vagina
vagina—located at the lower end of the cervix and leads to the outside of the body; also called the birth canal
estrogen—female sex hormone; causes or contributes to the menstrual cycle and to the development of female secondary sex characteristics
1) developing hips/breast
2) body hair
3) menstrual cycle
The Menstrual Cycle
menstrual cycle (def): female’s monthly cycle of change (approx. 28 days)
· mensis—Latin meaning monthly; controlled by hormones
· 2 purposes of the menstrual cycle:
a) development and maturing of an egg/ovum and it’s release for fertilization
b) preparation of the uterus to receive a fertilized egg
· follicle—pocket cells surrounding each ovum in the ovaries
· Changes taking place during the menstrual cycle:
a) ovulation—hormone-triggered release of a mature egg and its follicle from an ovary; usually 1 ovulation occurs each month
b) uterine lining—thickens with additional blood supply