All physical and chemical reactions in which atmospheric air oxides food in the body cells resulting in production of energy and liberation of
CO2 are included in respiration.
TYPES OF RESPIRATION
I. Anaerobic Respiration
When nutrients are oxidized without using O2 (also called fermentation)
In yeast, glucose forms ethyl alcohol and CO2. In bacteria anmuscles,glucose is converted into lactic acid. Endoparasites like Ascaris, Fasciola, Taenia also respire anaerobically.
It is a low energy yielding process.
II. Aerobic Respiration
Cells utilize O2 for oxidisinnutrients. O2 is used either from atmospheric air or from water.
I. NASAL CAVITY
The air in the nasal cavity gets warmed (because nasal cavity has a very good blood supply)and moistened before it enters lungs.
From the nasal cavity the air enters the pharynx. It serves as a common passage for both air and food.
The opening into the wind pipe or trachea is a narrow slit, the glottis. The glottis is protected against the entrance of food by a triangular flap of tissue, the epiglottis.
III. LARYNX (VOICE BOX)
Called Adam’s apple in man. It is the first part of trachea present in the neck.
It is four and a half inch long tube with Cshaped ring of cartilages in its walls. These rings of cartilage make the wall noncollapsable.
Surrounding each lung is a double walled sac, the pleural cavity. Hence the covering of lung are called pleural membrane.
The right lung is divided into three lobes and left into two. The left lung is smaller than the right and has a concavity, the cardiac notch,
where the heart lies.
Inside the lung, each bronchi divides into numerous bronchioles, each of which terminates into an elongated saccule, the alveolarduct, which bears on its surface air sac or alveoli. The latter provide a large surface for gaseous exchange.
PULMONARY VOLUMES & CAPACITIES
I. PULMONARY VOLUME
Volume of air in the lungs.
Tidal volume (TV): The volume of air inspired or expired involuntarily in each normal breath. It is about 500 ml of air in average young adult man.
Inspiratory Reserve volume (IRV): It is about 3000 ml.
Expiratory Reserve Volume (ERV): It is about 1200 ml
II. PULMONARY CAPACITIES
Combination of two or more pulmonary volumes.
Total lung capacity (TLC): TV + IRV + RV + ERV. It is about 5800 ml.
COPD: Chronic Obstructive Pulmonary Disease which includes Emphysema, chronic bronchitis and Asthma.
Tuberculosis: A bacterial disease caused by Mycobacterium tuberculosis.