Respiratory System

Two Respiratory Tracts Upper Respiratory Tract Nose Nasal cavity Paranasal sinuses Pharynx Epiglottis Lower Respiratory Tract Larynx Trachea Bronchial tree lungs

I. Upper Respiratory Tract A.Nose Supported by bones and cartilage Hairs guard nostrils that prevent entry of large particles

I. Upper Respiratory Tract B.Nasal Cavity Hollow space behind the nose Nasal septum: bone and cartilage that divides nose into left and right sides Nasal conchae: bones that divide nasal cavity into passageways and support mucus membranes (superior, middle, inferior passageways)

I. Upper Respiratory Tract

I. Upper Respiratory Tract B. Nasal Cavity Sticky mucus traps dust and other particles/filters air Particles in mucus are swallowed and destroyed by gastric juice in stomach ** deviated septum: can obstruct the nasal cavity ** Anthrax is a really small bacteria that bypasses the hair/mucus so it is inhaled

I. Upper Respiratory Tract C.Paranasal sinuses Air-filled spaces within bones of the face and opening into nasal cavity frontal sinus (above nose) & sphenoidal sinus (beside nose) Function: reduce weight of skull, affect voice Sinus headache: blocked drainage

I. Upper Respiratory Tract D.Pharynx (AKA the throat!) Passageway for food to travel to esophagus and for air to pass between nose and larynx E.Epiglottis Flap that separates the trachea from the esophagus while swallowing

II. Lower Respiratory Tract A.Larynx Airway at the top of the trachea and below the pharynx Conducts air in/out of trachea, prevents foreign objects from entering trachea, houses vocal cords Made of muscle and cartilages Largest = thyroid = “Adam’s apple” Vocal cords: folds in larynx that vibrate when air passes between them

Laryngitis: hoarseness/lack of voice: mucous membrane of larynx is swollen, prevents vocal cords from vibrating freely

II. Lower Respiratory Tract B.Trachea Windpipe Flexible cylindrical tube anterior to esophagus that runs anterior to thoracic cavity Splits into left and right bronchi Ciliated mucous membrane lines inner wall  filters air, moves trapped particles upwards Bands of hyaline cartilage  prevent trachea from collapsing/blocking airway

Lungs Spongy, air-filled organs located on either side of the thoracic cavity (chest) Gas exchange occurs in alveoli (O2/CO2) – Upper Lobe – Middle Lobe – Lower Lobe

Pleural Cavity Pleura – serous membrane that folds back on itself to form a double layer – Outer layer attaches to chest wall – Inner layer attaches to superior surface of lungs – Resulting “cavity” contains pleural fluid.

Diaphragm Skeletal muscle sheet that extends across the bottom of the rib cage Separates thoracic cavity from abdominal cavity Contracts during inhalation to enlarge the thoracic cavity