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A-Level Biology - OCR A > 3.2 Transport In Animals > Flashcards

3.2 Transport In Animals Flashcards

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1
Q

What is a single circulatory system?

A

When the blood is passed through a single circuit.

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2
Q

What do blood vessels need to transport?

A

Nutrients. Oxygen. Carbon Dioxide. Urea

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3
Q

What is in the blood?

A

Plasma. White Blood Cells. Red Blood Cells. Platelets

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4
Q

What is an open circulatory system?

A

When the blood is not contained in vessels and flows freely around the body. Tissues and cells are bathed directly in blood. Some animals require movement to circulate blood.

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5
Q

How does blood circulate in insects?

A

Hemolymph (insect blood) flows freely in the body cavity. A muscular tube located in the dorsal (back) acts as a heart. Blood enters the tube through pores called ostia. The blood moves via peristalsis through the heart and too the head where it pours back into the body cavity.

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6
Q

What are the disadvantages of an open circulatory system?

A

Low blood pressure. Slow blood flow. Circulation reliant on movement.

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7
Q

What is a closed circulatory system?

A

When the blood is contained within a vessel and tissue fluid bathes the tissues and cells instead of blood.

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8
Q

What are the two closed circulatory systems?

A

Single and double circulatory systems.

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9
Q

What are the advantages of a single circulatory system?

A

Less complex. Supplies resources to the body.

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10
Q

What are the disadvantages of a single circulatory system?

A

Slow moving blood reduces oxygen uptake.

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11
Q

What is a double circulatory system?

A

The blood flows in two circuits. From the heart to the gas exchange site (lungs) and back. From the heart to the body and back.

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12
Q

What are the advantages of a double circulatory system?

A

High pressure. Higher blood flow. More rapid delivery of oxygen and nutrients. Rapid removal of carbon dioxide and waste products. Transport is independent of body movement.

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13
Q

What are the disadvantages of a double circulatory system?

A

More complex as it requires two circuits and two sides of the heart.

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14
Q

What is an arteriol?

A

Where the artery splits off and narrows into a capillary.

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15
Q

What is a venual?

A

Where capillaries join together and widen to become a vein.

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16
Q

What is the role of the artery?

A

To carry blood away from the heart. Usually oxygenated.

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17
Q

What are the features of an artery?

A

Small lumen keep blood at a high pressure. Elastic fibers strech and recoil to maintain pressure. Smooth muscle contracts. Collagen provides support to help withstand high pressure.

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18
Q

What are the features of capillaries?

A

Very small lumen - Aprox 1 cell thick. Made of endothelial tissues for a short diffusion distance. Leacky to allow substances to pass through.

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19
Q

What is the role of the capillary?

A

Carry blood to the cells. Reduces flow rate of blood.

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20
Q

What is the role if the veins?

A

Carry blood towards the heart. Usually deoxygenated.

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21
Q

What are the features of veins?

A

Elastic fibers stretch and recoil to maintain blood pressure. Smooth muscle contracts. Collagen provides support. Contain valves. Relatively large lumen. Low blood pressure.

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22
Q

What are the functions of blood?

A

Transport. Defence. Homeostasis. Formation of Lymph. Formation of tissue fluid.

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23
Q

What is tissue fluid?

A

A fluid that is similar to blood and surrounds cells. Contains most of what is found in blood except red blood cells and large proteins. Arrives via capillaries and can leave via the lymphatic system.

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24
Q

What is the function of tissue fluid?

A

It transports oxygen and nutrients from blood cells. Takes waste products to the blood.

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25
Q

What is hydrostatic pressure?

A

The force of a fluid pushing on the walls of the vessel.

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26
Q

What is oncotic pressure?

A

The osmotic effect of a water potential. This moves substances back into capillaries.

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27
Q

Hoe does hydrostatic and oncotic pressure change across a capillary?

A

At the arterial end the blood pressure is high so hydrostatic pressure forces substances our of the capillaries. At the venual end there is a low concentration of substances in the venual so oncotic pressure moves substances back into capillaries by diffusion and osmosis.

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28
Q

Where does tissue fluid drain to?

A

The lymphatic system.

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29
Q

What is the lymphatic system?

A

Passive transport system that has vessels of various diameters. Vessels contain valves to prevent backflow. Muscular contractions in the body force lymph fluid back to lymph vessels. Lymph nodes contain lymphocytes that attack pathogens.

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30
Q

What is diastole and systole?

A

Diastole is the relaxing of heart muscles in the cardiac cycle. Systole is the contracting part of the cardiac cycle.

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31
Q

What are the types of muscle in the heart?

A

Smooth muscle/tissue. Myocardial/cardiac muscle.

32
Q

What are the stages of the cardiac cycle?

A

Atrial Systole. Ventricular Systole. Diastole.

33
Q

What happens in atrial systole?

A

SL valve shut. Artia contract and pressure increases in atria. Pressure is lower in ventricals. AV valves open and blood flows into ventricles. Takes 0.1 seconds.

34
Q

What happens in ventricular systole?

A

AV valve closes. Ventricals contract causing the pressure to increase in ventricals. Lower pressure in aorta and pulmonary artery. SL valve opens and blood flows out of the heart.

35
Q

What happens in diastole?

A

Pressure in ventricals decrease. Semi lunar valves close. All heart muscles relax. Blood flows into atria from vena cava and pulmonary vein.

36
Q

What sound does the heart make?

A

Lub - Dub sound

37
Q

What causes the Lub sound of the heart?

A

Closing of the atrioventricular valves

38
Q

What causes the Dub sound of the heart?

A

Closure of the semilunar valves.

39
Q

What happens to pressure in the atria during the cardiac cycle?

A

Atrial presure is always low due to thin walls. Pressure dips after atrial systole as valves close and walls relax. Atria fill with blood during diastole.

40
Q

What happens to the pressure in the aorta at the start of ventricular systole?

A

Drop in pressure as semi lunar valves open. Followed by rapid increase as ventricals in systole.

41
Q

What happens to the pressure in the aorta after ventricular systole?

A

Sudden drop and rise as blood begins to flow back towards the heart before SL valve is compleatly closed.

42
Q

What is plasma?

A

Fluid in the blood that contains substances.

43
Q

What is the role of plasma?

A

Distribute heat around the body. Contain usefull substances (Glucose. amino acids). Contains waste (Urea. Carbon Dioxide). Transport hormones and plasma proteins. thin center reduces diffusion distance.

44
Q

What are the features of an erythrocyte?

A

Biconcave disk for increased surface area. Flexible to squeeze through capillaries. No nucleus so there is more space for hemoglobin to maximise oxygen carried.

45
Q

What is the role of erythrocytes?

A

Contain Hemoglobin for transport

46
Q

What is the role of hemoglobin?

A

To readily associate with oxygen at respiratory surfaces. And readily dissociate from oxygen at deoxygenated tissues.

47
Q

What allows oxygen to bind to hemoglobin?

A

Iron Ions in hemoglobin attach to the oxygen and give it its high affinity.

48
Q

How does hemoglobins affinity for oxygen change?

A

At low partial pressures there is a low affinity for oxygen. At high partial pressures there is a high affinity for oxygen.

49
Q

How does oxygen attach to hemoglobin?

A

Not all at once. First oxygen molecule binds and distorts the shape - it takes a long time for the first molecule to bind. Once deformed it is easier for the 2nd and 3rd oxygen molecules this is a faster process. As the hemoglobin fills it makes it harder for the 4th one to join.

50
Q

What is the oxygen disassociation curve?

A

The affinity of hemoglobin at different partial pressures. A Sigmoid curve.

51
Q

What creates acidic conditions?

A

Respiring cells release Carbon Dioxide and hydrogen Ions making it acidic.

52
Q

How does the sigmoid curve change in acidic conditions?

A

In acidic conditions the curve shifts to the right.

53
Q

Why is the shift of the sigmoid curve important in acidic conditions?

A

Means that hemoglobin more readily dissociates from oxygen meaning there is more oxygen for respiring cells.

54
Q

What effect does acidity have on hemoglobin?

A

Changes the shape of hemoglobin and means that it is harder for it to bind to oxygen.

55
Q

How is carbon dioxide transported in the body?

A

Some directly in the plasma. Some diffuses into red blood cells. Most binds to hemoglobin and forms carbinohemoglobin.

56
Q

What is the process of oxygen disociating from hemoglobin?

A

CO2 enters the red blood cell and reacts with water to form carbonic acid (H2CO3) in a reaction catalysed by carbonic anhydrase. Hydrogen Ions are released and HCO3 is released into plasma. Cl- Ions move into RBC to establish electroneutrality. H+ Ions bind to hemoglobin and form hemoglobic acid. This causes it to dissociate with oxygen which diffuses into the tissue.

57
Q

What are the different types of hemoglobin?

A

Myoglobin. Foetal hemoglobin. Llama Hemoglobin.

58
Q

Where is myoglobin found?

A

Muscel cells where it acts as an oxygen reserve.

59
Q

What is the advantage of myoglobin?

A

Has a higher affinity for oxygen at all partial pressures so oxymyoglobin will only dissociate when oxygen levels are very low.

60
Q

Where is foetal hemoglobin found?

A

Fetus.

61
Q

What are the advantages of foetal hemoglobin?

A

Higher affinity for oxygen than adult hemoglobin. Helps to maximise oxygen uptake from mothers bloodstream. There is a low partial pressure of oxygen in the placenta as it is lost from the blood before it reaches the placenta.

62
Q

Where is llama hemoglobin found?

A

Llamas

63
Q

What are the advantages of llama hemoglobin?

A

Higher affinity to oxygen compared to lowland animals. Because at high altitudes the partial pressure of oxygen is lower.

64
Q

What causes a heart beat?

A

Sino Atrial (SA) node in the walls of the right atrium acts as a pace maker by sending out regular impulses of electrical activity to the atria walls. This causes both atria to contract. A layer of collagen prevents the signal passing to the ventricals. Atrioventricular (AV) node creates a slight delay before passing the electrical signal to the bundle of His. The electrical activity passes down the bundle of His in the septum to the purkinji fibers in the ventrical walls. The purkinji fibers carry electrical charge up the walls of the ventricals so they contract simultaneously from the bottom up.

65
Q

What is the test for heart rhythm and electrical activity?

A

Electrocardiogram (ECG). Sensors attached to the skin near the heart pick up periods of excitation each time the heart beats. The information is converted to a trace.

66
Q

What are the waves found on the trace?

A

P. Q. R. S. T.

67
Q

What is the P wave on an ECG?

A

The first positive deflection. Caused by excitation of the atria (atrial depolarisation).

68
Q

What is the Q wave in an ECG?

A

The negative deflection after the P wave. Caused by the contraction of the septum.

69
Q

What is the R wave in an ECG?

A

Largest deflection. Upwards. Caused by electrical passing through ventrical walls.

70
Q

What is the S wave in an ECG?

A

Slight downwards deflection straight after R wave. Caused by depolarisation of purkinji fibers.

71
Q

What is the T wave in an ECG?

A

The final positive deflection after the S wave. Caused by diastole where both ventricals depolarise.

72
Q

What is an ectopic heartbeat?

A

An extra heartbeat or a skipped beat. Caused by an early contraction of the atria. In healthy people an occasional ectopic heart beat is usually not an issue.

73
Q

What is bradycardia?

A

A slow heart beat. Leads to insufficient blood supply and can cause symptoms such as dizziness or feeling faint. Caused by problems in the SA node.

74
Q

What is tachycardia?

A

A fast heart beat. Caused by electrical signals firing abnormally. Does not allow the heart to fill up before contracting.

75
Q

What is atrial fibrillation?

A

An irregular heartbeat. Causes the heart to not fully empty this causes clots to form in the left over blood in the Chambers. If these get out they can block vessels and prevent blood flow. If they reach the brain they can cause brain damage.

A-Level Biology - OCR A (16 decks)

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