The Human Body: The Respiratory System

Introduction

Human body is composed of eleven systems, where they all contribute together in order for human to survive. However all the systems are important, and the body cannot dispense any of them. Human body requires many factors from the external environment, Oxygen is one of these factors and human body cannot be survived without oxygen. However in this assignment we are going to study the system that is responsible about oxygen supplying to the human body and it is known as the Respiratory system. Beside that Respiratory system does other functions that are important for our bodies.

Respiratory system is defined as a group of organs that work together in order to allow gas exchange between the internal human body and the external environment,

3- Pharynx (throat):

Pharynx is a muscular tube which function is to connect posterior end of the nasal cavity and to the superior end of the esophagus and larynx. Anatomically pharynx is divided into:

Nasopharynx: posterior of the nasal cavity, and it receives air that is inhaled by the nasal cavity.

Oropharynx: posterior of the oral cavity, and it receives air that is inhaled by oral cavity.

Laryngopharynx: the end of pharynx, when the air reaches laryngopharynx the air will be diverted to the larynx.

Epiglottis: it is an elastic cartilage covered with a mucus membrane located at the entrance of larynx. Epiglottis has a very important function where it closes the trachea during eating so the food is not accidently inhaled.

4- Larynx:

Larynx plays a dual function, first one is an air canal that connects laryngopharynx to the trachea, and secondly larynx is the source of sound where while talking the air pass through the vocal cords and the sound is

The act of breathing is achieved by 4 process as following:

1- Pulmonary ventilation:

Pulmonary ventilation is defined as the act of moving air into and out of the lungs in order to achieve inhalation and exhalation. However negative pressure system and muscles contraction are used by our respiratory system to allow the air to flow in and out of the body.

Negative pressure system function is to make the pressure of the alveoli lower than the atmosphere pressure, this can be achieved by the assistance of the pleural membrane, where pleural membrane impresses the lungs when they are at rest, as a result the air will flow into the lunges in order to rise up the lunges pressure until it matches the atmosphere pressure, at this point the diaphragm will contract and more air can be inhaled, meanwhile the contraction of external intercostal muscle will cause an increment in the thorax volume, so as a feedback the lungs pressure will go lower than the atmosphere pressure