3.1.1 Exchange surfaces

Question 1

Why are specialised exchange surfaces needed in multi-cellular organisms?

Answer 1

smaller SA:V ratio;
oxygen cannot diffuse quick enough due to long diffusion distance to meet metabolic need;
higher metabolic activity

Question 2

Why aren’t single celled organisms require a specialised exchange surface?

Answer 2

larger SA:V ratio;
oxygen/nutrient can supply their metabolic needs due to short diffusion distance;
lower metabolic activity

Question 3

What are the features for an efficient exchange surface?

Answer 3

increased surface area;
thin layer;
good blood supply;

Question 4

Why does an increased SA used for a specialised exchange surface?

Answer 4

larger SA = increase the rate of diffusion of substance (oxygen in humans, and minerals in plants)

root hair cell
lots of alveoli

Question 5

How is a thin layer surfaces specialised for exchange surfaces?

Answer 5

thin diffusion pathways

alveoli - squamous epithelial cells - one cell thick

Question 6

How is a good blood supply/ventilation help a specialised exchange surface?

Answer 6

maintained a concentration gradient

gills in fish
alveoli in humans

Question 7

Draw an image of the mammalian gaseous exchange system?

Answer 7

image on iPad

Question 8

What is the function of goblet cells?

Answer 8

secrete mucus that traps dust/bacteria that enters the lungs;

Question 9

What is the role of the cilia in the ciliated epithelial cells?

Answer 9

cilia waft the mucus to the top of the trachea/back of the mouth;
where it is swallowed or coughed out

Question 10

Where are ciliated epithelial cells and goblet cells found?

Answer 10

trachea

Question 11

What is the role elastic fibres?

Answer 11

recoil to their original shape;
expel air;
prevent the lungs from bursting;

Question 12

What is the role of a smooth muscle?

Answer 12

contract to constrict their airways;
prevent harmful substances entering the lungs

found in the trachea

Question 13

What is the role of the cartilage in the mammalian gas exchange system and where is it found?

Answer 13

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;

Question 14

What is the composition of the trachea?

Answer 14

C shape rings of cartilage;
ciliated epithelial cells/goblet;
elastic fibres;
smooth muscle;

Question 15

What is the composition of the bronchi?

Answer 15

pieces of cartilage;
smooth muscle;
elastic fibres;
ciliated epithelial cells;

Question 16

What is the composition of the bronchioles?

Answer 16

smooth muscle;
elastic fibres;
squamous epithelial cells;

Question 17

What is the composition of the alveoli?

Answer 17

elastic fibres;
squamous epithelial cells;

Question 18

When describe ventilation what are the mneumonic?

Answer 18

D - diaphragm
R - rib cage
V - volume of thorax
P - pressure of thorax
PG - pressure gradient

Dr VamPire PiG

Question 19

What is the mechanism of ventilation when breathing in?

Answer 19

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

Question 20

What is the mechanism of expiration?

Answer 20

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

Question 21

What is the function of the ribs?

Answer 21

protection of vital organs like the heart and lungs

Question 22

What is the function of the diaphragm?

Answer 22

aids inspiration and expiration;
by contracting and flattening

Question 23

What does a person do/have when using a spirometer?

Answer 23

healthy volunteer;
nose blocked by clip;
breathing in and out by their mouth;
at rest;

Question 24

What is the use of sodalime?

Answer 24

absorbs carbon dioxide that is produced when the volunteer exhales;
prevent individual inhaling carbon dioxide

Question 25

Draw a lung volume graph:

Answer 25

picture on iPad

Question 26

What is the vital capacity?

Answer 26

max volume of air person can breathe in and out in one breath; 4 - 4.5 dm3

Question 27

What is the residual volume?

Answer 27

air that cannot leave you lungs;

Question 28

What is tidal volume?

Answer 28

air breathed in and out at rest in a 500cm3

Question 29

What is the breathing rate?

Answer 29

number of breaths per minute count peaks

Question 30

What is oxygen uptake?

Answer 30

the volume of oxygen take up by the lungs

Question 31

How is oxygen uptake calculated?

Answer 31

work out the gradient of a trace gradient is steeper during exercise

Question 32

Why does the data from a data logger of a spirometer decrease over time in volume?

Answer 32

the air breathed into the spirometer has carbon dioxide; carbon dioxide is removed by soda lime; the oxygen is used in aerobic respiration;

Question 33

What is the formula to calculate pulmonary ventilation?

Answer 33

tidal volume x breathing rate

Question 34

How is a bony fish specialised for gas exchange?

Answer 34

- 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

Question 35

What is the mnemonic used for ventilation in fish?

Answer 35

V = volume P = pressure W = where is the water going? PG = pressure gradient VamPire Water PiG

Question 36

What happens when a fish opens its mouth?

Answer 36

fish opens it mouth; increase in volume in the buccal cavity; decrease in pressure; water moves down the pressure gradient over the gills;

Question 37

What happens when a fish closes its mouth?

Answer 37

decrease in volume in buccal cavity; increase in pressure; water moves down pressure gradient over the gill filaments out via the operculum;

Question 38

How does gases enter and leave insects?

Answer 38

via spiracles > trachea > tracheoles

Question 39

What is the function of tracheal fluid?

Answer 39

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

Question 40

How does an insect aid in the movement and pressure of oxygen?

Answer 40

thoracic and abdominal movements = helps change the volume of the body cavity = causes pressure changes = helping air drawn in and out

Question 41

How would you be able to observe the spiracles in insects and gill filaments in fish?

Answer 41

insects = remove exoskeleton fish = remove operculum

Question 42

What is the counter current flow in fish?

Answer 42

blood in the gill filaments and water moving over the gills flow in opposite directions, maintaining a steep oxygen concentration gradient = faster diffusion