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Biology > Transport In Animals 3.2 > Flashcards

Transport In Animals 3.2 Flashcards

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1
Q

Define translocation

A

-an energy -requiring process transporting assimilates ,especially sucrose, in the phloem between sources (e.g leaves) and sinks (e.g. roots , meristem))

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2
Q

What are the three main factors that influence the need for a transport system?

A

-size
-metabolic rate
-surface area to volume ratio

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3
Q

Why do very small animals not need a transport system?

A

-as their cells are surrounded by (or are very close to) the environment in which they live
-so diffusion will supply enough oxygen and nutrients to keep the cell alive

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4
Q

Why is size a factor for the need for transport systems in multicellular animals?

A

-the cells inside a large organism are further from its surface- the diffusion pathway is increased
-the diffusion rate is reduced and diffusion is too slow to supply all the requirements
-in addition the outer layers of cells use up the supplies so that less will reach the cells deep inside the body

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5
Q

Why is surface area to volume ratio a factor for the need to have a transport system in multicellular animals?

A

-as small animals have a large surface area to volume ratio so for each gram of tissue in their body they have a sufficient area of the body surface through which exchange can occur
-however, large animals have a smaller surface area to volume ratio so each gram of tissue has a smaller area of body surface for exchange. So sufficient exchange cannot occur across their surfaces

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6
Q

Why is metabolic rate a factor for the need for transport systems in multicellular animals?

A

-as animals need energy for food so that they can move around as well as this releasing energy from food by aerobic respiration requires energy
-so if an animal is very active and has a high metabolic rate it will need a good supplies of oxygen and nutrients

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7
Q

What animal has a single circulatory system?

A

-fish
-the blood takes the following route : heart—> gills—>body—>heart

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8
Q

What is a single circulatory system?

A

-one in which the blood flows through the heart once for each circuit of the body

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9
Q

What circulatory system do mammals have?

A
  • a double circulatory system
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10
Q

What is a double circulatory system?

A

-one in which the blood flows through the heart twice for each circuit of the body

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11
Q

What are the two circuits in a double circulatory system?
What does each one do?

A

-pulmonary circuit-> blood is carried from the heart to the lungs to pick up oxygen
-systematic circuit-> this carries the blood and nutrients around the body to the tissues

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12
Q

What route does the blood take in a double circulatory system ?

A

Heart—>body—>heart—>lungs—>heart

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13
Q

What are the disadvantages of a single circulatory system?

A

-the blood pressure drops as blood passes through the tiny capillaries of the gills
-blood has a low pressure as it flows towards the body and will not flow very quickly
-the rate at which oxygen and nutrients are delivered to respiring tissues, and carbon dioxide and urea is removed is limited

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14
Q

Why does the single circulatory system work for fish and not mammals?

A

-fish are not as metabolically active as mammals (they do not need to maintain their body temperature )
-so they need less energy
-so their single circulatory system delivers sufficient oxygen and nutrients for their needs

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15
Q

In the ________circulatory system of mammals :
-the blood pressure must not be too _____ in the pulmonary circulation as otherwise it may damage the delicate capillaries in the _____
-the ____ can increase the pressure of the blood after is has passed through the _____ , so the blood is under ______ pressure as it flows towards the the body and flows more ________
-the _________ circulation can carry blood at a higher pressure than the __________ circulation

A

-double
-high
-lungs
-heart
-lungs
-higher
-quickly
-systematic
-pulmonary

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16
Q

What is an open circulatory system?

A

-one in which the blood is not held in vessels
-insects have an open circulatory system

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17
Q

How is blood pumped in insects open circulatory systems?

A

-the tubular heart in the abdomen pumps haemolymph (blood ) into the dorsal vessel (one main blood vessel in insects)
-the dorsal vessel delivers the haemolymph into the haemocoel (body cavity)
-haemolymp surrounds the organs and eventually reenters the heart via one-way valves called ostia
-the heart pumps blood to the head by peristalsis

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18
Q

How are insects able to survive with open circulatory systems?

A

Insects are able to survive with this less efficient circulatory system because oxygen is delivered directly to their tissues via tracheae (a system of tubes) that connect directly to the outside

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19
Q

What are 2 disadvantages to open circulatory systems?

A

-blood pressure is low and blood flow is slow
-circulation of blood may be affected by body movements or lack of body movements

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20
Q

What is a closed circulatory system?

A

-one in which the blood is held in vessels

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21
Q

What are the advantages of closed circulatory systems over open circulatory systems ?

A

-higher pressure so that blood flows more quickly
-more rapid delivery of oxygen and nutrients
-more rapid removal of carbon dioxide and other wastes
-transport is independent of body movements

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22
Q

What is the function of arteries?

A

-to carry blood away from the heart to the rest of the body

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23
Q

What is the function of arterioles?

A

-they are small blood vessels that distribute blood from an artery to the capillaries

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24
Q

What is the function of capillaries ?

A

-allow exchange of materials between the blood and tissue fluid

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25
Q

What is the function of venules?

A

-small blood vessels that collect blood from capillaries and lead into veins

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26
Q

What is the function of veins?

A

-carry blood back to the heart

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27
Q

What is the structure of arteries?

A

-artery wall is thick to withstand high pressure from the blood coming from the heart
-small lumen to maintain a high pressure, the inner wall is folded to allow the lumen to expand as blood flow increases

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28
Q

What do the 3 layers of an artery wall consist of?

A

-inner layer (tunica intima)- consists of a thin layer of elastic tissue which allows the wall to stretch and then recoil to help maintain blood pressure
-middle layer (tunica media)- consists of a thick layer of smooth muscle
-outer layer (tunica adventitia)- a thick layer of collagen and elastic tissue to provide strength to withstand the high high pressure, and recoil to maintain the pressure

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29
Q

What is the structure of the walls of arterioles and how does it relate to their function?

A

-contain a layer of smooth muscle
—>contraction of this muscle will constrict the diameter of the arteriole this increases resistance to flow and reduces the rate of flow of blood. Constriction of the arteriole wall can be used to divert the flow of blood to regions of the body that are demanding more oxygen

30
Q

What is the structure of capillaries and how does it relate to their function?

A

-the lumen is very narrow- its diameter is the same as that of a red blood cell. The red blood cell may be squeezed against the walls of the capillary as they pass along it. This helps transfer oxygen as it reduces the diffusion path to the tissues, also it increases resistance and reduces rate of flow
-the walls consist of a single layer of flattened epithelial cells- reduces diffusion distance for the materials being exchanged
-the walls are leaky-allows blood plasma and dissolved substances to leave the blood

31
Q

What is the structure of a venule wall?

A

-consists of thin layers of muscle and elastic tissue outside the endothelium and a thin outer layer of collagen
-large lumen

32
Q

What is the structure of veins and how does it relate to their function ?

A

-lumen is large- to ease the flow of blood (reduce friction)
-walls have thinner layers of collagen, smooth muscle and elastic tissue than in artery walls (veins tunica media is much thinner) - as they do not need to stretch and recoil they don’t have to withstand high pressure, also they do not need to actively constrict to reduce blood flow
-contain valves- prevent back flow of blood -as their walls are thin, veins can be flattened by the action of the surrounding skeletal muscle. Contraction of surrounding skeletal muscle applies pressure to the blood ,forcing the blood to move along in a direction determined by valves

33
Q

What is blood?

A

-the fluid used to transport materials around the body

34
Q

What is hydrostatic pressure?

A

-the pressure that a fluid exerts when pushing against the sides of a vessel or container

35
Q

What is lymph?

A

-the fluid held in the lymphatic system, which is a system of tubes that returns excess tissue fluid to the blood system

36
Q

What is oncotic pressure?

A

-the pressure created by the osmotic effects of the solutes

37
Q

What is plasma?

A

-the fluid portion of the blood

38
Q

What is tissue fluid?

A

-the fluid surrounding the cells and tissues

39
Q

What happens to the tissue fluid that is not returned to the blood?

A

-remaining tissue fluid that is not pushed back into the capillaries is carried back via the lymphatic system
-the lymphatic system contains lymph fluid ,similar in content to tissue fluid, but lymph fluid contains less oxygen and nutrients compared to tissue fluid as its main purpose is to carry waste products
-lymph fluid contains more lymphocytes as these are produced in the lymph nodes
-lymphatic system drains excess fluid out of the chest and returns it to the blood system in the subclavian vein in the chest, lymph is transported through lymph vessels by muscle contarction

40
Q

How is tissue fluid formed?

A

At the arteriole end of capillaries:
1-A high hydrostatic pressure, exerted by the force of the heart pumping, forces fluid out of capillaries. By mass flow
2-This forms tissue fluid surrounding body cells.

At the venule end of capillaries:
1-The hydrostatic pressure is lower.
2-Proteins in blood exert a high oncotic pressure, a type of osmotic pressure, in capillaries.
3-The water potential is lower in capillaries than in tissue fluid due to fluid loss.
4-Some tissue fluid moves back into capillaries by osmosis.

41
Q

What are the differences in composition of blood, tissue fluid and lymph?

A

Blood
-high hydrostatic pressure
-a more negative oncotic pressure
-composed of- plasma, red blood cells, white blood cells (lymphocytes and neutrophils), platelets and plasma proteins
-it is transported in lipoproteins

Tissue fluid
-low hydrostatic pressure
-a less negative oncotic pressure than blood
-composed of no red blood cells, fewer proteins , fewer white blood cells (some neutrophils in infected areas)

Lymph
-low hydrostatic pressure
-a less negative oncotic pressure than blood
-composed of less oxygen and nutrients, more fatty acids more white blood cells (lymphocytes), fewer proteins

42
Q

What are the three main ways carbon dioxide is transported?

A

-a very small percentage of carbon dioxide dissolves directly in the blood plasma and is transported in solution
-carbon dioxide can bind to Haemoglobin forming carbaminohaemoglobin
-a much larger percentage of carbon dioxide is transported in the form of hydrogen carbonate ions (HCO3-)

43
Q

How do hydrogen carbonate ions form?

A

-Carbon dioxide diffuses from the plasma into red blood cells
-Inside red blood cells carbon dioxide combines with water to form H2CO3 (a weak acid called carbonic acid)
CO2 + H2O ⇌ H2CO3
-this reaction is catalysed by an enzyme called carbonic anhydrase
-carbonic acid dissociates readily into H+ and HCO3- (hydrogen carbonate ions)
H2CO3 ⇌ HCO3- + H+
-heamoglobin acts as a buffer (a compound that maintains a constant pH) as hydrogen ions can combine with heamoglobin forming heamoglobinic acid (HHb) and this prevents the H+ ions from lowering the pH of the red blood cell
-The hydrogen carbonate ions diffuse out of the red blood cell into the blood plasma where they are transported in solution

44
Q

What is the chloride shift?

A

-Negatively charged hydrogen carbonate ions formed from the dissociation of carbonic acid are transported out of red blood cells via a transport protein in the membrane
-To prevent an electrical imbalance, negatively charged chloride ions are transported into the red blood cells via the same transport protein
-If this did not occur then red blood cells would become positively charged as a result of a buildup of hydrogen ions formed from the dissociation of carbonic acid

45
Q

Define the chloride shift

A

-the movement of chloride ions into the erythrocytes to balance the charge as hydrogencarbonate ions leave the cell

46
Q

What is the Bohr effect?

A

-carbon dioxide enters the red blood cells forming carbonic acid which dissociates to release hydrogen ions. The hydrogen ions affect the pH of the cytoplasm ,making it more acidic
-as haemoglobin is a protein changes in the pH can affect the tertiary structure. The increased acidity alters the tertiary structure of the haemoglobin and reduces the affinity of the haemoglobin for oxygen
-the haemoglobin will therefore have a lower affinity for oxygen at higher partial pressures of carbon dioxide causing oxygen to be released e.g at respiring cells
-at the lungs partial pressures of carbon dioxide is low this increases the affinity of haemoglobin for oxygen so oxygen is readily associated to haemoglobin

47
Q

What does an increase to the partial pressures of carbon dioxide do to the oxygen disassociation curve?

A
48
Q

What is an electrocardiogram?

A

-a trace that records the electrical activity of the heart

49
Q

What does each part of the ECG show?

A

P wave- caused by depolarisation of the atria which results in atrial contraction (systole )
QRS complex- caused by the depolarisation of the ventricles, which results in ventricular contraction (systole).This is the largest wave because the ventricles have the largest muscle mass
T wave-caused by repolarisation of the ventricles which results in ventricular relaxation diastole

50
Q

What heart problem does this ECG show?

A

-Tachycardia -the heart is beating too fast as shown by the peaks being too close together
-resting heart rate is more than 100bpm

51
Q

What heart problem does this ECG show?

A

-Bradycardia
-the heart is beating too slowly as shown by the peaks being too far apart
-resting heart rate is below 60bpm
-a lot as fit individuals or athletes have this and it is usually not dangerous

52
Q

What heart problem does this ECG show?

A

-Ectopic heart beat
-this condition is caused by an early heartbeat followed by a pause
-the patient often feel as a heartbeat has been missed
-common in population and does not require treatment unless severe

53
Q

What heart problem does this ECG show?

A

-Fribillation
-an irregular heartbeat will disrupt the rhythm of the heart
-severe cases of fibrillation can be very dangerous even fatal

54
Q

Describe atrial systole

A

-walls of atria contract- atrial volume decreases, atrial pressure increases
-the pressure in the atria rises above that in the ventricles, forcing atrioventricular valves open
-blood is forced into ventricles-there is a slight increase in ventricular pressure and chamber volume as the ventricles receive the blood from the atria
-the ventricles are relaxed at this point: ventricular diastole coincides with atrial systole

55
Q

Describe ventricular systole

A

-walls of the ventricles contract-ventricular volume decreases, ventricular pressure increases
-the pressure in the ventricles rises above that in the atria -forces atrioventricular valves to close preventing back flow of blood
-pressure in ventricles rises above that in the aorta and pulmonary artery-this forces the semilunar valves open so blood is forced into the arteries and out of the heart
-during this the atria are relaxing :atrial diastole coincides with ventricular systole
-blood flow into heart continues so replaxed atria begin to fill with blood again

56
Q

Describe diastole

A

-the ventricles and atria are both relaxed
-the pressure in the ventricles drops below that in the aorta and pulmonary artery, forcing semilunar valves to close
-the atria continue to fill with blood -blood returns to the heart via the vena cava and pulmonary vein
-pressure in the atria rises above that in the ventricles forcing atrioventricular valves open
-blood flows passively into the ventricles without need of atrial systole
-the cycle begins again with atrial systole

57
Q

What is the equation for cardiac output?

A

Cardiac output= heart rate x stroke volume

58
Q

What is myogenic muscle?

A

-muscle that can initiate its own coordination

59
Q

What is Purkyne tissue?

A

-consists of specially adapted muscle fibres that conduct the wave of excitation from the AVN down the septum to the ventricles

60
Q

What is the Sino-atrial node (SAN)?

A

-the heart’s pacemaker
-it is a small patch of tissue that sends out waves of electrical excitation at regular intervals in order to initiate contractions

61
Q

What is heart muscle described as?

A

-it is myogenic-it can initiate its own contraction

62
Q

Why does the heart need a mechanism that can coordinate the contractions of all 4 chamber?

A

-as the muscles from the atria and the muscles from the ventricles each have their own natural frequency for contraction
-atrial muscle tends to contract at a higher frequency than the ventricular muscle
-this would cause inefficient pumping if the contractions of the chambers are not synchronised (a condition called fibrillation )
-so the heart needs a mechanism that can coordinate the contractions of all 4 chambers

63
Q

How is heart action initiated and controlled?

A

-the sino-atrial node initiates a wave of excitation at regular intervals
-the wave of excitation quickly spreads over the walls of both atria
-it travels along the membranes of the muscle tissue
-as the wave of excitation passes it causes the cardiac muscle cells to contract-this is an atrial systole
-the tissue at the base of the atria is unable to conduct the wave of excitation and so it cannot spread directly down to the ventricle walls
-the atrio-ventricular node (at the top of the interventricular septum) is the only route that can conduct the wave of excitation through to the ventricles, the wave of excitation is delayed at this node -allows time for atria to finish contracting and for the blood to flow down into thr ventricles before they can begin to contract
-after this short delay , the wave of excitation is carried away from AVN and down Purkyne tissue (specialised conducting tissue )
-this runs down interventricular septum
-at the base of the septum the wave of excitation spreads out over the walls of the ventricles
-as the excitation spreads upwards from the base (apex) of the ventricles it causes the muscles to contract-means that ventricles contract from the base upwards
-this pushes blood up towards the major arteries at the top of the heart

64
Q

What is affinity?

A

-a strong attraction
-“haemoglobin has a high affinity for oxygen”

65
Q

What is haemoglobin?

A

-the red pigment used to transport oxygen in the blood

66
Q

What is the equation for when haemoglobin binds with oxygen?

A

Haemoglobin + oxygen —-> oxyhaemoglobin

67
Q

What is the structure of haemoglobin

A

Haemoglobin is a water soluble globular protein which consists of two alpha and two beta polypeptide chains each containing a haem group. It carries oxygen in the blood as oxygen can bind to the haem (Fe2+)group and oxygen is then released when required. Each molecule can carry four oxygen molecules.

68
Q

How does haemoglobin’s affinity for oxygen change?

A

The affinity of haemoglobin for oxygen varies depending on the partial pressure of oxygen which is a measure of oxygen concentration. The greater the concentration of dissolved oxygen in cells the greater the partial pressure. Therefore, as partial pressure increases, the affinity of haemoglobin for oxygen increases, that is oxygen binds to haemoglobin tightly.
This occurs in the lungs in the process known as loading. During respiration, oxygen is used up therefore the partial pressure decreases, thus decreasing the affinity of oxygen for haemoglobin. As a result of that, oxygen is released in respiring tissues where it is needed.
After the unloading process, the haemoglobin returns to the lungs where it binds to oxygen

69
Q

Does saturation have an effect on haemoglobin’s affinity for oxygen?

A

Saturation can also have an effect on affinity, as after binding to the first oxygen molecule, the affinity of haemoglobin for oxygen increases due to a change in shape (conformational change), thus making it easier for the other oxygen molecules to bind.

70
Q

How is the fetal haemoglobin oxygen disassociation curve different to the adult one?

A

-it is to the left of the curve for adult haemoglobin
-as Fetal haemoglobin has a different affinity for oxygen compared to adult haemoglobin, as in needs to be better at absorbing oxygen because by the time oxygen reaches the placenta, the oxygen saturation of the blood has decreased. Therefore, fetal haemoglobin must have a higher affinity for oxygen in order for the foetus to survive at low partial pressure.

Biology (13 decks)

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