Exchange surfaces

Question 1

why the Titicaca water frog has evolved the unusually large folds of skin

Answer 1

.to increase SA:VOL ratio
.increasing the level oxygen absorption

Question 2

features of the lungs provides an efficient gas exchange surface.

Answer 2

.large SA for maximum diffusion
.sqaumous epithelium cells providing short diffusion path
.good bloody supply maintaining a steep conc gradient

Question 3

reading a electrocardiogram

Answer 3

.volume below lowest dip = residual volume
.0 to highest peak = total lung capacity
.average breath = tidal volume
.biggest change of lung volume = vital capacity

Question 4

What breathing instructions would be given to a person whose vital capacity is being measured

Answer 4

.breathe in as deeply as possible
.then force as much air out as possible

Question 5

Explain how carbon dioxide produced in the respiring body cells of worker termites is removed to
the air outside the termite mound.

Answer 5

.CO2 diffuses down conc gradient out of respiring cell
.carried through body from cell by blood pass out via tracheoles
.respiration generates heat
.hot gases expand and are less dense so rise by convection to the vents of the mound-top

Question 6

why the African termites need to build mounds in this shape and orientation.

Answer 6

.shape has large SA:VOL ratio
.smallest area exposed to greastest heat

Question 7

structucres of insect tracheal system that provides a large SA for gas exchange

Answer 7

.many branched tracheae

Question 8

structucres of fish tracheal gills that provides a large SA for gas exchange

Answer 8

many filaments,lamellae,plates

Question 9

why lugworms have evolved external gills

Answer 9

.oxygen in short supply
.rate of diffusion is too slow

Question 10

structural features of trachea

Answer 10

.has cartilage,elastic fibres and goblet cells

Question 11

structural features of bronchi

Answer 11

cartilage,elastic fibres,goblet cells

Question 12

structural features of bronchioles

Answer 12

.no but yes cartilage
.has elastic fibres and goblet cells

Question 13

structural features of alveoli

Answer 13

only elastic fibres

Question 14

apparatus used to measure and record these air movements.

Answer 14

spirometer

Question 15

contrast the mechanism of expiration during the first 60 seconds of the trace with
the mechanism of expiration when the subject was told to breathe out fully.

Answer 15

.normal expiration:
.passive
.diaphragm muscles relax
.dia moves up and becomes dome shaped
.exterenal intercostal relax
.ribs move down and in
.volume of thorax reduced
.pressure in thorax increases
.pressure inside is greater than atmospheric pressure so air moves out of lungs

force expiration:
.active
.requires energy
.intercostal muscles contract
.ribs pull down hard
.abdominal muscles contract forcing diaphragm up

Question 16

outline how the respiratory
systems in a bony fish and in an insect are adapted to maximise ventilation and gaseous
exchange.

Answer 16

bony fish ventilation:
.water enters mouth
.pressure, change in buccal
cavity
.water, flows / pushed, over gills
.water leaves via operculum
.throughflow system

bony fish gas exchange:
gill, filaments / lamellae
.large surface area
.short diffusion distance
.good blood supply
.steep concentration gradient
.counter current system

insect ventilation:
.muscular movement
.abdominal
.volume / pressure, change in abdomen
.thorax, movement change, in flight
.air drawn in or forced out
.size of spiracle, changes
.external gills in aquatic insects
small size / large SA:vol of insects, means
diffusion may be sufficient

insect gas exchange
.gas diffuses along
tracheae
.oxygen dissolves in water at tracheoles
.diffuses into surrounding cells
.many tracheoles so large surface area
.spirals of chitin hold tracheae open

Question 17

why maggots do not need such well-developed exchange surfaces and transport systems.

Answer 17

.smaller so greater SA:VOL ratio
.shorter diffusion distance
.less active so lower demand for O2

Question 18

Describe how the trachea of a mammal is different from the trachea in insects

Answer 18

.mammals have one trachea and insects have multiple
.mammals have larfer diameter and insects have smaller

Question 19

roles of cartilage

Answer 19

.stops trachea and bronchus from collapsing

Question 20

roles of elastic fibres

Answer 20

.recoil of alveoli

Question 21

Outline the structures involved in the mammalian gaseous exchange system.

Answer 21

Trachea:
* cartilage rings, stop it from collapsing
* ciliated epithelium and goblet cells secrete mucus, trap dust and microbes and move them towards stomach

Bronchi / bronchioles:
.smooth muscle, allows air to move in and out and maintains high concentration gradient of O2 / CO2

Alveoli:
* thin (epithelial) wall, reduces
diffusion distance
* collagen / elastic fibres, elastic
recoil to help squeeze air out during exhalation
*provide large surface area, to increase rate of diffusion
* good blood supply / capillaries,
maintains high concentration
gradient

Diaphragm / intercostal muscles
* contract to increase volume in
lungs, reduce pressure and cause inspiration

Question 22

Why can expiration be a passive process?

Answer 22

.it does not use muscle contraction
.rib cage, falls (due to gravity)
.lungs (elastic so) will recoil

Question 23

photo of insect exchange

Answer 23

.spikey thinhg = trachea
.holes that lead outside = spiracle

Question 24

Water moves across the gills
and out of the opercular cavity

Answer 24

.mouth closes
.Operculum opens
.Highest rate of oxygen diffusion into the blood

Question 25

Water moves into the buccal
cavity

Answer 25

.Buccal cavity
floor lowers

Question 26

What is the function of the circular bands of chitin labelled in insects

Answer 26

.prevents the tracheae from collapsing

Question 27

Suggest one other way in which the presence of the mites might affect the honeybee.

Answer 27

.restricts the airflow in the trachea

Question 28

Explain how Fig. 1.1 shows that gills are adapted for efficient gas exchange.

Answer 28

.lamellae provide large SA
.secondary lamellae on lamellae provides larger SA
.short distance between blood and water

Question 29

how you would carry out the dissection to display maximum detail of either gas exchange
system.

Answer 29

.removal of operculum (of fish) or cut open exoskeleton (of insect)
.observe gills/tracheae