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Alevel Biology > 3.1 > Flashcards

3.1 Flashcards

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1
Q

Exchange surface

A

Place that substances move across membranes into an organism

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2
Q

Squamous tissue

A

Single layer of flat cells in contact with one of the two layers of the basement membrane

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3
Q

Epithelium

A

Thin tissue forming the outer layer of bodies surface and lining the alimentary canal and other hollow structures

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4
Q

Villi

A

Can be found in small intestines and increase its surface area to help more nutrients enter blood stream

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5
Q

Concentration gradient

A

Difference in the concentration of a substance between two areas

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6
Q

Surfactant

A

A substance which tends to reduce the surface tension of a liquid in which it is dissolved

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7
Q

Inspiration

A

Breathing in / inhaling

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8
Q

Expiration

A

Exhaling from lungs

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9
Q

Diffusion

A

Net movement of particles down a concentration gradient, it is passive

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10
Q

Surface area to volume ratio

A

Surface area of organism divided by its volume expressed as a ratio

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11
Q

What are alveoli?

A

Tiny folds of the lung epithelium to increase SA

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12
Q

What are bronchi and bronchioles

A

Smaller airways leading into lungs

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13
Q

What is a diaphragm

A

Layer of muscle beneath lungs

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14
Q

Intercostal muscle

A

Muscles between the ribs

Contraction of external intercostal muscles raises rib cage

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15
Q

What is trachea

A

Main airway leading from back of mouth to lungs

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16
Q

Ventilation

A

Refreshing of air in lungs so there is higher oxygen concentration than in blood and lower carbon dioxide concentration

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17
Q

Cartilage

A

Form of connective tissue

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18
Q

Ciliated epithelium

A

A layer of cells that have many cilia

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19
Q

Elastic fibres

A

Protein fibres that can deform and recoil to their original size

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20
Q

Goblet cells

A

Cells that secrete mucus

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21
Q

Smooth muscle

A

Involuntary muscle that contracts without need of conscious thought

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22
Q

Exchange surface

A

Place that substances move across membranes in an organism

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23
Q

Squamous tissue

A

Single layer of flat cells in contact with one of the two layers of basement membrane

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24
Q

Epithelium

A

Thin tissue forming the outer layer of a body’s surface and lining alimentary canal and other hollow structures

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25
Q

Villi

A

Can be found in small intestines and increase their SA to help more nutrients into blood

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26
Q

Surfactant

A

A substance which tends to reduce surface tension of a liquid in which it is dissolved

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27
Q

Concentration gradient

A

Difference in concentration in a substance between two areas

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28
Q

Inspiration

A

Inhaling breathing in

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29
Q

Exhalation

A

Exhaling from lungs

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30
Q

Breathing rate

A

Number of breaths per minute

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31
Q

Oxygen uptake

A

Volume of oxygen absorbed by lungs in one minute

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32
Q

Tidal volume

A

Volume of air inhaled or exhaled in one breath at rest

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33
Q

Spirometer

A

Device which can measure movement if air in and out of lungs

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34
Q

Vital capacity

A

Greatest volume of air that can be expelled from the lungs after taking deepest breath possible

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35
Q

Buccal cavity

A

The mouth

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36
Q

Countercurrent flow

A

Where two fluids flow in opposite directions

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37
Q

Filaments

A

Slender branches of tissue that make up gill. Often called primary lamellae

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38
Q

Lamellae

A

Secondary lamellae, folds the filament to increase surface area, so are called gill plates

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39
Q

Operculum

A

A bony flap that covers and protects the gills

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40
Q

Spiracle

A

An external opening or pore that allows air in or out of tracheae

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41
Q

Tracheal fluid

A

Fluid found at end of tracheoles in tracheal system

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42
Q

Tracheal system

A

A system of air filled tubes in insects

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43
Q

How do singles felled organisms (amoeba, bacteria, Protozoa) and small organisms (flat worms) exchange materials across their membranes

A

By diffusion

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44
Q

What do single felled organisms have to ensure exchange surface is adequate for diffusion

A

Large SA:V ratio

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45
Q

Do smaller or larger organisms have larger SA:V ratio

A

Smaller, the bigger the organism the smaller the SA:V ratio

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46
Q

Why can’t large organisms get nutrients via diffusion

A

Nutrients and gases have a greater distance to travel and outer surface isn’t sufficient for nutrients and gases to enter body fast enough to keep cells alive

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47
Q

What materials and toxic waste to large organisms need and expel

A

Heat-large number of cells undergoing metabolism,
Waste must be rapidly removed to prevent enzymes denaturing,
Cells are distant from external environment and have to cross many barriers and travel long distances

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48
Q

Why do large organisms need intestines and lungs and circulatory system

A

Materials can’t diffuse quick enough so need specialised surfaces, intestines absorb digested nutrients, alveoli in lungs for gas exchange

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49
Q

Why is large SA necessary for exchange surface

A

allows more molecules to pass through, often achieved by folding walls and membranes involved, many spherical alveoli in lungs

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50
Q

How are thin walls designed for exchange surfaces

A

One cell thick which reduces diffusion distance between source and destination, eg, wall of alveoli one cell thick squamous epithelium cells

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51
Q

Epithelium cells have adapted in the body by

A

Certain ones have cilia which removed foreign substances

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52
Q

Why steep concentration gradient is necessary for diffusion

A

Constant supply of materials being exchanged on one side and constant removal on the other, ensuring rapid diffusion

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53
Q

How is small intestine adapted as special exchange surface

A

Villi and microvilli increase SA for absorption of soluble nutrients which are removed and transported to cells via circulatory system

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54
Q

How is root hair adapted for exchange

A

Large SA for absorption of water and minerals

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55
Q

How are alveoli in lungs adapted for exchange

A

Large SA for oxygen and carbon dioxide exchange

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56
Q

How is hyphae in fungi adapted for exchange

A

Large SA to absorb nutrients

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57
Q

How do we breathe?

A

Gaseous exchange in mammals consists of air flowing in&out of lungs and airways

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58
Q

What happens when we breathe

A

Lungs in chest cavity, air passes into them via nose, air goes along the trachea, bronchi & bronchioles before reaching alveoli where gas exchange happens

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59
Q

What protects the lungs and helps ventilation

A

Lungs protected by rib cage which is protected by intercostal muscles which with the diaphragm help produce breathing movement (ventilation)

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60
Q

What happens at the alveoli in gas exchange

A

Gases pass by diffusion through alveoli thin walls, oxygen passes to blood capillaries and carbon dioxide diffuses from blood to air in alveoli, lungs must maintain a steep concentration gradient for this to happen

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61
Q

Which part of the lungs have to largest surface area

A

Alveoli (small about 100-300um across), so many that SA of lungs in half tennis court

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62
Q

What is lined on the alveoli that evaporates when we breathe out

A

Small layer of moisture called surfactant which coats internal surface of alveoli and reduces cohesive force between water molecules to prevent alveoli collapsing

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63
Q

Why is the barrier to exchange In alveoli and blood capillaries permeable

A

Made of squamous epithelium cells and allows oxygen and CO2 through as the are small and non-polar

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64
Q

How have thin walls at alveoli and blood capillaries adapted

A

Capillaries and alveolus both one cell thick of squamous cells, capillaries are in close contact with alveolar wall, capillaries are narrow so RBC squeezed against wall reducing rate of flow and closer to air in alveoli, total diffusion barrier is two cells think (1um)

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65
Q

How is good blood supply useful in exchange

A

Maintains and concentration gradient, transports CO2 from tissues to lungs and transports oxygen away from lungs—> maintains gradient for diffusion to happen

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66
Q

Why is moisture lining alveoli useful

A

Let’s gassed dissolve to ease diffusion

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67
Q

Why do lungs produce surfactant

A

To reduce cohesive forces between water molecules so alveoli do not collapse

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68
Q

What is the purpose of ventilation

A

Replace used air with new air

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69
Q

Does the concentration of oxygen in alveoli remain higher or lower than in blood(inhalation)

A

Higher

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70
Q

Does carbon dioxide concentration remain higher or lower in alveoli than in blood (exhalation)

A

Lower

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71
Q

What happens to diaphragm when we inhale

A

Contracts and moves downwards and becomes flatter (moves digestive organs downwards)

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72
Q

What happens to external intercostal muscles when we inhale

A

They contract to raise the ribs

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73
Q

In inhalation does the chest cavity volume increase or decrease

A

Increase

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74
Q

In inhalation does the chest cavity pressure go higher or lower than the atmospheric pressure

A

Lower than atmospheric pressure

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75
Q

Does air move in or out of lungs in inhalation

A

Air moves into lungs

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76
Q

What happens to diaphragm when you exhale

A

It relaxes and pushed up the displaced organs underneath

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77
Q

What happen to external and internal intercostal muscles when we exhale

A

External relax and ribs fall but internal can contract to push more air out

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78
Q

Give example or when internal intercostal muscles will contract

A

Exercise, sneezing, coughing

79
Q

Does volume of chest cavity increase or decrease in exhalation

A

Decrease

80
Q

Does the lung pressure increase or decrease compared to atmospheric pressure in expiration

A

Increase

81
Q

Does are go in or out of lungs in expiration

A

Air moves out of lungs

82
Q

What are alveoli comprised or and surrounded by and what does this create

A

Comprised of squamous epithelium cells and surrounded by blood capillaries creating a short diffusion distance

83
Q

What do alveolus walls contain and what is their purpose

A

Elastic fibres that stretch in inhalation and recoil pushing air out in expiration

84
Q

Can alveolus walls be seen under a light microscope

A

There so thin they can’t be seen with light microscope

85
Q

Why is the lungs airway large

A

To allow air flow without obstruction

86
Q

Why does the trachea divide into smaller airways

A

To deliver air to all the alveoli

87
Q

Why must the airway be strong

A

So it won’t collapse in low pressure

88
Q

What are 2 key features of the lungs airways

A

Must be flexible and stretch and recoil

89
Q

What is the airway lined with that hero’s lungs healthy

A

Ciliates epithelium cells

90
Q

How does goblet cells and ciliates epithelium work

A

Goblet cells in epithelium secret mucus to trap pathogens cilia then woft musics to back of the mouth where it is swallowed

91
Q

What other tissue also produces mucus

A

Glandular tissue in loose tissue

92
Q

Is trachea or bronchi narrower

A

Bronchi

93
Q

In the trachea and bronchi what prevents them from collapsing in inspiration

A

Walls consist of cartilage

94
Q

What is the structure of cartilage and what is its function

A

C-shaped rings of cartilage which allows more flexibility than complete ring so there is space for food to pass down oesophagus

95
Q

What is on the inside surface of Cartilage and give examples

A

Layers of loose tissue for example glandular, connective tissue and elastic fibres, Smooth muscle, blood vessels

96
Q

What is the inner lining of trachea

A

Epithelium layer(goblet and cilia cells)

97
Q

What is space on the inside of a hollow tube inside the human body called

A

Lumen

98
Q

Are bronchi or bronchioles more narrow

A

Bronchioles

99
Q

Do bronchioles have cartilage

A

Larger ones do but smaller don’t

100
Q

What is bronchioles wall mostly consist of

A

Smooth muscle and elastic fibres

101
Q

What do the smallest bronchioles have at the end of them

A

Alveoli

102
Q

What are the functions of cartilage

A

Support trachea and bronchi holding them open, prevents collapse under low pressure in inhalation, not a complete ring so flexible, can move neck without constricting airway and allows oesophagus to expand during swallowing

103
Q

Function of smooth muscle

A

Can contract and restrict airway, makes lumen much narrower, restricted airway good if harmful substances in the air (not voluntary) and allergic reactions or asthma can cause it to contract

104
Q

Function of elastic fibres

A

When smooth muscle contracts it cannot reverse the lumen constriction, elastic fibres are deformed when airway constricts but when smooth muscle relaxes elastic fibres recoil to original shape and size causing airway to dialate

105
Q

Function of goblet cells and glandular tissue

A

Under epithelium they secret mucus which traps tiny particles of dust to reduce risk of infection

106
Q

Function of ciliates epithelium

A

Epithelium consists of epithelium cells which have many hair like structures projecting form membrane called cilia, they move in synchronised wave motion to waft mucus up airway to back of mouth where can be swallowed and acidity kills bacteria

107
Q

What does a spirometer measure

A

Lung volume, movement of are in and out of lungs as a person breathes

108
Q

What is the structure of spirometer

A

Float chamber consists of air or oxygen floating on a tank of water, when inhale air drawn from chamber so lid moves down and in exhalation air returns to chamber lifting lid which is recorded on data logger, CO2 rich air passes through soda lime to absorb it so only oxygen consumption measured and a trace marker attached to the mobile upper half

109
Q

Person using a spirometer should be….

A

Healthy and asthma free

110
Q

What happens if soda like is not fresh and functioning

A

CO2 levels can come dangerously high as oxygen used in respiration is replaced with CO2

111
Q

Why is it important there are no air leaks on a spirometer

A

Would give invalid results if it isn’t a closed system

112
Q

Gives two precautions when using a spirometer

A

Mouthpiece sterilised and water chamber can’t be overfilled as water may enter tubes

113
Q

Why are modern spirometer although easier not as good

A

Don’t measure oxygen consumption

114
Q

What is the total lung volume equation

A

Vital capacity + residual volume

115
Q

How is vital capacity measured

A

Taking deep breath and expelling as much air as possible from lungs

116
Q

What does vital capacity results depend on and what is an average result

A

Depends on height, size, age, gender, level of regular exercise (higher in trained athletes) is usually 2.5-5dm^3

117
Q

What is the average tidal volume and is it enough for whole body during exercise

A

0.5dm^3 and is enough oxygen for whole body at rest

118
Q

What does breathing do

A

Gives o2 for respiration and removes CO2 produced in respiration

119
Q

What happens in human body when person breathes from spirometer

A

Oxygen is absorbed by blood and replaced by carbon dioxide

120
Q

On the trace it is constantly decreasing, why

A

CO2 absorbed by soda like so volume of air in spirometer decreases

121
Q

Is the volume of CO2 released and absorbed by soda lime equal or different to volume of oxygen absorbed by blood

A

Equal

122
Q

What is inspiratory reserve volume and when do we use it and on average what is it

A

How much extra air you can breathe in with forces inhalation, needed when exercising and usually 3dm^3

123
Q

What is expiratory reserve volume and how would you work it out

A

How much extra air you can breathe out in forced exhalation, difference between tidal volume and vital capacity when you exhale

124
Q

How to calculate rate of oxygen uptake

A

Find gradient if the decrease in volume on a graph

125
Q

How to measure breathing rate from spirometer graph

A

Count number of peaks per minute, usually 12-14

126
Q

When does oxygen intake increase and why

A

Increased demand like exercise as muscles are respiring more due to deeper breaths or higher breathing rate

127
Q

How to calculate ventilation rate

A

Tidal volume x number of breathes per min

128
Q

How to calculate vital capacity

A

Tidal volume + inspiratory and expiratory reserve volume

129
Q

What do the normal vital capacity of normal person and an athlete

A

normal person=4-5L

Athlete=6L

130
Q

What is another word for dead space and in L how much is there usually

A

Residual volume about 1.5L

131
Q

Why is there a steep concentration gradient maintained between blood and alveoli

A

Blood reaching alveoli has lower partial pressure did oxygen and higher partial pressure of CO2 than the alveolar air

132
Q

How are results of spirometer test recorded

A

Pen attached to moving lid draws on a revolving drum creating a graph

133
Q

Why is a nose clip worn when using a spirometer

A

To keep a closed system between lungs and spirometer

134
Q

How do you achieve the best diffusion rate

A

Large, thin, permeable respiratory area

135
Q

What problem do land organisms have and what is there solution

A

If their cells exposed to air they will dehydrate so they have a waterproof cover (khitin, wax, keratin) however waterproof cover prevents diffusion so specialised structures developed for gas exchange (leaves, lungs, tracheae)

136
Q

What are problems aquatic organisms have and how are the resolved

A

Much less oxygen in water so diffusion is much slower than air so they developed large and efficient structures to overcome this

137
Q

How to bony fish respire

A

Use gills to absorb oxygen dissolved in water and release CO2 into water

138
Q

How many pairs of gill arches do fish have

A

4-5

139
Q

What is the operculum

A

Bony plate which covers the gills

140
Q

How many rows of gill filaments are there on each arch

A

2

141
Q

What are the filaments attached to the bony arch called

A

Primary lamellae

142
Q

What are features of fish filaments

A

Very thin and surface is folded many times to create a large SA

143
Q

What is the secondary lamellae

A

Surface of primary lamellae is folded many times and thus is called secondary lamellae

144
Q

Where do the capillaries go in order to get more oxygen in fish

A

Close to the secondary lamellae

145
Q

How does gas exchange work in a fish

A

Short diffusion distance for gas to cross, rich blood supply, water constantly pumped over gills to maintain concentration gradient, oxygen diffuses from water in gills and CO2 diffuses out of gills into water

146
Q

What is countercurrent flow and how does it optimise o2 intake

A

Blood flows along Gill arch, out along filaments to secondary lamellae, blood then flows in opposite direction to the flow of water over lamellae(countercurrent flow)

147
Q

When does gas exchange occur in fish

A

When water passes over the gills

148
Q

What is the distance between water and blood in lamellae

A

5um

149
Q

Give two features in fish for efficient gas exchange

A

Gills have extensive blood capillary network and haemoglobin used to carry oxygen, gills provide large surface area (filament and lamellae)

150
Q

How do bony fish keep blood flowing over gills

A

Using buccal-opercular pump

151
Q

Do bony fish actively or passively ventilation

A

Actively as is more Efficient

152
Q

How do bony fish actively ventilate

A

Floor of mouth moves downwards drawing water into the buccal cavity, when floor lowers volume increases so pressure decreases and water flows in, then mouth is closed, floor is raised pushing the water through gills due to pressure increase, as water pushes up from buccal cavity operculum moves outwards to reduce pressure in opercular cavity helping water flow through gills

153
Q

Why do fish die out of water

A

Without surrounding water gills stick together and there isn’t enough SA for fish to get oxygen in needs by diffusing through skin

154
Q

Why don’t insects transport oxygen in blood

A

Have an open circulatory system where body fluids act as blood and tissue fluid , this is slow and can be affected by body movement

155
Q

What animals have air filled tracheal systems

A

Insects

156
Q

What does the air filled tracheal system do

A

Supplies air directly to all responding tissue

157
Q

What is a spiracle

A

A pore in each segment of insect where air enters

158
Q

What are tracheae and tracheoles

A

Tracheae Series of tubes found in insects that get smaller and smaller tubes called tracheoles which air is transported in

159
Q

What is tracheal fluid and where’s it found

A

End of tracheoles are open and filled with this fluid

160
Q

Where does gaseous exchange occur in insects

A

Between air in tracheole and tracheal fluid and some can occur across thin walls of tracheoles

161
Q

What are the two segments of an insect

A

Thorax and abdomen

162
Q

What supports the tracheae

A

Chitchin

163
Q

What happen when insects are active and need a better blood supply

A

Tissues are active so tracheal fluids can be withdrawn into body fluids to increase SA of tracheole wall exposed to air so more oxygen can be absorbed

164
Q

Why can’t there be gas exchange through insects covering

A

Too thick

165
Q

What do insects have instead of lungs

A

Internal respiratory system with openings called spiracles which open when CO2 is needed

166
Q

Where do spiracles lead to

A

System of tubes which run to insects cells (tracheal system)

167
Q

Where does gas exchange occur in insects

A

Tracheoles

168
Q

Why are tracheoles good for gas exchange

A

Freely permeable to gases, tracheal fluid makes them moist, air pumped in and out of them by insects to maintain concentration gradient

169
Q

How do some insects ventilate using section of tracheal system

A

Sections of tracheal system expand and have flexible walls which act as air sacs which can be squeezed by action of flight muscle

170
Q

How do some insects ventilate using wings

A

Thorax volume decreases so air in tracheal system is under pressure and pushed out of tracheal system, when volume of thorax increase pressure inside drops and outside air pushed into tracheal system

171
Q

How do locusts ventilate

A

Can alter abdomen volume with breathing movement and coordinates with open and close valve on spiracles, as abdomen expand spiracle at front of body opens and air enters tracheal system and as abdomen reduces in volume spiracle at rear end of body opens and air leaves tracheal system

172
Q

Give examples of bony fish

A

Cod , mackerel, trout, lungfish

173
Q

How are insects body divided

A

Thorax, abdomen, head and 2 pairs of wings attached to thorax

174
Q

Where are lungs situated

A

In thorax, walls of which formed by ribs, sternum and intercostal muscles and diaphragm floor

175
Q

What directly surrounds the lungs and what does it do

A

A narrow pleural cavity lined by pleural membranes which has a thin layer of pleural fluid, lubricant, which allows pleural membranes to slide over each other when thorax expands and contracts

176
Q

What happens when we breathe in

A

Sternum moves forwards, ribs move up and out due to contraction of intercostal muscles

177
Q

What happens when we breathe out and what happens when we breathe out doing exercise

A

Passive process where elastic fibres recoil after being stretched or in exercise intercostal muscles contract to push more air out

178
Q

What is the pressure gradient in the lungs when we are relaxing compared to the outside atmosphere

A

Resting pressure in lungs is almost the same as atmospheric pressure , but, lungs are elastic and often pull away from thorax, pressure in pleural cavity is less than atmospheric

179
Q

What happen in inspiration and what happens in exhalation

A

Walls and floors of thorax move out and down, pleural pressure falls lowering lung pressure below atmospheric pressure so air enters lungs, this increases volume and returns to atmospheric pressure,, exact opposite in expiration

180
Q

What is the structure of lungs

A

Spongy and consist of 2 bronchi, which become bronchioles which lead to a bunch of alveoli

181
Q

When is gas exchange most efficient

A

When large amounts of alveoli are near extensive capillary system

182
Q

What is the purpose of the alveolar epithelium being covered in a thin layer of fluid

A

It dissolved oxygen before diffusion so alveoli don’t collapse and expanding would be difficult but fluid has surfactant so this doesn’t happen

183
Q

Wall of alveoli and capillaries both have squamous epithelium close to each other, why is this good

A

Diffusion distance only 2 cell thick so there is minimum resistance for gas diffusion

184
Q

What is dead space or residual volume

A

When we breathe not all the air is exchanged some remains in trachea and bronchial tubes

185
Q

What happens to blood o2 and CO2 levels when we exercise

A

Blood o2 decreases and blood CO2 will rise, if oxygen deprived for too long hypoxia occurs

186
Q

What happens if we breath pure oxygen

A

Isn’t bad u less at high pressure like diving where it can interfere with cell respiration

187
Q

What do the basement layer of epithelium cell

A

One side of epithelium is free and one has cells which support and control what passes through it to

188
Q

Difference between epidermis and endothelium

A

Epidermis is our skin and endothelium lines inner cavities and tubes

189
Q

How is epithelium protected from abrasion

A

Mucus acts as lubricant easing movement

190
Q

What is mucus membrane and where is it found

A

Moist epithelium contains goblet cells and connective tissue found in gut lining and breathing track

191
Q

What does connective tissue do

A

Fills gaps between organs and tissues, contains protein fibres and several other cells with similar composition to basement membrane

192
Q

What is elastic tissue properties

A

Contains elastic fibres and cells and is strong but flexible

193
Q

Cartilage properties

A

Cartilage is soft bone with collagen and elastic fibres, hayaline cartilage found in trachea walls to prevent them caving in

Alevel Biology (25 decks)

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