3.1.1 Exchange surfaces Flashcards
Why are specialised exchange surfaces needed in multi-cellular organisms?
smaller SA:V ratio;
oxygen cannot diffuse quick enough due to long diffusion distance to meet metabolic need;
higher metabolic activity
Why aren’t single celled organisms require a specialised exchange surface?
larger SA:V ratio;
oxygen/nutrient can supply their metabolic needs due to short diffusion distance;
lower metabolic activity
What are the features for an efficient exchange surface?
increased surface area;
thin layer;
good blood supply;
Why does an increased SA used for a specialised exchange surface?
larger SA = increase the rate of diffusion of substance (oxygen in humans, and minerals in plants)
root hair cell
lots of alveoli
How is a thin layer surfaces specialised for exchange surfaces?
thin diffusion pathways
alveoli - squamous epithelial cells - one cell thick
How is a good blood supply/ventilation help a specialised exchange surface?
maintained a concentration gradient
gills in fish
alveoli in humans
Draw an image of the mammalian gaseous exchange system?
image on iPad
What is the function of goblet cells?
secrete mucus that traps dust/bacteria that enters the lungs;
What is the role of the cilia in the ciliated epithelial cells?
cilia waft the mucus to the top of the trachea/back of the mouth;
where it is swallowed or coughed out
Where are ciliated epithelial cells and goblet cells found?
trachea
What is the role elastic fibres?
recoil to their original shape;
expel air;
prevent the lungs from bursting;
What is the role of a smooth muscle?
contract to constrict their airways;
prevent harmful substances entering the lungs
found in the trachea
What is the role of the cartilage in the mammalian gas exchange system and where is it found?
provide strength and support;
for the trachea and bronchi keeping them open;
it helps prevent collapse;
during breathing in;
as the chest volume increases;
there is negative pressure in the trachea;
What is the composition of the trachea?
C shape rings of cartilage;
ciliated epithelial cells/goblet;
elastic fibres;
smooth muscle;
What is the composition of the bronchi?
pieces of cartilage;
smooth muscle;
elastic fibres;
ciliated epithelial cells;
What is the composition of the bronchioles?
smooth muscle;
elastic fibres;
squamous epithelial cells;
What is the composition of the alveoli?
elastic fibres;
squamous epithelial cells;
When describe ventilation what are the mneumonic?
D - diaphragm
R - rib cage
V - volume of thorax
P - pressure of thorax
PG - pressure gradient
Dr VamPire PiG
What is the mechanism of ventilation when breathing in?
D = contracts and flattens
R = ribs move up and out;
external IM contract;
internal IM relax;
V = volume in the thorax increases
P = pressure in the thorax decreases
PG = air moves along the pressure gradient
What is the mechanism of expiration?
D = relaxes and rises
R = ribs move down and in;
external IM relax;
internal IM contract;
V = volume in the thorax decreases
P = pressure in the thorax increases
PG = air moves along the pressure gradient out
What is the function of the ribs?
protection of vital organs like the heart and lungs
What is the function of the diaphragm?
aids inspiration and expiration;
by contracting and flattening
What does a person do/have when using a spirometer?
healthy volunteer;
nose blocked by clip;
breathing in and out by their mouth;
at rest;
What is the use of sodalime?
absorbs carbon dioxide that is produced when the volunteer exhales;
prevent individual inhaling carbon dioxide
Draw a lung volume graph:
picture on iPad
What is the vital capacity?
max volume of air person can breathe in and out in one breath;
4 - 4.5 dm3
What is the residual volume?
air that cannot leave you lungs;
What is tidal volume?
air breathed in and out at rest in a
500cm3
What is the breathing rate?
number of breaths per minute
count peaks
What is oxygen uptake?
the volume of oxygen take up by the lungs
How is oxygen uptake calculated?
work out the gradient of a trace
gradient is steeper during exercise
Why does the data from a data logger of a spirometer decrease over time in volume?
the air breathed into the spirometer has carbon dioxide;
carbon dioxide is removed by soda lime;
the oxygen is used in aerobic respiration;
What is the formula to calculate pulmonary ventilation?
tidal volume x breathing rate
How is a bony fish specialised for gas exchange?
- have many lamella so there is a large SA for gas exchange
- presence of secondary lamellae on primary lamellae
- there is a short diffusion distance between blood and water
- countercurrent system; to maintain a conc gradient; for faster diffusion
What is the mnemonic used for ventilation in fish?
V = volume
P = pressure
W = where is the water going?
PG = pressure gradient
VamPire Water PiG
What happens when a fish opens its mouth?
fish opens it mouth;
increase in volume in the buccal cavity;
decrease in pressure;
water moves down the pressure gradient over the gills;
What happens when a fish closes its mouth?
decrease in volume in buccal cavity;
increase in pressure;
water moves down pressure gradient over the gill filaments out via the operculum;
How does gases enter and leave insects?
via spiracles > trachea > tracheoles
What is the function of tracheal fluid?
when muscle contraction occurs, aerobic respiration makes ATP;
less oxygen = anaerobic respiration;
lactic acid produced = cells pH decreases
tracheal fluid moves out of tracheoles into cell via osmosis
allows more oxygen to enter
How does an insect aid in the movement and pressure of oxygen?
thoracic and abdominal movements = helps change the volume of the body cavity = causes pressure changes = helping air drawn in and out
How would you be able to observe the spiracles in insects and gill filaments in fish?
insects = remove exoskeleton
fish = remove operculum
What is the counter current flow in fish?
blood in the gill filaments and water moving over the gills flow in opposite directions, maintaining a steep oxygen concentration gradient = faster diffusion
