transport in animals Flashcards
what is the circulatory system
a heart which pumps blood
a system of blood vessels that carry blood
valves that ensure flow in one direction
oxygenated blood
comes from the lungs, lots of oxygen
de-oxygenated blood
contains little oxygen, needs to go to the lungs to get more oxygen
double circulatory system
blood passes through the heart twice in 1 complete circuit in the body
found in all mammals, birds, reptiles
made of 2 parts: pulmonary, systemic system
single circulatory system
blood passes through the heart only once in one complete circuit of the body
found in fish
benefits of double circulation
when blood flows through tiny vessels at the lungs or gills it loses pressure
in mammals, blood goes back to the heart to increase pressure again
this is more efficient for getting energy to cells quickly for respiration
it enters a different chamber of the heart
in fish the pressure stays low, so blood gets to the organs more slowly than in mammals.
the 4 chambers of the heart
atria where blood flows in
ventricles which pump blood out
what is a septum
a structure that separates the left and right chambers.
how blood enters the heart
left atrium receives oxygenated blood through the pulmonary veins (from the lungs)
right atrium receives de-oxygenated blood from the rest of the body through ha vein called the vena-cava
then blood passes through the ventricles. strong muscles in the walls contract to pump blood out of the heart.
how blood leaves the heart
aorta- largest artery, receives oxygenated blood from the left ventricles and pumps it to the rest of the body
pulmonary artery- carries de-oxygenated blood from the right ventricle to the lungs.
red blood cells
full circulation takes about 1 min
deliver oxygen to every tissue in the body
live up to 120 days, then are recycled
don’t have a nuclei, making them even more efficient in carrying oxygen
biconcave
no nucleus or mitocondria
cytoplasm contains heamoglobin
large surface area
small
valves
atrioventricular valves- valves between atrium and ventricle in the heart. allows blood to flow form the atria to ventricles, not the other way
semilunar valve- close to entrance of aorta and pulmonary artery
prevent backflow of blood from the arteries back into the ventricles
thickness of ventricles
because ventricles have to pump blood out of the heart they have much thicker, more muscular walls that the atria.
the left ventricle is thicker as it needs to pump the blood to the rest of the body.
coronary arteries
vessels that supply blood to the heart muscles on outside of heart
heart needs oxygen to continue pumping blood.
preventing CHD
cannot completely eliminate the risk
not smoking
regular exercise
healthy diet
ECG
a graph showing the electrical activity of a heart plotted over time (electrodiogram)
arteries
vessels carrying high-pressure blood away from the heart
carry high-pressure blood
have strong walls to withstand high pressure
blood pulses through therefore arteries have elastic tissue in their walls.
capillaries
vessels that take blood close to body cells
arteries split again and again and eventually from capillaries
one cell thick
wall made of a single layer of cells
allow diffusion and active transport
veins
vessels take low-pressure blood towards heart
blood flows more smoothly, so they do not need to have thick and elastic walls
lumen is much bigger to allow blood to flow a bit faster
have valves to stop blood flowing backwards
capillaries eventually join up again to form veins
large lumen thin layer of muscles and elastic fibres.
heamoglobin
red pigment
a protein that contains iron
iron combines with oxygen in the lungs where there is a high conc. of O2
oxyheamoglobin
haemoglobin combines with O2 it released O2 when levels are low.
white bloods cells
have nucleus that large
move around easily. can squeeze out of capillaries
they fight of pathogens and to clear up dead body cells
phagocytes
destroy pathogens by engulfing them and digesting them. this process is called phagocytosis
have a lobed nucleus
white blood cell
lymphocytes
produce antibodies which fix onto pathogens and destroy them
lymphocytes usually have a large round nucleus that fills the cell
white blood cell
large nucleus
platelets
small fragments of cells with no nucleus
made in red bone marrow
involved in blood clotting
involdved in blood clotting
clotting prevents blood loss and stops pathogens getting in through breaks in the skin
how does blood clotting happen
blood plasma contains a soluble protein called fibrogen
when a blood vessel breaks, platelets release a substance that makes the fibrinogen change into insoluble fibrin
fibrin forms fibres that pile up on top of each other to seal the wound
clumps of platelets and red blood cells all come together to form a blood clot
plasma
mostly water
many substances dissolves in it
transports hormones like adreniline
transports waste products like CO2 and urea
55% of blood
