Science

The sperm cell

Designed to fertilise eggs.

• A sperm cell is VERY SMALL and had a little TAIL which provides MOVEMENT so it can SWIM and find an egg to fertilise.
• Its head contains ENZYMES which allow it to DIGEST its way through an EGG MEMBRANE so the two nuclei can JOIN.
• It contains CHROMOSOMES in the nucleus- these carry genetic information from the FATHER - which will passed onto the OFFSPRING.

The Ovum (egg) cell

Designed to be fertilised

• An ovum is LARGE and BULKY because NO active movement is needed- it just sits and waits for sperm to find it.
• It contains YOLK which provides a large FOOD STORE needed for the developing YOUNG ORGANISM, once its fertilised.
• It contains CHROMOSOMES which carry genetic information from the MOTHER- this will be passed on to the offspring.

The Palisade cell

Designed for Photosynthesis

• A palisade cell is tall with a LARGE SURFACE AREA. It's found on the top side of a leaf- ideal for good ABSORPTION of CO2 and LIGHT- both are needed for PHOTOSYNTHESIS.
• They're packed with CHLOROPLASTS which contain green pigment CHLOROPHLL, which is needed for photosynthesis.

The cilia cell

Designed to stop lung damage.

• CILIA CELLS line all the AIR PASSAGES in your lungs.
• They have TINY HAIRS which FILTER THE AIR as it blows through.
• The hairs sweep MUCUS (snot) with TRAPPED DUST and BACTERIA up to the back of the throat, where its SWALLOWED.

The Root Hair Cell

Designed for absorbing.

• The long root hair cell INCREASES the SURFACE AREA of the root which helps ABSORPTION of WATER and MINERALS.
• It has a really THIN cell wall, which makes it easier for minerals to PASS ACROSS into the root itself.

A group of SIMILAR CELLS come together to make a TISSUE.

A group of DIFFERENT TISSUES work together to make an ORGAN.

A GROUP OF ORGANS work together to make ORGAN SYSTEM, or maybe even a whole ORGANISM.

for example:

Root hair cells make up root tissue which makes up the Root "organ" system, which works with other systems to make up a plant.

MOVEMENT MOVING PARTS OF THE BODY

RESPIRATION TURING FOOD INTO ENERGY

SENSITIVTY RESPONDING AND REACTING

NUTRITION GETTING FOOD TO STAY ALIVE

EXCRETION GETTING RID OF WASTE

REPRODUCTION PRODUCING OFFSPRING

GROWTH GETTING TO ADULT SIZE

The digestive system

Digestion breaks down food into simpler substances so it can be used and absorbed into the body.

It takes place in the ALIMENTARY CANAL ( food tube) mainly in the STOMACH and SMALL INTESTINE.

Digested food is ABSORBED into the BLOOD system.

The Respriatory system

This is for taking in OXYGEN and removing waste carbon dioxide.

AIR enters the LUNGS by movement of the RIB MUSCLES and DIAPHRAGM.

OXYGEN is ABSORBED into the BLOOD SYSTEM.

The Excretory System.

This removes nasty WASTE materials from the body, some of which are POISONOUS.

WASTE material is FILTERED OUT of the blood by the KIDNEYS and made into URINE.

This is STORED in the BLADDER and released via the urethra.

The Circulatory System.

The HEART pumps the BLOOD around the body.

It SUPPLIES the CELLS with OXYGEN and FOOD , then carries away the WASTES like CARBON DIOXIDE.

The nervous system.

The five sense organs are: EYES, EARS, NOSE, TONGUE and SKIN.

They all contain NERVES which send MESSAGES to the BRAIN about WHAT'S HAPPENING.

The BRAIN produces a RESPONSE which it SENDS via OTHER NERVES to the MUSCLES ( and GLANDS ).

The Reproductive System.

This is for PRODUCING OFFSPRING.

EGGS are produced by the OVARIES in a WOMAN.

SPERM are produced by the TESTES of the MAN.

They then FUSE to FERTILISE the eggs.

The Endocrine System.

This system produces and discharges chemicals called HORMONES.

A number of GLANDS around the body produce these HORMONES.

Hormones control things like GROWTH, and SEXUAL CHARACTERISTICS and also bodily functions like MENTRUATION.

The Skeletal system

There are 206 BONES in the human body. Their main job is to SUPPORT.

Some bones (eg. the skull ) Provide a TOUGH BARRIER to PROTECT DELICATE ORGANS like the BRAIN.

MUSCLES are attached to bones which CONTRACT AND RELAX allowing MOVEMENT.

The Muscle System.

MUSCLES are attached to the BONES.

Muscles cause MOVEMENT when they CONTRACT and RELAX.

MUSCLES are found IN PAIRS round in a JOINT.