Transport in animals

Question 1

why do multicellular organisms need a transport system

Answer 1

relatively big
low surface area to volume ratio and a high metabolic rate

Question 2

what is a single circulatory system

Answer 2

where blood only passes through the heart once per complete circuit of the body

Question 3

what is a double circulatory system

Answer 3

blood passes through the heart twice per complete circuit of the body

Question 4

what is a closed circulatory system and what group of organisms have them

Answer 4

when blood is enclosed in blood vessels, vertebrates

Question 5

what is an open circulatory system and what group of organisms have one

Answer 5

blood is not enclosed in blood vessels and flows freely through body cavity, invertebrates

Question 6

describe the structure of arteries

Answer 6

walls are thick and muscular, have elastic tissue which allows stretch and recoil to maintain high pressure, inner lining is folded to allow artery to expand, carry oxygenated blood

Question 7

describe the structure of arterioles

Answer 7

much smaller than arteries, have a smooth muscle layer allowing them to contract to control amount of blood flowing to tissues , less elastic tissue than arteries

Question 8

describe the structure of capillaries

Answer 8

smallest blood vessel, walls one cell thick,

Question 9

describe the structure of venules

Answer 9

very thin walls, contain some muscle cells

Question 10

describe the structure of veins

Answer 10

wider lumen then arteries, very little elastic or muscle tissue, contain valves

Question 11

what is tissue fluid made up of

Answer 11

oxygen, water and nutrients

Question 12

describe what happens during pressure filtration

Answer 12

at the start of the capillary bed, near the arteries, hydrostatic pressure inside capillaries is greater than that in the tissue fluid, this forces fluid out of capillaries and into space around cells, as fluid leaves pressure inside capillaries lowers
as water leaves the capillaries the inc, of plasma proteins in the capillaries increases a w.p decreases
this causes oncotic pressure so at venue end there is high oncotic pressure but low w.p
because w.p is lower in capillaries than tissue fluid some water moves back in via osmosis

Question 13

describe what happens to excess tissue fluid that doesn’t not reenter the capillaries at vein end of capillary bed

Answer 13

gets returned to blood via lymphatic system
excess tissue fluid passes into lymph vessels
once inside is called lymph
valves in lymph vessels prevent lymph going backwards
it moves ro main lymph vessel in thorax and is returned to blood near heart

Question 14

what does blood contain

Answer 14

red blood cells, white blood cells, platelets, proteins, water and dissolved solutes

Question 15

what does tissue fluid contain

Answer 15

very few white blood cells(only when infection present), very few proteins, water and dissolved solutes

Question 16

what does lymph contain

Answer 16

white blood cells, water and dissolved solutes, antibodies

Question 17

draw an external diagram of the heart

Question 18

draw an internal diagram of the heart

Question 19

describe the cardiac cycle

Answer 19

ventricles relax, atria contract, decreasing volume of chambers and increasing pressure, blood passes through atrioventricular valve
ventricles contract, atria relax, pressure becomes higher in ventricles than atria AV valves forced shut, pressure higher than aorta and p artery so SL valves open
ventricles relax and atria relax closing SL valves atria fill again so pressure of atria increases and forces AV valves open passively

Question 20

what is the equation for cardiac output

Answer 20

heart rate x stroke volume

Question 20

describe how heartbeat is controlled

Answer 20

starts at Sino-atrial node
this sends waves of electrical activity over atrial walls
band of non conductive collagen tissue presents wave being passed directly to ventricles
instead the waves are transferred to atrioventricular node
AVN passes electrical activity to the bundle of His however there is a slight delay before AVN reacts to allow atria to fully empty
bundle of His transfers electrical activity to Purkyne tissue
purine tissue carries electrical activity to walls of ventricles causing them to contract

Question 21

heart muscle is

Answer 21

myogenic

Question 22

label an electrocardiogram

Answer 22

p wave- caused by contraction of atria
QRS complex- caused by contraction o ventricles
T wave- relaxation of ventricles

Question 23

how do you calculate heart rate

Answer 23

60/ timetaken for one heartbeat

Question 24

what is tachycardia

Answer 24

heartbeat is too fast

Question 25

what is bradycardia

Answer 25

heartbeat is too slow

Question 26

what is an ectopic heartbeat

Answer 26

an ‘extra’ heartbeat that disturbs the normal rhythm as as p wave comes earlier than it should

Question 27

when oxygen joins to iron in haemoglobin what is formed

Answer 27

oxyhaemoglobin

Question 28

when oxygen binds to haemoglobin what is it called

Answer 28

association

Question 29

when oxygen leaves oxyhemoglobin what is this called

Answer 29

dissociation

Question 30

what is oxygen affinity

Answer 30

the tendency a molecule has to bind with oxygen

Question 31

what is pO2

Answer 31

measure of oxygen conc,. (-partial pressure of oxygen)

Question 32

oxygen loads onto haemoglobin when partial pressure is

Answer 32

high

Question 33

oxyhemoglobin unloads oxygen when the pO2 is

Answer 33

low

Question 34

explain the s shaped curve on dissociation graphs

Answer 34

when a molecule of oxygen binds to haemoglobin it alters its shape to make it easier for molecules to bind however when the haemoglobin becomes saturated it gets harder for oxygen molecules to bind

Question 35

describe why metal haemoglobin has a higher oxygen affinity

Answer 35

when the mother’s blood reaches the placenta is has a low PO2 as some has been used by the mother, the placenta also has low pO2 so adult oxyhaemoglobin will unload

Question 36

what is the partial pressure of carbon dioxide

Answer 36

measure of CO2 conc in a cell

Question 37

what is the effect of a high pCO2

Answer 37

increase of oxygen unloading, the dissociation curve shifts right, called the Bohr effect

Question 38

what happens when CO2 diffuses into red blood cells

Answer 38

reacts with carbonic acid, catalysed by carbonic anhydrase
carbonic acid dissociates into H+ ions and HCO3- ions
decrease in pH causes oxygen to unload and be replaced by H+ ions forming haemoglobin acid
HCO3- ions diffuse out of red blood cells
to compensate for loss of HCO3- ions Cl ions diffuse into rbc this is called the chloride shift