Class 10th Biology Chapter 10 Short Questions: Stomata are the microscopic pores within the epidermis of leaves. they’re the passageways for gases and water vapours. Opening and shutting of stomata control the gaseous exchange.
In humans and other higher animals, the exchange of gases is administered by the systema respiratorium. we will divide the systema respiratorium into two parts i.e. the air passageway and therefore the lungs.
All the alveoli on one side constitute a lung. there’s a pair of lungs within the chest cavity. The chest wall is formed from 12 pairs of ribs and therefore the rib muscles called intercostal muscles. A thick musculature, called the diaphragm, is present below the lungs.
The left lung is slightly smaller and has two lobes and therefore the right lung is greater with three lobes
The physical movements related to the gaseous exchange are called breathing. There are two phases of breathing i.e. inhalation and exhalation.
1=Inspiration or Inhalation
During inspiration, the rib muscles contract and ribs are raised. At an equivalent time, the dome-shaped diaphragm contracts and is lowered. These movements increase the world of the chest cavity, which reduces the pressure on the lungs. As a result, the lungs expand and therefore the atmospheric pressure within them also decreases. The air from outside rushes into the lungs to equalize the pressure on each side.
2= Expiration or Exhalation
After the gaseous exchange within the lungs, the impure air is expelled call at exhalation. The rib muscles relax bringing the ribs back to the first position. The diaphragm muscles also relax and it gets its raised dome shape. This reduces the space within the thoracic cavity and increases the pressure on the lungs. The lungs contract and therefore the air is expelled out of them.
Humans breathe 16 -20 times per minute in normal circumstances i.e. at rest. the speed of breathing is controlled by the respiratory centre within the brain. The respiratory centre is sensitive to the concentration of CO2 within the blood.
There are a variety of respiratory disorders which affect people
- Bronchitis is the inflammation of the bronchi or bronchioles
- Emphysema is the destruction of the walls of the alveoli
- Pneumonia is an infection of lungs. If this infection affects both lungs then, it’s called lobar pneumonia
- Asthma may be a sort of allergy, during which there’s inflammation of the bronchi, more mucous production and narrowing of the airways
- carcinoma may be a disease of uncontrolled cell divisions within the tissues of the lung. The cells still divide with none control and form tumours