transport in animals

Question 1

why do multicellular organisms need transport systems

Answer 1

.large diffusion distance
.high metabolic rate
.low SA:VOL ratio
.so diffusion is too slow

Question 2

fish ciruclatory system

Answer 2

.single
.heart pumps blood to gills to pick up oxygem and then it flows to the rest of the body

Question 3

mammals circulatory system

Answer 3

.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

Question 4

mammals circulatory system structure

Answer 4

.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

Question 5

role of arteries

Answer 5

carry blood away from heart

Question 6

role of arterioles

Answer 6

carry blood from arteries into capillaries

Question 7

role of capillaries

Answer 7

site of diffusion between blood and body tissues

Question 8

role of venules

Answer 8

carry blood from cappillaries into veins

Question 9

role of veins

Answer 9

return blood to the heart

Question 10

adaptations of arteries

Answer 10

.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

Question 11

adaptations of capillaries

Answer 11

.narrow lumen
.thin walls for short diffusion pathway
.highly branched to provide a large SA

Question 12

adaptation of veins

Answer 12

.collagen provides strengths
.little smooth muscle and elastic fibre
.valves to prevent backflow

Question 13

what does tissue fluid do

Answer 13

.fills spaces between cells
.site of diffusion between blood and body cells

Question 14

differences between tissue fluid and plasma

Answer 14

.tissue fluid has no red blood cells, fewer proteins and white blood cells

Question 15

how is tissue fluid formed

Answer 15

.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

Question 16

the formation of lymph

Answer 16

.remaining tissue fluid that hadn’t return to the capillaries drains into lymph vessels forming lymph

Question 17

transportation of lymph

Answer 17

.lymph moves through the lymph vessels via muscle contractions
.lymph is passed through lymph nodes to filter pathogens and returns to the blood

Question 18

how is oxygen transported to body cells

Answer 18

.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

Question 19

how many oxygen molecules can each haemoglobin carry

Answer 19

.4(one for each haem group)

Question 20

factors affecting haemoglobin saturation

Answer 20

.parital pressure of oxygen - high = haemoglobin has a higher affinity for oxygen

.amount of oxygen already binding to it - more = harder

Question 21

how does fetal haemoglobin differ from adult

Answer 21

.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

Question 22

what is the bohr effect

Answer 22

.when haemoglobin affintiy to oxygen lowers due to higher partial pressure of CO2

.shifts graph to the right

Question 23

why is CO2 converted into HCO3- in the blood

Answer 23

.to maintain a steep concentration gradient between respiring tissues which need to remove CO2

Question 24

transport of CO2 as HCO3-

Answer 24

.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)

Question 25

how is HCO3- reformed into CO2 again

Answer 25

.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

Question 26

what happens in atrial systole in the cardiac cycle

Answer 26

.ventricles relax and atria contract
.this increases atrial pressure
.atrioventricular valves open
.blood flows into ventricle

Question 27

what happens in ventricular systole in the cardiac cycle

Answer 27

.ventricles contract and atria relax
.ventricular pressure increases
.semi-lunar valves open and atrioventricular valves close
.blood flows into arteries

Question 28

what happens in diastole in the cardiac cycle

Answer 28

.venticles and atria relax
.semi-lunar valves close
.blood flows passively into atria

Question 29

how to measure cardiac output

Answer 29

.measure heart rate
.measure stroke volume
.times them together

Question 30

controlling the heartbeat

Answer 30

.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

Question 31

ECG waves

Answer 31

P wave = atrial systole
QRS = ventricular systole
T wave = diastole

Question 32

heart abnormalities

Answer 32

tachycardia = fast
bradycardia = slow
ectopic heatbeats = extra heartbeat out of rhythm
atrial fibrillation = rapid and ineffective contraction of the atria