P4:.2. Explain the role of the respiratory system in energy metabolism by referring to- a) Inhalation and exhalation.
b) Gaseous exchange between alveoli and blood.
The respiratory system takes oxygen (O2) into the body and eliminates carbon dioxide (CO2). It also enables speech production. Our bodies need energy for movement, growth and reproduction. This energy can only be obtained from the food we eat. By the process of respiration, chemicals of food are eliminated to produce energy that can later be used by the cells of the body. Food + O2 → energy (36/38ATP) + CO2 + H2O Respiration is defined as the process of inhalation of oxygen and the exhalation of carbon dioxide with the help of certain organs of the human body. These organs include the nose, pharynx, larynx, trachea, bronchi and the lungs, altogether they make up the human respiratory system which is divided in two parts by the upper and lower respiratory tract.
Ventilation is the exchange of air between the lungs and the atmosphere. It is part of the external respiration system that includes gas exchange in pulmonary capillaries and breathing which is largely an involuntary activity. When breathing in (inhaling) intercostal muscles between the ribs contract, pulling the chest walls up and outwards. The diaphragm muscle below the lungs contracts and flattens, increasing the size of the chest (rib cage expands). The lungs increase in size, so the pressure inside them falls and enables air to rush in through the nose and mouth. When breathing out (exhaling) intercostal muscles between the ribs relax so that the chest walls move in and down. The diaphragm muscle below the lungs also relaxes and it bulges up, reducing the size of chest. The lungs increase in size, so the pressure inside increases and air is pushed up the trachea and out through the nose and mouth.
P4: 3. Explain the role of the...