Sexual Reproduction

Reproduction

the production of new individuals.

It involves two parents

Puberty

the age of sexual maturity

The Male Gamete

The Female Gamete

Sperm

Egg

The testes

produce sperm

Sperm is first made at puberty

Sperm cells can swim

3 Parts of a sperm

Head

Nucleus

Tail

The scrotum

is a sac which holds the two testes

allows the testes to be slightly cooler than the body temperature

Sperm Ducts

carry the sperm from the testes to the penis

attached to a number of glands which produce a liquid called seminal fluid

Penis

the two sperm ducts join the form a tube called the urethra

Sperm can pass through the urethra

Urethra is located in the centre of the penis

Ovaries

produce eggs

Eggs are produced:

from the age of sexual maturity

until the change of menopause (45-55)

Normally one is made each month

Fallopian Tubes

collect the eggs as it is released from the ovary

transport the egg towards the uterus

the location sperm and eggs join

Uterus (Or womb)

the location where embryo or baby develops during pregnancy

Cervix

the opening into the uterus (through which the penis can enter)

Vagina

a muscular into which the penis releases sperm

forms the birth canal when a baby is born

The Menstrual Cycle

a series of events that occur in the female every 28 days

starts at puberty and ends at menopause

stops happening if the female is pregnant

The Fertile Period

the time during the menstrual cycle when pregnancy is most likely

Around the middle of the cycle

Sexual Intercourse

the act of sexual union

How does sexual intercourse occur?

1. takes place when the erect penis is placed in the vagina

   also called copulation

2. Causes sperm to be released into the vagina

The path of sperm and eggs

the egg is released from the ovary and is pushed along the fallopian tube

The sperm swim - in through the cervix, along the wall of the uterus then towards the egg

what happens if no egg is present during sexual intercourse?

The sperm die

Fertilization

the joining of the sperm with the nucleus of the egg. forms a zygote

What happens after fertilization

the zygote divides by cell division to form a ball of cells. Gets pushed down into the uterus

Implantation

The ball of cells attaches to the lining of the uterus

What does the ball of cells develop into and do?

Into the embryo

becomes surrounded by amniotic membrane- the fluid is formed to surround the embryo and act as a shock absorber

Foetus

after 8 weeks the embryo looks like a human and is the foetus

The placenta

forms soon after implantation

contains blood vessels which pass to the foetus and pas through the umbilical cord

What does the placenta allow?

Food and oxygen to pass from the mother to the foetus

Waste products to pass to the mother

It also allows harmful substances to get to the baby

At the time of the birth →

The muscles in the wall of the uterus begin to contract

The amnion bursts

Amniotic fluid passes out of the vagina

The cervix widens

After the baby is born →

The umbilical cord is cut

The baby takes its first breath

The afterbirth

Contractions of the uterus force the placenta and umbilical cord out of the uterus

Benefits of breastfeeding

The ideal food needed by the baby

Antibodies made by the mum protect the baby from infectiosn

Contraception

the deliberate use of artificial methods to prevent pregnancy

2 main types of contraception

Preventing fertilization

Preventing implantation

Artificial methods of preventing fertilization

Condoms

A cap

Chemical sprays

Cutting the sperm ducts of fallopian tubes

Preventing implantation

taking pills

inserting a loop or coil into the uterus

IVF

In Vitro Fertilization

Involves taking sperm and eggs from the parents and allowing them to join outside the body

One of the embryos is placed back into the uterus

Problems with IVF

Small risk of more than one embryo developing

Slight risk to due to the side effects

Increased risk of the baby having defects

Costly process

Stem Cells

cells that can develop into any type of body structure

Sources of stem cells

Embryos

Umbilical cords

Adult bone marrow, fat, nose and other body cells

Uses of stem cells

Producing new organs for transplant

Treating things

What do stem cells treat?

Spinal cord injuries

Heart disease

Strokes

Parkinson’s disease