Chapter 7 Key Concepts

Question 1

Why are the amoeba able to rely on diffusion alone?

Answer 1

Low metabolic activity . So low oxygen demands and low CO2 production

Large SA: V

Question 2

4 charateristics of a specicalised exchange surface

Answer 2

Increased SA
Thin layers
Good blood supply
Ventilation to maintain diffusion gradient

Question 3

Why the increased SA for exchanged surfaces

Answer 3

Provides area needed for exchange

To overcome limitations of SA:V eg root hair cells and villi

Question 4

Why the thin layers for exchanged surfaces

Answer 4

Short diffusion distances
Process is fast and efficient
Eg alveoli and villi

Question 5

Why the good blood supply for exchanged surfaces

Answer 5

Steeper con grad means faster diff
Ensures substances constantly being removed and delivered to ex surface maiming steep con grad eg alveoli gills and villi

Question 6

Why the ventilation for exchanged surfaces

Answer 6

For gases
Helps maintain steep con grad for increased efficiency
Eg alveoli and fish (flow of water carrying dissolved gas)

Question 7

Adaptations of the nasal cavity

Answer 7

Large SA with good blood supply that warms air to room temp

hairy lining that secreted mucus to trap dust and bacterial protecting delicate lung tissue from irritation and infection

Moist surfaces, increase the humidity of incoming air to reduce Evap from the exchange surface

Question 8

Adaptations of the trachea

Answer 8

Main airway carrying clean warm moist air from nose to chest
Strong flexible Incomplete Cartilage rings
-stop trachea collapsing
-incomplete so food can move down the oesophagus behind the trachea

Lined with ciliated epith cells with goblet cells between and below the cili epith

Question 9

Adaptations of the bronchus

Answer 9

Left and right. Each leading to the lung.
Similar structure to trachea
Same supporting rings of cartilage but smaller

Question 10

Adaptations of the bronchioles

Answer 10

No cartilage
Walls have smooth muscle
-smooth muscle contracts, the bronchioles constrict and vice versa
-some gas ex poss as they’re lined with thin layer of flattened epith

Question 11

Adaptations of the alveoli

Answer 11

Epithelial cells, collagen, elastic fibres for elastic recoil so alveoli can stretch as air drawn in and they help squeeze air out 
Large SA
Thin layers
Good blood supply
Good ventilation

Question 12

Why does an alveoli need a large SA

Answer 12

If the lungs were like balloons SA nah big buff for amount of O2 needed to diffuse into the body

Question 13

Why does an alveoli need thin layers

Answer 13

Alveoli and Capps have one epithiual cell thin

Thin diffuse distance entre blood and air

Question 14

Why does an alveoli need good blood supply

Answer 14

Brings CO2 and carries away O2, maintain a steep con grad

Question 15

Why does an alveoli need good ventilation

Answer 15

Breathing moves air in and out of the alveoli helping maintain steep diff gradients

Question 16

Role of the lung surfactant

Answer 16

The inner layer of the alveoli is convered in a solution of water salts and lung surfactant

Surfactant makes it possible for alveoli to remain inflated
O2 dissolves in water before diffusing into the blood but also can Evap into air the in the alveoli

Question 17

What happens to the tidal volume and breathing rate as you exercise

Answer 17

Tidal vol of air moved in each breath increase from like 15 to 50 percent of the vital capacity

Breathing rate increases too so incre

Question 18

how is more SA exposed for gas exchange in an insect

Answer 18

when ox demand builds up, lactic builds up in tissues so water moves out of trachioles via osmosis

Question 19

how do larger insects eg beetles locust and grasshoppers with very high energy demands supply the excess oxygen they need

Answer 19

mechanical ventilation of the tracheal system

collapsible enlarged tracheae or airs sacs that act as reservoirs

Question 20

explain the use of collapsible enlarged tracheae or airs sacs that act as reservoirs in larger insects

Answer 20

used to increase amount of air moved thorough the gas ex system
usually inflated and deflated by the ventilating movements of the abdo and thorax

Question 21

how does the mechanical ventilation of the trachael system

Answer 21

air actively pumped into the system by muscular pumping of the abdo and or thorax

pumping changes the vol of bod
as pressure of the tracheae and tracheoles changes air moved in or expelled out

Question 22

why do fish need special respiratory systems?

Answer 22

water is viscous and has less o2 in it
it would use up too much energy to move viscous water in and out of lung like things
-SA V too small
-scales doesn’t allow gas ex

Question 23

describe the process of ram ventilation

Answer 23

ram water past the gills. meaning they cant stop moving

Question 24

in what primitive species does ram ventilation happen

Answer 24

cartilaginous fish eg sharks and rays

Question 25

5 adaptations of the thin feathery gills

Answer 25

large SA for diff
rich blood supply to maintain steep grad for diff
thin layers so short diff distance
countercurrent exchange system
tips of adjacent gill filaments overlap

Question 26

what does it mean if the tips of the gill filaments overlap?

Answer 26

increased resistance to flow of water over the gills
slows down movement of water

more time for gas ex to occur