The Heart
Diagram Left/Right are flipped because its as if you are looking though at somebody else’s heart
Most of the heart Is self explanatory or simply explained by the diagram so no extra info is needed
Blood
Blood is the transport medium of gas and nutrients it contains 4 major substances
Red Blood Cells
Transport oxygen after absorbing it from lungs. Their Adaptations are:
- They contain haemoglobin - a red protein that combines with oxygen
- They have no nucleus so they can contain more haemoglobin
- They are small and flexible so that they can fit through narrow blood vessels
- They have a biconcave shape (flattened disc shape) to maximise their surface area for oxygen absorption.
White Blood Cells
White blood cells defend the body against disease The majority of the white blood cells are a type of cell called phagocytes. More in Immune System
Platelets
They help to form scab and clot blood to prevent blood loss they do this by
- Releasing chemicals to form a mesh
- Sticking together to form clumps that get stuck in the mesh
Plasma
- Transports carbon dioxide from respiring cells to the lungs
- Transports digested food from the small intestine to respiring cells
- Transports urea from the liver to the kidneys for excretion
- Distributes heat all around the body
- Transports Hormones from the glands where they are made to the target organs
Blood Vessels
There are 3 types of blood vessels: Arteries, Veins, Capillaries and they all have different functions and adaptations
Arteries
- Carries blood (Usually oxygenated except from the pulmonary artery) AWAY from heart to places it’s needed in the body
- Thick elastic and muscular walls
- Narrow lumen
- Contain blood under HIGH pressure
Veins
More or less the opposite of arteries
- Carries blood (Usually de- oxygenated blood except from the pulmonary vein) INTO the heart.
- Thin, less muscular walls
- Wide lumen
- Contain blood under LOW pressure
- Has valves to prevent backflow of blood
Capillaries
Very different to veins and arteries. They are the Site of gas and nutrients (from the blood) exchange
- Found near every living cell
- Microscopic - walls are a single cell thick to allow easy diffusion into cells
- Very low blood pressure
Table of Properties
Information | Artery | Vein | Capillary |
---|---|---|---|
Type of blood | Oxygenated | Deoxygenated | Both |
Direction | Away from the heart | Towards the heart | From arteries to veins |
Pressure | High | Low | Low |
Size of hole (lumen) | Small | Large | Very small |
Wall thickness | Thick | Thin | One cell thick |
Valves | No | Yes | No |
Coronary Heart Disease
This is a disease that is caused by blocked coronary arteries (arteries that supply blood to the muscle of the heart) usual blocked by Fatty Plaques containing cholesterol
Symptoms
If a coronary artery is blocked, the blood supply to part of the heart muscle is cut off. That part of the heart cannot continue to contract, causing a heart attack.
Treatments
Treatment | Description | Advantages | Disadvantages |
---|---|---|---|
Statins | A daily medication to control blood cholesterol levels | Drugs reduce blood cholesterol levels | May cause side effects |
Angioplasty | Surgery to insert a small balloon into a blood vessel which is then inflated to remove a blockage | Improved blood flow in coronary vessels preventing heart attack | Sometimes only a temporary measure |
Lifestyle changes | Diet and exercise, stopping smoking etc | Reduces risk of heart disease and reduces blood pressure | A high level of willpower is required to maintain the changes |