Bood and circulation 1

Function of the circulatory system

it is needed because diffusion isn’t sufficient to supply organisms with glucose or oxygen

What is transported by the circulatory system

oxygen, carbon dioxide, nutrients, urea, hormones

Urea

Waste products from the liver

Sing circulatory system

blood is pumped from the heart to the gas exchange organ and then directly to the rest of the body

Double circulatory system

blood is pumped from the heart to the gas exchange organ , back to the heart and then to the rest of the body

Why do fish use a single circulatory system

low metabolic rate, exotherms

Parts of the double circulatory system

Pulmonary circulation, systemic circulation

What happens to the blood when it goes through the body

oxygen and nutrients are exchanged in the cells with carbon dioxide and toxic waste

Blood

acts as a transport medium where a lot of substances are dissolved in it

Arteries

carry oxygenated blood

Veins

carry deoxygenated blood

Capillaries

carry blood through organs

Arteries structure

thick and elastic walls to carry blood at high pressure, small lumen to maintain high pressure

Veins

contains valves to prevent backflow of blood, thin walls, large lumen

Capillaries

Walls one cell thick to minimise diffusion distance, small lumber

Attu-ventricular valves

tricuspid and bicuspid

Cardiac muscle

Muscle that never gets fatigued due to constant supply of O2

Structure of the atriums

walls are thin so they can be stretched as they receive blood

Coronary arteries

supply the heart with oxygen and nutrients

Coronary heart disease

causes by build up of cholesterol in the coronary arteries cutting off blood supply

Factors that increase chances of developing CHD

Heredity, high blood pressure, diet, smoking, stress, lack of exercise

Atherosclerosis

disease that causes plaque build up in the arteries

How is a blood clot formed

when a piece of fatty material ruptures, blood clot forms around it

How long is a cardiac cycle

0.8 seconds

Semi-lunar valves

pulmonary valve and aortic valve