module 3.1: exchange surfaces Flashcards
name the two types of epithelial tissue found in the lungs and airways.
- squamous
- ciliated
the epithelial cells in the lungs are arranged into structures called alveoli.
explain how the alveoli create a surface for efficient gaseous exchange.
- wall is one cell thick for short(er)
diffusion, distance / pathway ; - squamous, cells / epithelium , provide
short diffusion distance / pathway ; - elastic so, recoil / expel air / helps
ventilation ; - create / maintain, concentration
gradient / described ; - large number (of alveoli) provide large(r)
surface area ; - small size (of alveoli) provide large(r)
surface area to volume ratio ; - (cells secrete) surfactant to maintain
surface area ;
to improve gaseous exchange, the air in the alveoli is refreshed by ventilation. the air movement created by ventilation can be recorded using suitable apparatus.
(i) name the apparatus used to record these air movements
spirometer
when the rubber sheet is pulled down the balloons expand. explain why the balloons expand.
- volume, inside / of, jar increases
- pressure inside, jar / balloons, decreases
- to below pressure in atmosphere ;
- (therefore) air, moves / pushed / forced, into, balloons /glass tube
explain the meaning of the term tidal volume.
- volume of air, inhaled / exhaled
- in, one / each, breath
- during, steady / regular, breathing
suggest how the teacher may have used the model to demonstrate tidal volume.
- up / down, movements (of rubber sheet / band)
- idea of: small / steady / regular, movements (of rubber sheet)
explain the meaning of the term vital capacity.
- the maximum volume of air
- inhaled / exhaled, in one breath
suggest how the teacher may have used the model to demonstrate vital capacity
pulled down on rubber, sheet / band, as far as possible and pushed up as far as possible
explain the significance of the relationship between rate of diffusion and the surface area to volume ratio for large plants
- (large plants) have a, small / low, SA : VOL ratio
- idea of diffusion too slow (to supply requirements)
- idea of need transport system (for water / minerals / assimilates) ;
- idea of need (special) surface area for, gaseous exchange/ uptake of minerals ;
complete the table explaining how each adaptation improves efficiency of gaseous exchange
squamous epithelium
……………………………………….
large number of alveoli
……………………………………….
good blood supply
……………………………………….
good ventilation
……………………………………….
- squamous epithelium
short(er) diffusion, distance / path ; - large number of alveoli
large(r) surface area ; - good blood supply
high / large / steep, concentration gradient OR removes oxygen (from lung surface) / brings carbon
dioxide (to lung surface); - good ventilation
high / large / steep, concentration gradient OR supplies oxygen (to alveoli) / removes carbon dioxide (from alveoli) ;
list three reasons why a large, multicellular animal, such as a mammal, needs a transport system
- low / small, surface area to volume ratio
- diffusion, too slow / distance too great
- to supply enough, oxygen / (named) nutrients
- to prevent, CO2 / (named) waste product, building up
- active
explain what causes the change in the volume of air between points B and C on Fig. 5.1.
- (external) intercostal muscles / diaphragm, relax
- rib cage / ribs, move down OR diaphragm, moves / pushed, up
- volume of, thorax / chest cavity / lungs, drops / decreases ;
- pressure inside, thorax / chest cavity / lungs, increases ;
- above, external / atmospheric, pressure
- air leaves down pressure gradient
- (elastic) recoil of alveoli
suggest why it is not possible to expel all the air from the lungs.
- thorax / rib cage / lungs, cannot be completely, compressed / flattened
- trachea / bronchi, held open by cartilage
- bronchioles / alveoli, held open by elastic fibres
one of the symptoms of smoking is the development of a smoker’s cough.
explain how smoking causes a smoker’s cough and how the cough itself can lead to further problems in the lungs over a long period of time.
CAUSES
- tar
- (cigarette smoke) destroys / damages / paralyses, cilia / ciliated epithelium
- (cigarette smoke stimulates) goblet cells to release more mucus
- mucus ( in airways) , builds up / cannot be removed
- more, pathogens / bacteria / viruses / microbes, collect / trapped / accumulate (in mucus)
- idea that cough is an attempt to , increase air flow / remove microbes, by removing mucus
EFFECTS
- (frequent coughing) damages / inflames, - (named) airway / alveoli / elastic fibres
formation of scar tissue airway / bronchi / bronchiole, walls thicken
- lumen of, airway / bronchi / bronchiole , narrows
- flow of air restricted
- (damage to alveoli causes) reduced surface area for , gas exchange / oxygen diffusion
chronic obstructive pulmonary disease (COPD) is a combination of diseases that can result in coughing, breathing difficulties and fatigue. name two specific diseases that contribute to COPD.
- emphysema
- chronic bronchitis
- asthma
one form of COPD develops because enzymes are released by phagocytes entering the alveoli. this enzyme action can break down elastin in the lining of the bronchioles and alveoli.
use the example of elastin breakdown to explain the induced-fit hypothesis of enzyme action.
- elastin is substrate
- (elastin / substrate) binds to / fits into , active site
- active site / enzyme / elastase / substrate / elastin, shape changes
- idea of closer fit (between active site and substrate)
- more bonds form (between substrate and active site)
- forms enzyme-substrate-complex / ESC ;
- idea that (change in shape of active site) destabilises / weakens , bonds (in substrate) / substrate activation energy reduced
- idea of further shape change of, active site / enzyme, after products form
name the air sacs and state why there are many air sacs in the lungs
- alveoli
- to provide large(r), surface area / SA
Name the type of epithelium in the walls of the air sacs
squamous/ pavement
explain the role of these elastic fibres during ventilation.
- to prevent bursting
- recoil
- to return air sac to original, size / shape
- to help expel air
explain how refreshing the air in the air sacs helps to maintain a steep diffusion gradient
- increases, partial pressure / concentration, of oxygen (in the air sac)
- so concentration of oxygen (in the air sac) is higher than that in the blood
- decreases, partial pressure / concentration, of carbon dioxide (in air sac)
- so concentration of CO2 (in the air sac) is lower than that in the blood
describe and explain one other way in which a steep diffusion gradient is maintained in the lungs.
- (continuous) blood flow (in the capillaries)
- to, bring in (more) carbon dioxide / take away (more) oxygen ;
OR - oxygen combines with haemoglobin ;
- to keep concentration in, blood / plasma, low ;
using the mammalian gaseous exchange system as an example, explain how the different cells and tissues enable the effective exchange of gases
- thin endothelium (of capillary) ;
–> (provides) short diffusion distance / described ; - ref to surfactant (from epithelial cells) ,
–>reducing surface tension / preventing alveoli collapsing - blood / red blood cells / erythrocytes ;
–> transports (named) gas(es) , to / from ,
exchange surface / alveoli ; - diaphragm / intercostals , muscles ;
–> (maintains / creates) diffusion / concentration , gradient ; - ciliated epithelium / goblet cells / ciliated cells
–> idea of: protection from / removal of ,
dust / bacteria / pollen / spores - cartilage
–> hold airway open - smooth muscle
–> constrict / control diameter of , airway / blood vessel - elastic , fibres / tissue ;
–> for recoil / aiding ventilation - macrophage / neutrophil
–> engulf / destroy pathogens
or
protect from infection
describe how the spirometer would be used to measure tidal volume
- idea of not breathing through nose
- subject breathes , evenly / normally / regularly
- idea of (measure) height / amplitude , of waves (from trace)
- measure at least three waves and calculate mean
- detail of how spirometer works (e.g. as breathe in lid goes down
e.g. movement of lid recorded , on trace
e.g. pen attached to lid moves up
describe how you could use a spirometer trace to measure the rate of oxygen uptake.
- measure , volume of oxygen used /
decrease in volume in chamber - e.g. draw line along tips of , peaks / troughs and e.g. find difference in height from one ,
peak / trough , to another - measure time taken (to use this oxygen)
- divide (volume) by time taken
suggest two factors that should be considered when carrying out a risk assessment for an experiment using a spirometer
- check health of volunteer
- oxygen used
- new / sterilised / disinfected , mouthpiece (for each volunteer)
- idea of: soda lime working
- sufficient oxygen in chamber
- water level not too high / water must not enter tubes
- ensure valves working correctly
histamine is a cell signalling molecule that stimulates smooth muscle in the wall of structure A to contract. suggest how histamine stimulates smooth muscle contraction
- (histamine), binds / attaches, to, receptor / glycoprotein
- in / on, plasma / cell surface, membrane (of muscle cell)
- complementary (shape)
- triggers response / causes effect, inside
cells
another action of histamine is to make capillary walls more permeable.
suggest two effects this increased permeability may have on the surrounding tissues
- more tissue fluid formed / increase in volume of tissue fluid
- increase pressure in tissue
- swelling / inflammation / oedema
- (more) white blood cells pass into tissues
- larger molecules / (named) proteins ,
pass into tissue fluid
outline the mechanism of inspiration
- diaphragm / intercostal muscles, contract
- diaphragm moves down / ribs move upwards and outwards
- volume of thorax increased
- pressure inside thorax falls
- to below atmospheric pressure (so air enters lungs)
suggest a chemical that could be used in chamber T to absorb carbon dioxide
soda lime / sodium hydroxide / potassium hydroxide / calcium hydroxide
explain why a person using the spirometer to measure their vital capacity should wear a nose clip
- to prevent, escape of air / entry of air, through nose OR to ensure all air breathed comes from chamber
- make results invalid
state two other precautions that should be taken when using a spirometer to measure vital capacity
- use (medical grade) oxygen / fresh air
- disinfect mouthpiece
- e.g. maintain constant temperature (so that volume of gases is not
affected); ensure, valve / hinge, is working; level of water correct; no leaks / airtight / lips sealed around mouthpiece
name the two types of cell, A and B, shown lining the bronchus
- goblet / mucus (secreting) cell
- ciliated (epithelium)
describe how cell types A and B work together to keep the lung surface clear of dust and other particles
-(A / goblet cells) release mucus
–> (mucus) traps, dust / particles / named particle
- ciliated cell / B / cilia, wave / waft / move, mucus
- to, top of trachea / back of mouth
state the function of the smooth muscle fibres
- to constrict the bronchus
