Transport in animals Flashcards

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1
Q

Definition of double circulatory system

A

A system in which the blood flows through the heart twice for each circuit of the body

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2
Q

Describe the fishes circulatory system

A

Fish have a Single circulatory system. The blood takes the route: heart- gills- body- heart.

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3
Q

Define open circulatory system

A

One in which the blood is not held in vessels

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4
Q

Define closed circulatory system

A

One in which the blood is held in vessels

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5
Q

Described and insects circulatory system

A

Insects have an open circulatory system. This means that the blood fluid circulates through the body cavity so that the tissues and cells are directly based in blood

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6
Q

What are the advantages of double circulatory systems in mammals.

A

Higher blood pressure therefore blood can flow quicker. Faster delivery of oxygen and nutrients. Faster removal of carbon dioxide and other wastes.

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7
Q

External features of the heart

A

Two main pumping chambers- ventricles and atria (thinner). Coronary arteries.

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8
Q

Where are the AV valves found and what is there role?

A

There are two atrioventricular valve is the left and the right. In atrial systole blood in the atria pushes the atrioventricular valves open. The valves remain open while the atria contract but close when the atria begin to relax.

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9
Q

Definition of single circulatory system?

A

A system in which the blood flows through the heart once for each circuit of the body.

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10
Q

Where are the semi lunar valves found and what is there role?

A

Found at the base of the major arteries. Ventricular systole raises the blood pressure in the ventricles, once this pressure is above the pressure in the arteries the semilunar valves are forced open. Then during diastole as the ventricle begins to relax the pressure decreases and the semilunar valves are pushed closed.

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11
Q

Structure of an artery

A

Inner layer- elastic tissue allows wall to stretch and recoil
Middle layer- smooth muscle
Outer layer- collage.

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12
Q

Features of arteries?

A

Thick wall to withstand high pressure

Small lumen to maintain high pressure

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13
Q

Features and structure of vein?

A

Large lumen to ease flow of blood
Thinner walls- does not need to stretch and recoil
Contains valves to prevent backflow in opposite direction

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14
Q

Describe arterioles structure and function?

A

Small blood vessels that distribute the blood from an artery to capillaries.
Can constrict to reduce rate of blood flow and divert it.

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15
Q

Describe function of venules?

A

Collects blood from capillary bed and leads into veins.

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16
Q

Structure and function of capillaries?

A

Very thin wall- single layer of flattened endothelial cells. Narrow lumen- 7 micro meters.
Walls are leaky.

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17
Q

What cells does the blood contain?

A

Red blood cells
White blood cells
Platelets

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18
Q

What does tissue fluid not contain?

A

Plasma protein and most of the cells found in the blood. As they are to large

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19
Q

How is tissue fluid formed ?

A

By plasma leaking from the capillaries

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20
Q

What is the function of tissue fluid ?

A

Surrounds the cells in tissues and supplies them with oxygen. By diffusion, facilitated diffusion and active uptake.

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21
Q

What movement is the blood plasma leaking?

A

Mass flow

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22
Q

How does tissue fluid form?

A

Due to the high hydrostatic pressure in the arterial end of the capillary, blood fluid can be pushed out through the gaps in the capillary wall.

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23
Q

Why does tissue fluid only consist of dissolved nutrients and oxygen?

A

Blood cells, platelets and plasma proteins are too large to pass through the gaps in the capillary wall.

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24
Q

How does the tissue fluid exchange gasses and nutrients to body cells?

A

Across the cells plasma membranes, by diffusion, facilitated diffusion and active uptake.

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25
Q

Does tissue fluid return to the capillary?

A

Some as the blood pressure at venous end is much lower.

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26
Q

Does all tissue fluid re- enter the blood?

A

Some tissue fluid is diverted into the lymph system.

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27
Q

What is the job of the tendinous cords?

A

To prevent valves from turning inside out when ventricle walls contract

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28
Q

Why is the left ventricle thick?

A

Walls of left ventricle can be 2/3 times thicker than right ventricle. The left ventricle needs sufficient pressure to overcome the resistance of systemic circulation

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29
Q

What are the cross- bridges function in the cardiac muscle?

A

To ensure the muscle produces a squeezing action.

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30
Q

What is the cardiac cycle?

A

The sequence of events in a heart beat.

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31
Q

Where does heart contraction start?

A

At the apex

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32
Q

What happens at ventricular systole?

A

The ventricles contract.

33
Q

What happens at diastole?

A

The muscular walls of all 4 champers relax. Elastic recoil increases the volume of chambers to allow blood flow from veins to enter.

34
Q

What happens at atrial systole?

A

Right and left atria contract pushing blood into ventricles.

35
Q

Why is the heart muscle described as myogenic?

A

The heart muscle can initiate its own contraction.

36
Q

What is the condition fibrillation?

A

If the contractions of the heart chambers are not synchronises

37
Q

Where is the sino- atrial node found.

A

In the right atrium near the when the vena cava empties blood.

38
Q

Why is the sino- atrial node known as the pacemaker?

A

As it initiates a wave of excitation at regular intervals. Human - occurs 55-80 times a minute.

39
Q

Where is the atrio- ventricular node found?

A

At the top of the interventricular septum

40
Q

How does the sino- atrial node work?

A

Waves of excitation spreads over atrial walls.

When the waves of excitation pass it causes muscle walls to contract.

41
Q

Why is the AVN delayed?

A

To allow time for the atria to finish contracting and blood to flow into ventricles before they contract.

42
Q

How do we monitor electrical activity in the heart?

A

An electrocardiagram

43
Q

What does wave P show?

A

Excitation of atria

44
Q

What does QRS show?

A

The excitation of ventricles

45
Q

What does T show?

A

Diastole

46
Q

How many oxygen molecules can haemoglobin carry?

A

4

47
Q

What is each subunit of heamoglobim made up of?

A

A polypeptide chain and a haem group.

48
Q

What is dissociation?

A

Oxygen being released from oxyhemoglobin

49
Q

What does the haem group have?

A

A high affinity for oxygen

50
Q

What does fetal haemoglobin have?

A

A higher affinity for oxygen as fetal haemoglobin must be able to associate with oxygen where the oxygen tension is low enough for adult haemoglobin to dissociate.

51
Q

How is carbon dioxide transported?

A

Dissolved in the blood plasma- 5%
Combines with haemoglobin- carbaminohaemoglobin- 10%
In hydrogencarbonate ions- 85%

52
Q

What is the Bohr effect?

A

By increasing the carbon dioxide concentration in haemoglobin the hydrogen ions make the cytoplasm more acidic. This change in ph alters the tertiary structure reducing the affinity.

53
Q

How are hydrogencarbonate ions formed- step 1

A

Carbon dioxide in blood plasma diffuses into red blood cells.
Combined with water to make weak carbonic acid
This is catalysed by the enzyme carbonic anhydrase

54
Q

What does affinity mean?

A

A strong attraction

55
Q

Where is fetal haemoglobin found?

A

In the fetus

56
Q

What is oxygen transported in?

A

The red blood cells (erythrocytes)

57
Q

What does the haem group contain?

A

A single iron ion.

58
Q

When does dissociation occur?

A

When the O2 partial pressure is low - tissues

59
Q

How to describe how haemoglobin “picks up oxygen” ?

A

Binds with or association

60
Q

Describe the association of haemoglobin at low oxygen tension?

A

Haemoglobin does not readily associate with oxygen molecules. Due to the haem group being in the centre on the haemoglobin molecule making it difficult for the oxygen molecule to reach.

61
Q

Describe conformational change?

A

How when the first oxygen molecule associated with the haem the shape of the haemoglobin molecule slightly changes to allow more oxygen molecules to enter.

62
Q

Describe the shape of the haemoglobin dissociation curve.

A

S- shaped curve

63
Q

Describe the hydrostatic pressure at places?

A

High in blood plasma

Low in tissue fluid and lymph

64
Q

Describe the oncotic pressure at places?

A

More negative at blood plasma

Less negative at tissue fluid and lymph

65
Q

Why is hydrostatic pressure?

A

The pressure a fluid exerts when pushing against the sides of a vessel?

66
Q

Why do fish not require a double circulatory system?

A

Are not as metabolically active as mammals. Do not need to maintain body temperature.

67
Q

Why must blood pressure not be too high in pulmonary circulation?

A

May damage delicate capillaries

68
Q

Describe the lymph system?

A

Similar to plasma but contains more lymphocytes as these are produced in the lymph nodes.

69
Q

What happens at the lymph system?

A

Excess tissue fluid is drained and returned to the blood system via the subclavian vein.

70
Q

What are the two external features of the heart?

A

Cardiac muscle

Coronary arteries

71
Q

Function of coronary arteries?

A

Supplies oxygenated blood to the heart muscle.

72
Q

Describe structure from inside to out of vein and capillaries?

A
Lumen 
Endothelium
Elastic fibres 
Smooth muscle 
Collagen
73
Q

Differences between veins and arteries?

A

Arteries have smaller lumen- higher pressure

Arteries have thicker walls of smooth muscle and elastic fibres to stretch and recoil.

74
Q

How are hydrogencarbonate ions formed- step 2

A

The carbonic acid dissociates to release hydrogen ions and hydrogen carbonate ions

75
Q

How are hydrogencarbonate ions formed- step 3

A

The hydrogencarbonate ions diffuse out of the red blood cell into the plasma. Chloride ions move into the red blood cell to maintain the cells charge- chloride shift

76
Q

How are hydrogencarbonate ions formed- step 4

A

To prevent the red blood cell from becoming acidic hydrogen ions associate with haemoglobin to produce haemoglobinic acid. The haemoglobin acts as a buffer.

77
Q

What is Ostia?

A

Pores that allow blood from the body to enter the heart in open open circulatory systems

78
Q

What can restricted blood flow?

A

Angina or a heart attack- myocardial infarction