Gas exchange in mammals

Question 1

in what ‘segment’ of the body are the lunch found

Answer 1

thorax

Question 2

In what conditions are the lungs suspended and what does this mean

Answer 2

In an airtight compartment, bounded by the diaphragm and ribs so there is only one means of air entering the lungs

Question 3

Epiglotis

Answer 3

Flap of cartilage responsible for closing off the trachea to direct swallowed food into the oesophagus

Question 4

Trachea

Answer 4

Air pipe into the lungs

Question 5

Intercostal muscles?

Answer 5

Muscle between the ribs, involved in ventilation

Question 6

Bronchi

Answer 6

Air pipes following on from the trachea into the lungs

Question 7

Bronchioles

Answer 7

Air pipes branching off of bronchi, leading into the alveoli

Question 8

Diaphragm

Answer 8

Layer of muscle beneath the lungs

Question 9

Role of the cartilaginous rings on the trachea 4parts

Answer 9

Protect from impact
Support the trachea and bronchi, hold them open to prevent collapse when pressure drops during inspiration: low resistance to air flow

Question 10

Role of smooth muscle lining trachea

Answer 10

Caan contract and relax to change size of the trachea lumin, controls vol of air that enters

Question 11

Role of cilliated epithelium in trachea

Answer 11

Waft mucus/ debris up the trachea to be coughed up to the back of the throat ot be swallowed

Question 12

Role of goblet cells in trachea

Answer 12

Produce mucus to trap debris and pathogens

Question 13

What is the shape of cartilaginous rings of the trachea

Answer 13

C shaped: incomplete rings

Question 14

Why are the cartilaginous rings incomplete

Answer 14

To allow the oesophagus to expandin the back of the trachea when a bolus of food is passing down

Question 15

What type of epithelium are the diluted cells of the trachea

Answer 15

simple cuboidal

Question 16

What is the specific gas exchange surface in the lungs

Answer 16

alveoli

Question 17

How are alveoli suited for their role 5

Answer 17

They increase SA
They have a moist surface so gases can dissolve
The walls are thin: short diffusion path
Well ventilated bc of inhalation and exhalation

Question 18

What are the walls of the alveoli made of

Answer 18

Simple squamous epithelium

Question 19

Components of trachea

Answer 19

Cartilaginous rings
Elastic fibres
Smooth muscle
Cilliated epithelium
Goblet cells

Question 20

Function of elastic fibres in the alveolus

Answer 20

Stretch on inhalation, so alveoli expand increasing SA
Recoil on exhalation to force out more air

Question 21

Where are goblet cells found

Answer 21

Trachea, bronchi, bronchioles

Question 22

where are cilliated epithelium in gas exchange system

Answer 22

Trachea and bronchi

Question 23

where is cartilage found in gas exchange systems

Answer 23

Trachea, bronchi, bronchioles

Question 24

where are elastic fibres found in gas exchange systems

Answer 24

trachea, bronchi, bronchial and alveoli

Question 25

Where is smooth muscle found in gas exchange systems

Answer 25

Trachea, bronchi, bronchioles

Question 26

Without surfactant, why would an alveolus have the tendency of collapsing in on itself/ stick together

Answer 26

Has moist surface, cohesion between water molecules pulls the walls of the alveolus inwards

Question 27

What would be the overall problem caused if surfactant wasnt present 3

Answer 27

Collapsed alveoli Poor blood oxygenation Respiratory distress

Question 28

Surfactant? 3

Answer 28

Phospholipoprotein, stops alveoli from sticking/collapsing by reducing surface tension in alveoli

Question 29

How many pleural membranes surround the lung

Answer 29

2

Question 30

Function of the plural membranes

Answer 30

Ensure the thorax is air tight

Question 31

Pleural space/ cavity

Answer 31

Fluid filled space between pleural membranes

Question 32

Function of pleural fluid (between membranes) 2

Answer 32

Lubricates: reduces friction as lungs move Acts as shock absorber

Question 33

What happens to the external intercostal muscles and diaphragm during inspiration

Answer 33

External intercostal muscles contract, pulls ribcage upward and outward

Question 34

Effects of the movements of the system during inhalation 3

Answer 34

Vol of lungs and thorax increased Pressure reduced Air enters the lungs moving down the pressure grad

Question 35

What is a reduction in pressure called

Answer 35

negative pressure

Question 36

Is inspiration an active or passive process, y?

Answer 36

Active bc muscles contract

Question 37

Is relaxed expiration active or passive and y

Answer 37

Passive bc muscles relax

Question 38

What happens to external intercostal muscles and ribcage during relaxed expiration

Answer 38

External intercostal muscles relax and ribcage falls under its weight

Question 39

What happens to the diaphragm during inspiration

Answer 39

Contracts, pulls flat from domed

Question 40

What happens to the diaphragm during expiration

Answer 40

Relaxes and gut pressure pushes it back to dome

Question 41

What happens to lung tissue during expiration

Answer 41

elastically recoils

Question 42

Affect of physical changes during expiration 3

Answer 42

Volume of thorax and lungs decrease Pressure increases Air forced out

Question 43

Ventilation

Answer 43

Movement of air in and out of the lungs via trachea

Question 44

2 phases of ventilation

Answer 44

Inspiration and expiration

Question 45

Negative pressure breathing?

Answer 45

For air to enter the lungs, pressure in the lungs must be below atmospheric pressure

Question 46

what happens to the pleural membranes and alveoli during inspiration

Answer 46

Outer, attached to thoracic cavity wall so move up and out with ribs, inner follows Lungs expand, increase vol of alveoli

Question 47

Why is expired air high in water vapour

Answer 47

Alveoli are permanently lined with moisture, some water evapourates and is exhaled

Question 48

Which intercostal muscles are involved in forced expiration

Answer 48

Internal intercostal muscles

Question 49

What forces the diaphragm up into a dome during forces expiration

Answer 49

Abdominal muscles contracting

Question 50

What happens to the internal intercostal muscles during forced expiration

Answer 50

Contract, pulling ribcage in and down

Question 51

How does movement of the intercostal muscles and ribcage affect the pleural cavity, inner pleural membrane, lungs and alveoli

Answer 51

Pleural membran is pulled out so pressure in pleural cavity drops and inner pleural membrane is pulled outwards pulling th surface of the lungs and causing alveoli to expand.

Question 52

What is the benefit of internal lungs

Answer 52

minimise heat and water loss

Question 53

How do frogs do gas exchange when inactive and active

Answer 53

Through Moist skin when inactive Lungs when active