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Biology > Exchange Surfaces And Breathing > Flashcards

Exchange Surfaces And Breathing Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What are the 3 main factors that effect the need for an exchange system

A

Size
Surface area to volume ratio
Level of activity

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2
Q

Describe how size effects the need for a transport system

A

In very small organisms, such as single-celled organisms, all the cytoplasm is very close to the
environment in which they live. Diffusion will supply enough oxygen and nutrients to keep the cells
alive and active. However, multicellular organisms may have several layers of cells. Here, any oxygen
or nutrients diffusing in from the outside have a longer diffusion pathway. Diffusion is too slow to
enable a sufficient supply to the innermost cells.

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3
Q

Describe how surface area to volume ratio affects the need for a exchange rate

A

Surface area to volume ratio
Small organisms have a small surface area, but they also have a small volume. Their surface area is
relatively large compared with their volume. We say that they have a large surface area to volume ratio. This
means that their surface area is large enough to supply all their cells with sufficient oxygen (see Table 1).
Larger organisms have a larger surface area, but they also have a larger volume. As size increases,
the volume rises more quickly than the surface area. Therefore, their surface area is relatively small
compared with their volume. We say that they have a small surface area to volume ratio.
Some organisms increase their surface area by adopting a different shape. An animal such as a
atworm has a very thin, flat body. This gives it a larger surface area to volume ratio (SA V). But suc
body form limits the overall size that the animal can reach. Most large organisms need a range of
sues to give the body support and strength. Their volume increases as their body gets thicker, but
anism is relatively small.

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4
Q

Describe how the level of activity affects the need for a exchange surface

A

Some organisms are more active than others , metabolic activity uses energy from food and requires oxygen to release the energy in aerobic respiration , the cells of an active organism need good supply of nutrients and oxygen to supply the energy for movement. This need for energy is increased in those animals such as mammals that keep themselves warm

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5
Q

What are the features of a good exchange surface

A

Large surface area to provide more space for molecules to pass through , this is often achieved by folding the walls and membranes involves

A thin barrier to reduce the diffusion distance and that barrier must be permeable to the substance being exchanged

A good supply of blood , this can bring fresh supplies of molecules to one side , keeping the concentration high or it may remove molecules from the demand side to keep the concentration low , this is important to maintain a steep concentration gradient so that diffusion can occur rapidly

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6
Q

Define alveoli

A

Tiny folds of the lung epithelium to increase the surface area

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7
Q

Define bronchi and bronchioles

A

Smaller airways leading into the lungs

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8
Q

Define diaphragm

A

A layer of muscle beneath the lungs

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9
Q

Define intercostal muscles

A

Between the ribs , contraction of the external intercostal muscles raise the ribcage

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10
Q

Define trachea

A

The main airway leading from the back of the mouth to the lungs

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11
Q

Define ventilation

A

The refreshing of the air in the lungs , so that there is a higher oxygen concentration than in the blood , and lower carbon dioxide concentration

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12
Q

Define lungs

A

A pair of inflatable sacs lying in the chest cavity

Air can pass into the lungs through the nose and along the trachea , bronchi and bronchioles - then reaches alveoli

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13
Q

The lungs are protected by

A

The rib cage

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14
Q

The ribs are held together by

A

The intercostal muscles

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15
Q

Describe gaseous exchange in the lungs

A

Gases pass by diffusion through the thin walls of the alveoli. Oxygen passes from the air in the alveoli to the blood in the capillaries. Carbon dioxide passes from the blood to the air in the alveoli. The lungs must maintain a steep concentration gradient in each direction in order to ensure that diffusion can continue

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16
Q

What are the adaptations to reduce the distance the gases have to diffuse in the gaseous exchange

A
  • alveolus wall is one cell thick
  • the capillary wall is 1 cell thick
  • both consist of squamous cells
  • the capillaries are in close contact with the alveolus walls
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17
Q

How does a good blood supply help gaseous exchange

And how does the body do this

A

Maintains a steep concentration gradient

  • the blood system transports carbon dioxide fro the tissues to the lungs . This ensures that the concentration of Veblen dioxide in the blood is higher than that in the air of the alveoli . Therefore carbon dioxide diffuses into the alveoli

The blood also transports oxygen away from the lungs , this ensure that the concentration of oxygen in the blood is kept lower than that in the alveoli - so that oxygen diffuser into the blood

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18
Q

Ventilation ensures that

A
  • the concentration of oxygen in the air of the alveolus remains higher than that in the blood
  • the concentration of carbon dioxide in the alveoli remains lower than that in the blood

Therefore the concentration gradient necessary for diffusion is maintained

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19
Q

Inspiration / inhaling process

A

The diaphragm contacts to move down and become flatter

The external intercostal muscles contract to raise the ribs

The volume of the chest cavity is increases

The pressure in the chest cavity drops below the atmospheric pressure

Air is moved into the lungs

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20
Q

Expiration / exhaling process

A

The diaphragm relaxes and is pushed up by the displaced organs underneath

The external intercostal muscles relax and the ribs fall , the internal intercostal muscles can contract to help push air out more forcefully

The volume of the chest cavity is decreased

The pressure in the lungs increases and rises above the pressure in the surrounding atmosphere

Air is moved out of the lungs

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21
Q

Define cartilage

A

A form of connective tissue

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22
Q

Define ciliated epithelium

A

A layer of cells that have many hair like extensions called cilia

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23
Q

Define elastic fibres

A

Protein fibres that can deform and then recoil to originals size

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24
Q

Define goblet cells

A

Cells that secrete mucus

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25
Q

Define smooth muscles

A

Involuntary muscles that contact without the need for conscious thoughts

26
Q

Describe lung tissues

A

Lin consists of large numbers of tiny air filled sacs called alveoli , these are comprised of squamous epithelium and are surrounded by blood capillaries so that the distance that gases must diffuse is very short. The alveolus walls contain elastic fibres that stretch during inspiration but then recoils to help push air out during expiration . The alveolus walls are so thin that it may not be possible to distinguish separate cells under a light microscope

27
Q

describe the airways and what theyre lined with

A

includes the trachea, bronchi and bronchioles allows the passage of air into the lungs and out again

the airways are lined by ciliated epithelium which contributes to keeping lungs healthy .
goblet cells in the epithelium release mucus which traps pathogens .
the cilia then move the mucus up to the top of the airways where it is swallowed .
the glandular tissue in the loose tissue also produces mucus

28
Q

to be effective , airways must meet certain requirements , which are ?

A
  • to be large enough to allow sufficient air to flow without obstruction
  • to be supported to prevent collapse when the air pressure inside is low during inspiration
  • be flexible in order to allow movement
29
Q

describe the trachea and bronchi and what there made up of

A

bronchi are narrower than the trachea
these airways are supported by rings of cartilage which prevent collapse during inspiration . the ring of cartilage in the trachea are c- shaped rather than a complete ring which allows flexibility and space for food to pass down the oesophagus

30
Q

describe the bronchioles and what there made up of

A

they are much narrower than the bronchi . the larger bronchioles may have some cartilage , but smaller ones have no cartilage.
the wall is comprised of mostly smooth muscle and elastic fibres
the smallest bronchioles end in clusters of alveoli

31
Q

describe smooth muscles and elastic tissue

A

the smooth muscles can contract . the action of the smooth muscles will constrict airways this makes the lumen of the airways narrower. Constrictions of the lumen can restrict the flow of air to add to and from the alveoli . controlling the flow of air to the alveoli might be important if there are harmful substances in the air . the contraction of smooth muscles and control of airflow is not a voluntary act and may occur as a result of an allergic reaction . once the smooth muscle has contracted it cannot reverse this effect on its own. the smooth muscles is elongated again by the elastic fibres . when the muscles contract , it deforms the elastic . as the muscles relax, the elastic fibres recoil to the original sixe and shape . this acts to dilate the airways

32
Q

define breathing rate

A

the number of breaths per minute

33
Q

define oxygen uptake

A

the volume of oxygen absorbed by the lungs in one minute

34
Q

define tidal volume

A

the volume of air inhaled or exhaled in one breath , usually measured at rest

35
Q

define spirometer

A

a device that can measure the movement of air into and out of the lungs

36
Q

define lung capacity

A

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

37
Q

describe how a spirometer works

A

lung volumes can be measured by a spirometer .A float chamber spirometer consists of a chamber of air or medical oxygen floating on a tank of water. During inspiration , air is drawn from the chamber so that the lid moves down. During expiration the air returns to the chamber , raising the lid. these movements may be recorded on a datalogger. the carbon dioxide rich air is exhaled is passed through a chamber of soda lime which absorbs the carbon dioxide. This allows the measurement of oxygen consumption

38
Q

precautions that must be taken when using a spirometer

A
  • the subject should be healthy and , in particular, free from asthma
  • the soda lime should be fresh and functioning
  • there should be no air leaks in the apparatus , as this would give invalid or inaccurate results
  • the mouthpiece should be sterilised
  • the water chamber must not be overfilled or water may enter air tubes
39
Q

what does total lung volume consist of and which one can be measured

A

vital capacity - which can be measured

residual volume- which cannot me measured using the spirometer

40
Q

what factors does vital capacity depend on

A

size of person
age
gender
level of regular exercise

41
Q

what is the usual region of vital capacity

A

2.5-5.0 dm3

42
Q

a typical tidal volume at rest is

A

0.5 dm3

43
Q

describe how the oxygen uptake effects the spirometer trace

A

as a person breathes from the spirometer , oxygen is absorbed by the blood and replaced by carbon dioxide. this carbon dioxide is absorbed by the soda lime in the spirometer , so the volume of air in the chamber decreases . this decrease can be measured and observed on a spirometer trace
we can assume that the volume of carbon dioxide released and absorbed by the soda lime equals the volume of oxygen absorbed by the blood. therefore measuring the gradient of the decrease in volume enables us to calculate the rate of oxygen uptake

44
Q

how to calculate oxygen uptake from a spirometer trace

A

on the start of the trace in the top left hand corner (A) draw a line from point A down to the horizontal axis , and another line from the end of the spirometer trace (B). measure the length of time between these points

measure the difference in volume between points A and B

divide by the time taken for this decrease

the unit will be dm3s-1

45
Q

how to measure breathing rate

A

count the number of peaks in each minute

46
Q

a higher oxygen uptake will result from

A

increased demand such as during exercise when the muscles are respiring more

47
Q

increased oxygen uptake will result from

A

increased breathing rate

deeper breaths

48
Q

define buccal cavity

A

the mouth

49
Q

define filaments

A

slender branches of tissues that make up the gills , they are often called primary lamella

50
Q

define lamella

A

sometimes called secondary lamella

folds of the filament to increase surface area , they are also called gill plates

51
Q

define operculum

A

a bony flap that covers and protects the gills

52
Q

define spiracle

A

a external opening or pore that allows air in or out of the trachea in an insect

53
Q

define tracheal fluid

A

the fluid found at the ends of the tracheoles in the tracheal system

54
Q

define tracheal system

A

a system of air filled tubes in insects

55
Q

explain how bony fish exchange gases

A

bony fish must exchange gases with the water in which they live. they use gills in order to absorb oxygen dissolved in the water and release carbon dioxide into the water. the oxygen concentration will be typically much lower than found in air. most bony fish have five pairs of gills which are covered by a bony plate called the operculum
each gill consists of two rows of gill filament (primary lamella) attached to a bony arch. the filaments are very thin and their surface is folded into many secondary lamellae (gill plates) this provides a very large surface area. blood capillaries carry deoxygenated blood close to the surface of the secondary lamellae where exchange takes place

56
Q

describe countercurrent flow

A

blood flows along the gill arch and out along the filaments to the secondary lamellae . the blood then flows through capillaries in the opposite direction to the flow of water over the lamellae. the arrangement creates a countercurrent flow that absorbs the maximum amount of oxygen from the water

57
Q

describe ventilation in bony fish

A

bony fish can keep water flowing through the gills by using a buccal opercular pump. the buccal cavity can change volume. the floor of the mouth moves downwards, drawing water into the buccal cavity. the mouth closes and the floor is raised again water through the gills. movements of the operculum are coordinated with the movement of the buccal cavity.as water is pushed from the buccal cavity, the operculum moves outwards . this movement reduces the pressure in the opercular cavity, helping water to flow though the gills

58
Q

describe ventilation in insects

A

insects do not transport oxygen in the blood . insects have an open circulatory system In which the body fluid acts as both blood and tissue fluid . circulation is slow and effected by body movements

insects have an air filled tracheal system which supplied air directly to all respiring tissues. sir enters the system via a pore in each segment called a spiracle . the air is transported into thr body through a series of tubes called tracheae (singular trachea) . these divide into smaller and smaller tubes called thracheoles . the ends of the tracheoles are open and filled with tracheal fluid. gaseous exchange occurs between the air in the tracheoles and the tracheal fluid . some exchange can also occur across the thin walls of the tracheoles

59
Q

describe the tracheal fluid withdrawal

A

many insects are very active and need a good supply of oxygen .when tissues are active , the tracheal fluid can be withdrawn into the body fluid in order to increase the surface area of the tracheole wall exposed to air . this means that more oxygen can be absorbed when the insect is active

60
Q

larger insects can also ventilate their tracheal system by movements of the body . this can be achieved in a number of ways

A
  • in many insects ,sections of the tracheal system are expanded and have flexible walls. these act as air sacs which can be squeezed by the action of the flight muscles . repetitive expansion and contractions of these sacs ventilate the tracheal system
  • in some insects , movements of the wings alter the volume of the thorax. as the thorax volume decreases , air in the tracheal system is put under pressure and is pushed out the tracheal system. when the thorax increases in volume, the pressure inside drop and air is pushed into the tracheal system from outside

Biology (10 decks)

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