Respiration

Breathing:-

It take two processes ,taking oxygen rich air inside(inhalation) and giving out of air rich in carbon dioxide(exhalation).

Air passage: -

Nostrils→ Nasal cavity→ Pharynx-->Larynx→ Trachea→ Lungs

Nasal: -

Air enters through nasal cavity. Main work is sniffing. It secretes mucous approximately 0.5 liter per day to prevents the particles of sand, bacteria or other small organisms from entering inside and make air wet to equalizes it with temperature of the body.

Pharynx: -

Pharynx is common passage for food and air. Epiglottis cover glottis to prevent the entry of food into the larynx while eating.

Larynx: -

 Larynx is a cartilaginous (connective tissue) box which helps in sound production and hence called the sound box.

Trachea: -

Trachea is a straight tube extending up to the mid-thoracic cavity, which divides at the level of 5th thoracic vertebra (back bone ‘s 12 bones) into a right and left primary bronchi. Each bronchi undergoes repeated divisions to form the secondary and tertiary bronchi and bronchioles ending up in very thin terminal bronchioles. Each terminal bronchiole gives rise to a number of very thin, irregular-walled and vascularised bag-like structures called alveoli.

Lung:-

The branching network of bronchi, bronchioles and alveoli comprise the lungs. We have two lungs which are covered by a double layered pleura or pleural membrane, with pleural fluid between them. It reduces friction on the lung-surface. each alveoli attached by blood vessels.RBC in blood vessels contain Haemoglobin (is a red coloured iron containing pigment) that bind oxygen to form oxyhaemoglobin. Each haemoglobin molecule can carry a maximum of four molecules of O₂.

Respiration is of two types→ Aerobic respiration and anaerobic respiration.

Aerobic respiration:-

 This respiration takes place in the presence of oxygen. Oxidation of glucose takes place, as a result CO₂, H₂O and energy is produced.

Anaerobic respiration: -

 This respiration takes place in the absence of oxygen. During this process glucose is break and form CO₂, energy and lactic acid (ethanol (alcohol) in plant and yeast). 

Diseases: -

-Emphysema is a chronic disorder in which alveolar walls are damaged due to which respiratory surface is decreased. One of the major causes of this is cigarette smoking.

-Asthma is a difficulty in breathing causing wheezing due to inflammation of bronchi and bronchioles.