Question

Describe the structure of human respiratory system? 

Answer 1

The structure of human respiratory system consists of following organs: -

Nose: -

Nasal cavity is lined with mucous secreting epithelium and ciliated epithelium. The

function of cilia and mucus is to stop the dust and trapped particles going into the

respiratory tract.

Pharynx: -

The thin compartment of the nasal cavity opens into the pharynx by means of two

small apertures. Its function is to transport of air from nasal cavity to larynx.

Larynx: -

The upper most part of air tube (trachea) is called larynx. It is box like structure

made up of cartilage. Two fibrous bands called vocal cords are also present here.

They produce sound. Therefore this box is also called sound box. The air enters in

larynx though glottis. This opening has a lid like structure called epiglottis. It

prevents the food from entering into the trachea.

Trachea: -

It is also called air tube. It is present in front of oesophagus. The structure of trachea

is like the rings chain. These rings keep the trachea open all the time. Any other

particle present in air moved out of the trachea by beating of cilia in upward direction.

Bronchi: -

On entering into the chest trachea divides into two smaller tubes called bronchi.

(single bronchus). Each bronchus enters into the lungs of its own side.

Bronchioles: -

The bronchi divide into smaller and smaller branches called bronchioles.

Alveoli: -

Small air sacs are present at the end of bronchioles called alveoli (single alveolus).

These air sacs are present in the form of bunches of grapes. The are very large in

number. Small capillaries are present on the alveoli.

Lungs: -

Lungs are present in the chest box between ribs. The lungs are enclosed in double

layered membrane called pleural membrane. There is a thin fluid present between

two layers.