3. The Respiratory

System

COMBUSTIONCOAL + OXYGEN ENERGY (HEAT) + CARBON DIOXIDE

+ WATER VAPOUR

AEROBIC RESPIRATIONGLUCOSE (FOOD) + OXYGEN ENERGY + CARBON

DIOXIDE + WATER VAPOUR

Food and oxygen react in our cells to give us energy. Respiration is the release of energy from food. Carbon dioxide is toxic and the cells have to expel it.

3.1. The key to respiration

3.2. Parts of the human respiratory system

NOSE AND MOUTH

PHARYNX: Common to digestive and respiratory system. It has the eppiglotis that prevents food from entering the trachea.

LARYNX (VOICEBOX): Allows us to make sounds with the vocal cords, protected by cartilage.

TRACHEA: Passes air to lungs.

RINGS OF CARTILAGE: These surround the trachea, bronchi and bronchioles, they keep the airways open.

BRONCHI: Two tubes that carry air into and out each lung.

LUNGS: Two lungs made up of alveoli.

BRONCHIOLES: Tiny tubes taking air to the alveoli.

ALVEOLI: Blind tiny air sacs, surrounded by tiny blood vessels; oxygen passes from the alveoly into the blood, carbon dioxide passes from the blood into the alveoli.

DIAPHRAGM: A sheet of muscle that moves down to draw air into the lungs,and up to expel the air out of the lungs.

There are two movements: inhalation and exhalation

Inhalation Intercostal muscles contract.The diaphragm contracts and moves downward Chest expands.Air enters the lungs.

ExhalationIntercostal muscles relax.The diaphragm relaxes and moves upward .Chest contracts.The air is pushed out from the lungs and leaves them

3.3. Respiratory movements

http://www.youtube.com/watch?v=GiFzg1Ek-_E Lungs in Motion

Gas exchange between the lungs and the blood takes place in the alveoli.

Oxygen moves out the alveolus through its thin wall, across the wall of the blood capillary and into the blood.

Carbon dioxide moves out of the cell and into the blood. Bloodstream takes them to the lungs. From the alveoli, they are breathed out by the lungs.

3.4. Exchanging gases

Activities 3 and 4 page 67

Diseases of the respiratory systemAsthma narrows the airways by causing an allergy-induced spasms

of surrounding muscles or by clogging the airways with mucus.

mucus

SMOKING The smoke particles irritate the lungs causing them to produce

more mucus which cannot easily be cleared.

This could lead to bronchitis, emphysema or cancer.

Carbon monoxide in cigarette smoke replaces oxygen in the blood.

A smoker has to breathe faster. This lead to heart strain which could cause a heart attack.

Smoking during pregnancy reduces the oxygen available to the baby.

This can cause the stunted growth of the baby.

http://www.youtube.com/watch?v=o2OcGgJbiUk Respiratory system 3D