Section 3 Exchange and transport Flashcards

Question

Layout of Circulatory System?

Answer 1

 heart pumps blood which is carried in arteries which flow into arterioles which flow into capillaries which then are carried in venules then veins back to the heart  Artery to Arterioles to Capillaries to Venules to Veins  Artery/Arterioles carry blood away from the heart (arterioles are small arteries)  Capillaries are the site of exchange (nutrients out, waste in)  Veins/Venules return blood back to the heart (venules are small veins)

Answer 2

 job is to pump blood around the body (delivers nutrients to cells and remove waste)  made of 4 muscular chambers (2 atria, 2 ventricles)  atria pumps blood to ventricles, ventricles pump blood out of heart (R to lungs, L to body)  ventricles thicker then atria (has to pump blood further)  left ventricle has a thicker muscular wall then right ventricle, therefore has stronger contractions, so can generate higher pressure and pump the blood further around the body

Answer 3

 artery takes blood away from the heart, vein returns blood to the heart  Vena Cava supplies R atrium (with deoxygenated blood from body)  Pulmonary Vein supplies L atrium (with oxygenated blood from lungs)  R ventricle supplies Pulmonary Artery (deoxygenated blood to lungs)  L ventricle supplies Aorta (oxygenated blood to body)

Answer 4

 Ensure one way flow of blood, no backflow  (blood flows from atria to ventricles to arteries)  2 sets of valves: Atrio-ventricular Valve & Semi-lunar Valve  AV valve = between atria and ventricles  SL valve = between ventricles and arteries

Answer 5

Open = pressure in atria greater then pressure in ventricles, Closed = pressure in ventricles greater then pressure in atria

Answer 6

Open = pressure in ventricles greater then pressure in arteries Closed = pressure in arteries greater then pressure in ventricles

Answer 7

 Filling Stage = atria relaxed, ventricles relaxed, AV valve open, SL valve closed  Atria Contracts = the SAN located in the R atrium initiates the heart beat and sends the impulse across both atria making them contract, this pushes all the remaining blood into the ventricles so it becomes full  Ventricles Contract = the AVN picks up the impulse, delays it (stops the atria and ventricles contracting at the same time, so the atria empties and the ventricles fill), sends the impulse down the septum in the Bundle of His, then at the apex the impulse goes up both walls of the ventricles in the purkine fibres, so the ventricles contract from the base upwards, pushing the blood up thru the arteries, when the ventricles start to contract the AV valve closes then the SL valve opens and blood leaves the heart  Ventricles Relax = the SL valve closes then the AV valve opens and filling starts again

Answer 8

 when the valves close  1st = AV closes  2nd = SL closes

Answer 9

 CO = Stroke Volume x Heart Rate  stroke volume = volume of blood pumped out of the heart in one beat  heart rate = number of beats per minuted  Cardiac Output = volume of blood pumped out of the heart in one minute

Answer 10

 high blood pressure damages lining of coronary artery  fatty deposits/cholesterol builds up beneath the lining, in the wall = Atheroma  the atheroma breaks thru the lining forming a Atheromatous Plaque on the lining, in the lumen  this causes turbulent blood flow  a blood clot (thrombus) forms  this block the coronary artery  therefore less blood flow to the heart muscle  less glucose and oxygen delivered  the heart muscle cannot respire  so it dies (myocardial infarction)

Answer 11

 Age, gender, ethnicity  Saturated fats (increases LDL, LDL deposits cholesterol in the arteries to form atheroma)  Salts (increases blood pressure – lowers water potential of the blood so it holds the water)  Smoking (nicotine = increase HR and makes platelets more sticky – blood clot, carbon monoxide = permanently blocks haemoglobin)  Obesity and Lack of Exercise

Answer 12

atheroma weakens wall of artery, blood builds up in the wall, the wall swells then bursts = aneurysm

Answer 13

 generally carry oxygenated blood away from the heart  for example, Coronary Artery to heart muscle Hepatic Artery to liver Renal Artery to kidneys  exception = Pulmonary Artery carries deoxygenated blood to lungs

Answer 14

 generally carry deoxygenated blood back to the heart  for example, Coronary Vein from heart muscle Hepatic Vein from liver Renal Vein from kidneys  exception 1 = Pulmonary Vein carries oxygenated blood back to the heart  exception 2 = Hepatic Portal Vein carries deoxygenated blood from digestive system to liver (for filtering)

Answer 15

carry blood away from the heart so should be able to withstand high blood pressures & maintain high blood pressures

Answer 16

 narrow lumen = maintains pressure  lining made of squamous epithelial cells = smooth lining to reduce friction  thick wall = withstand pressure  elastic tissue in wall, ventricles contract – elastic tissue stretches to withstand pressure ventricles relax – elastic tissue recoils to maintain pressure and smooth out flow  smooth muscle in wall (particularly in arterioles), smooth muscle contracts – lumen narrows and arteriole constricts smooth muscle relaxes – lumen widens and arteriole dilates  collagen in wall prevents artery from tearing

Answer 17

return blood back to the heart, the blood is under low pressure

Answer 18

 wide lumen = ease of blood flow  lining made of squamous epithelial cells = smooth lining to reduce friction  thin wall = vein can be squashed by skeletal muscle pushing blood back to the heart  valves in lumen = prevents backflow of blood

Answer 19

 site of exchange  3 locations, With Alveoli, takes in O2 and removes CO2 With Microvilli, takes in glucose/amino acids/monoglyceride and fatty acids/vitamins/minerals With All Cells, deliver nutrients and remove waste

Answer 20

 many small capillaries = large surface area  thin wall, one cell thick, squamous epithelial cells = short diffusion distance  pores between cells = allows fluid to move in and out  narrow lumen = increase diffusion time and decrease diffusion distance

Answer 21

 main component = Plasma (fluid)  plasma carries,  Cells = red blood cells, white blood cells, platelets  Solutes = nutrients, waste, protein

Answer 22

 by mass flow  fluid moves out of the blood in the capillaries carrying the nutrients  fluid moves back into blood in the capillaries carrying the waste  (fluid in the blood called plasma, fluid surrounding cells called tissue fluid, fluid in lymph system called lymph)

Answer 23

 at the start of the capillary (arterial end) there is a build up hydrostatic pressure  this pushes fluid out of the capillary via the pores  the fluid carries the nutrients with it  the fluid surrounds the cells, this is called tissue fluid  at the finish of the capillary (venous end) the fluid moves back in by osmosis  the capillary has low water potential due to the presence of proteins (too large to move out of capillaries)  any excess tissue fluid is picked up by the lymph system and deposited in the vena cava

Answer 24

increases hydrostatic pressure, so more tissue fluid is formed – not as much can be returned to the circulatory system

Answer 25

the water potential in the capillary is not as low as normal, so not as much fluid can move back into the capillary by osmosis

Answer 26

Arteries = - highest pressure (connects directly with heart/ventricles) - pressure fluctuates (increases when ventricles contract which causes the elastic tissue to stretch, decreases when ventricles relax which causes the elastic tissue to recoil) - overall decrease in pressure due to friction Arterioles = large decrease in pressure due to increase in total cross-sectional area (ensures pressure is not to high to damage capillaries) Capillaries = pressure here is called hydrostatic pressure (decreases due to a loss in fluid) Venules/Veins = blood under low pressure

Answer 27

 found in humans/mammals (animals)  carries haemoglobin  haemoglobin carries oxygen

Answer 28

 globular protein (soluble & specific 3d shape)  quaternary structure made of 4 polypeptide chains (2α, 2β)  each chain carries a haem group  each haem group carries Fe2+  each Fe2+ carries an O2  therefore, each haemoglobin carries 4 lots of O2

Answer 29

load oxygen in the lungs and deliver it to the respiring tissues

Answer 30

the level of attraction haemoglobin has to oxygen | high affinity = strong attraction, low affinity = weak attraction

Answer 31

 haemoglobin has High Affinity in the lungs – due to high partial pressure of oxygen and low partial pressure of carbon dioxide, so haemoglobin loads/associates oxygen in the lungs and becomes saturated (full)  the haemoglobin is transported in the blood in the red blood cell  at the respiring tissues, haemoglobin has Low Affinity – due to low partial pressure of oxygen and high partial pressure of carbon dioxide, so oxygen is unloaded/dissociated/delivered and haemoglobin becomes unsaturated

Answer 32

 positive correlation  as O2 partial pressure increases, affinity/saturation of haemoglobin increases  the correlation is not linear but is curved (produces a s-shaped, sigmoid curve called Oxygen Dissociation Curve)  middle portion of ODC has a steep gradient so when respiring tissues change from resting to active and partial pressure of O2 falls, there is a large drop in affinity, so more O2 would be delivered to the respiring tissues

Answer 33

 negative correlation  as CO2 partial pressure increases, affinity/saturation of haemoglobin decreases  this occurs at the site of respiring tissues = the carbon dioxide lowers the pH of the blood, makes the haemoglobin change shape, so oxygen is released, lowering affinity. this shifts the ODC to the right, called the bohr shift. benefit = more oxygen delivered to respiring cells

Answer 34

from mother's blood, oxygen dissociates from mother's haemoglobin and associates with fetal haemoglobin in the placenta – fetal haemoglobin has a higher affinity compared to mother's haemoglobin

Answer 35

fetal haemoglobin's ODC will be to the left, it has high affinity – so the oxygen will dissociate from the mother's haemoglobin and associate with the fetal haemoglobin at the low partial pressures of oxygen in the placenta, so it has enough oxygen for its needs

Answer 36

the high affinity will mean less oxygen will be unloaded at the respiring tissues

Answer 37

has a high affinity, curve to the left, therefore it can readily associate oxygen at the low oxygen partial pressures

Answer 38

has a low affinity, curve to the right, therefore more oxygen can be unloaded to meet the cell's demand for more respiration

Answer 39

have a large surface area to volume ratio, lose a lot of heat, needs to respire to generate heat, therefore has a low affinity, curve to the right, so unloads enough oxygen for the cells demand of more respiration

Answer 40

 exchange systems = leaf and root  leaf to absorb light and CO2 for photosynthesis  roots to absorb water and minerals  transport systems = xylem and phloem  xylem transports water and minerals  phloem transports glucose/sugars  xylem transports in one direction from roots to leaves, phloem transports in both directions

Answer 41

 absorb water and minerals  absorbs water by osmosis  absorbs minerals by active transport  plants need water for photosynthesis, cytoplasm hydration, turgidity of cells  plants need magnesium, nitrate, phosphate (magnesium to make chlorophyll, nitrate to make amino acids, phosphate to make phospholipids/ATP/DNA)

Answer 42

transport water and minerals that has been absorbed via the roots up the plant to the leaves

Answer 43

 long continuous hollow tube (no resistance to water flow)  narrow lumen  wall made out of lignin  lignin: strong, waterproof, adhesive  wall contains pits/pores (water and minerals can leave)

Answer 44

 loss of water at the leaves (transpiration)  water moves from the top of the xylem into the leaf by osmosis (transpirational pull)  this applies TENSION to the column of water in the xylem  the column of water moves up as one as the water particles stick together, COHESION  this is is the cohesion-tension theory  it is supported by capillary action, adhesion and root pressure  (capillary action = water automatically moves up narrow lumen of xylem)  (adhesion = water particles stick to lignin in wall of xylem)  (root pressure = water absorbed at the roots pushes the column of water up slightly by hydro-static pressure)

Answer 45

 more light and higher temperature  increase rate of transpiration  increase transpirational pull  water pulled up xylem by cohesion-tension  because the water particles stick to the wall of the xylem (adhesion)  the walls of the xylem are pulled inwards

Answer 46

 upper layer called Upper Epidermis  waxy cuticle on upper epidermis (barrier to reduce water loss)  beneath the upper epidermis are Palisade Cells  palisade cells are were photosynthesis takes places  beneath palisade cells are Spongy Mesophyll Cells  are loosely packed leaving air spaces to allow ease of gas exchange  lower layer called Lower Epidermis

Answer 47

 located near top of leaf, closer to light  large size, large surface area for light  thin cell wall, short diffusion distance for carbon dioxide  contains many chloroplasts, site of photosynthesis  large vacuole, pushes chloroplast to the edge of the cell closer to light

Answer 48

 organelle for photosynthesis  has double membrane  contains discs called thylakoids  thylakoids contain chlorophyll  stack of thylakoids called granum  thylakoids surrounded by a fluid called stroma

Answer 49

 lower epidermis of leaf contains pairs of cells called Guard Cells  when turgid, guard cells form an opening called Stomata  gas exchange occurs via the stomata  In Day, plant photosynthesises and respires, CO2 moves in for photosysnthesis and O2 moves out (some is used in respiration)  At Night, plant only respires, O2 moves in for respiration and CO2 moves out

Answer 50

loss of water vapour from the leaf via the stomata

Answer 51

 moist lining of spongy mesophyll cells evaporate forming water vapour  water vapour builds up in air spaces  if water vapour concentration is high enough & stomata is open, water vapour diffuses out

Answer 52

 light = more light, more stomata open, increase surface area for transpiration  temperature = more temperature, more evaporation (increase water vapour concentration) & more kinetic energy  wind = more wind, maintains concentration gradient  humidity = less humidity, less water vapour in the surrounding air, increase in water vapour concentration gradient

Answer 53

apparatus used to measure the rate of transpiration

Answer 54

Volume of transpiration divided by time taken.

Answer 55

A plant adapted to reduce water loss (transpiration) E.g. Cacti

Answer 56

 spiky, needle like leaves = reduced surface area  thick waxy cuticle = waterproof, impermeable barrier  densely packed spongy mesophyll = less air spaces, less water vapour build up  sunken stomata/hairy leaves/rolled up leaves = traps moist layer of air, reduces concentration gradient

Answer 57

transport organic material (e.g. Sucrose) up and down a plant

Answer 58

made of 2 parts (Sieve Tube with Companion Cells alongside)

Answer 59

 by principle of Mass Flow (mass flow of water carries the sucrose)  Sucrose loaded into Phloem at Source  Hydrogen Ions (H+) actively transported from companion cells into source  therefore, H+ diffuses back into companion cells from source  as they do, they pull in sucrose with them by co-transport  sucrose then diffuses into sieve tube  this lowers the water potential of sieve tube so water follows by osmosis  this water will carry the sucrose by hydrostatic pressure (mass flow)  Sucrose unloaded from Phloem at Sink  sucrose moves out of phloem/sieve tube into sink by diffusion  water follows by osmosis

Answer 60

 Starch/Glycogen (Salivary Amylase in Mouth, Pancreatic Amylase in Small Intestine) into Maltose  Maltose (Maltase on lining of Small Intestine) into Glucose  Lactose (Lactase on lining of Small Intestine) into Glucose and Galactose  Sucrose (Sucrase on lining of Small Intestine) into Glucose and Fructose

Answer 61

 Endopeptidase (in stomach), hydrolyses peptide bonds in middle of polypeptide chain into many smaller chains  Exopeptidase (in small intestine), hydrolyses peptide bonds at end of chains to leave dipeptides  Deipeptidase (on lining of small intestine), hydrolyse dipeptides into amino acids

Answer 62

- Lipase in Small Intestine leaves Monoglyceride and 2 Fatty Acids

Answer 63

 folded to form Villus (large surface area)  cells lining SI have Microvilli (large surface area)  wall of SI is thin (short diffusion distance)  rich blood supply (maintains concentration gradient)  cells lining SI have transport proteins, enzymes (maltase, lactase, sucrase, didpeptidase) and many mitochondria

Answer 64

 sodium ions are actively transported from the cells lining the SI into the blood  lowers the sodium ion concentration in the cell  therefore sodium ions move from the lumen of the SI into the cell  this pulls in glucose and amino acids via a cotransport protein  therefore glucose and amino acids builds up in the cell and moves into the blood by diffusion

Answer 65

 Lipids initially emulsified by Bile into Micelles (smaller droplets)  Micelles digested by Lipase into Monoglyceride and 2 Fatty Acids  Monoglyceride and Fatty Acids absorbed by Cells lining SI by simple diffusion  Form a Chylomicron (lipid + cholesterol + lipoprotein)  Enters Lymph as Lacteal, then enters Blood

Answer 66

 Person does not make Lactase Enzyme  Lactose remains Undigested  Leads to Diarrhoea and Flatulence  Undigested Lactose in Lumen of Intestine lowers it's water potential, so water enters the lumen by osmosis leading to water faeces (Diarrhoea)  Undigested Lactose brokendown by micro-organisms in Large Intestine, giving off gas (Flatulence)