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A-Level Biology🌼 > Topic 3: Exchange + Transport: Transport in Animals > Flashcards

Topic 3: Exchange + Transport: Transport in Animals Flashcards

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1
Q

Why are specialised transport systems needed?

A

Specialised transport systems are needed because:
-Multicellular animals have high metabolic demand
-Surface area: volume ratio gets smaller as organisms get larger (diffusion distances longer)
-Molecules eg hormones/enzymes may be made in one place but needed in another
-Food will be digested in one organ system but needs to be transported to every cell eg for respiration
-Waste products of metabolism needs to be removed from cells and transported to excretory organs

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2
Q

Common features of circulatory systems

A

Common features of circulatory systems:
-Liquid transport medium that circulates around system eg blood
-Vessels that carry the transport medium
-Pumping mechanism to move fluid around the system

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3
Q

Why do organisms such as humans require a mass transport system?

A

Large multicellular organisms such as humans require a mass transport system due to being multicellular and having a small surface area to volume ratio

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4
Q

Mass transport definition

A

Mass transport = substances transported in a mass of fluid with a mechanism that moves the fluid around the body

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5
Q

Open circulatory systems

A

Open circulatory systems:
-Very few vessels
-Pumped straight from heart to body cavity (the haemocel) - where blood is under low pressure and comes into direct contact with cells

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6
Q

Insect blood

A

Insect blood is called haemolymph, which carries food and nitrogenous waste products rather than oxygen or carbon dioxide

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7
Q

Closed circulatory systems

A

Closed circulatory systems - blood enclosed in blood vessels and doesn’t come into direct contact with body cells
-Substances leave and enter blood by diffusion through blood vessel walls

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8
Q

Single closed circulatory systems

A

Single circulatory systems - blood travels through the heart once through each complete circuit
-Passes through two sets of capillaries (1st set = exchanges oxygen and carbon dioxide, 2nd set = substances exchanged between blood and the cells)

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9
Q

Double closed circulatory systems

A

Double closed circulatory systems - Blood passes through the heart for each complete circuit
-1st circuit: blood pumped from heart to lungs to pick up oxygen and unload carbon dioxide then returns to the heart (pulmonary circulation)
-2nd circuit: Blood flows through heart and pumped to travel whole body before returning to heart (systemic circulation)

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10
Q

Components of blood vessels

A

Components of blood vessels:
-Elastic fibres - composed of elastin, stretches and recoils, provides vessel walls with flexibility
-Smooth muscle - contracts and relaxes, changes size of lumen (the channel within the blood vessel)
-Collagen - provides structural support to maintain the shape and volume of the vessel

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11
Q

Artery functions

A

Arteries carry oxygenated blood (except in pulmonary artery) away from the heart to the tissues of the body
-Blood under higher pressure than in the veins

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12
Q

Elastic fibres in artery walls

A

Elastic fibres enable arteries to withstand the force of blood pumped out the heart and stretch to take the larger blood volume
-They recoil in between heart contractions then return to normal length to help even out blood surges to give a continuous flow

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13
Q

Endothelium of arteries

A

The endothelium of arteries have smooth lining to allow for flow of blood

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14
Q

Arterioles

A

Arterioles - branch of arteries
-They have more smooth muscle and less elastin in their walls than arteries due to having little pulse surge, but constricts and dilates to control flow of blood into organs

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15
Q

Smooth muscle in arterioles

A

Smooth muscle in the arterioles contracts to constrict the vessel and prevents blood flow into a capillary bed (vasoconstriction), or relaxes to allow blood flow through a capillary bed (vasolidation)

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16
Q

Vasoconstriction

A

Vasoconstriction - smooth muscle in arterioles contract to constrict vessels and prevent blood flow into a capillary bed

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17
Q

Vasolidation

A

Vasolidation - smooth muscle in arterioles relaxes to allow blood flow through into the capillary bed

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18
Q

Capillary lumen

A

The lumen of capillaries is so small that red blood cells have to travel through in single file

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19
Q

How do substances pass out capillaries?

A

Capillaries have gaps between their endothelial cells that are large enough for substances to pass out capillaries and into the surrounding fluid

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20
Q

Capillary adaptations

A

Adaptations of the capillaries:
-Large surface area
-Total cross-sectional area of capillaries greater than arteriole supplying them - slows rate of blood flow - to give more time for exchange of materials by diffusion
-Walls are single endothelial cell thick to give thin layer for diffusion

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21
Q

Veins function

A

Veins carry blood away from cells towards the heart and carry deoxygenated blood (except pulmonary vein and umbillical vein)

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22
Q

Inferior vena cava location

A

The inferior vena cava is in the lower parts of the body

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23
Q

Superior vena cava location

A

The superior vena cava is found in the upper parts of the body

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24
Q

Why do veins not have a pulse?

A

Veins do not have a pulse as the surges from the heart pumping are lost as the blood passes through the narrow capillaries

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25
Q

Main adaptations that enable low blood pressure to be carried back into the heart against gravity

A

Adaptations:
-Valves = closes to prevent the backflow of blood
-Bigger veins run between big active muscles - muscles contract to squeeze the veins and force blood towards heart
-Breathing movements - acts as pump

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26
Q

Platelets

A

Platelets = fragments of large cells called megakaryocytes found in red bone marrow - involved in clotting mechanism of the blood

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27
Q

Functions of the blood

A

Function of the blood - maintenance of body temp + acts as buffer to minimise pH changes +
transport of:
-Oxygen to and carbon dioxide from respiring cells
-Digested food from the small intestine
-Nitrogenous waste products from cells to the excretory organs
-Chemical messages (hormones)
-Food molecules from storage compounds to cells that need them
-Platelets to damaged areas
-Cells and antibodies involved in the immune response

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28
Q

Plasma proteins

A

Plasma proteins have an osmotic effect, where they give the blood in capillaries a high solute potential (so a low water potential) compared to surrounding fluid, and so water moves into blood in the capillaries from surrounding fluid by osmosis

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29
Q

Oncotic pressure definition

A

Oncotic pressure is the tendency of water to move into the blood by osmosis (about -3.3kPA)

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30
Q

Hydrostatic pressure definition

A

Hydrostatic pressure - blood being under pressure due to blood surges that occur when the heart contracts

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31
Q

Movement of tissue fluid

A

-Hydrostatic pressure at the arterial end of the capillary is higher than oncotic, so fluid leaves out of the capillaries
-Hydrostatic pressure falls as the venous end as fluid has moved out and the pulse is lost. As the oncotic pressure is higher (still -3.3kPA), water moves back into the capillaries

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32
Q

Lymph

A

Lymph - 10% of tissue fluid leaves the blood vessels and drains into a system of blinded tubes called lymph capillaries
-Similar in composition to plasma and tissue fluid but have less oxygen and fewer nutrients, and contains fatty acids

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33
Q

Lymph nodes

A

Lymph nodes are found along the lymph vessels. Lymphocytes build up in these nodes when necessary and produce antibodies which are passed into blood
-Lmpyh nodes are enlarged - sign that the body is fighting off invading pathogens

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34
Q

Erythrocyte adaptations

A

Adaptations of erythrocytes:
-Biconcave shape - large surface area + helps them to pass through narrow capillaries
-Lack of nuclei = maximises space for haemoglobin (however this limits their life to 120 days in the bloodstream)

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35
Q

Haemoglobin makeup

A

Haemoglobin:
4 polypeptide chains - each with iron-containing haem prosthetic group - each binds to an oxygen molecule

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36
Q

Oxygen + haemoglobin

A

Oxygen + haemoglobin = oxyhaemoglobin

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37
Q

Positive cooperativity / cooperative binding

A

Positive cooperativity / cooperative binding : Arrangement of the haemoglobin molecule allows them to bind to oxygen molecules and then change shape, making it easier for the next oxygen molecule to bind

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38
Q

Effect of a drop in oxygen levels in respiring tissues

A

Effect of a drop in oxygen levels in respiring tissues:
Oxygen will release rapidly from haemoglobin to diffuse into the respiring cells
-This effect is enhanced by the low pH in the tissues compared with the lungs

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39
Q

Effect of increasing haemoglobin saturation with oxygen

A

As haemoglobin becomes increasingly saturated with oxygen, the partial pressure increases, and more oxygen is picked up

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40
Q

What happens to oxygen carried in the erythrocytes for when you aren’t active?

A

When you aren’t active, 25% of oxygen carried in the erythrocytes is released into the body cells and the rest acts a reservoir when the body demands increase suddenly

41
Q

Bohr effect

A

Bohr effect - carbon dioxide partial pressure increases, and so haemoglobin gives up more oxygen more easily

42
Q

Result of the bohr effect

A

Result of the bohr effect:
-In active tissues with a high partial pressure of carbon dioxide, haemoglobin gives up its oxygen more rapidly
-In the lungs where the proportion of carbon dioxide in the air is relatively low, oxygen binds to the haemoglobin molecules more easily

43
Q

Fetal haemoglobin

A

Fetal haemoglobin has a high affinity for oxygen, so it removes oxygen from the maternal blood as their blood moves past eachother

44
Q

3 different ways that carbon dioxide is transported from the tissues to the lungs

A

3 different ways that carbon dioxide is transported from the tissues to the lungs:
-5% = dissolved in plasma
-10-20% = combined with amino groups in the polypeptide chains of haemoglobin = forms carbaminohaemoglobin
-75-80% = converted into hydrogen carbonate ions in the cytoplasm of rbc

45
Q

Formation of carbonic acid

A

Carbon dioxide reacts slowly with water to form carbonic acid, increased by the aciton of carbonic anhydrase

46
Q

Dissociation of carbonic acid

A

Carbonic acid partially dissociates to form hydrogen ions and hydrogen carbonate ions

47
Q

Chloride shift

A

The chloride shift is when negatively charged hydrogen carbonate ions move out of erythrocytes into plasma by diffusion, and so negative chloride ions move into erythrocytes to maintain the electrical balance

48
Q

Effect of removing carbon dioxide and converting it into hydrogen carbonate ions

A

Removing carbon dioxide by converting it into hydrogen carbonate ions maintains a steep concentration gradient for carbon dioxide to diffuse from respiring tissues into erythrocytes

49
Q

Haemoglobonic acid

A

Haemoglobin acts as a buffer and prevents changes in the pH by accepting free hydrogen ions in a reversible reaction to form haemoglobonic acid

50
Q

Cardiac muscle

A

Cardiac muscle is what the heart is made up of, and contracts and relaxes in a regular rhytm involuntarily

51
Q

Coronary arteries

A

Coronary arteries supply the cardiac muscle with oxygenated blood to keep it contracting and relaxing all the time

52
Q

Role of the inelastic pericadial membranes that surround the heart

A

The inelastic percadial membranes helps prevent the heart from over-distending (expand/enlarge) with blood

53
Q

Why does the left side of the heart have more muscular walls than the right side of the heart?

A

The left side of the heart has to produce sufficient force to overcome the resistance of the aorta and move the blood under pressure to the whole of the body

54
Q

Why is the foremen ovale open in the fetus before birth?

A

The foremen ovale is open in the fetus before birth as their lungs are not yet functioning, and so blood is not completely oxygenated, meaning the blood mixes freely in the heart

55
Q

Atrial systole

A

Atrial systole:
-Both atria contract, increasing the blood pressure
-This causes the atrioventricular valves to open and the semilunar valves close
-When these valves open, blood is forced in to the ventricles

56
Q

Ventricular systole

A

Ventricular systole:
-Blood pressure inceases in the ventricles as blood enters from the atria and through the atrioventricular valves
-As pressure is higher infront of the AV valves, they close, and the semilunar valves open
-Blood leaves through the semilunar valves and through either the aorta (left) or the pulmonary artery (right)

57
Q

Diastole

A

In diastole, the atria and ventricles relax. The blood starts to fill the heart, and the volume/pressure of blood increases

58
Q

How can we hear the sounds of the heart beating

A

Sounds of the heart beating is caused by the blood pressure closing the heart valves (lub-dub)
-Lub = blood forced against the av valves as the ventricles contract
-Dub = Backflow of blood closing the semilunar valves

59
Q

Why is cardiac muscle myogenic?

A

Cardiac muscle is myogenic as it doesn’t require action of nerve cells and beats involuntarily

60
Q

Action of the sino-atrial node (SAN)

A

The SAN sends a wave of depolarisation, causing the atria to contract and therefore initiating the heartbeat

61
Q

Action of the atrio-ventricular node (AVN)

A

The AVN picks up the wave of depolarisation, imposing a slight delay before stimulating the bundle of His

62
Q

Wave of electrical depolarisation in the heart

A

Wave of electrical depolarisation in the heart:
1) Wave of electrical depolarisation initiated by SAN, causes atria to contract
2) Wave picked up by AVN, imposing a slight delay before stimulating the bundle of His
3) Electrical activity passed to the apex of the purkyne fibres and triggers the ventricles to contract

63
Q

Bundle of His

A

The bundle of His is a bundle of conducting tissue made up of purkyne fibres

64
Q

Function of an ECG

A

ECG measures the electrical acitivty of the heart by measuring the tiny electrical differences in your skin

65
Q

Tachycardia

A

Tachycardia - rapid heartbeat above 100bpm (often normal eg due to exercise)

66
Q

Bradycardia

A

Bradycardia - heart rate slows down to below 60bpm (usually due to being fit, but can be severe and may require an artificial pacemaker)

67
Q

Ectopic heartbeat

A

Ectopic heartbeat - extra heartbeats that are out of the normal rhythm

68
Q

Atrial fibrillation

A

Atrial fibrillation - examples of arrhythmia - abnormal rhythm of the heart - rapid electrical impulses in atria, but they don’t contract properly so only some of the impulses are passed on to the ventricles, so the heart doesn’t pump effeciently

69
Q

Hepatic portal vein

A

In the hepatic portal vein, blood does not go straight back to the heart, as it allows blood from gut to flow to liver

70
Q

Myogenic contraction

A

Myogenic contraction: myocytes (muscle cells) in the heart has polarized charge across their membrane
-Reversing the charge (depolarizing) causes contraction

71
Q

Cardiac output calculation

A

Cardiac output = stroke volume x heart rate

72
Q

Varicose veins

A

Varicose veins: weakened vein wall causes valves to not close properly > backflow of blood > vein becomes enlarged and bumpy

73
Q

How to measure heart beats on an ECG diagram

A

How to measure heart beats on an ECG diagram:
-One square = 0.2s
-Measure time between start of one P wave (of atrial systole) to the start of the next P wave. Divide 60 by this number.

74
Q

P,Q,R,S,T waves on ECG

A

P wave = Atrial systole
QRS = Ventricular systole
T = diastole

75
Q

Stroke volume

A

Stroke volume is the volume of blood pumped out of a ventricle in each contraction
-Measured in cm cubed

76
Q

Cardiac output unit

A

Cardiac output = Cm cubed per min

77
Q

Differences between the circulation systems of mammals and fish

A

Differences between the circulation systems of mammals and fish:
-Mammals: Systemic+Pulmonary circuit (double), blood is maintained at higher pressure, blood passes through one set of capillaries
-Fish: Single system, blood pressure is maintained at lower pressure, blood passes through to sets of capillaries

78
Q

Difference between the structure of arteries, veins and capillaries

(note: include their functions in an exam question)

A

-Arteries: Lots of collagen for structural support, lots of smooth muscle that contracts and relaxes to control blood pressure
-Veins: More collagen than arteries to give structural support as they carry larger volume of blood, thicker lumen
-Capillaries: Lumen diameter slightly large than rbc to ensure they travel in single file, and to increase contact of rbc with capillary walls

79
Q

Why do veins have a thicker lumen?

A

Veins have a thicker lumen to reduce resistance and friction, so to maintain a constant flow of blood to the heart

80
Q

Why do arteries have a smaller lumen than veins?

A

Arteries have a smaller lumen to maintain their blood pressure (high)

81
Q

Difference between the circulatory systems of amphibians (eg frogs) and humans

A

-Amphibians (eg frogs): Blood is mixed in the heart, single circulatory systems, less effective circulation as there is less oxygen for body cells
-Humans: Blood is separate in heart, double circulatory system, cells get more oxygen for cells, blood never mixes as it is separates in the lungs

82
Q

Why does the oncotic pressure of the blood rely only on the concentration of plasma proteins?

A

Oncotic pressure of the blood relies only on the concentration of plasma proteins because:
-Large plasma proteins cannot pass through capillary wall
-Imbalance of large plasma proteins between blood and tissue fluid results in the oncotic pressure

83
Q

Effect of reducing plasma albumin concentration

A

Reducing plasma albumin concentration will decrease the oncotic pressure which increases the net movement of fluid

84
Q

What can cause red, swollen skin?

A

Red, swollen skin can be due to inflammation caused by the increased bloodflow from vasolidation, so that immune cells can go to infected tissue (red). More tissue fluid causes swelling (oedema).

85
Q

What causes the blood to stop when someone is injured ie cut their hand?

A

Exposure of blood/platelets to collagen in damaged blood vessel causes clotting, which prevents bleeding and produces scabs

86
Q

What can cause discomfort under your collarbone/armpit area when injured/infected?

A

Excess tissue fluid drains into lymph vessels , pathogens enter fluid - fluid is transported along lymph system to lymph nodes - activity of phagocytes + lymphocytes causes swelling of lymph nodes (discomfort in collarbone/armpitarea)

87
Q

Similitaries between ultrafiltration of the kidneys and tissue fluid?

A

Similarities between ultrafiltration in the kidneys and tissue fluid:
-Small molecules filtered out blood
-Both occur in capillaries
-High hydrostatic pressure in both processes

88
Q

Differences between ultrafiltration of the kidneys and tissue fluid

A

Differences between ultrafiltration of the kidneys and tissue fluid:
-In the kidneys, molecules are not reabsorbed by capillaries from urine (but will form lymph)
-In ultrafiltration, blood is filtered through three layers wheras in tissue fluid, blood is filtered thorugh one layer
-Knot of capillaries in kidneys, network of capillaries in formation of tissue fluid

89
Q

Visibility of the structures in the heart when there are no atria (in dissection)

A

Visibility of the structures in the heart when there are no atria (in dissection):
- Not visible = AV valve, pulmonary vein, purkyne fibres, SA node, bundle of His
- Visible = Left ventricular walls, Semilunar valve, septum

90
Q

Why is there a higher unloading of oxygen at respiring tissues, causing the curve on oxygen dissociation curves to shift to the right?

A

At respiring tissues > partial pressures of carbon dioxide are high > decreased oxygen affinity > therefore haemoglobin unloads more oxygen

91
Q

Why does the haemoglobin of llamas load up on more oxygen?

A

Llamas - live at high altitutes where partial pressure of oxygen is low > so their haemoglobin has to have a high oxygen affinity to load up on oxygen

92
Q

What is positive cooperativity / co-operative binding of haemoglobin?

A

Positive cooperativity = when one oxygen binds, the quaternary structure of haemoglobin molecules change -> increased affinity of haem groups for oxygen -> binding more molecules requires small increase in partial pressure

93
Q

Animals that have open circulatory systems

A

Most invertebrates (except earthworms, octopuses and squids) have open circulatory systems

94
Q

Effect of superventricular tachycardia (ventricle walls contracting twice after every atrial contraction)

A

less blood leaves the heart; ventricles do not have time to fill before contracting

95
Q

Why erythrocytes can’t enter into capillaries?

A

Erythrocytes are too large to enter through capillary walls; gaps between endothelium cells too small

96
Q

Health definition

A

Health = physical or mental state of an individual; absence of disease

97
Q

How components of tobacco smoke can effect the cardiovascular systems of smokers

A

How components of tobacco smoke can effect the cardiovascular systems of smokers:
-Nicotine = increases stickiness of platelets = blood clot formation = release of adrenaline = constriction of arterioles = reduced blood flow
-Carbon monoxide = combines permanetly with haemoglobin (carboxyhaemoglobin) = reduced oxygen carrying capacity of blood
-Increased heart rate/blood pressure
-Damage to lining/endothelium
-CHD

98
Q

Subunits that the protein of fetal haemoglobin is made up of

A

The protein in fetal haemoglobin is made up two of alpha subunits, and two gamma subunits rather than beta - the gamma subunits increase the haemoglobin’s affinity for oxygen

A-Level Biology🌼 (25 decks)

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