3.1.1 - exchange surfaces and breathing🫁

Question 1

why can single-celled organisms use diffusion alone?

Answer 1

metabolic activity of a single celled organism is usually low so o2 and co2 demands are low
large surface area to volume ratio

Question 2

features of specialised exchange surfaces

Answer 2

increased surface area
thin layers
good blood supply
ventilation to maintain a diffusion gradient

Question 3

nasal cavity features

Answer 3

large surface area with a good blood supply
goblet cells secrete mucus to trap dust and bacteria
moist surface to gases dissolve helping them to pass across gas exchange surfaces.

Question 4

trachea

Answer 4

main airway carrying clean warm moist air from the nose into the chest

Question 5

structure of the trachea

Answer 5

wide tube supported by incomplete rings of strong and flexible cartilage which stops the trachea from collapsing. lined with ciliated epithelium with goblet cells to trap dirt and other microorganisms

Question 6

effect on smoking on lungs?

Answer 6

stops the cilia from beating

Question 7

bronchus

Answer 7

trachea divides into two tubes. they are a similar structure to the trachea with same cartilage rings but smaller.

Question 8

bronchioles

Answer 8

the bronchi divide to form small bronchioles.

Question 9

structure of bronchioles

Answer 9

no caryilage rings but instead contain smooth muscle
lined with a thin layer of flattened epithelium

Question 10

role of smooth muscle in the bronchioles

Answer 10

when the smooth muscle contracts, the bronchioles constrict and vice versa, this changes the amount of air reaching the lungs

Question 11

alveoli

Answer 11

tiny air sacs which are the main gas exchange surfaces of the body

Question 12

structure of the alveoli

Answer 12

consists of layer of thin flattened epithelial cells along with collagen and elastic fibres

Question 13

adaptations of the alveoli

Answer 13

large surface area, thin layers, good blood supply, good ventilation, lung surfactant to keep the alveoli inflated

Question 14

inspiration process

Answer 14

diaphragm contracts, flattening
external intercostal muscles contract moving rib outwards and upwards
increases the volume of the thorax and the pressure is then reduced to lower than atmospheric pressure
means air is drawn in

Question 15

expiration process

Answer 15

diaphragm relaxes so moves up into the dome shape.
the external intercostal muscles relax, moving the ribs down and in
decreasing the volume of the thorax increasing pressure above atmospheric
this means air is drawn out

Question 16

exhaling forcibly

Answer 16

uses energy
internal intercostal muscles contract pulling ribs down fast and abdominal muslces contract forcing diaphragm up to increases pressure in lungs rapidly

Question 17

peak flow meter

Answer 17

simple device that measures the rate at which air can be expelled from the lungs.

Question 18

vitalographs

Answer 18

more sophisticated peak flow meter that produces a graph of the amount the person breathes out and how quickly it is breathed out

Question 19

spirometer

Answer 19

commonly used to measure different aspect of the lung volume or go investigate breathing patterns

Question 20

tidal volume

Answer 20

amount of air that moves in and out of the lungs during a normal breath

Question 21

vital capacity

Answer 21

volume of air that can be breathed in when the strongest possible exhalation is followed by deepest possible intake of breath

Question 22

inspiratory reserve volume

Answer 22

amount of air that can be forcefully inhaled after a normal tidal volume inhalation

Question 23

expiratory reserve volume

Answer 23

amount of air that can be forcefully exhaled after a normal tidal volume exhalation

Question 24

residual volume

Answer 24

amount of air remaining in lungs after a forced exhalation

Question 25

total lung capacity

Answer 25

vital capacity + residual volume

Question 26

breathing rate

Answer 26

number of breaths per minute

Question 27

ventilation rate

Answer 27

total volume of air inhaled in one minute
tidal volume x breathing rate

Question 28

exoskeleton

Answer 28

a body covering, typically made of chitin, that provides support and protection

Question 29

spiracles

Answer 29

openings in the exoskeleton of insects
air enters and leaves these holes

Question 30

spiracle sphincters

Answer 30

can open and close the spiracles to maximise gas exchange but minimise the loss of water

Question 31

tracheae

Answer 31

largest tubes of the insect respiratory system, carrying air into the body

Question 32

structure of tracheae

Answer 32

tubes are lined with spirals of chitin which keep them open.

Question 33

tracheoles

Answer 33

in insects, narrow tubes branching from tracheae and making direct contact with cells to facilitate gas exchange.
this is where most gas exchange takes place in insects

Question 34

tracheal fluid

Answer 34

fluid found at the end of the tracheoles in insects that helps control the surface area available for gas exchange and water loss

Question 35

difficulties of the fish respiratory system

Answer 35

water is 1000 times denser than air
much lower oxygen content

Question 36

parts of the gill

Answer 36

gill arches, gill filaments, gill rakers, lamelle

Question 37

lamellae

Answer 37

main site of the gaseous exchange in the fish

Question 38

operculum

Answer 38

body flap

Question 39

ram ventilation

Answer 39

continual movement to ventilate the gills - they ram the water past the gills

Question 40

gills adaptations

Answer 40

• large surface area for diffusion
• rich blood supply
• thin layers

Question 41

effect of the gill filaments overlapping

Answer 41

increases the resistance to the flow of water over the gill surfaces and slows down the movement of water - more time for gas exchange

Question 42

why does water and blood flow in different directions in fish?

Answer 42

steep concentration gradient for effective fast diffusion to take place