Question

WHat are the major functions of the respiratory system? name and define the four process of respiration

Answer 1

First question

Major functions of respiratory system:

• GAS EXCHANGE:

Gaseous exchange is one of the major functions of the respiratory system. Inhalation of oxygen into the body and the removal of carbon dioxide from the body takes place through the lungs.

• REGULATION OF BLOOD pH:

By controlling carbon dioxide output from the body, the lung controls the plasma bicarbonate concentration. The lungs play an important role in acid-base balance.

• DEFENSE FUNCTION:

The defense functions of respiratory system are:

Organisms that are the lungs are phagocytosed by pulmonary alveolar macrophages (dust cells) or interstitial macrophages in the lungs. Thus, lungs play an important role in nonspecific defense of the body. The particles less than 2 micrometers in diameter reach alveoli where they are phagocytosed by alveolar macrophages. Particles with 2 to 10 micrometers in diameter are generally removed by conducting airways.

IgA present in the bronchial secretions provide resistance to infection. IgA also maintains the integrity of the mucosal lining of the respiratory tract.

The epithelium of the lungs contain protease-activated receptors that on activation release Prostaglandin- E2, which in turn protects pulmonary epithelial cells. Particles more than 10 micrometers in diameter are removed by hair cells.

• FILTRATION OF INHALED AIR:

Filtration of inhaled air in the conducting airways is a respiratory function. This prevents the entry of toxic substances and infected organisms into the body. The conducting airways filter these particles and expel them in expelled air. Warming and moisturizing of air by conducting airways also help in preventing alveolar damage.

• SPEECH:

Movement of air in the respiratory passage helps in the improvement of voice. The voice becomes thick with nasal intonation in nasopharyngitis and nasal obstruction.

Other non-respiratory functions:

• MAINTENANCE OF WATER BALANCE:

Respiratory tract plays a role in the water loss mechanism. During expiration, water evaporates through the expired air and some amount of body water is lost by this process.

• REGULATION OF BODY TEMPERATURE:

During expiration, along with water, heat is also lost from the body. Thus, the respiratory tract plays a role in heat loss mechanism.

• OLFACTION:

Olfactory receptors present in the mucous membrane of nostrils are responsible for olfactory sensation.

• ANTICOAGULANT FUNCTION:

Mast cells in lungs secrete heparin. Heparin is an anticoagulant and it prevents the intravascular clotting.

• SECRETION OF ANGIOTENSIN- CONVERTING ENZYME:

Endothelial cells of the pulmonary capillaries secrete the angiotensin­ converting enzyme (ACE). It converts the angiotensin I into active angiotensin II, which plays an important role in the regulation of ECF volume and blood pressure.

• SYNTHESIS OF HORMONAL SUBSTANCES:

Lung tissues are also known to synthesize hormonal substances, prostaglandins, acetylcholine, and serotonin, which have many physiological actions in the body including regulation of blood pressure.

Second question:

Four processes of respiration:

• Pulmonary ventilation (Breathing)
• External respiration
• Transport
• Internal respiration

Pulmonary ventilation:

Breathing or pulmonary ventilation is a process by which the atmospheric air is drawn in and CO2-rich alveolar air is released out.

External respiration:

It is the gas exchange between the lungs and the pulmonary capillaries (blood).

Transport:

Transport of gases (carbon dioxide and oxygen) between the lungs and the tissues through the circulatory system.

Internal respiration:

It is the gaseous exchange between the systemic blood capillaries and tissue cells.