Body Systems

When cells divide they transfer genetic information to daughter cells

• Mitosis - Growth & Repair
• Meiosis - Formation of gametes

Binary fission, Budding, Spores Runners, Bulbs, Tubers

Cancer is caused by the uncontrolled cell divison

Ovulation – this is the process of egg release from an ovary, it occurs about every 28 days.

The eggs transported through the fallopian tube to the uterus. If the egg is not fertilised by sperm, it will pass out of the body in the menstruation.

This blood flow lasts about 4-5 days due to the breakdown of the thickened lining of the uterus. This lining regrows in the next cycle.

If the egg is fertilised by a sperm in the Fallopian tube, it will begin to divide into a ball of cells. This ball of cells takes 8 days to travel into the uterus where it becomes implanted in the uterine wall. The pregnancy has begun.

The developing embryo is connected to its mother by the placenta. The umbilical cord is an extension of the placenta.

Nutrients and oxygen pass across the placentas to the developing embryo.

• Wastes pass the other way and are eliminated by the mother. The blood of the mother and the baby never mix.
• From 8 weeks until its birth, the fetus grows and matures.

When the baby is mature it is expelled from the uterus by strong muscular contractions. It passes through the vagina and is born. This normally occurs 270 days after fertilisation.

• _{Large chance of evolution taking place}
• Better adapted, lower chance of extinction
• Lowered chance of disease due to mixed gametes

Only the females can mate (half the population)

Two parents have to be involved

Trying to find a mate

No grantee that offspring will be born

Only one parent is needed

Large guarantee that an offspring will be born

Short period of time

No chance of evolution happening

The offspring will be identical to parents, so diseases and bad qualities are passed down

There are two systems (endocrine and nervous) that coordinate body functioning

Endocrine - The endocrine system is made up of glands that secrete chemicals called 'hormones' into the bloodstream. Together with the nervous system and the immune system, the endocrine system helps the body to cope with different events and stresses. Glands of the endocrine system include the pituitary gland, thyroid gland, parathyroid gland, adrenal glands, pancreas, ovaries and testes.

Nervous - The nervous system helps all the parts of the body to communicate with each other. The brain and spinal cord make up the central nervous system.

All the systems work simultaneously in a co-ordinated manner to keep the body alive

Example

Endocrine:

Cell signaling performed by the secretion of chemicals which are carried by the blood and tissue fluids to target cells.

Hormone:

A chemical substance produced in the body that controls and regulates the activity of certain cells or organs.