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reproduction.notebook

November 05, 2012

Reproduction in humans

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reproduction.notebook

November 05, 2012

Objectives: • To look at changes in the body from birth to adult • To appreciate changes in behaviour in adolescence

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reproduction.notebook

November 05, 2012

How do people change as they get older?

• Growth • Grow hair on body • Develop mentally (emotions) and physically (sexual characteristics) • Start to get wrinkles, grey hair • Become more frail in older age

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reproduction.notebook

November 05, 2012

What are some differences between: Male Develop later than females

More muscle

Bigger bones

Female Develop faster than males

Higher pitch voice

wider hips

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reproduction.notebook

November 05, 2012

Adolescence - what do you think happens?

Physical change

(Puberty)

• Rapid growth spurts • Change in body • Hair growth on body

Emotional change: • • • •

Mood swings Try to be too independent at times Rebellious at times Becomes interested in boyfriend/ girlfriend

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reproduction.notebook

November 05, 2012

Hormones: Chemicals that are produced in one part of the body that circulate in the blood and affect a certain organ.

Growth hormone - stimulates growth in hands and feet, hips and chest

Gonadotrophin - stimulates production of sex hormones. Females - oestrogen and progesterone in the overies Males - testosterone in the testicles

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reproduction.notebook

November 05, 2012

Secondary sexual characteristics

Males

Females

growth of hair on the face, armpits and pubic region

growth of hair in the armpits and pubic region

voice becomes deeper

breasts develop

growth of penis and testicles

growth of vagina and uterus

pelvis widens

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reproduction.notebook

November 05, 2012

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reproduction.notebook

November 05, 2012

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reproduction.notebook

November 05, 2012

Menstrual Cycle: Thickness of womb lining

egg

0

7

10

14

21

28

The egg is released from the ovary after about 10 days. Why do you think this is about the right time?

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reproduction.notebook

November 05, 2012

Fertilisation: happens in the oviduct

• The sperm enter the vagina • They swim into the uterus and then the oviduct • The egg is released from the ovary

• Fertilisation will happen in the OVIDUCT

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reproduction.notebook

November 05, 2012

What differences can you see in the sperm and the egg cells?

Sperm

• smaller • has a tail

Egg

• large • has own food storage

• Both cells have a nucleus, but with 1/2 the amount of genetic material

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reproduction.notebook

November 05, 2012

After fertilisation happens, the cells form a zygote, which continues to develop into an embryo

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reproduction.notebook

November 05, 2012

The developing embryo in the uterus becomes a foetus.

Placenta: Transfers nutrients and oxygen from the mother to the foetus, and removes waste products such as carbon dioxide. The structure contains lots of surfce area to allow rapid exchange of substances

Umbilical cord: Contains blood vessels that connects the baby to the placenta. The mother's blood and baby's blood DO NOT MIX Amniotic fluid: Protects the baby form bumps and damage 14


reproduction.notebook

November 05, 2012

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reproduction.notebook

November 05, 2012

What do you think would happen if the mother drank alcohol or smoked during pregnancy?

For each case, think how this could reach the baby

Mother

Baby

Alcohol:

Nicotine from smoking:

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reproduction.notebook

Alcohol

mother's stomach

November 05, 2012

Nicotine from smoking

mother's lungs

mother's blood stream

mother's blood stream

placenta

placenta

baby's blood stream

baby's blood stream

baby's brain

baby's brain

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reproduction.notebook

November 05, 2012

How long does the baby take to develop?

The gestation period for a human is about 38 weeks or 9 months

Time

2 weeks

Development

flat disc of tissue

4 weeks

simple body shape with stumps where limbs will grow

8 weeks

all organ systems formed and the embryo is called a foetus

14 weeks

sex of the foetus can be identified

16 weeks

foetus starts moving

20 weeks

the legs grow quickly

32 weeks

the baby turns upside down so the head is near the cervix

38 weeks

The baby is ready to be born

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reproduction.notebook

November 05, 2012

Birth

3 stages: 1: Muscles of uterus begin to contract 2: Mother's stomach muscles begin to contract The baby leaves the uterus through the cervix

3: The placenta leaves the uterus and vagina - the after birth

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reproduction.notebook

November 05, 2012

Twins - identical or not? How do you think this could happen? What must they both have in common if they are identical?

Discus and write down how the twins must be formed in each case

non-identical

Two eggs are released and fertilised by different sperm

identical

One egg is fertilised The egg then splits in two

splits in two

• Different

• identical (same)

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reproduction.notebook

November 05, 2012

What you should know:

• Changes in the body at puberty are caused by sex hormones • The structure of the male and female reproductive organs • The menstrual cycle occurs due the monthly release of an egg • Fertilisation is the joining of a sperm nucleus a¡with an egg nucleus • The development of the embryo takes place in the uterus • The palcenta and amniotic fluid (amnion) are impotanat in the development of the embryo and foetus • The uterus and and stomach muscles are used in the birth process

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reproduction.notebook

November 05, 2012

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Reproduction