Exchange surfaces

Question 1

why do multicellular organisms need specialised surfaces

Answer 1

.diffusion distance is too far
.higher metabolic rates
.smaller SA:VOL ratio

Question 2

features of specialised exchange surfaces

Answer 2

.large SA
.thin walls
.good blood ventilation
.surrounded by paritaly permeable membranes

Question 2

ciliated epithelium tissue contains

Answer 2

goblet cells- produce and secrete mucus
.cilia on ciliated epithelial cells- waft mucus upwards to the mouth to be swallowed

Question 3

trachea adaptations

Answer 3

.rings of cartilage to keep airways open
.smooth muscle to contract or relax to change airflow
.elastic tissue to allow stretching and recoiling
.lined with ciliated epithelial and goblet cells

Question 4

bronchi adaptations

Answer 4

.reinforced with cartilage to keep airways open
.smooth muscle to contract or relax to change airflow
.elastic tissue to allow stretching and recoiling
.lined with ciliated epithelial and goblet cells

Question 5

bronchioles adaptations

Answer 5

.not cartilage to change shape
.smooth muscle to contract or relax to change airflow
.elastic tissue to allow stretching and recoiling
.squamous epithelium cells

Question 6

how do alveoli carry out gas exchange

Answer 6

.oxygen diffuses from alveoli into capillaries
.CO2 dissociated from haemoglobin into alveoli

Question 7

adaptations of alveoli for gas exchange

Answer 7

.large SA
.partially permeable
.surrounded by capillaries
.ventilation of air

Question 8

adapatations of capillaries for gas exchange

Answer 8

.thin walls
.red blood cells pressed against capillary walls
.large SA
.movement of blood
.slow movement of blood

Question 9

what happens in inspiration

Answer 9

.external intercoastal muscles contract while internal intercostal muscles relax
.moving the ribcage up and out
.diaphragm contracts and flattens
.this increases the volume of the thorax
.the pressure inside is lower than outside the lungs so air flows in

Question 10

what happens in expiration

Answer 10

.external intercostal muscle relax while the internal intercostal muscles contract
.moving the rib cage down and in
.diaphragm relaxes and flattens
.this decreases the thoraxs volume
.pressure inside the lungs is higher than the outside so air moves out

Question 11

spirometer traces

Answer 11

breathing rate = num of breaths per min

.tidal volume = vol of air in or out per breath at rest

.vital capacity = maximum amount of air in or out

.residual volume = vol of air still remaining in lungs after largest expiration

Question 12

how to calculate oxygen consumption

Answer 12

change in vol of gas/time

Question 13

how to calculate ventilation rate

Answer 13

tidal volume(dm3) X breathing rate

Question 14

why do insects need gas exchange

Answer 14

.they have high oxygen demands but their tough exoskeleton prevents direct gas exchange

Question 15

structure of insect gas exchange

Answer 15

tracheae = air-filled tubes branching throughout the body

tracheoles = fine branches of tracheae that deliver gases to cells

spiracles = openings of the tracheal system on the exoskeleton

Question 16

how does insect gas exchange work

Answer 16

.air enters the tracheal system through open spiracles
.air moves into tracheae and diffuses into tracheoles
.tracheoles transport the air directly into the cells
.oxygen diffuses in water in tracheal fluid and diffuses into body cells
.CO2 diffuses out into the tracheoles
.air is carried back to the spiracles and is released

Question 17

why do bony fish need respiratory systems

Answer 17

.water has less oxygen than air
.they are very active
.water us denser than air = slower diffusion of oxygen

Question 18

structure of gills

Answer 18

.gills are covered by operculum flap
.consist of stacked filament containing gill lamellae
.gill lamellae surrounded by blood vessels

Question 19

adaptations of gills

Answer 19

.lamellae give large SA
.lamellae have thin membranes
.gills have rich blood supply
.countercurrent flow of blood
.overlapping filament tips slows water down to have more time for gas exchange

Question 20

how does the countercurrent flow system work

Answer 20

.blood and water flow over lamellae at opposite directions
.oxygen-rich blood meets oxygen rich air and vise versa
.always a steep concentration gradient

Question 21

how does fish gas exchange system work

Answer 21

.fish open mouth, increasing vol of buccal cavity and decreasing pressure
.this pulls the water into the buccal cavity
.water flows over gills
.water flows out through the operculum