The circulatory system and heart disease

Why are transport systems needed in multicellular organisms?

Because they have small surface area to volume ratios and greater metabolic demands.

Blood vessels are what the blood …

Flows through.

Blood transports …

Nutrients and waste products.

What is blood plasma?

A fluid in which cells, nutrients and waste products are dissolved.

What are platelets?

They plug holes in vessel walls and cause blood clotting and scab formation.

What 2 things make up most of the blood?

Blood plasma = 55%, red blood cells = 45%.

Blood plasma is lost when we …

Sweat, to regulate body temperature.

How are red blood cells adapted to maximise oxygen transport?

They are biconcave and have no nucleus so they have a large SA to carry the most haemoglobin.

What are arteries?

A type of blood vessel that takes blood away from the heart.

What are veins?

A type of blood vessel that takes blood into the heart.

What are capillaries?

A type of blood vessel that allows nutrients to leave and gas and waste products to be exchanged between the blood and surrounding tissues.

What are the properties of arteries?

Small lumen and thick muscular wall to maintain high pressure. They can expand and constrict. You can feel your pulse in an artery.

What are the properties of veins?

Wide lumen and thin muscular wall to maintain low pressure. Have pocket valves to prevent backflow of blood. Carry blood back to the heart at low pressure.

What are the properties of capillaries?

One cell thick cell wall. Located at lungs and muscle sites. Very narrow lumen that allows only one blood cell through at a time. Allow gaseous exchange of CO2, oxygen and nutrients.

The left side of the heart (aorta, left atrium and ventricle) has …

Oxygenated blood.

The right side of the heart (pulmonary artery, right atrium and ventricle) has …

Deoxygenated blood.

What are the atria?

They receive blood from the body and lungs. They contract and squeeze blood into the ventricles. Right atrium gets blood from the body; left atrium gets blood from the lungs.

What are ventricles?

They contract to push blood towards the body. The left ventricle pushes towards the aorta; the right ventricle pushes towards the pulmonary artery.

Why is the left side of the heart thicker than the right?

The left side is thicker as it pumps blood to the whole body.

Where does the pulmonary artery take deoxygenated blood and why?

To the lungs so it becomes oxygenated blood.

Why do humans have a double circulatory system?

Since blood passes through the heart twice in one circuit.

What is coronary heart disease (CHD)?

Fatty deposits build up in the coronary artery and this restricts and slows down blood flow to the heart.

What can CHD be caused by?

High blood pressure, high cholesterol, diabetes, smoking, obesity, age and a lack of physical activity.

What are the main symptoms of CHD?

Pain/uncomfortable feeling in your shoulders, arms, neck, jaw, back or stomach, or shortness of breath.

What is the solution for CHD?

Stents.

What is a stent?

A balloon put into the artery with the block and is then inflated to push the fats to the walls of the artery.

What are the advantages of stents?

1) Blocked arteries are opened. 2) Allows blood flow to the heart. 3) Stays in place for a long time. 4) Rapid recovery.

What are the cons of stents?

1) Risk of infection. 2) Risk of surgery. 3) Risk of blood clotting.