Preksha Dhyana Human Body Part 2

Author(s): Jethalal S Zaveri
Publisher: Jain Vishva Bharati

Page 14

librium, carbon dioxide enters the alveoli and oxygen goes into the capillary blood. Fully oxygenated blood with 100 mm. tension and 100% saturation leaves the lungs for the left side of the heart and aorta. Haemoglobin, which fills the red blood cells and colours the blood) is a chemical compound which combines with oxygen and readily releases it to the cells when reqired. The process of combination which takes place in the lungs turns the purplish reduced haemoglobin into bright-red oxy-haemoglobin. The delivery of oxygen to the cells is the function of another organ-the heart-pumping oxygen-bearing haemoglobins in the blood to all parts of the body. Thus, the process of internal breathing which occurs in the active tissues of the body, consists of the release of oxygen and carrying away carbon dioxide for delivery to the lungs. If the oxygen-tension falls below 40 mm, of mercury, the oxygen saturation of the blood falls precipitously; oxygen-supply to the tissues reduces to zero and they may die.
While the regulation of most of the important systems of the body, notably the heart rate, is under automatic control, that of breathing is both autonomous as well as voluntary. The normal rhythmic pattern of respiration is maintained by nerve-information fed back to the respiratory centre (which is located in the medualla oblongata) by the respiratory muscles and lungs. The centre is under many other influences and can also be affected by voluntary activity, e.g. one can hold the breath for short intervals. The respiratory centre is sensitive to changes in the carbondioxide content, oxygenation and acidity of the blood that passes through the centre as well as that in the carotid arteries. Rhythmic impulses from the centre pass down through the spinal cord to the intercostal muscles and the diaphragm. Rise in the level of blood-carbon-dioxide or acidity stimulates the centre. Consequently it alters the impulses to the muscls of breathing in order to co-ordinate rhythm, rate and depth of breathing with other activities of the body.
For Private Personal Use Only