TOPIC 1: Blood & Blood Clotting

What is blood made of?

• Plasma

• Erythrocytes (red blood cells)

• White blood cells - lymphocytes & phagocytes

What are the two types of white blood cells?

1. Phagocytes

2. Lymphocytes

What is the function of white blood cells?

Help fight against the pathogens that might enter the body

What is the function of red blood cells?

Contain haemoglobin, which carries oxygen around the body

What is the function of plasma?

Yellow part of the blood which contains dissolved chemicals, eg, glucose

What is the function of platelets?

Help clot the blood

What are the structures of Erythocytes/ Red blood cells?

1. Biconcave shape

2. No nucleus

3. Haemoglobin

4. Flexible cell membrane

What is the importance of RBC having a biconcave shape?

• Large SA to volume ratio- allows more rapid diffusion of oxygen into and out of cell.

What is the importance of RBC having no nucleus?

• Provides more space in the cell = contain more haemoglobin= more oxygen can be transported

What is the importance of RBC containing haemoglobin?

• Molecule that binds to oxygen in the lungs and binds to oxygen in the tissues

What is the importance of RBC having a flexible cell membrane?

• Allows cell to change shape= squeeze through small capillaries= blood cells carrying oxygen reaches all cells

What is the function of lymphocytes?

Produces and secretes antibodies that bind to foreign cells, which helps to destroy them

What is the function of phagocytes?

Engulfs foreign cells (phagocytosis)

What is the function of platelets?

Produces substances needed to clot the blood in site of an injury

What else does plasma carry?

1. Glucose

2. CO2

3. Urea

What does hypertension mean?

High blood pressure

What lifestyle factors put individuals at risk of blood clot formation?

1. High level of salt

2. Smoking

3. Genetics

4. Gender (males)

Why does having high level salt in your diet increase the risk of CVD?

High salt diet increases risk of high blood pressure- high blood pressure increases risk of endothelial damage- increases risk of blood clots.

Why does smoking increase the risk of CVD?

Smoking increases blood pressure- increases risk of damage to endothelial lining. This activates platelets. Nicotine makes platelets sticky- increases chance of blood clots.

Why does genetics and gender affect the risk of excessive blood clotting?

Genetics= some inherit alleles that increases risk of high blood pressure- more likely to form blood clots.

Age= males have a higher risk.

How do blood clots form in the coronary arteries?

High blood pressure causes damage to artery walls= causes release of thromboplastin from platelets.

What is the consequence of blood clots forming in the coronary arteries?

Heart attack- due to reduced supply of oxygen to heart.

What is anticoagulant?

Drugs that prevent the formation of blood clots, which means less chance of blood vessels becoming blocked.

How can anticoagulant drugs reduce the risk of heart attack?

Lack of prothrombin means that thrombin cannot be produced= fibrinogen is not converted in fibrin= no mesh forms so platelets are not trapped= there is reduced clot formation.

What risks can anticoagulants cause?

If a person is badly injured, blood clotting can cause excessive bleeding, internal bleeding, fainting and maybe death.

What is a platelet inhibitor?

Reduces the risk of blood clots forming by preventing platelets aggregating together.

Coronary artery less likely to be blocked