Amazing Facts, Activity and Summary - Human Respiration

AMAZING FACTS

                   The World TB Day is March 24.

                     Direct Observation Therapy (DOTs) can treat about 95% of the TB patients.

                     The surface area of the lungs is roughly the same size as a tennis court (525 feet long).

                     It is possible to live with one lung.

                     The highest recorded ‘sneeze speed’ is 165 km per hour.

                     Adults breathe around 12 – 16 times per minute where as new borns breathe around 30–60 times per minute.

                     Yawning helps us to breathe more oxygen to the lungs. When our brain senses the shortage of O_2, it send a message to CNS to imbalance to O₂ demand and trigger us to yawn.

                     Breathing through mouth results in bladder shrinkage and creates an urge to urinate in the middle of the night.

                     Most people can hold their breath between 30 seconds to one minute.

                    Hiccups are due to eating too fast or having occasional spasms of the diaphragm.

Activity

To test the presence of CO₂ in exhaled air Take two test tubes A and B with few mL of clear lime water. Blow exhaled air into A with a help of a straw and pass normal air into B with a help of a syringe for about 15 times and observe the changes that occur in the tubes A and B. The lime water (Calcium Hydroxide) in the test tube A turns milky.

Summary:

The process of intake of oxygen rich air and giving out of air rich in carbon dioxide is generally called respiration. Pollutants and micro organism are filtered from the inspired air by the hair and mucus present in the nostrils. The two main steps in the mechanism of respiration are inspiration and expiration which takes place due to pressure gradient in the atmosphere and lungs.

O₂ is transported in blood in dissolved form and is also bound to haemoglobin. One molecule of haemoglobin can bind four molecules of O₂. The Sigmoid shape of the O₂ haemoglobin dissociative curve shows increased affinity for each O₂ molecule.

CO₂ is transported in blood in dissolved form as carbamino haemoglobin and as HCO_3. HCO₃ is produced in RBCs from CO₂ and water catalysed by carbonic anhydrase. Breathing is controlled by medullary respiratory centre.

Respiratory volumes and capacities indicate the amount of air inspired and expired during normal respiration. Our respiratory system can be affected by pollutants, pathogens and other chemical substances found in air. Lung cancer and emphysema cannot be cured and these diseases are common among cigarette smokers.

People at higher level than the sea level are prompted to altitude sickness as the barometric pressure is low in those regions. Surfactant, emphysema, Asthma and Dead space have been discussed. During vigorous exercise the rate of respiration increases.