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Respiratory System. Allied Health Sciences I. Upper Respiratory Tract. Nasal Cavity.
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Respiratory System Allied Health Sciences I
Nasal Cavity • The anterior nares are our nostrils where air enters into our bodies. Our nasal cavity is divided into the R and L chamber, or smaller cavity. The nasal septum divides these R and L chambers. These cavities are lined with mucous membranes. • Cilia or small hairs entrap and prevent the passage of larger dirt particles. • The olfactory nerves are located in the mucous membrane in the upper part of the nasal cavity. These nerves endings are responsible for our sense of smell. • Mucous membrane line the sinuses and they help to warm and moisten air that passes through them. The sinuses also give resonance to the voice.
Pharynx • This is known as your throat. The air enters this area after leaving the nasal cavity. The throat serves as a passageway for air and food. • The pharynx is divided into three sections. 1. The upper pharynx also called the nasopharynx. 2. The middle section is called the propharynx and is located just behind the mouth. 3. The lowest area is called the laryngopharynx. This is where air passes through the lungs and food passes through to go to the stomach. • The epiglottis acts as the “lid” to cover the opening into the larynx when food is swallowed.
Larynx • This is known as the voice box and is triangular chamber found below the pharynx. • It is made of fibro-cartilaginous plates and the largest of these is called the Adams Apple. • The vocal cords are located in the larynx. The glottis is a space b/w the vocal cords. • When air is expelled from the lungs, it passes the vocal cords. This sets off a vibration, creating sound. The action of the lips and tongue on this sound produces speech.
Trachea • The trachea is also known as the wind pipe. • The trachea is in front of the esophagus and continues and forms the two bronchi (one for each lung). • The walls of the trachea are composed of alternate bands of membranes, and fifteen to twenty C- shaped rings of hyaline cartilage. This cartilage allows the trachea not to collapse. • The trachea can be obstructed by large pieces of food, tumorous growths, or the swelling of inflamed lymph nodes in the neck. • The trachea is lined with mucous membrane and cilia. The cilia helps to sweep any entrapped dust particles from pharynx.
Bronchi and Bronchioles • The lower end of the trachea divides in two into the R bronchus and L bronchus. • The R bronchus is shorter, wider and more vertical in position. These bronchi enter each lung and further divides into bronchial tubes and then to smaller bronchioles. The bronchi have cilia just like the trachea. • The bronchial tubes and smaller bronchi are ringed with cartilaginous plates. • At the end of each bronchiole, there is an alveolar duct which ends in a sac-like cluster called alveolar sacs (alveoli).
Alveoli • The alveoli sacs have many alveoli and are composed of single layer of epithelial tissue. • There are about 500 million alveoli in the adult lung. • Their inner surfaces are covered with a lipid material known as surfactant. This material helps stabilize the alveoli, preventing them from collapsing. • Each alveolus is encased by a network of capillaries. The rapid exchange of 02 and C02 occurs through moist walls of the alveoli and capillaries.
Lungs • Two fairly large cone shaped organs that fill the two lateral chambers of the thoracic cavity. They are separated from each other by the mediastinum also called the interpleural space and is situated b/w the lungs along the median plane of the thorax. • The upper part of the lung is underneath the collarbone is the apex and the broad lower part is the base. Each base is concave and this shape allows it to fit snuggly next to the convex part of the diaphragm. • Because the lungs have so much air in them, they are very porous and spongy. • The R lung is larger and broader than the L lung because the heart is positioned toward the left side. • The R lung is divided by fissures (clefts) into three lobes: superior, middle, and inferior. The L lung is smaller and is subdivided into two lobes: superior and inferior. • The lungs are covered with a thin, moist slippery membrane made up of tough endothelial cells or pleura.
Functions of the Respiratory System • Provides the structures of the exchange of 02 and C02 in the body through respiration. • Responsible for the production of sound, the larynx contains the vocal cords. When air is expelled from the lungs it passes over the vocal cords and produces sound.
Subdivisions of the Respiratory System • External Respiration- the exchange of 02 and C02 b/w the lungs, the body, and the outside environment. • Internal Respiration- the exchange of C02 and 02 b/w the cells and the lymph surrounding them, plus the oxidative process of energy in the cells. • Cellular Respiration- involves the use of oxygen to release energy stored in the nutrient molecules. Much of the energy that is released is in the form of heat to maintain body temperature. • Control of Breathing- controlled by neural (nervous) and chemical factors. ***
Subdivisions of the Respiratory System cont… • Neural Factors- the respiratory center is located in the medulla oblongata in the brain. • An increase of C02 or lack of 02 in the blood will trigger the respiratory center. • There are two neuronal or nerve pathways that are involved in breathing. • There are motor nerves and one group called the phrenic nerves leads t0 the diaphragm and the intercostals muscles. • The other nerve pathway carries sensory impulses from the nose, larynx, lungs, skin, and abdominal organs via the vagus nerve in the medulla. • The HeringBrewer reflex is a lung reflex that prevents the lungs from overstretching.
Chemical Factors • ***Chemical control of respiration is dependent upon the level of carbon dioxide in the blood. As the C02 rich blood circulates through the respiratory center it senses the increased C02 in the blood and increases the respiratory rate.***
Lung Capacity and Volume • A spirometer is a device used to measure how much air you can hold which would be your lung capacity. • Tidal Volume is the amount of air that moves in and out of the lungs with each breath. Normal amount is about 500 ml. • Inspiratory Reserve Volume (IRV) is the amount of air you can force a person to exhale over and above the tidal volume. The normal amount is 1000ml. • Vital Lung capacity is the total amount of air involved with tidal volume, inspiratory reserve volume, and expiratory reserve volume. Normal vital capacity is 4500ml. • Residual volume is the amount of air that cannot be voluntarily expelled in the lungs. It allows for the continuous exchange of gases b/w breaths. The normal residual amount volume is 1500ml. • Functional Residual Capacity is the sum of the expiratory reserve volume plus the residual volume. The normal amount is 2500ml. • Total lung capacity includes tidal volume, inspiratory reserve, expiratory reserve, and residual air. The normal amount is 6000ml.
Types of Respiration • Apnea is the temporary stoppage of breathing movements. • Dyspnea is difficult, labored or painful breathing, usually accompanied by discomfort and breathlessness. • Eupnea is normal or easy breathing with the usual quiet inhalations and exhalations. • Hyperpnea is an increase in the depth and rate of breathing accompanied by abnormal exaggeration of respiratory movements. • Orthopnea is difficult or labored breathing when the body is in a horizontal position. It is usually corrected upon taking a sitting or standing position. • Tachypnea is an abnormally rapid and shallow rate of breathing. • Hyperventilation can be caused by disease or stress. Rapid breathing occurs which causes the body to lose carbon dioxide too quickly.
Infectious Causes • The common cold causes the greatest loss in production each year. This respiratory infection spreads quickly through the classroom, factory, or business office. • Pharyngitis is more commonly known as the sore throat. • Laryngitis is an inflammation of the voice box. Laryngitis can be recognized by the incidence of hoarseness or loss of voice. • Sinusitis is an infection of the mucous membrane that lines the sinus cavities. • Bronchitis is an inflammation of the mucous membrane of the trachea and the bronchial tunes which produces excessive mucous. • Chronic Bronchitis usually occurs in muddle or old age. Cigarette smoking is the most common cause of chronic bronchitis. • Influenza or more commonly known as the “flu” is a viral infection characterized by inflammation of the mucous membrane of the respiratory system. • Pneumonia is caused by a bacteria or virus and is an infection of the lung or lungs.
Infectious Causes cont… • Tuberculosis is an infectious disease of the lungs. • Systems of TB are cough, low grade fever in the afternoon, weight loss, and night sweats. • Diphtheria is caused by the Corynebacterium diphtheria and is very infectious. Children receive an immunization for this. • Pertussis (whooping cough) is characterized by severe coughing episodes that end in a “whooping” sound and dyspnea. Children also receive an immunization for this.
Noninfectious Causes • These are respiratory problems that aren’t infectious or are unrelated to an infectious cause. • Rhinitis is the inflammation of the nasal mucous membrane causing swelling and increased secretions. More commonly know as “hay fever”. • Asthma is an inflammatory response which causes the airway to be obstructed. • Symptoms include difficulty exhaling, dyspnea, wheezing (sound produced by a rush of air through a narrowed passageway), and tightness in the chest. • Treatment= anti-inflammatory drug • Atelectasis results when there is bronchial occlusion which causes the lungs to fail normal expansion. • Bronchiectasis is an inflammation accompanied by heavy pus secretion that causes dilation of a bronchus. • Silicosis is when the lungs become fibrosed which results in a reduced capacity for expansion. • Nasal polyps are growths that occur sometimes in the sinus cavity and caused an obstruction of the air pathway.
Noninfectious Causes cont… • Chronic Obstruction Pulmonary (COPD) indicates chronic lung conditions, especially emphysema and chronic bronchitis. • Emphysema- the alveoli of the lung become over dilated, lose their elasticity and cannot rebound. The alveoli may eventually rupture. Air becomes trapped and it is very difficult to exhale. The patient with emphysema becomes very dyspneic which becomes more severe as the disease progresses. • Cancer of the lungs- caused by small cell (also know as the oat cell) and spreads very rapidly to other organs. This type is found mainly in smokers. • Cancer of the larynx- usually found is men over 50 and is usually curable if found early. • Pulmonary Embolism occurs when a blood clot (embolism) breaks off and travels to the lung. • Sudden Infant Death Syndrome (SIDS) also known as “Crib Death” and usually occurs b/w two weeks to one year of age. Infant stops breathing while asleep. Exact cause is unknown.
