Smoking - much of the information needed for the Unit 2 OCR AS Biology Exam

Here's some information on the smoking section from Unit 2 of the OCR Biology Exam. It's probably best if you print this out and highlight the key bits yourself as it's not very colourful! Hope you find it useful however :)

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  • Created by: hols_95
  • Created on: 22-04-13 20:40
Preview of Smoking - much of the information needed for the Unit 2 OCR AS Biology Exam

First 342 words of the document:

SMOKING
CIGARETTES CONTAIN:
TAR
Settles on the lining of the airways and alveoli increasing the diffusion distance for gaseous
exchange
Chemicals in the tar may cause an allergic reaction which causes smooth muscle to contract
restricting the lumen of the airway
Tar paralyses or destroys cilia. They are then unable to move mucus away and to the back of the
mouth
Stimulates goblet cells and mucus-secreting glands to enlarge and release more mucus; this traps
bacteria and may block the bronchioles
Presence of bacteria means lungs are more susceptible to infection
Smoker's cough is attempt to shift the bacteria-laden mucus
Constant coughing can damage the lining of the airways and alveoli which will eventually be
replaced by scar tissue, which is thicker and less flexible
CARBON MONOXIDE
Enters red blood cells and combines with haemoglobin to form carboxyhaemoglobin
This reduces the oxygen-carrying capability of the blood
Can also damage the lining of the arteries
NICOTINE
Causes addiction
Mimics action of transmitter substances at synapses between nerves ­ nervous system becomes
more sensitive
Causes the release of adrenaline which may lead to increased heart rate and increased breathing
rate
Constriction of the arterioles leads to reduced blood flow
Makes platelets sticky ­ increases risk of blood clotting or thrombus
DISEASES ASSOCIATED WITH SMOKING:
CHRONIC BRONCHITIS
Inflammation of the lining of the airways
Accompanied by damage to the cilia and overproduction of mucus; mucus collects in the lungs
EMPHYSEMA
Loss of elasticity in the alveoli, which causes the alveoli to burst
Lungs have reduced surface area for gaseous exchange
Leads to shortness of breath and makes it harder to exhale
CHRONIC OBSTRUCTIVE PULMOANY DISEASE
Combination of diseases that include bronchitis, emphysema and asthma
LUNG CANCER
Recognised by continual coughing and shortness of breath
Blood may be coughed up in the sputum
Chest pains

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PROBLEMS CAUSED BY CHANGES TO THE BLOOD SYSTEM:
ATHEROSCLEROSIS
Carbon monoxide can damage the endothelium (inner lining) of the arteries
Damage caused is repaired by the action of white blood cells which encourage growth of smooth
muscle and deposition of fatty substances (such as LDL's and cholesterol)
The deposits are known as atheromas
The process of deposition is called atherosclerosis
Build-up of atheromas occurs under the endothelium, in the artery wall
Atheroma eventually forms a plaque, which sticks out into the lumen of the artery…read more

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