Systems c2

Questions to think about…

What is air made up

of?

What are the organs of the human respiratory system,

and what are their functions?

How do fish, mammals and plants take in oxygen and

give out carbon dioxide?


All mixed up!

• Air is a mixture of gases.

• About one-fifth of air is oxygen.

• The remaining four-fifths are mostly made up of nitrogen and a small amount of carbon dioxide, water vapour and some other gases.


All mixed up!

oxygencarbon dioxide, water vapour and other gases

nitrogen


All mixed up!

• Oxygeno Most living things need oxygen to stay

alive.o Living things take in oxygen in order to

break down digested food to produce energy in a process called respiration.

o Living things on land take in oxygen from the air around them.

o Animals and plants that live in water use oxygen that is dissolved in water.

o Animals living in the ground and roots of plants use oxygen that is found in the soil.


All mixed up!

• Oxygeno Oxygen is also needed for burning.o When we light a candle, burn a piece of paper

or set fire to wood, oxygen is used up.o A continuous supply of fresh air rich in oxygen

is needed to keep things burning.


All mixed up!

• Nitrogeno Although nitrogen makes up four-

fifths of the air, this gas is not used by most living things.

o Only some bacteria living in the soil are able to use nitrogen from the air around them.

o Plants must have nitrogen to live, but they are not able to use nitrogen from the air.

o Bacteria that live in the roots of plants change nitrogen from the air that is in the soil, into a form plants can use.


All mixed up!

• Carbon dioxide, water vapour and other gaseso When living things respire or when things

burn, oxygen is used up and carbon dioxide is produced.

o Carbon dioxide is important to plants. o During the day, plants use carbon dioxide

and water to make food in a process called photosynthesis.

o Oxygen is produced at the same time.


Respiratory system

• Breathing is the process of taking in air into our bodies and giving it out again.

• We breathe so that we can take in oxygen for respiration.

• At the same time, carbon dioxide is formed.

• Carbon dioxide is removed from our bodies and released into the air when we breathe out.

• The parts of a living thing that help it to breathe form the respiratory system.

• Different animals have different parts in their respiratory systems.


Human respiratory system

• Lungso When you breathe in,

your ribs move out and upwards.

o Your diaphragm, a thin sheet of muscle moves downwards.

o This causes your chest to become bigger.

diaphragm

air



• Lungso As a result, air rushes

into your body through your nose or your mouth.

o Air that enters your respiratory system is cleaned, warmed and moistened.

diaphragm

air



• Lungso The air then moves down

your windpipe.o Your windpipe branches to

the left and right into two smaller tubes.

windpipe



• Lungso Each of these tubes lead to

one of your two lungs. o These tubes branch further

into tiny tubes that end in balloon-like air sacs.



• Lungso The air sacs have a rich supply of

blood vessels.o When the air you breathe in

reaches your air sacs, oxygen passes through the walls of the sacs into the blood vessels.

o Your body then carries the oxygen to all parts of your body.



• Lungso When you breathe out,

your ribs move in and downwards.

o This time, your diaphragm moves upwards.

o This causes your chest to become smaller and the air that has carbon dioxide in it, is forced out of your lungs.

diaphragm

air


Animal respiratory system

• Fisho Fish breathe with their

gills.o Gills are feather-like

structures with a rich supply of blood vessels.

o They are found under the gill covers of fish.

gills



• Fisho A fish makes use of the oxygen

that is dissolved in the water around it.

o When water enters the mouth of the fish and flows over its gills, oxygen passes through the walls of the blood vessels and into the blood.

o Oxygen is then carried by the blood to different parts of the fish.



• Fisho Carbon dioxide passes

through the walls of the blood vessels, dissolves in the water and is carried away as the water flows out from under the gill covers.



• Mammals living in watero The whale and dolphin are

mammals that live in water. o Just like fish, they stay in

water all the time.o Like all mammals, the whale

and dolphin breathe through lungs.

o They need to come up to the water surface to take in air, otherwise they will drown.



• Mammals living in watero The whale and dolphin have

special nostrils called blowholes on top of their heads.

o During breathing, the whale and dolphin only need to stick part of their heads out of the water to expose their blowholes to the air.

o A whale often blows through its blowhole to get ride of water that has entered it.

blowhole of a dolphin

blowhole of a whale


Plant respiratory systemPlant respiratory system

• Like animals, plants also exchange gases with their surroundings.

• The exchange takes place through tiny openings on the surface of the leaves.

• These tiny openings are called stomata.

• One such opening is referred to as a stoma.

stoma


Plant respiratory systemPlant respiratory system

• Stomata are usually found on the underside of leaves, away from direct sunlight.

• This is to prevent water inside the plant from evaporating through the stomata.

stoma


Plant respiratory system

• In respiration, plants use oxygen from the air to release energy from the food they have made.

• Carbon dioxide is produced in the process.

• This process of respiration takes place all the time.

carbon dioxide

oxygen

All the time



• Besides respiration, plants also carry out photosynthesis during the day.

• Carbon dioxide enters the plants through the stomata.

• Oxygen that is produced is released into the surroundings through the stomata too.

carbon dioxide

oxygen

During photosynthesis



• At night, only respiration takes place.

• Oxygen is taken in and carbon dioxide is given out through the stomata.

carbon dioxide

oxygen

All the time


Systems c2

Technology

Transcript of Systems c2