3.1.2 transport in animals Flashcards
what is a closed system
blood is enclosed in blood vessels
what is a single closed system and what animals are they found in
one circuit around the body straight to and from the heart
fish and worms
what is a double closed system
two circuits going from heart to lungs to heart to body
mammals and birds
what is an open system
blood flows from heart to haemocoel (few vessels contain transport medium)
what are the blood vessels attached to the heart
vena cava
aorta
pulmonary artery
pulmonary vein
what are the valves in the heart
atrioventricular (tricuspid and bicuspid)
semi-lunar valves (pulmonary and aortic)
summarise blood flow through the right side of the heart
blood into vena cava
enters right atrium
goes through tricuspid valves
into right ventricle
goes through pulmonary valves
into pulmonary artery
into lungs
summarise blood flow through the left side of the heart
blood into pulmonary vein from lungs
enters left atrium
goes through bicuspid valves
into left ventricle
goes through aortic valves into aorta
into body
what is the word for the heart being able to stimulate it’s own contraction
myogenic
explain how the heart’s basic rhythm is stimulated
SAN causes atria to contract
AVN delays slightly then stimulates bundle of His
conducts excitational wave through to apex
purkinje fibres spread it to ventricle walls
ventricles contract
what is a healthy electrocardiogram trace
typical PQRST trace
when does systole occur on the ECG
QRS
when does diastole begin on the ECG
T
what is bradycardia
increased stroke volume of the heart that decreases beats per min
athletes or disease
what is tachycardia
ver fast heart rate greater than 100bpm
fear, panic, excersise or SAN issues
what is an ectopic heartbeat
extra beat as heart contracts before the first contraction finishes then there’s a short pause
very common
what is atrial fibrillation
irregular waves of electrical impulses in atria that causes rapid contraction (arrythmia)
what does the cardiac cycle consist of
passive filling, systole and diastole
explain the process of systole in the cardiac cycle
atria contract so pressure in atria increases - atrioventricular valves OPEN
blood goes down pressure gradient into ventricles
atria relax
ventricles contract
pressure in ventricles increases above pressure in atria
atrioventricular valves CLOSE
pressure in ventricles gets higher than in arteries - semi-lunar valves OPEN
blood forced into arteries
explain the process of diastole in the cardiac cycle
ventricles relax
when pressure in ventricles drops below arteries semi-lunar valves CLOSE
when pressure in ventricles drops below atria atrioventricular valves OPEN again to allow for passive filling
what do arteries transport
oxygenated blood away from heart
what do veins transport
deoxygenated blood to heart
what do capillaries do
exchange oxygen, nutrients and waste between blood and cells
describe an artery
small lumen maintains high pressure
thick, smooth muscular wall provides strength and can contract/relax to cope with changing pressure
collagen elastic fibres to recoil and provide strength
folded endothelium lining
describe a vein
large lumen to allow a greater volume of blood through at low pressure
thin wall as less support is needed
valves to prevent backflow of blood
describe a capillary
squamous endothelial cell thick for short diffusion pathway
large surface area for more diffusion
what are arterioles and venules
smaller versions of arteries and veins that link to capillaries to provide deoxygenated/oxygenated blood
what is tissue fluid
allows transport between blood and cells via diffusion
what is hydrostatic pressure
generated by heart
exerted by fluid in vessels
what is oncotic pressure
exerted by plasma proteins in blood
make a water potential gradient
describe hydrostatic pressure at the arterial end of the capillary
higher in the arterial end than venous end
forces fluid out of capillaries through tiny gaps in capillary walls
a smaller hydrostatic pressure forces some pressure back into capillaries
what moves with fluid in arterial end of capillaries
dissolved gases and nutrients
describe oncotic pressure in the arterial end of the capillary
oncotic pressure means water potential of capillaries becomes more negative as hydrostatic pressure pushes blood and fluid out so water moves into capillaries down the gradient
is hydrostatic pressure greater in the arterial end or the venous end of the capillary
arterial
what happens to excess fluid in vessels
not all goes through capillaries, net excess is drained into vessels of lymphatic system
what is lymph fluid
made in lymph nodes
contains lymphocytes which produce antibodies and remove bacteria and pathogens
why do people with high blood pressure produce less tissue fluid
net outward pressure from the arteriole end increases
forces tissue fluid out of capillary
decreases net hydrostatic pressure at venous end
how does haemoglobin behave with oxygen generally
it has a high affinity for oxygen
can carry 4 oxygen molecules
how does haemoglobin behave with oxygen in the lungs
oxygen diffuses into plasma
then into erythrocytes
binds to haemoglobin to maintain concentration gradient
how does haemoglobin behave with oxygen in respiring tissue
oxygen dissociates from oxyhaemoglobin so it can diffuse out into respiring cells
describe the shape of the oxygen dissociation curve
sigmoidal as % saturation of haemoglobin is not directly proportionate to po2
explain why the oxygen dissociation curve is shaped like that
hard for 1st oxygen molecule to bind due to structure of Hb
conformation then changes
after 1st oxygen molecule associates conformation changes
conformational change makes it easy for 2nd and 3rd to associate
po2 rises, gradient steepens, more o2 diffuses into Hb
more difficult to associate 4th o2 molecule as Hb gets full and gradient less steep
what is fetal haemoglobin
placenta allows transfer of o2 to foetus
low po2
describe and explain the affinity fetal haemoglobin has for oxygen
stronger affinity so it gets more saturated at a lower po2, meaning oxygen can dissociate from maternal Hb easily
how is co2 transported in blood
5% dissolved in plasma
10% associated with Hb to make carbaminohaemoglobin
85% uses carbonic anhydrase and chloride shift to take co2 into an erythrocyte
explain the role of carbonic anhydrase
co2 diffuses into erythrocyte
co2 + h2o = carbonic acid using the enzyme carbonic anhydrase
what happens to carbonic acid in an erythrocyte after being formed
a hydrogen carbonate ion and a H+ proton are produced
hydrogen carbonate ion diffuses out
H+ ion is added to Hb which acts as a buffer, making haemoglobinic acid
Cl- diffuses in to counteract negative charge (chloride shift)
what is the bohr shift
in a co2 rich environment, more o2 dissociates from oxyhaemoglobin
H+ reduces affinity of haemoglobin for o2 so curve goes to the right
