RESPIRATION in Human Beings

RESPIRATION

This is the process in which the organic molecules are stepwise oxidised to release energy.

Glucose molecule (6 carbon atoms) breaks to form three-carbon molecule called Pyruvate.

Types of respiration

Aerobic respiration	Anaerobic Respiration
1)    This takes place in presence of oxygen 2)    Pyruvate breaks to carbon dioxide and water. 3)    Large amount of energy is released 4)    This takes place in higher organisms. Human beings	1)    This takes place in absence of oxygen. 2)    Pyruvate is converted to Ethanol and carbon dioxide. This takes place during fermentation. 3)    Small amount of energy is released 4)    This takes place in lower organisms. Yeast, bacteria

Sometimes, in our muscles cells, due to the lack of oxygen, the Pyruvate molecules break to form Lactic acid. This activity causes cramps in muscles.

The energy released in cellular respiration is used to synthesize ATP molecule.

This serves as a fuel for other cellular activities.

Plants – In plants exchange of gases take place by diffusion.

During day time, CO₂ released during respiration is utilized for photosynthesis and O₂ is released. Therefore oxygen release is the major event.

At night, there is no photosynthesis and so CO₂ elimination is major event.

Aquatic organisms use dissolved oxygen for respiration. As the amount of dissolved oxygen is comparatively low the rate of breathing is faster in aquatic organisms.

Gills are the respiratory organs of fish.

Respiration in Human Beings

·        Respiratory system includes nose, pharynx, trachea, bronchi, bronchioles, alveoli and lungs.

·        Air enters the respiratory system through nostrils. Fines hairs and mucous in the nostrils filters the air. The air becomes moist and warm according to the body temperature

·        The air passes through the throat, trachea and then to the bronchi which leads to each lung. The ‘C’ shaped cartilaginous rings keeps the trachea open, prevents it from collapsing, and this ensures the continuous flow of air.

·        The bronchi are further branched in to bronchioles and terminate with the balloon like structures called ‘Alveoli’. Alveoli contain the networks of capillaries. This increases the surface area for the exchange of gases.

·        The Haemoglobin, a pigment present in RBC take up the oxygen and carry it to the tissues all over the body.

·        Carbon dioxide is transported in the dissolved form in our blood.