IGCSE Biology Breathing and Gas Exchange
- Created by: Juliet
- Created on: 26-03-13 18:26
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- Breathing and Gas Exchange!
- Inhalation
- Lower Pressure in lungs than outside body
- Air flows in
- Volume of chest cavity expands
- Diaphragm muscles contract
- Diaphragm flattens
- External intercostal muscles contract
- Pulls ribcage up and out
- Lower Pressure in lungs than outside body
- Exhalation
- Higher pressure in lungs than outside body
- Pushes air out
- Volume of chest cavity decreases
- Diaphragm muscles relax
- Diaphragm becomes dome shaped
- Internal intercostal muscles contract
- Pulls ribs down and in
- Higher pressure in lungs than outside body
- Structure of human gas exchange
- Nasal passaeges
- Epiglottis
- Oesophagus
- Larynx
- Trachea
- Left Bronchus
- Bronchioles
- Alveoli
- Diaphram
- Ribs
- Internal intercostal muscles
- External Intercostal Muscles
- Pleural Membranes
- Pleural Fluid
- Liquid filling pleural cavity acting as lubrication so surfaces of lungs do not stick to chest wall.
- Moist membrane forming airtight seal around lungs and separating thorax from lungs
- Pleural Fluid
- Push ribs up and out when inhaling
- Pleural Membranes
- Pull ribs down and out when exhaling
- External Intercostal Muscles
- Bones that protect the vital organs
- Internal intercostal muscles
- Sheet of muscle with fibrous middle part which is domed
- helps make breathing movement and seporates thorax from the abdomen.
- Ribs
- Carry air to lungs
- Diaphram
- Carry air to lungs
- Alveoli
- Carries air to lungs
- Bronchioles
- Tube with incomplete rings of cartilage that carries air to lungs.
- Lined with cells making mucus and cilia which move mucus away from lungs
- Left Bronchus
- Voice Box
- Trachea
- Carries food to stomach
- Larynx
- Stops Food getting into lungs when you swallow
- Oesophagus
- Warm, Clean, Add moisture to air
- Epiglottis
- Nasal passaeges
- Gas Exchanges In The Alveoli
- Alveoli
- Large Surface Area
- Rich Blood supply
- removes oxygen from and delivers carbon dioxide to the air in the alveoli
- Maintains a steep diffusion gradient between the alveoli and the blood
- Short diffusion distances between the air and the blood
- Process
- Blood pumped from the heart to the lungs
- Passes through network of capillaries surrounding the alveoli
- Carbon Dioxide diffuses from the blood into the air in the alveoli
- Oxygen diffuses from the air in the lungs into the blood
- Oxygenated blood travels back to the heart to be pumped around the body
- Oxygen dissolves in the layer of fluid lining the alveolus before it diffuses into the blood
- Oxygenated blood travels back to the heart to be pumped around the body
- Oxygen diffuses from the air in the lungs into the blood
- Carbon Dioxide diffuses from the blood into the air in the alveoli
- Passes through network of capillaries surrounding the alveoli
- Blood pumped from the heart to the lungs
- Alveoli
- Smoking And Health
- Nicotine
- Addictive substance found in tobacco
- Carbon Monoxide
- Reduces the amount of oxygen carried in the blood by bonding with the red blood cells' haemoglobin
- Tar + Other Chemicals
- Can cause lung cancer, bronchitis, emphysema + diseases of the heart and blood vessels.
- Tobacco smoke
- Cilia are destroyed so dirt and bacteria are not removed
- Emphysema - walls of alveoli are damaged and break down to form large irregular air spaces which do not exchange gas efficiently
- Lung Cancer - tar and other chemicals cause cells to mutate and form cancers in the lungs and throat
- Carbon Monoxide binds to haemoglobin.In pregnant woman not enough oxygen in blood = not enough oxygen to fetus = still born
- Affects Circulatory system and can increase risk of heart attacks and strokes
- Nicotine
- Breathing
- For Cellular respiration to take place, your cells need a constant supply of oxygen for this to happen aerobically.
- Cells need to have waste Carbon Dioxide removed
- Inhalation
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