Respiratory System

functions of respiratory system

deliver oxygen from atmosphere to lungers, provide method of gaseous exchange within the lungs (oxygen enter the blood, carbon dioxide exits), create speech as air passes over the vocal cords, facilitate sense of smell

structure of respiratory system

air passages, lungs, diaphragm

air passages

pharynx - where the back of mouth and nose meet

larynx - produces sound when are passes over larynx

trachea - assists with air delivery. aka wind pipe

bronchi - 2 tubes that provide air to lungs

bronchioles - each bronchus subdivides into smaller branches called bronchioles

alveoli - cup shaped sacs found at end of bronchioles. surrounded by capillaries, provide site for continual exchange of O2 and CO2. occurs by process of diffusion - movement of gas from area of high concentration to low concentration

lungs

located within the thoracic cavity and protected by the sternum, ribs and vertebral column. contain the bronchi, bronchioles and alveoli. gas exchange occurs at site of alveoli

diaphragm

involuntary or smoot muscle that contracts and relaxes to aid breathing at all times. As diaphragm moves up and down, size of chest cavity changes, causing breathing

mechanics of breathing

consists of two movements (inhalation, exhalation) operating on principle that gases move from area of high pressure to low pressure

inhalation (inspirtation)

volume of lunges increases. External intercostals muscles contract and internal intercostals muscles relax to loft rib cage up and the diaphragm contracts to become flatter (causes bigger surface area and thus area of low pressure). Air enters lungs moving from area of high pressure to low pressure

exhalation (expiration)

volume of lungs decreases. external intercostals muscles relax and internal intercostals muscles contract to lower rib cage and diaphragm relaxes to become dome shaped (this causes a smaller surface area and thus an area of high pressure). Air exits the lungs from an area of high pressure to low.

gaseous exchange

is the absorption of oxygen from the air in exchange for carbon dioxide removed from the body. takes place in the alveoli of the lungs

process of gaseous exchange in lungs

oxygen enter the alveoli as air is breathed in to the lungs. The venous blood in the capillaries that surround each alveolus is low in oxygen and high in carbon dioxide. The pressure of oxygen in each alveolus is higher than the pressure of oxygen in the blood of the capillaries. A gas will move from areas of high pressure to low pressure in process of diffusion, so oxygen will move from alveoli to capillaries, and carbon dioxide will move from capillaries to alveoli where it can be breathed out. Blood in capillaries is now rich in oxygen which will be returned to heart for distribution around the body.