respiration and gaseous exchange

Question 1

how is the inside of the thorax separated from the 2 lungs

Answer 1

by pleural membranes

Question 2

what is the function of pleural fluid

Answer 2

acts as lubrication so surfaces of lungs dont stick to inside of chest wall

Question 3

describe the mechanism of keeping airway clean

Answer 3

mucus is secreted to trap bacteria and dirt

cilia beat backward and forward sweeping mucus out

Question 4

what does ventilation mean

Answer 4

moving air in and out of lungs

Question 5

what happens to the muscles during exhalation

Answer 5

diaphragm muscles relax
becoming dome shaped
intercostal ms contract pulling ribs down and in
volume of thorax dec
vice versa during inhalation

Question 6

design an experiment comparing CO2 content of inhaled and exhaled air

Answer 6

2 test tubes
one long tube and one short in each
same vol of limewater in each test tube
connecter between test tubes
seal with bung
person breathes in and out gently through test tube
limewater in exhaled test tube will turn milky
clean tube to prevent infection

Question 7

how can breathing volumes be measured

Answer 7

spirometer

Question 8

what is tidal vol

Answer 8

vol of air breathed in and out with one normal breath

Question 9

what is vital capacity

Answer 9

diff between max breath in and max breath out

Question 10

what is the residual vol

Answer 10

vol of air left even after a person has breathed out

Question 11

what is lung capacity

Answer 11

max total vol of lungs

Question 12

how can lung capacity be measured

Answer 12

large bell jar is marked to 6dm3
placed open end downward in a large bucket
rubber bung is removed
position of bell jar is adjusted until water mark is at 0
bung is then replaced
person wearing nose clip breaths in as deeply as possible through piece of rubber tubing
second person supports weight of bell jar and slowly moves it up so water levels inside and outside stays the same
when person is finished exhaling new vol on scale is noted
repeats

Question 13

which receptors detect inc in CO2 in blood

Answer 13

medulla in brain

aorta and carotid arteries leading to heart

Question 14

effects of smoking

Answer 14

smoke destroys cilia so mucus builds up with trapped bacteria causing infections and bronchitis
damages walls of alveoli causing them to break down which dec SA for gas exchange and emphysema
carcinogens which cause cells to divide uncontrollably causing tumours and lung cancer
nicotine is addictive
carbon monoxide combines with Hb forming carboxyhb and less O2 binds with Hb