NOTES: Respiratory System (UNIT 7) Part 1 – Organs of the Respiratory System *The respiratory system includes tubes that remove particles from incoming air and transport air to and from the lungs and the air sacs where gases are exchanged. Respiration is the entire process of gas exchange between the atmosphere and body cells.

Functions of the Respiratory System: 1) Gas exchange; 2) Filter, warm & humidify air we breathe; 3) Influence speech; 4) Help maintain body’s pH; 5) Make sense of smell possible.

**Gas exchange supplies O2 for cellular respiration and disposes of CO2.

Composition of atmospheric air and expired air in a typical subject Composition of atmospheric air and expired air in a typical subject. Note that only a fraction of the oxygen inhaled is taken up by the lungs. Think about CPR!! Component Atmospheric Air (%) Expired Air (%) N2 (plus inert gases) 78.62 74.9 O2 20.85 15.3 CO2 0.03 3.6 H2O 0.5 6.2 100.0%

ORGANS OF THE RESPIRATORY SYSTEM *The organs of the respiratory system can be divided into two groups: 1) Upper Respiratory Tract: nose, nasal cavity, sinuses, pharynx 2) Lower Respiratory Tract: larynx, trachea, bronchial tree (within lungs), alveolar sacs

upper lower

● NOSE  supported by bone and cartilage openings for air: NOSTRILS Many internal hairs guard the nostrils  filter dust & particles

● NASAL CAVITY hollow space behind the nose; divided by nasal septum lined with mucous membrane to filter, warm, and moisten incoming air Deviated septum: septum is displaced to 1 side

● SINUSES  spaces in the bones of the skull that open into the nasal cavity lined with mucous membranes Affect the quality of the voice

● PHARYNX  behind the oral cavity  between the nasal cavity and the larynx  passageway for food and air

● LARYNX  conducts air and prevents foreign particles from entering trachea  composed of muscles and cartilage; lined with mucous membrane the GLOTTIS and EPIGLOTTIS help prevent foods and liquids from entering the trachea (animation- 45 sec in)

● LARYNX (continued)  contains the VOCAL CORDS **VOCAL CORDS vibrate from side to side and produce sounds when air passes between them Steven Tyler’s Vocal Cords

● TRACHEA extends into the thoracic cavity; in front of the esophagus (a.k.a. “windpipe”) “C” shaped rings of cartilage Approximately 12.5 cm long  splits into R and L BRONCHI

● BRONCHIAL TREE consists of branched, mucus lined air passages that lead from the trachea to the air sacs in the lungs Its branches begins with the R and L primary bronchi Each primary bronchus divides into secondary bronchi, and these into tertiary bronchi

● BRONCHIAL TREE Tertiary bronchi continue to branch into smaller and smaller tubes: bronchioles Bronchioles give rise to ALVEOLAR DUCTS alveolar ducts lead to ALVEOLAR SACS Alveolar sacs lead to microscopic air sacs called ALVEOLI which lie within capillary networks (lots of surface area!)

DIFFUSION!

CILIA: Function: carry particles trapped in the mucus up to the top of the esophagus, where they end up in the stomach Located in pharynx, trachea, and bronchi Animation

● LUNGS  enclosed by the DIAPHRAGM and the thoracic cage closely surrounded by the PLEURA *R has 3 lobes! *L has "space" for heart

-VISCERAL PLEURA: attaches to the surface of the lungs -PARIETAL PLEURA: lines the thoracic cavity (pleural cavity) -PLEURAL CAVITY: the potential space between the two pleurae; contains fluid to lubricate and cushion lungs during breathing; fluid also holds the two pleurae together which aids in breathing (animation)

Parietal Pleura in blue Pulmonary Pleura in purple

SUMMARY OF PATHWAY OF AIR (OXYGEN) IN THE RESPIRATORY SYSTEM: Nostrils Nasal cavity Pharynx Glottis/epiglottis Larynx

Trachea Bronchi Bronchioles Alveoli Blood (capillaries) Body cells

Measuring Your Vital Capacity! Turn dial to 0. Put on a mouthpiece. Big giant breath in! Breathe out, out, out!!!!! Bring me your data.