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✅Biology AS Unit 2 > 🔴2.3 Adaptations For Transport In Animals > Flashcards

🔴2.3 Adaptations For Transport In Animals Flashcards

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1
Q

What 3 things do transport systems in animals have to have?

A
  • suitable medium in which to carry materials
  • pump, such as the heart, for moving the blood
  • valves to maintain the flow in one direction
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2
Q

What other features do some transport systems in animals have?

A
  • respiratory pigment in vertebrates and some invertebrates but not insects which increase the volume of oxygen that can be transported
  • A system of vessels with a branching network to distribute the transport medium to all parts of the body
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3
Q

Define an open circulatory system

A

A system where the blood does not move around the body in blood vessels but it bathes the tissues directly while held in a cavity called the haemocoel

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4
Q

What is the haemocoel

A

A large space in the body cavity where the transport medium in an open system is moved to

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5
Q

Name an example of a group of organisms that have open systems

A

Insects

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6
Q

Describe the open circulatory system in an insect

A
  • have a long dorsal tube shaped heart along entire length of the body
  • pumps blood out at low pressure into the haemocoel
  • haemocoel = where materials are exchanged between blood and body cells
  • blood returns slowly to the heart and open circulation starts again
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7
Q

Why do insects not require respiratory pigment?

A

Because oxygen diffuses directly to the tissues from the tracheae so the blood does not need to transport oxygen

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8
Q

Define closed circulatory system

A

The blood in an organism moves in blood vessels.

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9
Q

What are the 2 types of closed circulatory system?

A
  • single circulation

- double circulation

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10
Q

What happens in single circulation

A

The blood moves through the heart once in its passage around the body

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11
Q

Describe the circulation in an earthworm

A

1-blood moves forward in he dorsal vessel and back in the ventral vessel
2-five pairs of ‘pseudo hearts’ (thickened muscular blood vessels) pump the blood from the dorsal to the ventral vessel and keep it moving.

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12
Q

Describe the circulation in fish

A

1) ventricle of the heart pumps deoxygenated blood to the gills
2) pressure falls
3) oxygenated blood is carried to the tissues
4) deoxygenated blood returns to the atrium of the heart
5) blood moves to the ventricle and circulation starts again

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13
Q

What happens in double circulation

A

The blood passes through the heart twice in its circuit around the body

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14
Q

Name an example of an organism with a close circulation system

A

Mammals

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15
Q

Are organs in direct contact with the blood

A

No, but they are bathed by tissue fluid which seeps out of the capillaries

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16
Q

Describe briefly the pressure changes in the heart

A

1- blood pumped by muscular heart at High pressure
2- blood pressure is reduced in the lungs
3-blood returned to the heart raising pressure again to pump it to rest of the body

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17
Q

Describe the circulation type in insects, earthworm, fish and mammals

A 
Insect= open 
Earthworm= closed single
Fish= closed single
Mammal= closed double
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18
Q

Is there respiratory pigment in insects, earthworms, fish and mammals

A 
Insect = no 
Earthworm = yes
Fish = yes 
Mammals = yes
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19
Q

Describe the heart shape/type in insects, earthworms, fish and mammals

A 
Insects = dorsal tube shaped 
Earthworm = ‘pseudohearts’
Fish = 1 atrium and 1 ventricle 
Mammals = 2 atrium and 2 ventricles
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20
Q

LEARN SINGLE CIRCULATION DIARGAM ON PG 183

A

LEARN DOUBLE CIRCULATION DIAGRAM ON PG 183

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21
Q

What does a great metabolic rate require

A

Requires more rapid delivery of oxygen and glucose and more rapid removal of waste such as CO2

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22
Q

What are the two key features of a double circulation system

A

The pulmonary circulation

The systemic circulation

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23
Q

Describe the pulmonary circulation in mammals

A

Pulmonary circulation serves the lungs

1) right side of the heart pumps deoxygenated blood to the lungs
2) Oxygenated blood returns from the lungs to the left side of the heart

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24
Q

Describe the systemic circulation in mammals

A

Systemic circulation serves the body tissues

1) left side of the heart pumps oxygenated blood to the tissues.
2) deoxygenated blood from the body returns to the right side of the heart

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25
Q

Which is more efficient the double circulation of a mammal or single circulation of a fish and why?

A

The double circulation of a mammal because oxygenated blood can be pumped around the body at a higher pressure

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26
Q

What are the 3 types of blood vessels

A

Arteries
Veins
Capillaries

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27
Q

What is the endothelium (in arteries and veins)

A

Innermost layer
One cell thick
Surrounded by the tunica initma

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28
Q

What is the purpose of the tunics intima

A

Smooth lining reducing friction with a minimum resistance to blood flow

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29
Q

What is inside the artery and veins from the centre outwards

A 
Lumen 
Endothelium 
Tunica initma 
Tunica media 
Tunica externa
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30
Q
  • What is the middle layer of the artery/vein

- what does it contain

A

The tunica media

-contains elastic fibres and smooth muscle

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31
Q

Where is the tunica media thicker, the arteries or veins

What does this allow?

A

Thicker in the arteries

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32
Q

What does the elastic fibres in the tunica media allow?

A

Allows stretching to accommodate changes in blood flow and pressure as blood is pumped from the heart

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33
Q

What happens when the elastic fibres in the tunica media recoil?
How can we tell when this occurs and what’s its purpose?

A
  • At certain point stretched elastic fibres recoil pushing blood on through the artery
  • this is felt as the pulse and maintains blood pressure
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34
Q

What regulates blood flow and also maintains blood flow?

A

The contraction of smooth muscle in the tunica media maintains blood flow and the blood pressure as the blood is transported further from the heart

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35
Q

What is the outer layer of veins/arteries called?

What does it contain?

A

Tunica externa

Contains collagen fibres which resist over-stretching

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36
Q

Name the average diameter of arteries, veins and capillaries

A 
Artery = 10mm 
Vein = 6mm 
Capillary = 0.02 mm
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37
Q

Which has a larger lumen, the vein or artery?

Why is this needed?

A

The vein has a larger lumen
-Needed as veins carry deoxygenated blood towards the heart at low pressure :: blood moves slower and often against gravity :: large lumen ensures it’s still transported efficiently

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38
Q

Describe the purpose of arteries

A
  • carry blood away from the heart
  • contain thick, muscular walls
  • branch into smaller vessels called arterioles which further subdivide into capillaries
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39
Q

Why is it essential for artery walls to be thick and muscular

A

To withstand the bloods high pressure, derived from the heart

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40
Q

Describe the purpose of capillaries

A

-form a vast network that penetrates all tissues and organs of the body

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41
Q

How does blood return to the heart

A

Blood from capillaries collects into venules which takes blood into veins which return it to the heart

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42
Q

Why is the blood pressure and flow rate lower in veins than arteries

A

Because they have a lumen with a larger diameter and thinner walls with less muscle than arteries

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43
Q

How does blood return to heart for veins above the heart

A

By gravity

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44
Q

How does blood return to heart for veins below the heart

A

By pressure from surrounding muscles

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45
Q

What valves do veins have along their length?
What does this ensure?
Where are such valves not found?

A
  • Semi lunar valves
  • ensure one directional flow (prevent backflow)
  • not found in arteries except the aorta and pulmonary artery
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46
Q

What can the faulty functioning of valves cause? (Disease)

A

Varicose veins and heart failure

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47
Q

Why is exchange of materials between the blood and tissues efficient?

A

Capillaries are one cell thick (short diffusion distance) and have pores between the cells causing the capillary walls to be permeable to water and solutes.

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48
Q

Why does blood slow down when entering capillaries

Why is this an advantage

A

Because they have a small diameter

-advantage as there is plenty of time for the exchange of materials with surrounding tissue fluid

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49
Q

Why is capillaries being branched an advantage

A

Numerous and highly branched :: large surface area for diffusion

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50
Q

Define myotonic contraction

A

The heartbeat is initiated within the muscle cells themselves, and not dependent on nervous or hormonal stimulation.

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51
Q

What are the names of the thin/thick walled collection chambers in the heart

A

The atria (relatively thin) located above two thicker walled pumping chambers called the ventricles

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52
Q

What does the septum prevent

A

Prevents the mixture of oxygenated and deoxygenated blood

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53
Q

What is cardiac muscle?

A

Specialist muscle only found In the heart with myogenic contraction

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54
Q

What is a benefit of cardiac muscle

A

Never tires :: heart continues to beat unlike voluntary muscles

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55
Q

What is the heart rate in a mammal modified by

A

Nervous (brain) and hormonal stimulation.

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56
Q

Describe the different sections of a heart

A 
Vena Cava 
Right atrium 
Right AV valve (tricuspid) 
Right ventricle 
Left pulmonary artery 
Left pulmonary veins
Left atrium 
Left AV valves (bicuspid) 
Left ventricle 
Aorta 
Semi lunar valves 
Septum 
Chordae tendineae
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57
Q

How does the heart form during embryonic development in mammals?

A

2 separate pumps grow together to form one overall structure the heart

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58
Q

How long does the average heartbeat last?

A

0.8 seconds in an adult

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59
Q

What is the name for a contraction of the atrium and relaxation of the atria

A 
Contraction = atrial Systole 
Relaxation = atrial Diastole
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60
Q

What proportion of the cardiac cycle is diastole occurring?

A

Approx 50%

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61
Q

Describe the 3 stages in the cardiac cycle

A

Atrial systole
Ventricular systole
Diastole

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62
Q

Describe atrial systole

A

Atrium walls contract
blood pressure in the atria increases
Pushes blood through the tricuspid and bicuspid valves down into the ventricles which are relaxed

63
Q

Describe ventricular systole

A

Ventricle walls contract
Increased blood pressure in ventricles
Forces blood up through semi lunar valves out of the heart and into the pulmonary artery/aorta

64
Q

Why does blood not flow back from the ventricles into the atria?

A

Because the bicuspid and tricuspid valves are closed by the rise in ventricular pressure

65
Q

What is the role of the pulmonary artery/aorta?

A

Pulmonary artery= Carries deoxygenated blood to the lungs

Aorta= carries oxygenated blood to the rest of the body

66
Q

What is the name of the sound made by the heart?

What causes it?

A

“Lub dub” sound

Caused by the AV valves and then semi lunar valves closing

67
Q

What is the name of the volume of blood expelled by the heart in one cycle? In one minute?

A

One cycle = stroke volume

One minute = cardiac output

68
Q

What is the cardiac output equation?

A

Cardiac output = stroke volume x heartbeats per minute

69
Q

Describe the diastole

A
  • ventricles relax
  • volume of the ventricles increases and pressure decreases
  • low pressure risks backflow of blood from pulmonary artery/aorta into ventricles
  • tendency of backflow causes the semi-lunar valves to shut preventing backflow
  • atria also relax during diastole so blood from the vena cava/ pulmonary veins enters the atria and cycle continuous
70
Q

Describe the flow of blood through the left side of the heart

A
  1. Left atrium relaxes and receives oxygenated blood from pulmonary vein
  2. When full, the pressure forces open the bicuspid valve
  3. Relaxation of the left ventricle draws blood from the left atrium
  4. Left atrium contracts, pushing the remaining blood into the left ventricle through valve closing it
  5. With left atrium relaxed and bicuspid valve closed, the left ventricle contracts. It’s strong muscular wall exerts High pressure
  6. Pressure pushes blood up out of the heart through the semi lunar valves and into the aorta and closes the bicuspid valve, preventing backflow into the left atrium
71
Q

What do I mean by the phrase “the two sides of the heart work together during the cardiac cycle”

A

The atria contract at the same time, followed millisecond later by the ventricles contracting together

72
Q

What is a heartbeat?

A

The complete contraction and relaxation of the whole heart

73
Q

What happens when the chamber of a heart contacts/relaxes during the cardiac cycle?

A 
Contracts = It empties with blood 
Relaxes = fills with blood again
74
Q

Why do atrial walls have little muscle?

A

Because the blood only has to go to the ventricles

75
Q

Why do ventricle walls have more muscle?

A

Because they need to generate more pressure to send the blood further, either to the lungs (pulmonary vein) or rest of the body (aorta)

76
Q

Why does the left ventricle have a thicker muscular wall than the right ventricle

A

Because the left ventricle has to pump blood all round the body, whereas the right ventricle has only to pump the blood a shorter distance to the lungs

77
Q

How do all veins operate?

A

All close under high blood pressure preventing blood flowing backwards
(Valves close when the blood pressure downstream is higher than the blood pressure upstream)

78
Q

LEARN THE CHANGES IN PRESSURE IN THE HEART DIAGRAM ON PG 187

A

LEARN THE CHANGES IN PRESSURE IN THE HEART DIAGRAM ON PG 187

79
Q

Define the term Sino-atrial node (SAN)

A

An area of the heart muscle I. The right atrium that initiated a wave of electrical excitation across the atria, to generate contraction of the heart muscle.

80
Q

What is the SAN also known as

A

The pacemaker

81
Q

Define the term Atrio-ventricular node (AVN)

A

The only conducting area of tissue in the wall of the heart between the atria and ventricles, through which electrical excitation passes from the atria to conducting tissue in the walls of ventricles

82
Q

Describe in one word the contraction of cardiac muscle

A

Myogenic

83
Q

Describe the role of the SAN in controlling the heartbeat

A

A wave of electrical stimulation arises at the SAN and spreads over both atria, so they contract together

84
Q

Why does the electrical stimulation only spread to the ventricles via the AV node?

A

Because the ventricles are insulated from the atria by connective tissue, except at the AVN

85
Q

Describe the role of the AVN in controlling the heartbeat

A

AVN introduces a delay in transmission of the electrical impulse and then pass the excitation down the nerve bundle of His.

86
Q

Why is there a delay in passing the electrical excitation from the AV node to the bundle of His

A

Because it ensures that he atria are empties before the ventricles contract

87
Q

What happens to the electrical excitation after passing down bundle of Hiss until it reaches the muscles of the ventricle walls?

A

AVN passes excitation down the bundle of His and to the apex of the heart where the excitation is transmitted to the Purkinje fibres in the ventricle walls which carry it upwards through the muscles of the ventricle walls.

88
Q

What happens after the electrical excitation reaches the walls of the ventricles

A

Impulses cause the cardiac muscle In each ventricle to contract simultaneously, from the apex upwards pushing the blood up to the aorta and pulmonary artery, emptying the ventricles completely
Process repeats

89
Q

LEARN CONTRACTION OF HEART DIAGRAM ON PG 188

A

LEARN CONTRACTION OF HEART DIAGRAM ON PG 188

90
Q

What is an Electrocardiogram?

A

A trace of the voltage changes produced by the heart detected by the electrodes on the skin

91
Q

Name the parts of the cardio gram that you are expected to explain

A

P wave
QRS complex
T wave

92
Q

What is the P wave?

A
  • first part of the trace
  • shows the voltage change generated by the sino-atrial node, associated with the contraction (depolarisation) of the atria.
93
Q

Why are p waves smaller than the QRS complex and T waves?

A

Because the atria have less muscle than the ventricles

94
Q

What does the time between the p wave and start of the QRS complex show

A

The time taken for the excitation to spread from the atria to the ventricles through the atria-ventricular node

95
Q

What does the QRS complex show?

A

The depolarisation and contraction of the ventricles

96
Q

Why is the amplitude bigger of the QRS complex than the P wave

A

Ventricles have more muscle than the atria :: amplitude is bigger than the P wave

97
Q

What does the T wave show?

A

Shows the repolarisation if the ventricle muscles.

98
Q

What does the line between the T wave and P wave represent?

A

Called the isoelectric line and is the baseline of trace.

99
Q

What would show is a person has atrial fibrillation (rapid heart)

A

May lack a P wave

100
Q

What would show on an ECG if a person have a heart attack

A

May have a wide QRS complex

101
Q

What would show on an ECG if a person has enlarged ventricle walls

A

May have a QRS complex showing greater voltage charge

102
Q

What causes the changes in height of the ST segment and T wave

A

Insufficient blood being delivered to heart muscle, such as what happens to those with atherosclerosis

103
Q

How to calculate beats per minute

A

1- calculate length of cycle (point to same point on ECG E.g 0.85s)
2- divide 60 by the value of 1 heart beat
E.g 60/0.85 = 71 bpm

104
Q

Where is blood pressure highest?

How does it change?

A

In the aorta and pulmonary artery (large arteries)

It rises and falls rhythmically with ventricular contraction

105
Q

What causes a drop in pressure in the arterioles?

A

Friction between the blood and vessel walls as well as the large total surface area despite their narrow lumen

106
Q

Describe the relationships between pressure and blood flow in arteries and capillaries

A

Higher the blood pressure, faster the blood flows :: both pressure and speed fall as the distance from the heart increases

107
Q

Why is pressure constantly low in the veins

A

Because their pressure isn’t affected by the contraction of ventricles :: remains low

108
Q

Why does blood flow faster in the veins than in the capillaries

A

Because veins have a large diameter lumen :: blood flows faster despite lower pressure

109
Q

As blood does not return the the heart rhythmically what enhances the return to the heart?

A

Blood returns enhanced by massaging effects of muscles around the veins

110
Q

Define blood

A

Blood is a tissue made up of cells (45%) in a solution called plasma (55%)

111
Q

What is another name for a red blood cell

A

Erythrocyte

112
Q

Why are erythrocytes red?

A

Because they contain the pigment haemoglobin

113
Q

What is the main purpose of the haemoglobin in erythrocytes?

A

Transport oxygen from the lungs to the respiring tissues

114
Q

What shape do erythrocytes have, how is this a benefit (2 benefits)

A

Shape = Bioconcave disc
Benefit= surface area is larger so more oxygen diffuses across the membrane
Benefit 2= thin centre reduces the diffusion distance making gas exchange faster

115
Q

Name another advantage of an erythrocytes based on its structure

A 
Structure= no nucleus 
Benefit= more room for haemoglobin, maximising the oxygen that can be carried
116
Q

What is another name for a white blood cell?

What are the two main types of white blood cell?

A

Name = leucocyte
Type 1= granulocytes (contain granular cytoplasm and loved nuclei)
Type 2= lymphocytes (contain clear cytoplasm and spherical nucleus)

117
Q

What to lymphocytes produce?

A

Antibodies and antitoxins

118
Q

What colour is plasma?

What % water is plasma?

A

Colour= pale yellow liquid

% =90% water

119
Q

Describe what is found inside plasma

A

1-solutes (food molecules e.g glucose/amino acids)
2-waste products (e.g urea)
3-hormones
4-plasma protein (antibodies etc)

120
Q

Define the term affinity

A

The degree to which two molecules are attracted to each other

121
Q

Define the term cooperative binding

A

The increasing ease with which haemoglobin binds it’s second and third oxygen molecules as the confirmation of the haemoglobin molecule changes

122
Q

Name the reversible reaction involving haemoglobin in the blood

A

Oxygen + haemoglobin —>< oxyhaemoglobin

4O2 + Hb —>< Hb.4O2

123
Q

Where does haemoglobin associate and dissociate with oxygen for effective oxygen transport

A

Associate= where gas exchange takes place e.g at the alveoli

Disassociate= at respiring tissues such as muscle

124
Q

How can haemoglobin perform association and disassociation

A

It can change its affinity for oxygen because it is able to change shape

125
Q

Describe basic structure of haemoglobin

A

Each haemoglobin molecule contains 4 harm groups each containing an ion of iron

126
Q

How many oxygen molecules can bind to one haemoglobin molecule?

A

One oxygen molecule can bind to each iron ion :: 4 oxygen molecules can bind to each haemoglobin molecule

127
Q

How does the fourth oxygen molecule bind to the haemoglobin if the third does not induce a shape change?

A

A large increase in oxygen partial pressure is required

128
Q

What does the term partial pressure mean?

A

Pressure a gas would exert if it were the only one present e.g atmospheric pressure = 100kPa and oxygen comprises of 21% of atmosphere so it’s pressure = 21 kPa

129
Q

Why does the graph of partial pressure vs saturation of haemoglobin to with oxygen show a sigmoid curve (s shapes curve)

A

At very low partial pressure it is difficult for haemoglobin to bind with oxygen
At high partial pressures of oxygen the percentage saturation of oxygen is very high

130
Q

What does the steep gradients on the oxygen dissociation curve show?

A

Represents the oxygen binding increasingly easily

131
Q

Why does oxygen affinity reduce as partial pressure of oxygen decreases?

A

Because oxygen is readily released meeting respiratory demands

132
Q

If the relationship between oxygen partial pressure and % saturation of haemoglobin with oxygen were linear why would high partial pressure of oxygen be dangerous?

A

Haemoglobin oxygen affinity would be too low and so oxygen would be readily released :: not reach respiring tissues
LOOK ON GRAPH

133
Q

If the relationship between oxygen partial pressure and % saturation of haemoglobin with oxygen were linear why would low partial pressure of oxygen be dangerous

A

Haemoglobin’s oxygen affinity would be too High and oxygen would not be released in respiring tissues
LOOK ON GRAPH

134
Q

Describe the events in the body which cause the oxygen disassociation curve

A
  • red blood cells load oxygen in the lungs where oxygen partial pressure is high
  • haemoglobin is saturated with oxygen
  • cells carry oxygen as oxyhaemoglobin to respiring tissues
  • at respiring tissues partial pressure of oxygen is low because oxygen is used up during respiration
  • oxyhaemoglobin unloads oxygen (dissociation)
135
Q

Why does a foetus have a higher affinity for oxygen than its mothers haemoglobin?

A

Foetus has haemoglobin that differs In two of the four polypeptide chains giving it a higher affinity for oxygen at the same partial pressure

136
Q

Why is the foetus’ % haemoglobin saturation with oxygen higher than the mothers?
Which way does this shift the graph?

A

Their Blood flows close in the placenta :: oxygen transfers to the foetus at any partial pressure :: the percentage saturation of the foetus blood is higher than mothers

Shifts dissociation curve to the left

137
Q

Which direction does the dissociation curve shift when animals live in low oxygen environments e.g lugworm buried in sand/mountain llamas?

A

Shifts to the left

138
Q

Why is the disassociation curve of lugworms shifted to the left of humans?

A

Because it lives in a low oxygen environment and has a low metabolic rate :: haemoglobin need to load oxygen readily and only release it when partial pressure of oxygen is very low

139
Q

Why is the oxygen dissociation curve shifted to the left in mountainous animals?

A

Bearcats haemoglobin has a higher affinity for oxygen at all oxygen pressures :: loads more oxygen in the lungs and only releases oxygen when partial pressure is low in respiring tissues

140
Q

Define the term Bohr effect

A

The movement of the oxygen dissociation curve to the right at higher partial pressures of carbon dioxide, because at a given oxygen partial pressure, haemoglobin has a lower affinity for oxygen

141
Q

What happens when carbon dioxide concentration increases?

Describe how this affects curve?

A

The haemoglobin releases oxygen more readily :: at any oxygen partial pressure the haemoglobin is less saturated with oxygen :: curve moves to the right

142
Q

What is the shift of the oxygen disassociation curve to the right when encountering increasing CO2 called?

A

The Bohr effect

143
Q

What happens when the partial pressure of carbon dioxide is high to efficiency of loading and unloading

A

Haemoglobin has a lower affinity for oxygen :: less efficient at loading oxygen and more efficient at unloading it

144
Q

Name the 3 ways carbon dioxide is transported

A

1- in solution in the plasma (5%)
2- as the hydrogen carbonate ion, HCO3- (approximately 85%)
3- Bound to haemoglobin as carbamino-haemoglobin (10%)

145
Q

Describe how carbon dioxide is transported out of red blood cells into the plasma

A
  1. Carbon dioxide in the blood diffuses into the red blood cell
  2. Carbonic anhydride catalysed the combination of carbon dioxide with water making carbonic acid
  3. carbinic acid dissociates into H+ and HCO3- ions
  4. HCO3- ions diffuse out of the red blood cell into the plasma
  5. Chloride shift occurs
  6. H+ ions cause oxyhaemoglobin to dissociate into oxygen and haemoglobin
  7. H+ ions combine with haemoglobin to form haemoglobinic acid (HHb)
  8. Oxygen diffuses out of the red blood cell into the tissues
146
Q

Describe the chrloride shift

A
  1. To balance the outflow if negative ions and maintain electrochemical neutrality, chloride ions diffuse into the red blood cell from the plasma.
    This is the chloride shift
147
Q

Why does the H+ ions combine with the haemoglobin to form HHb?

A

To remove hydrogen ions and so the pH if the red blood cell does not fall

148
Q

What does the transport of carbon dioxide out of red blood cells and into plasma show us?

A
  • why co2 is carried in the plasma as HCO3 ions
  • The Bohr effect, more CO2 produces more H+ ions so more oxygen is released from oxyhaemoglobin
  • more respiration means more CO2 is present so more oxyhaemoglobin dissociates and provides oxygen to the respiring cells
149
Q

Where does exchange between blood and body cells occur?

A

In the capillaries

150
Q

What moves into cells and what moves interesting blood through capillaries

A

Into cell from blood= plasma solutes and oxygen

Into blood from the cells= carbon dioxide and in the liver urea

151
Q

How are capillaries adapted to allow exchange of materials?

A
  • thin permeable walls
  • large surface area for exchange of materials
  • blood flows very slowly through capillaries allowing for time for exchange of materials
152
Q

What does the plasma, as tissue fluid when going through capillaries supply cells with?

A

Solutes such as glucose, amino acids, fatty acids, salts, hormones and oxygen.

153
Q

What is another purpose of the tissue fluid

A

Removes waste made by the cells

✅Biology AS Unit 2 (5 decks)

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