Respiratory system and gaseous exchange

Question 1

function of nose (3)

Answer 1

1. nostril hair and mucus trap dust
2. detect scent and chemicals
3. air warmed and moistened before entering lungs

Question 2

function of trachea (2)

Answer 2

1. mucus trap foreign particles

2. cillia sweep mucus with trapped particles up and out into oesophagus

Question 3

describe how the alveoli in the lungs are structurally adapted for their function (4)

Answer 3

1. one-cell thick alveolar wall
   - decrease diffusion dist, increase rate of exchange
2. thin film of moisture (lining inner alveolar walls)
   - dissolve gases, increase rate of diffusion
3. dense network of capillaries (surrounding alveoli)
   - constant flow of blood in cap., steep concentration gradient for diffusion, continuous and increased rate of gaseous exchange
4. bulbous shape and numerous in number (only for plural alveoli!!)
   - increase surface area of alveoli, increase rate of exchange

Question 4

movement of carbon dioxide at respiring tissues (3)

Answer 4

1. higher concentration of co2 at tissue cells, constant respiration, co2 diffuses into blood, and RBCs
2. co2 + h2o in reversible reaction, catalysed by carbonic anhydrase, form carbonic acid h2co3
3. h2co3 reversibly dissociates into h+ and hco3-, carried in blood plasma (some dissolved co2 carried in RBCs)

Question 5

movement of co2 at alveolus

Answer 5

1. hco3- ions diffuse back into RBCs, converted back to h2co3
2. h2co3–> h2o + co2 (w carbonic anhydrase)
3. lower concentration of co2 in alveolus due to constant exhalation, co2 diffuse into alveolus and is expelled

Question 6

what happens during inhalation and exhalation to intercostal muscles

Answer 6

inhalation:
Relaxed Internal Contracted External (RICE)
exhalation:
External Relaxed, Internal Contract

Question 7

what happens during inhalation and exhalation to Ribs and sternum

Answer 7

inhalation:
ribcage swing upwards and outwards, sternum raised
exhalation:
ribcage swings downwards and inwards, sternum lowered

Question 8

what happens during inhalation and exhalation to diaphragm muscles and diaphragm

Answer 8

inhalation:
diaphragm muscles contract, diaphragm flattens
exhalation:
diaphragm muscles relax, diaphragm arches upwards

Question 9

what happens during inhalation and exhalation to thoraccic cavity

Answer 9

inhalation:
volume increases, pressure decreases
exhalation:
volume decreases, pressure increases

Question 10

what happens during inhalation and exhalation to lungs

Answer 10

inhalation:
expand, pressure decreases to lower than atmospheric pressure
exhalation:
compresses, pressure in lungs increases to higher than atmospheric pressure

Question 11

what is the air movement during inhalation and exhalation

Answer 11

inhalation: air rushes into lungs
exhalation: air rushes out of lungs