Cardiovascular disease (AQA GCSE Biology): Revision Notes
Cardiovascular disease
What is cardiovascular disease?
Cardiovascular disease is a general term that describes problems with the heart and blood vessels. These are non-communicable diseases, which means they cannot be spread from person to person like a cold or flu.
These diseases usually develop slowly over many years. They happen when parts of the cardiovascular system stop working properly.
Non-communicable diseases are conditions that cannot be transmitted from one person to another through direct contact, airborne droplets, or other means of infection. They typically develop due to genetic, lifestyle, and environmental factors.
Coronary heart disease
Coronary heart disease occurs when fatty material builds up inside the coronary arteries. These are the blood vessels that supply oxygen and nutrients to the heart muscle itself.
When fatty deposits block these arteries, several problems happen:
- Less blood can flow to the heart muscle
- The heart gets less oxygen
- This causes chest pain, heart attacks, or even death
Treatment with stents
Doctors can treat blocked coronary arteries by inserting a stent. This is a small wire frame that props open the artery.
Worked Example: Stent Insertion Procedure
Step 1: The stent is inserted into the blocked artery Step 2: A tiny balloon expands the stent Step 3: The balloon is removed, leaving the stent in place Step 4: Blood can now flow freely through the artery again
Faulty heart valves
Heart valves control blood flow through the heart. They make sure blood flows in the right direction.
When valves become faulty, they may:
- Not open fully
- Develop leaks
This makes the heart less efficient at pumping blood to the lungs and body. Patients feel tired and breathless, and this can be life-threatening.
Valve replacement options
Faulty valves can be replaced with:
- Mechanical valves - made from metals or strong plastics
- Biological valves - taken from human donors, cows, or pigs
Patients need to take special drugs to prevent blood clots with mechanical valves, and to stop the immune system rejecting biological valves. These medications require careful monitoring and can have significant side effects.
Heart failure
Heart failure happens when the heart cannot pump enough blood to meet the body's needs. This is a serious condition that requires immediate treatment.
Treatment options
- Heart transplant - replacing the whole heart
- Heart and lung transplant - when both organs are damaged
- Artificial hearts - mechanical devices that keep patients alive while waiting for a transplant
Artificial hearts are expensive and carry significant risks, but they can save lives when used as a bridge to transplantation.
Types of treatment
Cardiovascular diseases can be treated using:
- Drugs - medicines to improve heart function
- Artificial devices - like pacemakers to control heart rhythm
- Transplants - replacing damaged parts
Artificial pacemakers are devices placed under the skin. They send electrical signals to the heart through a wire, helping to correct irregular heartbeats. Modern pacemakers can adjust automatically to the patient's activity level.
How statins help prevent heart disease
Statins are drugs that lower cholesterol levels in the blood. When cholesterol levels drop, less fatty material builds up in the coronary arteries. This reduces the chance of blockages forming.
However, statins can cause side effects like muscle pain and may increase diabetes risk. Doctors must weigh the benefits against these risks for each patient.
While statins are highly effective at preventing heart disease, they are not suitable for everyone. Patients should never stop taking statins without consulting their doctor, as this can increase the risk of heart attacks.
Key Points to Remember:
- Cardiovascular disease affects the heart and blood vessels and cannot be passed between people
- Coronary heart disease happens when fatty deposits block arteries supplying the heart
- Stents can reopen blocked arteries by propping them open
- Faulty heart valves can be replaced with mechanical or biological alternatives
- Heart failure may require transplants or artificial hearts to keep patients alive
- Prevention through drugs like statins is often better than treatment after disease develops