3.2 Transport in Animals Flashcards

Question

PAG: heart dissection

Answer 1

- pigs/cows heart, dissecting tray, scalpel, apron, lab gloves externally: - look outside the heart and identify the 4 main vessels attached to it ( feel inside to help, as arteries are thicker and rubbery, but veins are thinner) - also identify the 4 chambers, and draw sketches of outside with labels internally: - cut along left and right side to look inside each ventricle - measure and record the thickness of the ventricle walls and not any difference between them - cut open the atria and look inside them too, and note thickness differences between atria and ventricles - find the valves and note the structure - draw sketches to draw the valves and inside of the ventricles and atria

Answer 2

- left side has to pump blood all the way to the body, so needs more force and blood at higher pressure - so travel a longer distance - lungs are nearby and delicate, so right side only has to travel short distance and overcome resistance of pulmonary circulation

Answer 3

they have to push blood out of the heart, whereas atria only pump blood into ventricles, right next to them

Answer 4

an ongoing sequence of contraction and relaxation of the atria and ventricles that keeps blood continuously circulating round the body

Answer 5

- the volumes of the atria and ventricles change as they contract and relax - alters pressure in each chamber - causes valves to open and close - directs blood flow through the heart

Answer 6

atrial systole (atria contract) ventricular systole (ventricles contract) diastole (both relaxed)

Answer 7

- the ventricles are relaxed - the atria contract, decreasing their volume and increasing their pressure - this opens the atrioventricular valves, and pushes blood through them into the ventricles - there's a slight increase in ventricular pressure and volume as they receive the ejected blood from the contracting atria

Answer 8

- the atria relax - the ventricles contract, decreasing their volume, increasing their pressure - pressure in ventricles becomes higher than the atria, forcing the atrioventricular valves shut to prevent back-flow - the high pressure in the ventricles opens the semi-lunar valves, and blood is forces out through the pulmonary artery and aorta

Answer 9

- the ventricles and the aorta both relax - higher pressure in the pulmonary artery and aorta cause the semilunar valves to close, preventing backflow - the atria fill with blood, increasing their pressure, due to the higher pressure in the pulmonary vein and vena cava - as the ventricles continue to relax, their pressure falls below the pressure in the atria, causing the atrioventricular valves to open - blood flows passively (without being pushed by atrial contraction) into the ventricles from the atria - the atria contract, and whole process repeats again

Answer 10

heart rate x stroke volume (bpm and cm^3) (cm^3/min) stroke volume= volume of blood pumped during each heartbeat

Answer 11

lub= when atrioventricular valve closes and blood is forces against it dub= when the semi-lunar valve closes

Answer 12

it can contract and relax without receiving signals from nerves - this pattern of contraction controls a regular heartbeat

Answer 13

- starts with the sino-atrial node ,SAN, in the right atrium - all set out via the wave of electrical excitation 1) SAN is like a pacemaker, sets the rhythm of the heartbeat by sending out regular waves of electrical activity to the atrial walls 2) this causes the left and right atria to contract at the same time 3) a band of non-conducting collagen tissue prevents the waves of electrical activity from being passed directly from the atria to the ventricles 4) instead, waves of electrical activity are transferred from the SAN to the atrioventricular node AVN 5) AVN is responsible for passing the wave of electrical activity on to the bundle of His (runs through the septum) 6) however, there is a slight delay before the AVN reacts, to make sure the ventricles contract after the atria have emptied 7) the bundle of His is a group of muscle fibres responsible for conducting the waves to the finer muscle fibres in the left and right ventricle walls, called Purkyne tissue 8) the Purkyne tissue carries the waves into the muscular walls of the ventricles, from the apex up, causing them to contract simultaneously, from the bottom up (both ventricles contract at the same time, upwards)

Answer 14

- wave of excitation would stop at the AVN, and there would be no transmission of it to the heart apex - therefore, no ventricular systole - cause an uncoordinated heartbeat, fibrillation - with irregular rhythm - so blood not squeezed up and out of ventricles - but atrial contraction would still continue

Answer 15

a machine that records the electrical activity of the heart

Answer 16

-the heart muscles depolarise ( lose electrical charge) when they contract and repolarise (regains charge) when they relax -the graph records these changes in electrical charge using electrodes placed at the chest - trace produced is an ECG

Answer 17

- P wave is caused by contraction (depolarisation) of the atria - the main peak of the heartbeat, along with dips on either side, is called a QRS complex, caused by the contraction (depolarisation) of the ventricles - the T wave is due to the relaxation (repolarisation) of the ventricles

Answer 18

- how much electrical charge is passing through the heart - bigger wave means more electrical charge, so for P and R waves, bigger wave means stronger contraction

Answer 19

tachycardia bradycardia ectopic heartbeat fibrillation

Answer 20

- the heartbeat is too fast - may be normal during exercise, but at rest shows that blood is not pumping efficiently

Answer 21

- where the heartbeat is too slow - may need artificial pacemaker to keep heart beating steadily - healthy in athletes, not in normal

Answer 22

- where there is an extra heartbeat - usually everyone has one a day - can be caused by early contraction of the atria (p wave is different and comes out before it should) or early contraction of ventricles too

Answer 23

- a really irregular heartbeat - atria and ventricles completely lose their rhythm and stop contracting properly - can result in chest pain, fainting, lack of pulse and death - irregular contraction, so less blood leaves heart and less O2 reaches cells and tissues

Answer 24

- 55% plasma, the yellow liquid that carries all other features -carries dissolved glucose, amino acids, mineral ions, hormones and large plasma proteins - carries red blood cells - carries white blood cells - carries platelets, responsible for blood clotting (fragments of megakaryocytes found in red bone marrow)

Answer 25

- carries oxygen too and carbon dioxide away from respiring cells - transports digested food from small intestines - carries nitrogenous waste products from cells to excretory organs - carries hormones (chemical messengers) - carries food molecules from storage compounds to cells that need them - carries platelets to damaged areas - carries cells and antibodies involved in immunity

Answer 26

the fluid that surrounds cells in tissues

Answer 27

everything present in the blood plasma, e.g. oxygen, water, nutrients, amino acids - does NOT contain red blood cells or big plasma proteins, as they're too large to be pushed out of the capillary wall through the fenestrations

Answer 28

- take in oxygen and nutrients - release metabolic waste into it (how substances travel from blood to cells)

Answer 29

- the network of capillaries in an area of tissue - substances move in and out of the capillaries, into the tissue fluid, by pressure filtration

Answer 30

hydrostatic oncotic

Answer 31

1) at the start of the capillary bed, nearest to the arteries, the hydrostatic (liquid) pressure inside the capillaries is higher than the hydrostatic pressure in the tissue fluid 2) this difference in hydrostatic pressure forces fluid out of the capillaries and into spaces around the cells, forming tissue fluid, as well as due to HP being greater than oncotic pressure 3) as the fluid leaves, the hydrostatic pressure reduces in the capillaries, so the hydrostatic pressure is much lower at the end nearest to the venules 4) another form of pressure also at work, called oncotic pressure 5) OP is generated by plasma proteins, mainly albumin, present in the capillaries, which lower the water potential 6) at the venule end, the water potential in the capillaries is lower than the water potential in the tissue fluid due to the water loss from the capillaries and high oncotic pressure 7) this means water reenters the capillaries by osmosis

Answer 32

- only 90% reenters - some excess tissue fluid is left over - does eventually get returned to the blood through the lymphatic system, a drainage system made of out lymph vessels

Answer 33

- blind-ended tubes - smallest are called lymph capillaries - fill with excess tissue fluid, which once inside is called lymph ( same makeup, but fewer nutrients, less oxygen and has fatty acids which have been absorbed at the villi of the small intestine) - the lymph has valves in the vessels, which stop the lymph from going backwards, and the lymph is moved along by squeezing of body muscles - lymph gradually moves to the main lymph vessels in the thorax (chest cavity) and return into left and right subclavian veins, near the heart - also have lymph nodes along vessels, which build up lymphocytes as a part of the immune defense to pathogens

Answer 34

tissue fluid formed from blood, and lymph formed from tissue fluid

Answer 35

in blood, not in tissue fluid or lymph - too big to get through the capillary walls into the tissue fluid

Answer 36

- in the blood, very few in tissue fluid, and present in the lymph - most WBC are in the lymph system, but only enter the tissue fluid when there's and infection

Answer 37

in the blood, none in tissue fluid or lymph - only present in the tissue fluid if capillaries are damaged

Answer 38

- present in blood, very few in tissue fluid and only antibodies in the lymph - most plasma proteins are too big to get through the capillary walls

Answer 39

- present in all, but tissue fluid and lymph have a higher conc. than blood

Answer 40

- present in all, as can move freely, such as salt

Answer 41

- a whole in the septum, which usually should go away few days after birth - means that blood can freely mix in the heart, and is all very similar - oxygenated blood can leak from left ventricle to right ventricle - deoxygenated blood can move into left ventricle - means that less oxygenated blood! is pumped around the body and reaches body tissue and cells - so less O2 available for aerobic respiration, so less ATP produced - also decreases the pressure and force at which blood leaves the left ventricle

Answer 42

- large, quaternary, conjugated protein - with 4 polypeptide chains - each containing a haem prosthetic group - which contains iron and gives red colour

Answer 43

- tendency to combine with oxygen - has a high affinity, and each molecule of haemoglobin can carry 4 O2 molecules - millions of haemoglobin molecules in each RBC, so loads of O2 can be carried

Answer 44

1) IN THE LUNGS - low conc of O2 in RBC's, and high conc. in air of haemoglobin, so O2 enters via diffusion - O2 joins/associates to the iron in haemoglobin, forming oxyhaemoglobin 2) IN BODY CELLS - conc. of O2 in cytoplasm of body cells is lower than that of erythrocytes, so O2 moves out of RBC down gradient - O2 leaves/dissociates from oxyhaemoglobin, forming haemoglobin - REVERSIBLE REACTION: - haemoglobin + oxygen ===> oxyhaemoglobin - Hb + 4O2 ===> HbO8

Answer 45

the partial pressure of O2 - measure of O2 concentration - greater the conc. of dissolved O2 in cells, the higher the pO2 - so the proportion of atmospheric pressure produced by oxygen, so as atmospheric pressure decreases (you get higher up), so does pO2

Answer 46

the partial pressure of CO2 - measure of the concentration of CO2 in a cell

Answer 47

1) O2 LOADS onto haemoglobin to form oxyhaemoglobin where there's a high pO2 2) oxyhaemoglobin UNLOADS its oxygen where there's lower pO2

Answer 48

1) LUNGS - oxygen enters blood capillaries at the alveoli, which have a high pO2, so O2 LOADS onto haemoglobin and forms oxyhaemoglobin 2) RESPIRING BODY CELLS - use up oxygen, lowering their pO2, so RBC deliver oxyhaemoglobin to respiring tissues, where it UNLOADS the O2 - cycle repeats as Hb is returned to lungs to pick up more O2

Answer 49

- plots the percentage saturation of haemoglobin with oxygen in blood (y-axis) - against the partial pressure of oxygen in surroundings (x-axis)

Answer 50

1) where pO2 is low (e.g. in respiring tissues) 2) haemoglobin has a low affinity for O2 3) and will rather release and unload the O2 rather than combine and load it 4) so their is low saturation of O2 with haemoglobin

Answer 51

- once one O2 molecule has attached to haemoglobin - its SHAPE CHANGES (an allosteric effect) - makes it easier for other molecules of O2 to join too - called cooperative binding

Answer 52

- where the pO2 is high (e.g. in the lungs) - haemoglobin has a high affinity for O2 - and will readily combine with it and load it - causing a high saturation of it

Answer 53

- the curve levels out as - all the haem groups are bound to O2 molecules - so the haemoglobin becomes saturated - and it is harder for more O2 molecules to become attached

Answer 54

- causes a BIG CHANGE in the amount of O2 carried by the Hb - a small drop in O2 of respiring tissues will cause the O2 to be unloaded into the respiring cells - a small rise will cause the O2 to be loaded in

Answer 55

- every haemoglobin molecule is carrying the maximum 4 molecules of O2 - none of the haemoglobin molecules are carrying any oxygen

Answer 56

fetal haemoglobin has a higher affinity for oxygen at the same pO2 of oxygen than adult haemoglobin - so the fetus blood is better at absorbing oxygen than its mothers blood

Answer 57

1) fetus gets its oxygen from its mother's blood across the PLACENTA 2) by the time the mother's blood reaches the placenta, its O2 saturation is already decreased (used up in the mother's body) 3) for fetus to get enough O2 to survive, haemoglobin has to have a higher affinity for O2, so that it can take up enough 4) if it were to have the same affinity as mother's, its blood would not be saturated enough - means that maternal haemoglobin releases O2, as oxygen is more attracted to (has a higher affinity for) fetal haemoglobin, and maintains a diffusion gradient of O2 always entering the fetus

Answer 58

if still fetal: - oxygen would not be released readily enough,as affinity of fetal haemoglobin for oxygen would be too high - in adult females, they would need to have different haemoglobin than their fetuses in due course, to make sure the new baby gets enough O2

Answer 59

- as the partial pressure of CO2 increases, pCO2 - haemoglobin gives up its oxygen more readily - known as the Bohr effect

Answer 60

- at a higher concentration of CO2 - the dissociation curve would shift to the right - showing that more oxygen is released from the blood ( as there is a lower saturation of haemoglobin with O2, so more O2 released)

Answer 61

- means that cells get more oxygen during activity - as respiring cells have more CO2, so more O2 is given up from RBCs to tissue

Answer 62

ACTIVE TISSUES: have a high pO2 as cells are respiring and producing CO2, so haemoglobin unloads its O2 more readily LUNGS: the proportion of CO2 in the air is relatively low, so oxygen binds to the haemoglobin molecules easily

Answer 63

as CO2 levels of the surroundings increase, so does the amount of O2 released from the RBCs in the blood

Answer 64

5% = directly in the blood plasma 10-20% = bound directly to the haemoglobin, as carbaminohemoglobin 75-85% = as hydrogencarbonate ions

Answer 65

1) some in plasma, some binds directly to the amino groups of haemoglobin 2) most of the CO2 reacts with water in the red blood cells to form carbonic acid, catalysed by the enzyme carbonic anhydrase (CO2 + H20 ===> H2CO3) 3) the carbonic acid is a weak acid, so dissociates (splits up) to give H+ ions and HCO3- ions (H2CO3 === HCO3- + H+) 4) the increase in H+ ions causes haemoglobin to unload its oxygen so that haemoglobin can take up the H+ ions instead - MEANS THAT WHEN MORE CO2, MORE O2 UNLOADED 5) this forms a compound called haemoglobinic acid (this process also stops the H+ ions from increasing the cells acidity, as the haemoglobin acts as a buffer) 6) the HCO3- ions diffuse out of the red blood cell and are transported in the blood plasma 7) to compensate for the loss of the HCO3- ions (the loss of negative charge, with positive H+ ions still present), CL- ions diffuse into the RBC 8) this is called the chloride shift, and maintains the balance of charge between the RBC and the plasma 9) when the blood reaches the lungs, the low pCO2 causes some of the HCO3- and H+ ions to recombine into CO2 (and H2O) 10) the CO2 then diffuses into the alveoli and is breathed out

Answer 66

- maintains blood pressure - smaller volume of blood is required - blood supply to different organs can be varied

Answer 67

- energy dissipates due to elastic recoil (which evens out the surges of blood) - further distance away from the heart - good as means that capillaries don't get damaged (as delicate and less smooth muscle, and blood flows slower, so more time for gas exchange