Compiled by: M Nortje Year 9 Science/2012 1

CONTROL AND COORDINATIONCHAPTER 3 SCIENCE QUEST 9

Compiled by: M Nortje Year 9 Science 2

3.3 LUNGSBLOOD AND CARBON DIOXIDE

Compiled by: M Nortje Year 9 Science 3

LUNGS Did you know that your body is more

sensitive to changes in levels of carbon dioxide than oxygen?

If there is too much carbon dioxide in your body, it dissolves in the liquid part of blood and forms an acid.

The resulting acidic blood can affect the functioning of your body.

Compiled by: M Nortje Year 9 Science 4

BLOOD AND CARBON DIOXIDE The amount of carbon dioxide in your

blood influences your breathing rate. The level of carbon dioxide in the blood is

detected by receptors in the walls of some arteries and in the brain.

If the levels of carbon dioxide in your blood increase, your breathing rate will be increased so that carbon dioxide can be exhaled from your lungs and passed out of your body.

Compiled by: M Nortje Year 9 Science 5

EXAMPLE:BLOOD AND CARBON DIOXIDE If you were to climb up high on a mountain,

you would need time for your body to adjust. Initially you would feel tired and out of breath

because you would be restricted by the limited amount of oxygen available to your cells.

Your breathing and heart rate would increase in an effort to get more oxygen around your body. In time, your body would begin to produce more red blood cells and hence more haemoglobin.

After this, your breathing and heart rate would return to normal.

Compiled by: M Nortje Year 9 Science 6

CELLULAR RESPIRATION Glucose is an example of a nutrient that

may be released from digested food.

It is absorbed in your small intestine and then taken by the capillaries to cells for use in cellular respiration.

In this process the glucose is combined with oxygen, and is then broken down into carbon dioxide (a waste product that needs to be removed from the cell) and water.

Compiled by: M Nortje Year 9 Science 7

CELLULAR RESPIRATION During this reaction energy, in the form

of ATP (adenosine triphosphate), is also released.

ATP provides the cells with the energy needed to perform many of its activities, and is essential to life.

Compiled by: M Nortje Year 9 Science 8

WORD EQUATION FOR CELLULAR RESPIRATION

Glucose + oxygen → carbon dioxide + water + energy (ATP)

Compiled by: M Nortje Year 9 Science 9

RESPIRATORY & CIRCULATORY SYSTEMS

This is an example of systems working together. Glucose is supplied via the digestive system and oxygen is supplied via the respiratory system.

The circulatory system transports nutrients (such as glucose) and oxygen to your cells and removes wastes (such as carbon dioxide) from your cells.

These wastes are then removed from your body by your excretory systems.

Without a supply of glucose and oxygen, cellular respiration could not occur.

Without removal of wastes, your cells may die. If you systems did not work together like they

do, you would not be able to stay alive.

Compiled by: M Nortje Year 9 Science 10

3 AEROBIC AND ANAEROBIC RESPIRATION

Click icon to add picture

Compiled by: M Nortje Year 9 Science 11

AEROBIC RESPIRATION  ANAEROBIC RESPIRATION  ATP  CARBON DIOXIDE  GLUCOSE  LACTIC ACID OXYGEN

Compiled by: M Nortje Year 9 Science 12

BLOOD, OXYGEN AND ENERGY FOR LIFE

Compiled by: M Nortje Year 9 Science 13

HUMAN BODY NEEDS... A supply of energy to keep it working

efficiently.

During exercise the body needs more energy than usual.

Energy for the cells of the body comes from chemical reactions.

Compiled by: M Nortje Year 9 Science 14

ENERGY – CHEMICAL ATP The energy is stored in a chemical called ATP. Muscles use ATP as a source of energy.

→glucose + oxygen carbon dioxide + water + (36–38) ATP

The glucose comes from the food we eat and the oxygen comes from the air we breathe.

Endurance sports like running a marathon or playing netball or football use energy released by aerobic respiration.

The body has another chemical reaction called anaerobic respiration:

glucose lactic acid + (2) ATP

Compiled by: M Nortje Year 9 Science 15

AEROBIC RESPIRATION

→glucose + oxygen carbon dioxide + water + (36–38) ATP

Compiled by: M Nortje Year 9 Science 16

AEROBIC RESPIRATION makes a lot of energy in cells uses oxygen and glucose makes large amounts of energy over a

long period of time.

Compiled by: M Nortje Year 9 Science 17

ANAEROBIC RESPIRATION

glucose lactic acid + (2) ATP

Compiled by: M Nortje Year 9 Science 18

ANAEROBIC RESPIRATION gives less energy than aerobic

respiration gives energy to cells quickly does not use oxygen makes lactic acid which builds up in our

muscles.

Compiled by: M Nortje Year 9 Science 19

LACTIC ACID Lactic acid build-up makes our muscles

feel sore after exercise.

During a 1500 m race, 55% of the ATP used would be made by anaerobic respiration.

ATP can be stored in the cells of the body for a short time.

This gives us an energy source that is very good for sports that do not last too long, like 100 m sprints or high jumping.