blood and organs Flashcards
what are the 4 main components of blood
- plasma
- platelets
- red blood cells
- white blood cells
what is plasma
it is the liquid bit of your blood. it is the blood minus the blood cells
what colour is plasma
pail yellow liquid that carries just about everything that needs transporting around your body
what are platelets
they are small fragments of cells that help blood clot
what is in plasma
- red and white blood cells and platelets
- digested food products ( like glucose and amino acids) from the gut to all the body cells
-carbon dioxide from the body cells to the lungs - urea from the liver to the kidneys
- hormones which act as a chemical messengers
- heat energy
what happens when you damage a blood vessels
platelets clump together to ‘plug’ the damaged area
this is known as blood clotting. blood clots stop you losing too much blood and prevent micro organisms from entering the wound.
in a clot. platelets are held together by a mesh of a protein called fibrin
what is the job of the red blood cell
to carry oxygen
how do red blood cells work
- they transport oxygen from the lungs to all cells in the body.
how are red blood cells well adapted to its function
- red blood cells are small and have a biconcave shape to give a large surface area for absorbing and releasing oxygen
- they contain haemoglobin which is what gives blood its colour - it contains lots of iron. in the lungs, haemoglobin reacts with oxygen to become oxyhaemoglobin. in the body tissues the reverse reaction happens to release oxygen to the cells
- red blood cells do not have a nucleus - this frees up space for more haemoglobin, so they can carry more oxygen.
what does white blood cells deal with
pathogens
what are pathogens
they are micro organisms that cause disease
what happens when pathogens have entered the body
they will reproduce rapidly unless they are destroyed. that is the job of the immune system and white blood cells are the most important part of it.
what are the two types of white blood cells
phagocytes
lymphocytes
what do phagocytes do
they detect things that are ‘foreign’ to the body, eg pathogens. they then engulf the pathogens and digest them.
phagocytes are non specific - they attack anything that is not meant to be there
what do lymphocytes do
produce antibodies
what happens when lymphocytes come across a foreign antigen
the lymphocytes will produce proteins called antibodies - these lock on to the invading pathogens and mark them out for destruction by other white blood cells. the antibodies produced are specific to that type of antigen - they won’t lock on to any others
what are the unique molecules on the surface of the pathogen
anitgen
what do antibodies then do
they produce rapidly and flow around the body to mark all similar pathogens
what are memory cells
they are produced in response to a foreign antigen. these remain in the body and remember a specific antigen. they can reproduce very fast if the same antigen enters the body again.
what is vaccination
can protect from future infection
what happens when you are infected with a new pathogen
it can take your lymphocytes a while to produce the antibodies to the deal with it, you can get very ill and even die.
how can you avoid some diseases
vaccinated
state –> blood vessels are designed for their function
what does vaccination involve
injecting dead or inactive pathogens into the body. these carry antigens, so even though they are harmless, they still trigger an immune response - your lymphocytes produce antibodies to attack them
memory cells will also be produced and will remain in the blood, so if live pathogens of the same type ever appear, the antibodies to kill them will be produced much faster and in greater numbers.
what are the three types of blood vessels
arteries - carry the blood away from the heart
capillaries - these are involved in the exchange of materials at the tissues
veins - these carry blood to the heart
state –> arteries carry blood under pressure
arteries
- the heart pumps the blood at high pressure, so the artery walls are strong and elastic
- the elastic fibres allow arteries to expand
- the walls are thick compared to the size of the hole down the middle (the lumen) They contain thick layers of muscle to make them strong
- the largest artery in the body is the aorta
state –> capillaries are really small
capillaries
- arteries branch into capillaries
- capillaries are really tiny - too small to see
- they carry the blood really close to every cell in the body to exchange substances with them
- they have permeable walls, so substances diffuse in and out
- they supply food and oxygen, and take away wastes like CO2
- their walls are usually only one cell thick. This increases the rate of diffusion by decreasing the distance over which it happens
veins
- capillaries eventually join up to form veins
- the blood is at lower pressure in the veins so the walls do not need to be as thick as artery walls
- they have a bigger lumen than arteries to help the blood flow despite the lower pressure
- they also have valves to help keep the blood flowing in the right direction
- the largest vein in the body is the vena cava
state –> veins take blood back to the heart
what are all the parts of the heart
pulmonary artery
pulmonary vein
vena cava
aorta
right atrium
left atrium
right ventricle
left ventricle
semi lunar valve (x2)
tricuspid valve
bicuspid valve
how does the heart work
- the right atrium receives deoxygenated blood through the vena cava
- the deoxygenated blood moves through the right ventricle which pumps it to the lungs via the pulmonary artery
- the left atrium receives oxygenated blood from the lungs through the pulmonary vein.
- the oxygenated blood then moves through to the left ventricle which pumps it out round the whole body via the aorta
- the left ventricle has a much thicker wall than the right ventricle. it needs more muscle because it has to pump around the whole body, where as the right ventricle only has to pump it to the lungs. this also means that the blood in the left ventricle is under high pressure than the blood in the right ventricle
- the valves prevent the backflow of blood
state –> exercise increases heart rate
what happens to your muscles when you exercise
- your muscles need more energy so you respire more.
- you need to get more oxygen into the cells and remove more carbon dioxide
- for this to happen the blood has to happen faster so your heart rate increases, heres how:
- exercise increases the amount of carbon dioxide in the blood
- high levels of CO2 are detected by receptors in the aorta and carotid artery ( an artery in the neck)
- these receptors send signals to the brain
- the brain sends signals to the heart causing it to contract more frequently and with more force
how does the hormonal system help to control heart rate
- when an organism is threatened, the adrenal glands release adrenaline
- adrenaline binds to specific receptors in the heart. this causes the cardiac muscle to contract more frequently and with more force, so heart rate increases and the heart pumps more blood
- this increases oxygen supply to the tissues, getting the body ready for action
what is CHD
- is when the coronary arteries that supply the blood to the muscle of the heart get blocked by layers of fatty material building up
- this causes the arteries to become narrow , so blood flow is restricted and there is a lack of oxygen to the heart muscle - this can lead to a heart attack
what do risk factors mean in CHD
risk factors are things that are linked to an increase in the likelihood that a person will develop a certain disease during their lifetime
what are the three risk factors of developing CHD
- having a diet in saturated fat
- smoking
- being inactive
having a diet in saturated fat
this can lead to fatty deposits forming inside arteries, which can lead to CHD
smoking
smoking increases blood pressure, which can cause damage to the inside of the coronary arteries. chemicals in cigarette smoke can also cause damage. the damage makes it more likely that fatty deposits will form, narrowing the coronary arteries.
being inactive
it can lead to high blood pressure, which can damage the lining of arteries. this damage makes it more likely that fatty deposits will form.
state –> the kidneys are excretion organs
what are the kidneys 3 roles
removal of urea from the blood. urea is produced in the liver from excess amino acids
adjustment of ion levels in the blood
adjustment of water content of the blood
state –> each kidney contains thousands of nephrons
how does ultrafilteration work
- blood from the renal artery flows through the glomerulus - a bundle of capillaries at the start of the nephron
- a high pressure is built up which squeezes water, urea, ions and glucose out of the blood and into the Bowman’s capsule.
- the membranes between the blood vessels in the glomerulus and the Bowman’s capsule act like filters, so big molecules like proteins and blood cells are not squeezed out. they stay in the blood. the filtered liquid in the bowman’s capsule is known as the glomerular filtrate
what useful substances are selectively reabsorbed into the blood
- all the glucose is reabsorbed from the proximal convoluted tubule so that it can be used in respiration. the reabsorption of glucose involves the process of active transport against the concentration gradient
- sufficient ions are absorbed
- sufficient water is reabsorbed from the collecting duct into the bloodstream by osmosis
reabsorbsion
- as the filtrate flows along the nephron, useful substances are selectively reabsorbed back into the blood
releases of wastes
the remaining substances (including water, ions and urea) form urine. This continues out of the nephron, through the ureter and down the bladder, where it is stored before being released via the urethra.
