2 (h) Transport in Humans

four components of blood

• plasma

• platelets

• red blood cells

• white blood cells

what does plasma do

• pale yellow liquid that transports carbon dioxide, digested food, urea, hormones and heat energy around the body

how are the red blood cells shape adapted to make them suitable for the transport of oxygen

• small and biconcave shape to give large surface area for absorbing and releasing oxygen

how are the red blood cells absence of a nucleus adapted to make them suitable for the transport of oxygen

• it frees up space for more haemoglobin, so they can carry more oxygen

how are the red blood cells presence of haemoglobin adapted to make them suitable for the transport of oxygen

• contains a lot iron

• in the lungs, haemoglobin reacts with oxygen to become oxyhaemoglobin

• in body tissues, the reverse reaction happens to release oxygen to the cells

how does the immune system responds to disease using phagocytes

• phagocytes ingest pathogens by detecting foreign pathogens

• then they engulf the pathogens and digest them

• phagocytes are non-specific so they attack anything that is not meant to be there

how does the immune system responds to disease using lymphocytes

• every pathogen has unique molecules called antigens on its surface

• when lymphocytes come across a foreign antigen, they start producing antibodies, which lock on to the the invading pathogens and mark them out for destruction by other white blood cells

• the antibodies are specific to that type of antigen, they wont lock on to any others

• antibodies are then produced rapidly and flow around the body to mark all similar pathogens

right atrium

• receives deoxygenated blood from the body through the vena cava

right ventricle

• receives deoxygenated blood which is then pumped to the lungs via the pulmonary artery

left atrium

• receives oxygenated blood from the lungs through the pulmonary vein

left ventricle

• receives oxygenated blood from the left atrium which pumps it ou around the whole body via the aorta

why is left ventricle wall thicker than right ventricle

• left ventricle needs more muscle because it has to pump blood around the whole body

• but right ventricle only has to pump it to the lungs

• this means that the blood in the left ventricle is under higher pressure than the blood in the right ventricle

valves

• prevent the backflow of blood

how does heart rate change during exercise

• muscles need more energy so you respire more

• you need to get more oxygen into the cells and remove more carbon dixoide

• blood has to flow faster so heart rate increases

how does heart rate change under the influence of adrenaline

• when an organism is threatened, the adrenal glands release adrenaline

• adrenaline binds to specific receptors in the heart, cuasing the cardiac muscles to contract more frequently and with more force

• so the the heart rate increases and the hear pumps more blood

• this increases oxygen supply to the tissues getting the body ready for action

coronary heart disease

• when the coronary arteries that supply the blood to the muscle of the heart get blocked by layers of fatty material building up

• causes the arteries to become narrow, so blood flow is restricted and there is a lack of oxygen to the heart muscle

• leading to a heart attack

factors leading to coronary heart disease

• having a diet high in saturated fat can lead to fatty deposits forming inside the arteries which can lead to coronary heart disease

• smoking increases blood pressure, which can cause damage to the inside of the coronary arteries,

• chemicals in cigarette smoke makes it more likely that fatty deposits will form, narrowing the coronary arteries

• being inactive cand lead to high blood pressure, which can damage the lining of arteries, making it more likely that fatty deposits will form

arteries

• heart pumps blood out at high pressure so the artery walls are strong and elastic

• elastic fibres allow arteries to expand

• walls are thick compared to the size of the lumen, that contain thick layers of muscle to make them strong

function of arteries

structure of capillaries

• arteries branch into capillaries

• capillaries are really small

• they carry blood very close to every cell in the body to exchange substances with them

• they have permeable walls for substances to diffuse in and out

• they supply food and oxygen and take away wastes like carbon dioxide

• walls are usually only one cell thick which increases the rate of diffusion by decreasing the distance

function of capillaries

exchange of materials at the tissues

structure of veins

• capillaries eventually join up to form veins

• blood is at lower pressure in the veins so the walls dont need to be as thick as artery walls

• bigger lumen than artereies to help blood flow despite the lower pressure

• also have valves to help keep blood flowing in the right direction

function of veins

carry blood to the heart

pulmonary

to do with the lungs

hepatic

to do with the liver

renal

to do with the kidneys