Biology: Human Reproduction (Chp. 2)

By Audrey and me

A.1 Parts

Female

Ovary (ovarium): where the eggs are produced and kept until it reaches its maturity.

female

Fallopian tube (tuba fallopi): a hollow tube that connects the ovary to the uterus. (Infundibulum à mouth of fallopian tube where oogenesis and fertilization takes place)

Uterus: where the embryo will implant and develop into a fetus (endometrium à also known as uterine lining, which sheds during menstruation).

Vagina: a structure below the uterus that consists of the vulva and the cervix and is where copulation takes place.

Cervix: the opening where menstruation blood flow will exit, as well as where the baby will be taken out during the process of giving birth (in normal conditions). The cervix has an elastic muscle that closes du ring pregnancy and opens during birth.

Vulva: opening of the vagina

MALE

MaleTestes: where production of sperm takes place.

Scrotum: a sac that contains the testes to protect it from mechanical shock and to maintain a lower temperature than the body temperature.

Epididymis: a curled structure that contains the sperm to mature after released from testes and mixes it with certain substances to form semen.

Sperm duct (vas deferens): connects epididymis to the bladder.

Seminal vesicle (vesikula seminalis): stores semen temporarily before released to bladder where it is mixed with enzymes that nourishes the sperm.

Cowper’s gland and prostate glands (kelenjar cowper’s dan kelenjar prostat): Cowper’s secrete an acid that washes the urethra away of urine before ejaculation. Prostate provides an enzyme that is alkali, and neutralises the acidic vagina.

Together with enzymes from seminal vesicle, they provide seminal fluid which is a medium that is also the place where sperm can swim in.

Urethra: connects the bladder to the outside.

Penis: a copulatory organ that transmits the semen into the female organ during sexual intercourse.

A.2 Sperm and Ovum

Sperm

Ovum

 www.biology.lifeeasy.org  human-ovum-structure
Motile, has a tail (flaggela) that enables it to swim, and also many mitochondria that provides energy for movement and also small size. Immobile, swept along by peristaltic contractions of oviduct wall
Numerous sperms are produced throughout life from puberty onwards and a large number is released per ejaculation. Number of eggs is determined at birth, (70 000 potential ova, 500 will mature), released once a month.
Small size: 0.05 mm long, to swim faster, and can be released in large number Large size: have abundant cytoplasm that will nourish the zygote when travelling from the oviduct to uterus
Nucleus contains X or Y chromosome. Nucleus contains X chromosome.

A.3 Fertilization -> Birth

After fertilization the ovum, now a zygote, travels down the oviduct to the uterus. It then implants itself at the endometrium, where embryonic villi begin to form. Inside these embryonic villi are embryonic blood vessels (the umbilical vein carry the food for the zygote/embryo, the umbilical artery carry the waste material from the zygote/embryo). Then, the placenta is formed. The placenta is as a thin layer of tissue that allow diffusion of nutrients and waste material across it. The embryo is connected to the placenta by the umbilical cord. The amniotic sac encloses the embryo and inside is the amniotic fluid. It functions to reduce mechanical shock and to reduce friction. When it’s time for birth, the cervix opens and the muscles in the uterus pushes the fetus through the vagina and finally a baby is born.

Placenta

Allows oxygen and dissolved food substances to difuce to the foetal blood systemAllow mother to confer passive immunityProduces various hormones to maintain pregnancy
Umbilical Cord Two umbilical arteries transport deoxygenated blood and metabolic wastes from the foetus to the placenta.One umbilical vein transport oxygenated blood and nutrients from placenta to foetus
Amniotic sac Contains the amniotic fluid
Amniotic Fluid Supports and allows the foetus to move freely during growth, protects foetus from mechanical shock, lubricates vagina during birth

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