Human Reproduction : Leaving Cert

Site of sperm production and testosterone production

Where sperm matures and is stored

Produce seminal fluid which keeps sperm in an alkaline environment, nourishes the sperm and allows them to swim.

To keep the testes less than 37 degrees for sperm production

To produce eggs(ovas) and to produce the female hormones oestrogen and progesterone

Site of fertilisation

Testosterone

It promotes the development of the male primary and secondary characteristics

1. The enlargement of the larynx and the 'breaking' of the voice 2. Increased muscular development 3. A growth spurt 4. Broadening of the shoulders 5. Increased secretion of sebum

Oestrogen and Progesterone

Oestrogen: Causes the lining of the uterus to build up, prevents another egg from developing Progesterone: Causes endometrium at thicken, prevents another egg from developing

A 28 day sequences of events that produces and egg and prepares the body for pregnancy

Menstruation and the production of another egg inside a Graafian follicle

The shedding of the lining of the uterus

The lining of the uterus is built up again to prepare for implantation

The Graafian follicle bursts and an egg is released - ovulation

Ovulation is the release of an egg from an ovary

The Graafian follicle bursts and is filled with yellow cells. This becomes the Corpus Luteum

The Corpus Luteum begins to disintegrate

It causes the reduction in progesterone. The lack of the hormones means the endometrium is no longer built up.

Day 12-16

The time where a woman is most fertile as 1. Sperm can survive in an uterus for 2 days 2. An egg can last in the uterus for 2 days

Sexual intercourse

Sexual arousal, copulation, orgasm and insemination

1. The penis becomes erect 2. The vagina becomes lubricated

The penis is inserted into the vagina

1. Sperm is released from the penis (ejaculation) 2. The vagina and uterus contract

It should move the sperm from the vagina to the fallopian tube within 5 minute

If an egg is present it releases a chemicals to attract the sperm

The fusion of an egg and sperm nuclei to form a diploid zygote

1. The acrosome of the sperm releases enzymes that digests the membrane 2.The sperm loses its tail and the head enters the egg. 3. A chemical reaction occurs in the membrane and prevents other sperm from entering

The embedding of the fertilised egg into the lining of the uterus

6-9 days after fertilisation

A membrane that forms around an embryo. It secretes amniotic fluid

Acts as a shock absorber

An outer membrane that develops aroind an embryo

Chorion villi

Allows nutrients, wastes, gases, antibodies and hormones to be exchanged between the blood of the mother and the embryo

1. The blood group of mother and child might not be compatible 2. The blood pressure of the mothers system may cause damage to the embryo

Progesterone

Umbilical cord

Oestrogen and Progesterone. First by the Corpus Luteum for 3 months the the placenta

An endocrine gland

A drop in progesterone causes the uterus to contract, the release of oxytocin causes further contractions.

1. Labour 2. Birth 3. After Birth

1.Labour usually lasts around 12 hours. 2.Contractions of the uterus pushes the foetus towards the cervix. 3.This causes the cervix to dilate. 4. The contractions cause the amnion to break ('water breaks')

1. Birth usually lasts 20mins to an hour 2. The foetus passes through the cervix and vagina 3. The umbilical cord is cut 4. This leaves a scar that will become the navel (belly button)

1. The uterus contracts again 2. The placenta is delivered

The release of milk from the mammary gland?

Milk produced within the first few days that is high in nutritional value and contains essential antibodies.

1. Colostrum and milk provide passive immunity (antibodies) 2. Ideal balance of nutrients for the baby 3. Ideal temperature of milk 4. Easily digestible for child

Methods used to limit the number of children that are born

Removing the possiblites of conception

Male: Condom Female: Diaphragms

Male: Spermicides Female: Oral contraception

Male: Cutting/ tying of the sperm duct Female: Cutting/ tying of the fallopian tubes

Not having intercourse during fertile period.

The inability to achieve conception

1. Low sperm count 2. Low sperm mobility 3. Endocrine gland failure

1. Persistent use of drugs 2. Abnormalities in sperm production or obstruction of tubes 3. Stress

1. Change of lifestyle 2. Reduce stress

1. Blockage of the fallopian tube 2. Endocrine gland failure

1. Fragments of the endometrium may be spreading into the fallopian tube 2. Inflammation as a result of infection

1. In-vitro fertilisation (IVF)

Removing of eggs from the ovary and fertilising them outside the body

1. Fertility drugs are given to stimulate the production of eggs 2. The eggs are collected aswell as sprm 3. The egg and sperm are mixed together in conditions ideal for fertilisation 4. The zygote should becomes a morula the a blastocyst then a embryo