Heart, Blood Vessels & CHD (Hard Exam Questions)

Describe how the structure of an artery is adapted to its function 4.

• Thick muscular walls withstand high blood pressure

• Elastic fibres allow the artery to stretch and recoil

• Small lumen maintains high pressure

• Smooth inner lining reduces friction

Describe how the structure of a vein is adapted to its function 4.

• Thin walls as blood pressure is low

• Large lumen reduces resistance to blood flow

• Valves prevent backflow of blood

• Blood flow is helped by surrounding muscles

Explain how capillaries are adapted for efficient exchange 4.

• Walls are one cell thick, reducing diffusion distance

• Very narrow lumen slows blood flow

• Extensive networks give a large surface area

• Close contact with body cells increases diffusion rate

Compare arteries and veins 4.

• Arteries carry blood away from the heart; veins carry blood towards the heart

• Arteries have thick muscular walls; veins have thin walls

• Arteries have a small lumen; veins have a large lumen

• Veins contain valves; arteries do not

Explain why blood pressure is higher in arteries than veins 4.

• Blood is pumped directly from the heart into arteries

• Ventricular contraction generates high pressure

• Pressure is lost as blood flows through capillaries

• Veins are further from the heart

Describe the pathway of blood through the heart 6.

• Blood enters the right atrium from the vena cava

• Passes into the right ventricle

• Pumped to the lungs via the pulmonary artery

• Returns to the left atrium via the pulmonary vein

• Passes into the left ventricle

• Leaves the heart through the aorta

Explain the function of valves in the heart 4.

• Prevent backflow of blood

• Ensure blood flows in one direction

• Open and close due to pressure changes

• Maintain efficient circulation

Explain why the left ventricle has a thicker wall than the right ventricle 4.

• Pumps blood to the entire body

• Blood travels a greater distance

• Higher pressure is required

• Thicker muscle produces greater force

Describe the role of the septum in the heart 3.

• Separates the left and right sides of the heart

• Prevents mixing of oxygenated and deoxygenated blood

• Maintains efficient oxygen delivery

Explain the importance of a double circulatory system 4.

• Blood passes through the heart twice per cycle

• Allows high pressure blood flow to the body

• Increases the rate of oxygen delivery

• Protects the lungs from high pressure

Compare pulmonary and systemic circulation 4.

• Pulmonary circulation moves blood between the heart and lungs

• Systemic circulation moves blood between the heart and the rest of the body

• Pulmonary circulation operates at lower pressure

• Systemic circulation operates at higher pressure

Describe what is meant by coronary heart disease 4.

• Fatty deposits build up in coronary arteries

• Arteries become narrowed

• Blood flow to heart muscle is reduced

• Oxygen supply decreases

Explain how coronary heart disease can cause a heart attack 4.

• Plaque narrows coronary arteries

• Blood flow to heart muscle is restricted

• Oxygen supply becomes insufficient

• Heart muscle cells die

Describe two risk factors for coronary heart disease and explain their effects 4.

• Smoking damages artery walls and increases plaque formation

• Diets high in saturated fat increase cholesterol levels

• Lack of exercise can lead to obesity

• Obesity increases blood pressure

Explain how smoking increases the risk of coronary heart disease 4.

• Nicotine increases heart rate

• Raises blood pressure

• Carbon monoxide reduces oxygen transport

• Artery walls are damaged

Explain how a high-fat diet increases the risk of coronary heart disease 4.

• Increases blood cholesterol levels

• Cholesterol deposits form plaques

• Arteries become narrowed

• Blood flow is reduced

Describe the benefits of regular exercise on the heart 4.

• Strengthens the heart muscle

• Lowers resting heart rate

• Reduces blood pressure

• Reduces risk of coronary heart disease

Explain how a stent is used to treat coronary heart disease 4.

• Inserted into a narrowed coronary artery

• Holds the artery open

• Improves blood flow

• Increases oxygen supply to the heart muscle

Explain how statins reduce the risk of coronary heart disease 4.

• Lower blood cholesterol levels

• Reduce plaque formation

• Slow artery narrowing

• Reduce the risk of blood clots

Compare stents and statins as treatments for coronary heart disease 4.

• Stents give immediate improvement in blood flow

• Statins act over a long period

• Stents require surgery

• Statins must be taken regularly

Explain why heart rate increases during exercise 4.

• Muscles respire more

• Oxygen demand increases

• Heart pumps faster

• Carbon dioxide is removed more quickly

Explain how red blood cells are adapted for oxygen transport 4.

• Biconcave shape increases surface area

• No nucleus allows more haemoglobin

• Haemoglobin binds oxygen

• Thin membrane shortens diffusion distance

Explain how white blood cells defend the body against disease 4.

• Phagocytes engulf pathogens

• Lymphocytes produce antibodies

• Antibodies bind to antigens

• Pathogens are destroyed

Explain the importance of platelets in the blood 4.

• Cause blood clotting

• Form a fibrin mesh

• Prevent excessive blood loss

• Reduce risk of infection

Explain why reduced blood flow is dangerous to the heart muscle 4.

• Less oxygen is delivered

• Aerobic respiration decreases

• Less energy is released

• Heart muscle cells may die