Slides in this set

Slide 1

Preview of page 1

Unit 2
Module 2…read more

Slide 2

Preview of page 2

2.2.14 The Effects of Smoking
· Cigarette smoke contains 4000+ chemicals which are mostly harmful. These include:
Short Term Effects of Tar
· Tar settles on the lining of the airways + alveoli ­ this increases the diffusion distance for oxygen entering the blood + for
carbon dioxide leaving the blood.
· Tar in these places could cause an allergic reaction ­ this causes the smooth muscle in the airways walls to contract which
restricts the flow of air to the alveoli.
· Tar paralyses/destroys cilia on airway surfaces + stimulates goblet cells and mucus-secreting glands to release more mucus ­
bacteria and viruses become trapped in the mucus and are not removed. They multiply and may block bronchioles.
· Presence of bacteria + viruses means that lungs are more susceptible to infection such as pneumonia.
Longer Term Effects of Tar
· Smoker's Cough is an attempt to shift the mucus that collects in the lungs ­ due to irritation of the airways and because air
has to get down. The cough damages the lining of the airways and alveoli. This will eventually be replaced by scar tissue
which is thinker and less flexible. The lumen of the airway is reduced so air flow is permanently restricted.
· Frequent infections damages the linings of the airways due to the presence of white blood cells and so the release of
enzymes which eat away at the lining of the lungs.
· Loss of elastic tissue will reduce elasticity of the alveolus walls. They will not recoil as we push air out ­ bronchioles will
collapse + air will be trapped in the alveoli. This can cause them to burst.
Lung Cancer
· Cigarette smoke contains lots of carcinogenic compounds ­ cause cancer.
· These compounds enter the cells of the lung tissue and have a direct effect on the genetic material of these cells ­ mutation.
· If the mutation affects the genes that control cell division then uncontrolled cell division will occur ­ this is cancer.…read more

Slide 3

Preview of page 3

2.2.14 Diseases Associated with Smoking
Chronic Bronchitis
· The inflammation of the lining of the airways.
· Also causes damage to the cilia and the overproduction of mucus so the mucus collects in the lungs.
· Symptoms = irritation in the lungs, coughing, coughing up mucus, increases risk of lung infection.
· The loss of elasticity in the alveoli.
· Causes the alveoli to burst which reduces the lungs' surface area for gaseous exchange.
· Symptoms = short of breath, blood is less well oxygenated, fatigue.
Chronic Obstructive Pulmonary Disease
· Combination of diseases including chronic bronchitis, emphysema and asthma.
· Symptoms = combination of symptoms from each disease.
Lung Cancer
· Symptoms = coughing, short of breath, chest pain, coughing up blood.…read more

Slide 4

Preview of page 4

2.2.15 Nicotine + Carbon Monoxide
· The chemical in cigarette smoke that causes addiction ­ has lots of effects on the body and the body becomes used to these
effects and the smoker no longer feels well unless they have nicotine in their blood.
· Nicotine mimics the action of transmitter substances at the nerve synapses ­ makes nervous system more sensitive and
makes smoker feel more alert.
· Nicotine causes the release of adrenaline ­ increases heart/breathing rate and it raises blood pressure.
· Nicotine causes constriction of the arterioles leading to bodily extremities ­ reduces blood flow/oxygen delivery to the
extremities which may lead to amputation.
· Nicotine affects the platelets to make them sticky which increases the risk of a blood clot.
Carbon Monoxide
· Enters the red blood cells and combines with haemoglobin to form carboxyhaemoglobin ­ this reduces the oxygen-carrying
capacity of the blood.
· Carbon monoxide can damage the lining of the arteries.…read more

Slide 5

Preview of page 5

2.2.15 Problems Caused by Changes to the Blood
· Carbon monoxide can damage the inner lining of the arteries ­ this is repaired by white blood cells which encourage the
growth of smooth muscle + the deposition of fatty substances.
· The deposits (ATHEROMAS) include cholesterol, fibres, dead blood cells and platelets (increased deposition from high blood
· The process of deposition is called atherosclerosis.
· The atheroma eventually forms a plaque which leaves the wall of the artery rougher/less flexible/narrows lumen which
reduces blood flow.
· Blood flowing past the plaque cannot flow smoothly ­ increases chance of clotting (also the sticky platelets).
· Red blood cells may become stuck to the plaque ­ a blood clot is called a thrombus and it can stop blood flow in the artery.
· Sometimes, a clot or part of a clot may break free and be carried around the body until it reaches a narrow artery which it
will lodge and stop blood flowing through that artery.
Coronary Heart Disease (CHD)
· Arteries that carry blood TO the heart are called the coronary arteries ­ they carry blood at a high pressure so they are
prone to damage + atherosclerosis.
· CHD can take 3 forms:
­ ANGINA: severe chest pain which can extend down your arm/up your neck.
­ HEART ATTACK: death of part of heart muscle usually due to a clot blocking blood flow to the heart.
­ HEART FAILURE: when heart cannot sustain its pumping action due to blockage of artery.
· The death of a part of the brain tissue.
· Caused by the loss of blood flow to that part of the brain, 2 possible causes:
­ THROMBUS: blood clot floating around the body blocks a small artery leading to part of the brain.
­ HAEMORRHAGE: an artery leading to the brain bursts.…read more

Slide 6

Preview of page 6

2.2.16 Cardiovascular Diseases
· Cardiovascular disease are those diseases that affect the heart and the circulatory system:
­ Atherosclerosis
­ Stroke
­ Arteriosclerosis
· One of the greatest causes of premature death in the MEDCs.
· Cardiovascular disease can be disabling and will eventually cause death.
· Treatment can be very expensive ­ may involve drugs to reduce blood pressure/blood cholesterol levels or surgery.
· If atherosclerosis can be reduced by reducing risk factors then the need for treatment will be reduced.
Factors that Increase the Risk of CHD
· CHD is a multifactorial disease ­ no one factor can be said to cause it. There are lots of factors that increase the risk of
developing CHD:
­ AGE: risk increases as you get older. - DIET: high level of animal fats increases risk.
­ SEX: men under the age of 50 are more likely to die of CHD than women. - HIGH SALT INTAKE
· CHD is less of a problem in LEDCs because the people living there have a lower life expectancy ­ they don't live long enough
to develop CHD.
· Also, they lead different lifestyles ­ more active + have less harmful diets.
· Less likely to be heavy smokers due to financial situation.…read more

Slide 7

Preview of page 7
Preview of page 7


No comments have yet been made

Similar Biology resources:

See all Biology resources »