Life Processes – Respiration
* Respiration is the process of oxidation of food and releasing energy.
* Breathing is the process o f inhaling oxygen and exhaling carbon dioxide.
* Exhaled air contains more carbon dioxide than when compared to atmospheric air.
* Aerobic organisms break down their food into carbon dioxide and water while anaerobic organisms breakdown food into alcohol and carbon dioxide.
* Adenosine Triphosphate (ATP) is the molecular currency for transferring energy.
* Diffusion is the process by which a gas moves from an area of high concentration to an area of low concentration until a balance is reached.
* Plants release oxygen in the day time and given out carbondioxide at night.
* The rate of breathing in aquatic organisms is much faster than in terrestrial organisms.
* Air enters a human body through the nostril. It moves through the throat and then the trachea.
* The bronchi form a network of tubes. Each bronchus has alveoli at the end.
* Haemoglobin absorbs oxygen from the lungs from the lungs and carries it to tissues all over the body.
Respiratory Organs
* The process of breathing accompanied by the breakdown of foods to produce energy is called respiration.
* Among all animals, mammals have a well – developed respiratory system.
* In human beings, and generally in all mammals, the organs of respiration include the nose, pharynx, larynx, trachea, bronchi, lungs and diaphragm.
* Based on function, the respiratory system is divided into two parts – the conducting part and the respiratory part.
* The conducting part spreads from the external nostrils to the terminal bronchioles.
* The respiratory part contains the alveoli and the alveolar ducts.
Mechanism of Breathing
* Respiration involves: breathing, external respiration, internal transport, internal respiration and cellular respiration.
* As carbon dioxide is twenty to twenty five times more soluble than oxygen the amount of carbon dioxide that can diffuse through the diffusion membrane is much higher compared to that of oxygen.
* The volume of air inspired and expired by the lungs can be estimated by using a procedure called spirometry.
Exchange of Gases
* Oxygen and carbon dioxide are exchanged by simple diffusion based on the pressure and concentration gradients of these respective gases.
* Oxygen and carbon dioxide are transported to various organs of the body by blood.
* Haemoglobin is red – coloured, iron – containing protein. Each haemoglobin molecules can carry four molecules of oxygen.
* About ninety – seven percent of oxygen is transported by red blood cells, whereas the remaining three percent is carried in a dissolved state through plasma.
* For every hundred millilitres of deoxygenated blood, haemoglobin releases approximately four millilitres of carbon dioxide to the alveoli.
* The whole respiratory system, including the exchange and transport of gases, work to a rhythm controlled by the human brain.