surfaces

Question 1

what factors affect the need for an exchange system?

Answer 1

size
SA to V ratio
level of activity

Question 2

what adaptations give a large SA to V ratio

Answer 2

shape of body e.g flatworm

Question 3

how should SA to V be represented

Answer 3

ratio: 1

e. g 2.5:1

Question 4

what are the features of a good exchange surface?

Answer 4

A large surface area through folding

a thin barrier

a good blood supply

Question 5

what is the diaphragm

Answer 5

a layer of muscle beneath the lungs

Question 6

what are the intercostal muscles

Answer 6

muscles between the ribs

contraction raises ribcage.

Question 7

what gives lungs a large surface area?

Answer 7

the number of alveoli makes the total SA more than that of our skin 70m^2
it is lined by moisture preventing from collapse.

Question 8

permeability of lungs

Answer 8

barrier is comprised of alveoli wall and capillary wall which allow diffusion as o2 and CO2 molecules are small and non polar

Question 9

thin barrier of lungs

Answer 9

alveolus 1 cell thick
capillary wall 1 cell thick
both walls squamous cells
both walls in close contact 
narrow capillary so blood cell closer to air

Question 10

blood supply to the lungs

Answer 10

CO2 transported to lungs

O2 transported away from lungs

Question 11

Inspiration

Answer 11

diaphragm contracts moving down
intercostal muscles contract raise ribs
volume of chest increases 
pressure is chest drops
air moves in

Question 12

Expiration

Answer 12

diaphragm relaxes and is pushed up
intercostal muscles relax and ribs fall (or can contract during coughing)
volume of chest decreased 
pressure in lungs increases
air forced out

Question 13

cartilage

Answer 13

form of connective tissue

Question 14

elastic fibres

Answer 14

protein fibres that deform and recoil to original size

Question 15

smooth muscle

Answer 15

involuntary muscle

Question 16

what helps push air out during expiration?

Answer 16

elastic fibres in the alveoli walls

Question 17

what are the requirements of the airways?

Answer 17

be large enough for sufficient air flow
be supported to prevent collapse
be flexible for air movement

Question 18

how are the airways supported

Answer 18

by c shaped rings of cartilage allowing flexibility

Question 19

the bronchioles

Answer 19

narrower that bronchi
larger ones have some cartilage but smaller ones have none
comprised of smooth muscle and elastic fibres

Question 20

how can the air flow be controled

Answer 20

by the contraction of the smooth muscle making the lumen narrow

Question 21

why is controlling air flow important

Answer 21

if there is harmful substances in the air

Question 22

what elongates the smooth muscle after contraction?

Answer 22

the elastic fibres

Question 23

oxygen uptake

Answer 23

the volume of oxygen absorbed by the lungs in one minute

Question 24

tidal volume

Answer 24

the volume of air inhaled or exhaled in one breath usually at rest

Question 25

spirometer

Answer 25

a device that can measure movement of air into and out of the lungs

Question 26

vital capacity

Answer 26

the greatest volume of air that can be expelled from the lungs after taking the deepest breath possible

Question 27

what does a float chamber spirometer consist of

Answer 27

a chamber of air or medical grade oxygen floating on a tank of water movement of lid is measured

Question 28

what happens to the exhaled air

Answer 28

it passes through a soda lime which absorbs CO2

Question 29

precautions with spirometer

Answer 29

``` healthy subject fresh soda lime no air leaks sterilised mouth piece water chamber not overfilled ```

Question 30

what does vital capacity depend on?

Answer 30

the size of the person the age level of exercise

Question 31

what is residual volume

Answer 31

volume of air that remains in lungs after forced expiration | aprox 1.5dm^3

Question 32

how can we find rate of O2 uptake?

Answer 32

CO2 is absorbed by soda lime so the volume in the tank decreases therefore by finding the gradient of the decrease we can find the rate of decrease

Question 33

breathing rate

Answer 33

breaths per min

Question 34

filaments

Answer 34

slender branches of tissue that make up the gill often called primary lamellae

Question 35

lamellae

Answer 35

folds of the filament to increase SA sometimes called secondary lamellae

Question 36

operculum

Answer 36

bony flap that covers and protects the gills

Question 37

spiracle

Answer 37

external opening that allows air in and out of tracheae

Question 38

tracheal system

Answer 38

a system of air filled tubes in insects

Question 39

how does O2 concentration in water compare to air

Answer 39

its lower

Question 40

what provides a large surface area on the gills?

Answer 40

the lamellae folds on the fillaments

Question 41

point of counter current flow

Answer 41

to absorb the maximum amount of oxygen from water

Question 42

how is water pushed over the gills

Answer 42

the bucal cavity opens and closes pushing water down and movement of operculum is coordinated with this movement

Question 43

how do insects transport oxygen?

Answer 43

with an open circulatory system acting as both blood and tissue fluid

Question 44

airs pathway through the insect

Answer 44

enters through spiracle and enters tracheal system first through trachea the branch of into tracheoles filled with tracheal fluid were gas exchange takes place

Question 45

ventilation in insects

Answer 45

sections of trachea system expands and contracts | movement of wings alter volume of thorax