transport in animals Flashcards
why do multicellular organisms need transport systems
.large diffusion distance
.high metabolic rate
.low SA:VOL ratio
.so diffusion is too slow
fish ciruclatory system
.single
.heart pumps blood to gills to pick up oxygem and then it flows to the rest of the body
mammals circulatory system
.have a double circulatory system
.right side of heart pumps deoxygenated blood to lungs
.left side pumps oxygenated blood to the rest of the body
mammals circulatory system structure
.deoxy blood enters heart via vena cava from the body
.deoxy blood is pumped to the lungs via the pulmonary artery
.oxy blood returns from lungs via pulmonary vein
.oxy blood pumped to the body via aorta
role of arteries
carry blood away from heart
role of arterioles
carry blood from arteries into capillaries
role of capillaries
site of diffusion between blood and body tissues
role of venules
carry blood from cappillaries into veins
role of veins
return blood to the heart
adaptations of arteries
.collagen provides strength
.elastic fibes contain elastin to let it stretch and recoil to minimise pressure change
.thick smooth muscle layer contracts and relaxes to change the size of the lumen to control blood flow
adaptations of capillaries
.narrow lumen
.thin walls for short diffusion pathway
.highly branched to provide a large SA
adaptation of veins
.collagen provides strengths
.little smooth muscle and elastic fibre
.valves to prevent backflow
what does tissue fluid do
.fills spaces between cells
.site of diffusion between blood and body cells
differences between tissue fluid and plasma
.tissue fluid has no red blood cells, fewer proteins and white blood cells
how is tissue fluid formed
.at the arteriole end of capillaries, high hydrostatic pressure from the heart pumping forces fluid out
.this forms tissue fluid surrounding body cells
.at venule end, hydrostatic pressure is lower
.proteins in blood cause high oncotic pressure
.water potential is lower in capillaries then in tissue fluid
.some tissue fluid moves back into capillaries via osmosis
the formation of lymph
.remaining tissue fluid that hadn’t return to the capillaries drains into lymph vessels forming lymph
transportation of lymph
.lymph moves through the lymph vessels via muscle contractions
.lymph is passed through lymph nodes to filter pathogens and returns to the blood
how is oxygen transported to body cells
.in capillaries in the lungs, oxygen binds to iron in the haem groups of haemoglobin forming oxyhaemoglobin
.the oxyhaemoglobin is transported to the body cells via blood
how many oxygen molecules can each haemoglobin carry
.4(one for each haem group)
factors affecting haemoglobin saturation
.parital pressure of oxygen - high = haemoglobin has a higher affinity for oxygen
.amount of oxygen already binding to it - more = harder
how does fetal haemoglobin differ from adult
.need to obtain oxygen from mothers blood
.so has a higher affinity for oxygen
.this alows for oxygen to dissociate from the mother’s blood to the fetal blood
.on graph = fetal haemoglobin is shifted to the left
what is the bohr effect
.when haemoglobin affintiy to oxygen lowers due to higher partial pressure of CO2
.shifts graph to the right
why is CO2 converted into HCO3- in the blood
.to maintain a steep concentration gradient between respiring tissues which need to remove CO2
transport of CO2 as HCO3-
.CO2 reacts with water to form H2CO3 catalysed by carbonic anhydrase
.H2CO3 dissociates to H+ and HCO3-
.H+ binds to haemoglobin forming haemoglobinic acid, causing the release of oxygen
.this prevent the blood from becoming too acidic and causes the bohr effect
.HCO3- ions leave red blood and is transported via plasma
.Cl- enters red blood to maintain charge balance(chloride shift)
how is HCO3- reformed into CO2 again
.the low partial pressure of CO2 at the lungs causes HCO3- and H+ to reform into CO2
.CO2 diffuses out of the body during expiration
what happens in atrial systole in the cardiac cycle
.ventricles relax and atria contract
.this increases atrial pressure
.atrioventricular valves open
.blood flows into ventricle
what happens in ventricular systole in the cardiac cycle
.ventricles contract and atria relax
.ventricular pressure increases
.semi-lunar valves open and atrioventricular valves close
.blood flows into arteries
what happens in diastole in the cardiac cycle
.venticles and atria relax
.semi-lunar valves close
.blood flows passively into atria
how to measure cardiac output
.measure heart rate
.measure stroke volume
.times them together
controlling the heartbeat
.SAN starts electrical impulse down the atria causing it to contract
.AVN picks up the electrical impulse and causes a slight delay
.bundle of His picks up the electrical impulse from the AVN and conducts it to the apex
.purkyne fibres that branch of the bundle of His causes the right and left ventricle to contract starting from the bottom upwards
ECG waves
P wave = atrial systole
QRS = ventricular systole
T wave = diastole
heart abnormalities
tachycardia = fast
bradycardia = slow
ectopic heatbeats = extra heartbeat out of rhythm
atrial fibrillation = rapid and ineffective contraction of the atria
