respiratory system

Question 1

describe homeostatic functions of the lung. (4)

1. gas exchange occurs…

Answer 1

1. between atmosphere and blood to provide oxygen to tissues and remove CO2 generated in oxidative metabolisation

O2 + food =CO2 = HO2 +APT

Question 2

2. regulates body PH by

Answer 2

retaining or eliminating CO2

Question 3

3. controls blood pressure

Answer 3

through the conversion of angiotensin 1 to angiotensin 2

Question 4

airflow occurs by

Answer 4

bulk flow

Question 5

airflow occurs by

Answer 5

bulk flow i.e.
high pressure to low pressure

(1r to the 4th power)

F=(P1-P2)/R

Question 6

lung connected to chest wall by

Answer 6

pleura

Question 7

describe conducting zone (4)

Answer 7

1. leads from outside body to inside lungs
2. nasal cavity, pharynx, trachea, bronchus and bronchioles
3. total volume 150ml
4. anatomical dead space

Question 8

respiratory zone

Answer 8

1. gas exchange
2. bronchioles, alveolar ducts, alveoli
3. 3 litre volume

Question 9

3 types of cells in lungs

Answer 9

TYPE 1- thin epithelial cells that line 90% of alveoli surface area. gas diffuses across these cells and into blood

TYPE 2- synthesise, secrete and metabolise alveolar surfactant, a lipid rich substance that prevents lungs from collapsing

ALVEOLAR MACRROPHAGES - the clean-up cells, attracted to infection, trauma or inhaled particles

Question 10

PA

Answer 10

pressure in alveoli

Question 11

Patm

Answer 11

atmospheric pressure

Question 12

pressure in breathing

Answer 12

air flows into the mouth until PA=Patm

Question 13

normal ventilation rate

Answer 13

10-18 breaths per min

Question 14

ventilation rate controlled by

Answer 14

medulla oblongata

Question 15

FRC

Answer 15

functional residual capacity

resting volume of lung and chest wall 2.5 litres

Question 16

RV

Answer 16

residual volume

air left after maximal exhalation (1.5l)

25% of TLC

Question 17

TV

Answer 17

tidal volume

air inhaled/exhaled each breath .5 l (females 20-25%less)

Question 18

ERV

Answer 18

expiratory reserve volume

maximal exhalation volume from resting exhalation level (1 Litre in males)

Question 19

IRV

Answer 19

volume of air that can be inspired after normal insipiration (3 Litres in males)

Question 20

IC

Answer 20

Inspiratiory Capacity

Maximal volumme of air tha can be inspired from resting level 3.5 litres

Question 21

VC

Answer 21

Vital Capacity

maximal volume of air that can be exhaled after maximal inspiration

Question 22

TLC

Answer 22

Total Lung Capacity

Volume in lungs at end of maximal inhalation 6 litres

Question 23

Lung Compliance

Answer 23

stretchability of lung for any 1 cm change in pressure

determined by elastic tissue in lung and surface tension generated at water-air interfaces withing alveoli