b3.2 transport Flashcards
progression to heart attack [4]
- atheroma
- anigma
- thrombosis
- heart attack
atheroma
- fat deposits in coronary arteries
- blockage as an occlusion
anigma
- pain in chest
- symptom: shortness of breath
thrombosis
formation of blood clot
what is thrombosis caused by
fatty deposits in the artery wall becoming impregnated with calcium salts
- hardens the artery
- inner surface becomes rough
what will hypertension cause
increased risk of thrombosis
heart attack
when blood clots block the blood flow to part of the muscular wall of heart
- deprives it of oxygen
- prevents normal contractions
causes of coronary artery occlusion [9]
- hypertension
- smoking
- consuming too much saturated fat and cholesterol
- obesity
- high salt intake
- too much alcohol
- sedentary lifestyle
- genetic predisposition
- old age
tunica externa
tough outer layer of connective tissue with collagen fibres
tunica media
thick layer containing smooth muscle and elastic fibres made of protein elastin
tunica intima
- smooth endothelium forming the lining of artery
importance of thick muscle layer
make arteries strong enough to withstand high and variable blood pressure without bulging outwards
importance of large amount of elastic tissue
- reduces the amount of energy expended in transporting blood to the organs of the body
when elastic tissue is stretched
store potential energy
how does the elastic tissue return the energy
recoiling and squeezing the blood in the lumen
importance of semilunar valves
prevents back flow of blood to heart and forces it towards the organs
differences between arteries and veins [5]
wall: thicker vs thinner
lumen: narrower vs wider
section: section vs section/flattened
inner surface: corrugated vs no corrugation
fibres: visible in the wall vs no visible (or only few are)
how does blood move
by gravity and muscular movement
why does the lymph move slowly
no pump to assist in movement
- close to muscles so aided by muscle contraction
where is deoxygenated blood + lymph
right atrium
what do lymph contain [8]
- lipids
- lymphocytes
- blood plasma
- wbc
- waste
- water
- minerals
- proteins
why cant the pressure be high when pumping to the lungs
alveoli will burst
what happens to blood flow when pressure increases
- blood can go long distances
- increases metabolism
- homeostasis
why can fishes only have single circulation
- surrounding water prevents capillaries from bursting
- travelling quickly- increases diffusion
- quick exchange of nutrients
pressure from artery
high
- doesnt have to be oxygenated
path of blood
artery -> arterioles -> capillaries -> venules ->veins -> heart
capillary action
- tissue fluid squeezes past
- blood plasma + wbc leak out form blood in capillaries
pacemaker
generates an electrical signal that causes the upper heart chambers (atria) to contract
what is the pacemaker also known as
SA node
how does the heart beat [7]
- myogenic so generate own electrical signal
- SA node indicated electrical impulse for heartbeat
- electrical impulse travels along walls of atrium -> contracts
- electrical impulse moves along to the atrioventricular node (AV node)
- delay for 0.1 sec to let all the blood travel ventricles
- AV node sends another electrical impulse down the Purkinje fibre in the bundle of His of the septum and ventricle walls
- vesicles contracts and blood leaves the heart
myogenic cells
can generate their own electrical impulse for muscle contraction
factors that change the pace of pacemakers
- adrenaline
- blood ph
- decreases when co2 increases
what is the pace of pacemaker signalled by
medulla oblongta
nerve that causes pacemaker to speed up
sympathetic nerve
nerve that causes pacemaker to slow down
vagnus nerve
properties of water molecules that permit them to move upwards in plants
- water molecules are polar so can form hydrogen bonds
- cohesion between water molecules allows continuous water columns
- adhesion of water to the walls of xylem vessel helps water rise
- water evaporates at environmental temperatures allowing transpiration pull
Describe the distribution of vascular tissues in the stem of dicotyledonous plants
- stem vascular tissue is in bundles
- bundles form a ring
- phloem is towards outside «of bundle»
- xylem is towards centre «of bundle»
which blood vessel connected to the heart does blood have the lowest carbon dioxide cocnetration
pulmonary vein
what helps to keep blood flowing onwards away from the heart in an artery
elastic fibres
when will pressure in the left atrium decrease
as left ventricle fills up
how increase in co2 concentration affects the release of oxygen to respiring cells
- lower the pH of the blood
- decreased affinity of the haemoglobin for oxygen so greater release of oxygen
oxygen dissociation curve shifts to the right
