the role of the circulatory system is to transport substances around the body via the blood.
our circulatory system has two loops one that passes through the lungs and one that passes around the body.
Because there are 2 loops we call it a double circulatory system.
A double circulatory system is good as it allows the pressure in the blood to be increased again before being pumped around the body.
the hearts role is to pump blood to the lungs and the body.
The heart has 4 chambers:
Right atrium
right ventricle
left atrium
left ventricle
The pulmonary artery carries blood from the heart to the lungs.
The pulmonary vein carries blood away from the lungs.
the right side of the heart pumps deoxygenated blood to the lungs.
the pulmonary vein carries oxygenated blood to the left atrium.
Vena cava - carries deoxygenated blood from the body to right atrium.
Pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.
Pulmonary vein carries oxygenated blood from the lungs to the left atrium.
Aorta carries oxygenated blood from the left ventricle to the body
The left ventricle has thicker walls as it has to pump blood around the entire body.
valves prevent the backflow of of blood.
Right side of heart= tricuspid valve
left side of heart= bicuspid valve
Semi-lunar valves are the ones in between the ventricles and the arteries.
The route blood takes as it passes around the body
Vena cava -> right atrium -> right ventricle -> pulmonary artery -> lungs -> pulmonary vein -> left atrium -> left ventricle -> aorta -> body -> vena cava
Coronary arteries supply the heart muscle with oxygenated blood.
Approximate value of resting heart rate is 70bpm
Heart rate is controlled by a group of cells in the right atrium which act as a pace maker. They release waves of electrical activity causing the heart muscle to contract rhythmically.
The 3 main types of blood vessels are:
Arteries
capillaries
veins
Arteries carry blood away from the heart
Capillaries exchange substances with the cells of the body.
Veins carry blood towards the heart.
Veins have valves
Arteries are adapted. they have:
Thick muscle layer
thick elastic layer
thick walls
capillaries are adapted. they are:
one cell thick
permeable walls
narrow lumen
Veins are adapted. they have:
wide lumen
valves
rate of blood flow= vol of blood/time
4 components of blood:
red blood cells
white blood cells
platelets
plasma
Plasma is yellow liquid that transports substances around the body
Nutrients, waste products, antibodies and more are all dissolved in plasma.
Red blood cells transport oxygen around the body.
Red blood cells are adapted:
contain haemoglobin
biconcave shape
no nucleus
white blood cells protect the body from invading pathogens.
white blood cells are adapted:
some can produce antibodies
some can produce antitoxins
some can engulf and digest pathogens
platelets are small cell fragments which help the blood clot