Question

Write an essay on respiration in human beings.

Answer 1

NOSTRILS: either of two external openings of the nasal cavity in vertebrates that admit air to the lungs and smells to the olfactory nerves.NASAL CAVITY: The nasal cavity (or nasal fossa) is a large air filled space above and behind the nose in the middle of the face. Eachcavity is the continuation of one of the two nostrils.PHARYNX:the membrane-lined cavity behind the nose and mouth, connecting them to the oesophagus.
LARYNX:the hollow muscular organ forming an air passage to the lungs and holding the vocal cords in humans and other mammals; the voice box.TRACHEA:a large membranous tube reinforced by rings of cartilage, extending from the larynx to the bronchial tubes and conveying air to and from the lungs; the windpipe.
BRONCHUS:any of the major air passages of the lungs which diverge from the windpipe.BRONCHIOLES:any of the minute branches into which a bronchus divides.ALVEOLI:any of the many tiny air sacs of the lungs which allow for rapid gaseous exchange.

Answer 2

We know that the breathing is the process of inhaling and exhaling .the organs involved are mainly the lungs.You cannot see your lungs,it's easy to feel them in action.Put your hands on your chest and breathe in very deeply.You will feel your chest getting slightly bigger.Now breathe out the air,and feel your chest return to its regular size.You have just felt the power of your lungs.The lungs themselves can neither draw in air nor push it out.Instead the chest wall muscles and another flexible muscle called diaphragm helps the lungs in moving air into and out of them.

The chest wall is made up of ribs,muscles,and the skin.The ribs are attached at an angle to the spine.When we inhale,the chest wall moves up and expands.This causes an increase in the volume of the chest cavity.

The diaphragm may be imagined as the floor if you think of the chest cavity as a room.When the diaphragm is relaxed when we breathe out,it is in the shape of the dome with the convex side of the dome extending into the chest cavity.When the diaphragm contracts during inhalation it flattens out a bit or the dome moves downward.As a result, the volume of the chest cavity is increased.

When the diaphragm flattens and the volume of the chest cavity is increased ,its internal pressure decreases and the air from the outside rushes into the lungs.This is inspiration.

Then the reverse occurs.The chest wall is lowered and moves inward and the diaphragm relaxes and assumes its dome shape.These changes increase the pressure on the lungs;their elastic tissue contracts and squeezes the air out through the nose to the external atmosphere.This is expiration.