Respiration

Respiration

Requires oxygen  therefore = AEROBIC (with air)
This is a series of chemical reactions -

glucose + oxygen = carbon dioxide + water

Glucose and oxygen = REACTANTS
Carbon dioxide and water = PRODUCTS
ENERGY is released by this is not a chemical substance

Glocose come from DIGESTION of carbohydrates.
It is ABSORBED into the blood by the small intestine
Carried around the body dissolved in the PLASMA of the blood.
Blood travels through the BLOOD VESSELS and is pumped by the heart
Heart and blood vessels = CIRCULATORY SYSTEM

Lungs
Oxygen is absorbed by the LUNGS
Lungs are part of the Respiratory System
The AlVEOLI give the lungs a large surface area so that oxygen can quickly diffuse from the air into the blood carried in the CAPILLARIES.  The walls of the ALVEOLI are only 1 cell thick to help this process.  Oxygen is then carried by the red blood cells to capillaries around the body.

Tissue Fluid
This comes out of the capillaries and bathes the tissues in the body.  It contains oxygen and glucose.
The cells take the oxygen and glucose from the tissue fluid and put carbon dioxide back into the tissue fluid.
The Tissue fluid soaks back into other capillaries and the carbon dioxide dissolves in the blood plasma.

In the lungs the dissolved carbon dioxide diffuses out of the blood and into the air we EXHALE.  The carbon dioxide is EXCRETED by the lungs.

Oxygen diffusing in to the blood and carbon dioxide diffusing out of the blood = GAS EXCHANGE.

CO2 test

Carbon dioxide turns lime water from clear to cloudy.

 Composition of inhaled air

Nitrogen gas - 78%
Oxygen gas - 21%
Carbon Dioxide gas - 0.03%
Water Vapour - variable

 Composition of exhaled air

Nitrogen gas - 78%
Oxygen gas - 16%
Carbon Dioxide gas - 4%
Water Vapour - more

Breathing rate (number of breaths per minute) increases
Pulse rate (number of heart beats per minute) increases
Cells need more oxygen and glucose for respiration

Diseases (eg emphysema)
(or eg mountain top)
The body does not get enough air = people fell short of breath and tired. 
Too little oxygen = cells cannnot release energy from food and die

Most organisms RESPIRE using oxygen. 

Fish and many water organisms use GILLS to take oxygen from water.

Oxygen from water diffuses into leaves of underwater plants.