The Respiratory System

Overall Functions To dissolve O2 gas into the blood so that it can reach all the cells To Remove CO2 waste products from the blood and excrete them Filter, warm and humidify air Allow for sound production Involved in regulating blood pH

Structure of Respiratory System Upper Respiratory Tract Nose Nasopharynx Oropharynx Laryngopharynx Larynx Lower Respiratory Tract Trachea Bronchial tree segments Lungs

The Upper Respiratory Tract

The Nose Exterior portion of the nose is made of cartilage and bone Internal nose rests on the palatine bones of the mouth When these two bones do not meet you get a cleft palate The cribriform plate separates the nasal cavity from the brain It is perforated to allow olfactory nerves to reach the brain The septum separates the two sides of the nose It is highly vascular thus susceptable to nosebleeds (epistaxis)

The Nose The nostrils are also referred to as anterior nares Vibrissae are coarse hairs which line the vestibule (inner part of nostril) The vestibule is covered with many sebaceous and sweat glands Respiratory mucosa lines the inside of the nasal cavity

Nasal Sinuses Air-containing spaces that drain into the nasal cavity They are lined with respiratory mucosa which helps to moisten air The maxillary sinuses are the largest Sinuses serve as resonating chambers for speech

Pharynx “throat” Extends from base of skull to the esophagus Composed of smooth muscle 3 parts Nasopharynx Oropharynx Laryngopharynx Is part of respiratory and digestive systems

Openings of the Pharynx Right and left Eustachian tubes Mouth Two Posterior nares Laryngopharynx opening Opening to esophagus

Larynx “voice box” Starts at root of tongue and upper part of trachea Lined with ciliated mucosa membranes to filter out particulate matter Vocal cords(glottids) make up the most narrow part of the larynx, the opening is called the rima glottidis

Cartilage of the Larynx Thyroid Cartilage (Adam’s apple) Is larger in men and has less fat covering it Epiglottis Flap of cartilage that moves up and down during swallowing to prevent food from entering larynx

The Lower Respiratory Tract

Trachea “windpipe” Extends from larynx to bronchi Made of smooth muscle embedded in incomplete c-shaped ring Cartilage rings keep airway from collapsing

Bronchi and Alveoli Trachea splits to form two bronchi Bronchi enter lungs and branch further into secondary bronchi which then branch into tertiary bronchioles. All these branches are referred to as the bronchial tree Bronchioles further divide into alveolar ducts that terminate in alveolar sacs containing numerous alveoli

Alveoli Structure Each alveolus is extremely thin-walled and lies in contact with capillaries Gases are exchanged across the respiratory membrane Alveoli are lined with surfactant that reduces surface tension to prevent the alveoli from collapsing Air is thoroughly cleaned and warmed by the nose and mucus linings before reaching the alveoli

The Lungs Bronchi enter each lung through a small slit called a hilum The right lung is divided into three lobes by the horizontal fissure and oblique fissure The left is divided into two lobes by the oblique fissure

Function of the Lungs Respiratory membrane provides enormous surface area where thin-walled alveoli come into contact with thin-walled capillaries This surface area allows for large amounts of gas to be exchanged very rapidly. What type of cells make up lung tissue???