Respiratory System

1. Respiratory System Mason Markham and Steven Stokes

2. The respiratory system delivers oxygen to the blood stream • The system then removes waste gases (such as CO2) from the body • This process is commonly called “breathing” Overview

3. Nose • Pharynx • Larynx • Trachea • Bronchi • Lungs Major Organs

5. Only exterior part of respiratory system • Air enters through the nostrils, divided by the nasal septum • The interior of the nose consists of the nasal cavity • The nose, along with the rest of the respiratory tract, is lined with respiratory mucosa • The respiratory mucosa: • Warms and moistens the air • Traps bacteria and other foreign debris Nose

6. Muscular passageway with about a 5” diameter • Commonly called the throat • Pharynx is divided into three sections: • Nasopharynx- Only carries air; most superior part of pharynx • Oropharynx- Where food enters the pharynx; middle part of pharynx • Laryngopharynx- Where food and air divide into the esophagus and larynx; most inferior part of pharynx Pharynx

7. Commonly known as the voice box • The epiglottis guards the superior opening of the larynx • Generally open (allowing air into the larynx) • Closes when swallowing • Inferior to the pharynx Larynx

9. Commonly called the wind pipe • About 4 inches long • Lined with C-shaped rings of hyaline cartridge • Open side adjacent to esophagus (allows for expansion when swallowing) Trachea

10. Formed by a division of the trachea into a left and right side • Right bronchi is wider, shorter, and straighter than the left • By the time air reaches the main bronchi it is warm, humid, and cleaned of most impurities • Broken up into smaller subdivisions inside the lungs that bring air to the air sacks Main Bronchi

12. The apex (top narrow portion) is deep to the clavicle • The base rests on the diaphragm • Site of Oxygen-Carbon Dioxide exchange • Contains bronchioles which lead to alveoli (air sacs) • Alveoli are lined with simple squamous epithelium • The basement membranes of the capillaries and alveoli walls are fused • Allows O2 and CO2 to diffuse across • This is called the respiratory membrane • Alveolar Macrophages diffuse in and out of the alveoli to dispose of bacteria, carbon particles and other debris Lungs

16. 4 steps • Pulmonary ventilation- air moves in and out of lungs and keep alveoli continuously refreshed (breathing) • External respiration- Gas exchange between blood and exterior of body • Respiratory gas transport- Oxygen and carbon dioxide are transported to and from body tissues • Internal respiration- Gas exchange between blood and tissue cells Respiration

17. Inspiration- Air flowing to the lungs • Occurs when the diaphragm and the external intercostals contract • Causes the size of the thoracic cavity to increase • The volume of the lungs increases and internal air spreads out • Decreases pressure in lungs sucking air in • Expiration- Air flowing out of the lungs • Occurs when the diaphragm and the external intercostals relax • Causes the size of the thoracic cavity to decrease • The volume of the lungs decreases • Increases pressure in lungs forcing air out Mechanics of Breathing