Respiration and Gas Exchange

During inspiration (breathing in), the diaphragm contracts, drawning downward, creating a vacuum in the thoracic cavity. This vacuum inflates the lungs by drawing air into the body through the trachea, or windpipe.

In reptiles, respiration takes place through skin. It is known as cutaneous respiration.

Exchange of gases in lung alveoli occurs through simple diffusion,O2 diffusing from the alveoli into the blood & CO2 from the blood into the alveoli.

Inhaled substances that are not deposited in other parts of the respiratory tract get deposited in gas-exchange sacs. The conducting airways terminate in gas-exchange sacs, which are made up of respiratory bronchioles and alveolar ducts.

Both the lungs and the skin serve as respiratory organs in amphibians. The skin of these animals is highly vascularized and moist, with moisture maintained via secretion of mucous from specialized cells. While the lungs are of primary importance to breathing control, the skin's unique properties aid rapid gas exchange when amphibians are submerged in oxygen-rich water.

All of the above given options are non-respiratory functions of respiratory system.

The nasal chamber opens into nasopharynx, which is a portion of pharynx, the common passage for food and air. Nasopharynx opens through glottis of the larynx region into the trachea. Larynx is a cartilaginous box which helps in sound production and, hence, called the sound box.

The trachea, or windpipe, divides into two principal bronchi (plural for bronchus) as it enters the lungs. The principal bronchi are further divided into smaller bronchi. Further divisions of the bronchi eventually lead to tiny tubes, called bronchioles, which lead to tiny air sacs known as alveoli.

Asthma is a condition in which the airways of the lungs become either narrowed or completely blocked, obstructing normal breathing. This obstruction of the lungs, however, is reversible, either spontaneously or with medication. That is why asthma is technically called Reversible Obstructive Airway Disease (ROAD).

Breathing begins with a dome-shaped muscle located at the bottom of the lungs which is known as diaphragm. When we breathe in, the diaphragm contracts and flattens out and pulls downward. Due to this movement the space in the lungs increases and pulls air into the lungs. When we breathe out, the diaphragm expands and reduces the amount of space for the lungs and forces air out.

Air breathed in through the nose is warmed, moistened and filtered as it passes through the conchae, three bony projections which are lined with mucous membrane composed of cells which can trap particles of dust and germs.

A collapsed lung or pneumothorax is the collection of air in the space around the lungs. This buildup of air puts pressure on the lung, so, it cannot expand as much as it normally does when one takes a breath.

The diaphragm assists in Respiration. When the scalenes and external intercostals contract while the diaphragm descends, your lungs inhale air. When your abdominal muscles contract and the diaphragm rises, you exhale.

Found in the lung parenchyma, the pulmonary alveoli are the terminal ends of the respiratory tree, which outcrop from either alveolar sacs or alveolar ducts, which are both sites of gas exchange with the blood as well.

Trachea bifurcates at the level of 4^th cervical vertebra.It divides into the right and left main bronchi and is marked internally by the presence of a carina or keellike ridge between the diverging bronchi.