Human Physiology

Lesson 35 : Gas Transport & Respiratory Adaptation

Breathing Pattern and its Control

In spite of vital process, the respiration is regulated and adjusted several times daily to meet out varying oxygen requirements during different activities of the body. One must have observed that we breath faster and inhale more air when on exercise or physical work and much lesser and slower when at rest or asleep. How this adjustment is brought about? Does it is physiologically important?

Respiratory regulation is brought about chiefly by brain (especially medulla oblongata) in man. During exercise or physical work when demand for oxygen in higher, the brain sends stimuli more frequently to cause rapid and faster breathing that results in intake of more oxygen per unit time from atmosphere. Reverse takes place when there is less demand for oxygen i.e. during rest or sleep. Hypoxia (less oxygen in the blood) is an important stimulus for faster breathing. Quantification of breathing is done in following two ways:

1. Respiration rates or frequency of breathing: mean number of breaths per minute. Its normal value in man is 20 breaths per minute.
2. Depth of air or tidal volume means the volume of air inspired with each breath. Respiratory adjustment under different physiological states in animals can either occur in respiratory rate or breathing depth or both.

Respiratory changes during Physical work: You know that a sports person can perform their activity through extensive use of their muscular system. Prolonged and sustained contraction of muscles demands higher amount of oxygen and eliminates more carbon dioxide, since muscle drives energy through oxygen and produce CO2 during metabolism. A sprinter running at fastest speed may require 40 times more oxygen that at resting state. Respiratory system, therefore adjust to higher side, both through respiration rate and depth, to meet out oxygen demand. Athlete thus inhales more air into lungs and eliminates more carbon dioxide into atmosphere.

SUMMARY:

Respiratory system is involved in uptake of oxygen and elimination of carbon dioxide between body and atmosphere. Respiratory tract and lungs are involved in respiration. External respiration exchanges the gases between lungs and blood whereas internal respiration exchanges between blood and tissue. Oxygen is mainly transported in blood in combination with hemoglobin and carbon dioxide as plasma bicarbonate. Respiratory system is also involved in regulation and adjustment of body ph.