BELL JAR/ RIB CAGEBRONCHUSBALLOON/LUNGRUBBER SHEET/DIAPHRAGM TRACHEAE

EXPLAIN HOW YOU CAN RELATE THE ACTION PULLING AND PUSHING THE RUBBER SHEET TO THE PROCESS OF INHALATION AND EXHALATION IN THE HUMAN BREATHING MECHANISMWhen the rubber sheet is pulled downwards, The air pressure inside the bell jar is loweredThis causes the balloon to expandThis action represents the inhalation process in breathing mechanismANSWER

When the rubber sheet is pushed upwards,The air pressure inside the bell jar is increased,This causes the balloon to contractThis action represents the exhalation process in the breathing mechanism

STERNUMBACKBONEBACKBONERIB CAGEEXTERNAL INTERCOSTAL MUSCLEADBCINTERNAL INTERCOSTAL MUSCLE

SITUATION ASITUATION BRUBBER BAND ARUBBER BAND B

When rubber band A is elongated by being pulled down, Rubber band B is shortensCausing X and Y to move downwards

When the external intercostal muscle relax (A is elongated and extended),The internal intercostal muscle (B is shortened),This action causes the ribs (X and Y) to move downwards and inwards.This stimulates the process exhalation

When rubber band B is elongated by being pushed up,Rubber band A shortens,Causing X and Y to move up

When external intercostal muscle contract (A is shortened) The internal intercostal muscle (B is elongate and extended)This causes the ribs to move upwards and outwardsThis stimulates the process of inhalation

Why is cotton wool used in this experiment? What analogy can you draw by using the cotton wool?to make it easy to observe the color changes.cotton wool represents the alveoli/lung tissuesWhat is the function of the universal indicator?to determine whether the content of cigarrete smoke is acidic or alkaline

3.Explain the changes in the temperature, smell and colour of the cotton wool and the colour of the universal indicator after the cigarrete is lighted.After the experiment the temperature will increase due to the heat released by the lighted cigarrete The color of the cotton wool changes from white to yellow ish/brownish because the tar from the cigarrete smoke condenses on the cotton wool. The cotton wool emits a strong nicotine smell.The colour of universal indicator changes from yellow because oxides of nitrogen in cigarrete smoke dissolve in it and make it acidic

4. How do these changes affect the respiratory system and the body tissues of a person who smokes?

The heat released by the burning cigarette increases the body temperature and damages the tissue lining in the alveoli in the respiratory tractTobacco tar from the cigarrete deposits on the lungs to become blackishThe acidic condition corrodes and damages the ephitelial tissues of the lungs

Length of air column(inhaled air) = x cmLength of air column upon adding the alkaline potassium hydroxide solution = y cmLength of air column upon adding the potassium pyrogallate solution = z cmLength of air column occupied by carbon dioxide = ( x-y ) cmLength of air column occupied by oxygen = ( y-z ) cm

Percentage of carbon dioxide in inhaled air = (x-y) cm x 100% x cm = P%

Percentage of oxygen in inhaled air = ( y-z ) cm x 100% x cm = Q%

Why is it necessary to use potassium hydroxide solution before the potassium pyrogallate solution?Potassium hydroxide solution absorbs only carbon dioxide while alkaline potassium pyrogallate solution absorbs both oxygen and carbon dioxide

Compare the percentages of carbon dioxide in inhaled air (P) and exhaled air ( R ) and the percentages of oxygen inhaled air (Q) and exhaled air (S). Which samples have a higher percentage ? Explain why. The percentage of carbon dioxide in inhaled air (P%) is lower than the percentage of carbon dioxide in exhaled air (R%) while the percentage of oxygen in inhaled air (Q%) is higher than the percentage of oxygen in exhaled air (S%)This is because inhaled air has a higher oxygen content but a lower carbon dioxide content as compared to exhaled air which has a lower oxygen content but a higher carbon dioxide content

3. What inferences can you make from these experiments?