Respiration and Gas Exchange

A ventilator is a medical device that provides mechanical ventilation by moving breathable air into and out of the lungs for patients who cannot breathe on their own.

The vocal cords (or vocal folds) vibrate when air from the lungs passes through the larynx, producing sound. The epiglottis prevents food from entering the airway, trachea is the windpipe, and neither produces sound on their own. Note: 'cards' should be 'cords'.

Lungs remove about 18 litres of CO₂ and 400 ml of water per hour in normal resting condition.

Gas exchange in the alveoli occurs via simple diffusion, where oxygen moves from an area of higher partial pressure in the alveoli to lower partial pressure in the blood, and carbon dioxide moves in the opposite direction.

This is the correct option as this statement is false. Gases like carbon dioxide, helium and water vapours constitute only 1 % of the volume of air.

In simple multicellular animals, such as, sponges, cnidarians, etc., each cell of the body remains in contact with the environment (water) and thus, exchange of gases takes place through the surface of the cell by diffusion.

The human rib cage, also known as the thoracic cage, is a bony and cartilaginous structure which surrounds the thoracic (chest) cavity and supports the pectoral (shoulder) girdle, forming a core portion of the human skeleton. A typical human rib cage consists of 24 ribs, the sternum, costal cartilages, and the 12 thoracic vertebrae. The human rib cage is a component of the human respiratory system. It encloses the thoracic cavity, which contains and protects  the lungs.

Pneumatophores are erect roots that are some form of upward appendage or extension of the underground root system. Because these roots are exposed at least part of the day and not submerged underwater, the root system can obtain oxygen in an otherwise anaerobic substrate.These are known as breathing roots.

The diaphragm is crucial for breathing and respiration. During inspiration, the diaphragm contracts , thus enlarging the thoracic cavity (the external intercostal muscles also participate in this enlargement). 

The hilum of the lung is a triangular part which allows the other structures forming the root of the lung to enter and exit. It permits arteries, veins, nerves, bronchi and other structures to enter and exit.

Sleep is a period of reduced activity. Sleep is associated with a typical posture, such as lying down with eyes closed in humans. Sleep results in a decreased responsiveness to external stimuli.

Ans - 1

Forced breathing (hyperventilation) lowers the partial pressure of CO2 in the blood. Since CO2 is the primary chemical stimulus for the respiratory center, its reduction leads to a temporary cessation of breathing (apnea) until levels rise again.

Tidal volume is defined as the volume of air inspired or expired during a normal, quiet breath.