exchange surfaces and breathing

Question 1

why does diffusion work alone for single celled organisms

Answer 1

metabolic activity low
Sa:V large

Question 2

why larger organisms can’t depend on diffusion

Answer 2

distance between supply of oxygen and cells that need it too large
higher metabolic activity

Question 3

volume of a sphere

Answer 3

4/3 pi R^3

Question 4

surface area of sphere

Answer 4

4 pi R^2

Question 5

exchange surfaces have common characteristics

Answer 5

increased SA
thin layers
good blood supply
ventilation

Question 6

why is there a conflict for humans between the need for gaseous exchange and for water

Answer 6

exchange surfaces moist so oxygen dissolves in water before diffusing into body tissues
this also ideal for evaporation of water but this wants to be minimised

Question 7

why do mammals have high metabolic activity

Answer 7

maintain body temperature independent of environment

Question 8

features of a nasal cavity

Answer 8

large sa and good blood supply warms air to body temp
hairy lining secretes mucas protect lungs from infection
moist surfaces increase humidity of air which reduces evaporation

Question 9

trachea is a wide tube supported by

Answer 9

strong flexible cartilage
stops it collapsing

Question 10

why are the rings of cartilage incomplete

Answer 10

food can move down oesophagus which is behind trachea

Question 11

what is trachea lined with

Answer 11

ciliated epithelium and goblet cells between

Question 12

why is smoking harmful in terms of trachea

Answer 12

stops cilia beating which moves the trapped microorganisms to the throat to be digested

Question 13

trachea divides into

Answer 13

left and right bronchus
same supporting rings of cartilage but smaller than trachea

Question 14

in the lungs bronchi divide into

Answer 14

bronchioles
no cartilage rings
contain smooth muscle
lined with flattened epithelium

Question 15

when smooth muscle of bronchiole contract

Answer 15

bronchioles constrict, when relax they dilate
changes amount of air reaching lungs
flattened epithelium makes some gas exchange possible

Question 16

alveoli are tiny air sacs and consist

Answer 16

of one layer of flattened epithelium cells along with collagen and elastic fibres(elastin) allowing to stretch and return to shape

Question 17

what is the elastic recoil of the lungs

Answer 17

alveoli stretch as air drawn in and return to resting size squeeze air out

Question 18

adaptations of alveoli

Answer 18

large SA
thin layers (capillaries and alveoli single epithelial cell thick) diffusion distance short
good blood supply maintains steep concentration gradient for CO2 and O2
good ventilation helps maintain diffusion gradient

Question 19

what does lung surfactant do

Answer 19

prevents alveoli from collapsing during exhalation

Question 20

describe process of inspiration (inhalation) which requires energy

Answer 20

diaphragm contracts (flattens and lowers)
external intercostal muscles contract which moves ribs up and out
vol of thorax increases pressure decreases lower than atmospheric air so air drawn in

Question 21

describe expiration (passive)

Answer 21

muscles of diaphragm relax moves up and into done shape
external intercostal muscles relax which moves ribs move down and inwards
elastic fibres in alveoli return to normal length
decreases volume increases pressure so air moves out

Question 22

when you exhale using energy

Answer 22

internal intercostal muscles contract which moves ribs down hard and fast
abdominal muscles contract which forces the diaphragm up which increases pressure in lungs rapidly

Question 23

Tidal volume is the

Answer 23

volume of air that is breathed in or out

Question 24

vital capacity

Answer 24

is the volume of air that can be expelled after the deepest breathers strongest exhalation

Question 25

inspiratory reserve volume is

Answer 25

the max volume of air you can breathe in over a normal inhalation

Question 26

expiratory reserve volume

Answer 26

is the extra amount of air that you can force out of lungs above the normal tidal volume of air you breathe out

Question 27

residual volume

Answer 27

the volume of air that is left in lungs after exhale as hard as possible

Question 28

Total lung capacity is the

Answer 28

sum of residual volume and vital capacity

Question 29

ventilation rate =

Answer 29

tidal volume x breathing rate

Question 30

What do insects have or not have that makes gaseous exchange difficult

Answer 30

tough exoskeleton no blood pigments that carry oxygen

Question 31

what are the small openings in the thora of insects called

Answer 31

spiracles

Question 32

what is the tracheae of insects made up of and features of this

Answer 32

Chitin keep open if pressed impermeable to gases so little gas exchange takes place here

Question 33

what are tracheoles

Answer 33

single elongated cells with no chitin lining permeable to gas exchange large SA because amount of them moisture on tracheole walls mean oxygen dissolves then diffuses into surrounding cells

Question 34

when oxygen demands are low in an insect, what limits gas exchange

Answer 34

tracheal fluid at end of tracheoles limits penetration of air for diffusion

Question 35

when oxygen demands are up in an insect,

Answer 35

lactic acid build up in tissues(due to anaerobic respiration) means water moves out of tracheoles by osmosis. Exposes more SA for diffusion

Question 36

Two adaptations of insects like bees that have high energy demands

Answer 36

mechanical ventilation of tracheal system (muscular pumping movements of thorax and abdomen changes pressure) collapsible enlarged tracheae (increases amount of air moved through. inflated deflated by ventilating movements of thorax and abdomen)

Question 37

Features of gills

Answer 37

larger surface area thin walls good blood supply

Question 38

afférent blood vessel brings

Answer 38

blood into system and efferent takes it out

Question 39

what is the main site of gas exchange in fish and features

Answer 39

gill lamellae good blood supply and large SA

Question 40

Gill filaments occur in stacks (gill plates) they need

Answer 40

water flow to separate them and expose the large SA

Question 41

Describe ventilation system of bony fish when mouth opens

Answer 41

buccal cavity increases in volume and decreases in pressure so water moves into it opercular valve is shut opercular cavity expands which lowers pressure in it buccal cavity decreases in size increasing pressure so water moves over gills

Question 42

describe ventilation system of bony fish when mouth closes

Answer 42

operculum opens and sides of opercular cavity move in which increases pressure which forces water over gills and out of operculum

Question 43

Name two extra adaptations of gills

Answer 43

1.tips of adjacent gill filaments overlap increases resistance to flow of water which slows movement of water over gills allowing for more gas exchange 2. counter current exchange system of blood in gill filaments and water flow ensures steeper concentration gradients so more gaseous exchange can take place