Name: Respiratory System in Vertebrate Animals
Uploaded: 2019-07-19
Duration: 20 min 2 s
Description: Animals must be able to get rid of carbon dioxide for proper metabolism. Animal respiratory systems are designed to facilitate gas exchange. Learn more.

Question

Describe in detail the human respiratory system with a diagram.

Accepted Answer

The organs in an organism that carry oxygen and help in the removal of carbon dioxide from the body collectively constitute the respiratory system. The complete respiratory system in humans can be categorised into two major components, i.e. respiratory tract and lungs.

1. Respiratory Tract:
It is the passage for the air (transport of respiratory gases to and from the lungs). It starts with nostrils and ends with the bronchioles.

The various parts of the respiratory tract are as follows:
(i) Nostrils: These are a pair of slits at the lower end of the nose which opens into the nasal chamber. In these chambers, the air is filtered (by hairs) and moistened (by mucus secreted by the goblet cells).
(ii) The pharynx: It is the part of the throat behind the mouth and nasal cavity. It is a common passage for air and food.

(iii) Larynx (voice box): It is the upper part of the trachea. It allows the air to pass into the lungs. The pharynx opens through the glottis of the larynx into the trachea. Glottis is a slit-like aperture that is present in the larynx. The glottis has a leaf-like flap made up of cartilage (our ears and nose are also made up of this) called epiglottis in its anterior region. It closes the glottis to check the entry of food during swallowing. The larynx helps in sound production and hence, is called the sound (voice) box.

(iv) Trachea (windpipe): It is a thin-walled tube, about 11 cm long and 2.5cm wide. It extends up to the mid-thoracic cavity. It is made up of 16-20 C-shaped rings made up of cartilage. It passes the air to the bronchi.
(v) The bronchi: The immediate branches of the trachea which enters into the two lungs through two tubes, i.e., right and left bronchi.

(vi) Bronchioles: The branches of bronchi are called bronchioles.
(vii) Alveoli (air sacs): The small terminal bronchioles give off a number of thin, irregular walled, vascular bag-like structures called alveoli. They are the sites for gaseous exchange. They are lined by thin network blood vessels called capillaries.

2. Lungs:
These are the primary respiratory organs that are thin-walled, spongy, and elastic in nature. They lie in the thoracic cavity and are enclosed dorsally by a thoracic cage (comprised of ribs, sternum, and a muscular sheet called the diaphragm). The left lung comprises two lobes. It also has a cardiac notch, a concavity where the heart lies. On the other hand, the right lung is slightly bigger and has three lobes. Each lung is enclosed by two membranes called the pleura.

Describe in detail the human respiratory system with a diagram.

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