Respiratory system

Question 1

exhalation

Answer 1

internal intercostals contract, pulling the ribs inwards and downwards, and increasing air pressure

diaphragm and external intercostals relax, reducing thoracic volume and increasing air pressure

internal air pressure is now greater than the external air pressure, air flows out

Question 2

gas exchange

Answer 2

passive process, oxygen and carbon dioxide molecules move through diffusion

O2 enters blood stream
CO2 enters alveoli

Question 3

alveoli gas exchange features

Answer 3

1. large surface area
2. large blood supply
3. permeable structures
4. moist surfaces

Question 4

pleural membranes

Answer 4

consists of two layers

prevents friction, keeps lungs separated, holds tissue to chest wall

Question 5

nasal cavities

Answer 5

contain conchae covered by mucous and hair, increase surface area

warms, filters and moistens the air

Question 6

trachea

Answer 6

hold open by c-shaped rings of cartilage held together by muscle - maintains shape, allows movement of the bolus

Question 7

ciliated epithelium

Answer 7

cilia rhythmically beat to move mucous and debris upwards and out of the lungs
once debris reach the mouth, it’s usually swallowed

Question 8

inhalation

Answer 8

diaphragm contracts during inhalation - increases thoracic volume and decreases lung air pressure

external intercostals contract, lifting ribs upwards and outwards, increasing thoracic volume and decreases air pressure

external air pressure is now greater than internal air pressure - air flows into the lungs