Respiratory System - Respiratory System Functions • Gas...

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Unformatted text preview: Respiratory System Functions • Gas exchange • Smell • Filters inspired air • Sound production Respiration The exchange of gases between the atmosphere, blood and cells. • Involves three processes – Pulmonary ventilation­ inspiration and expiration. – External repiration­ the exchange of gas between the lungs and blood. – Internal respiration­ the exchange of gases between the blood and cells. Structures of the Respiratory System Upper Respiratory System • Nose • Pharynx (throat) Lower Respiratory System • larynx (voice box) • Trachea (windpipe) • Bronchi • Lungs Structures of the Respiratory System Functionally, the respiratory system consist of two parts • Conducting portion­ a series of interconnected tubes and cavities that conduct air to the lung. • Respiratory portion­ where gas exchange occurs. Nose Function • Warms, moistens, and filters incoming air – nasal hairs – superior, middle, and inferior nasal conchae (turbinates)­ lined with mucus membranes containing goblet cells and is vascular (moistens and traps particles). • Receives olfactory stimulation – above the superior nasal conchae is the olfactory epithelium (olfactory bulb), which receives olfactory stimuli. • Provides a resonating chamber for speech sounds – ethmoid, maxillary, sphenoid, and frontal sinuses • Connects the eyes with the nose via the nasolacrimal duct. Nasal Respiratory Epithelium Paranasal sinus­ an air­filled cavity within a bone connected to the nasal cavity. Cribriform plate of ethmoid bone Ethmoid Sinuses Perpendicular plate of ethmoid bone Middle nasal concha Maxillary sinus Vomer Inferior Nasal Conchae­ scroll­like bones that project into the nasal cavity inferior to the superior and middle nasal conchae of the ethmoid bone. Vomer­ triangular shaped bone that forms the lower and back part of the nasal septum. The nasal septum is composed of three structures: perpendicular plate of the ethmoid bone, vomer, and the septal cartilage. A deviated septum may cause partial or complete blockage of the nasal passage leading to nasal congestion, blocked paranasal sinuses, chronic sinusites, headaches, or nose bleeds. Sinusitis • Sinusitis starts as a result of blockage of the drainage pathway of the sinuses. This blockage can occur as a result of – an anatomical obstruction, – swelling due to a cold or allergy, – or chronic recurrent sinus infections. • When this occurs, mucus that normally is expelled from the sinus builds up in the sinus. – cause pressure or pain – mucus is an excellent culture medium for bacteria • If the mucus is not cleared immediately, a bacterial infection exists until the blockage is cleared and the sinuses drain normally again. Normal Sinus Drainage Block Sinus Drainage Resulting in Sinusitis Nasal Polyp Obstructing the Sinuses Deviated Septum Obstructing the Sinuses Post Nasal Drip • When excess mucous produced in the sinus cavities drips down the back of the throat. • Excess mucous, once settled on your nasal and throat lining, can irritate, causing a sore throat, and the belief that you may be coming down with a cold. • Excess mucous production or Post Nasal Drip (PND) will directly affect your breath as it is high in proteins and is an excellent food source for anaerobic bacteria. Small white or yellow crystals lodged in your tonsils. . If you have excess mucous this will cause an increase of anaerobic bacteria. These bacteria feed on the mucous as it is high in protein. They then make condensed sulphur granules called TONSILLOLITHS which are laid down in the back of the throat. Every time your tongue touches the back of the throat when you swallow, it will carry these Tonsilloliths into the crypts or folds of the tonsils. If you have ever picked these out with a Q tip you will notice the foul smell that they have. Tonsilloliths are not only a sign of post nasal problems, but also a sign of bad breath. Signs of Post Nasal Drip • Bad Breath • Needing to clear your throat • Constantly swallowing or feel that you have something trapped in the back of your throat. • Continual sore throats that do not develop into illness. • Small white or yellow crystals lodged in your tonsils. • Nasal and Sinus Congestion Causes of PND • Inhaled Irritants ­ swelling of the nasal and sinus linings • Dairy Products­ cause mucous to thicken dramatically. This can then inhibit proper drainage. • Allergies to foods­ These will once again thicken mucous, and inhibit proper drainage. • Illnesses­ as flu, colds, bronchitis, ear infections and tonsillitis are the main culprits in post nasal drip and excess mucous • Asthma­ excess mucous Functional Endoscopic Sinus Surgery (FESS) • Straightening the septum (the bone and cartilage separating the two sides of your nose), • Removing tissue from inside the nose • Making an opening into the sinus(es) on either side of the nose so that drainage can occur more effectively, and • Remove some of the lining of the sinuses for biopsy if indicated.. Pharynx (Throat) • A tube that starts at the internal nares and extends part way down the neck. • Its walls are lined with skeletal muscle and lined with mucous membrane. • Functions – passageway for air and food – resonating chamber for speech sounds Parts of the Pharynx Nasopharynx­ • connects with – the two internal nares – Eustachian tubes­ two openings that lead into the ear – The single opening into the oropharynx • The posterior wall contains the pharyngeal tonsil • It is lined with pseudostratified ciliated columnar epithelium, and – the cilia moves the dust laden mucous toward the mouth. • Exchanges a small amount of air with the auditory canal to equalize air pressure between the pharynx and middle ear. Have you noticed that hearing is worse just before your ears pop? This is because of the property called co mpliance. If the air pressure is not equal on both sides of the eardrum, the ear drum will not mo ve or vibrate efficient ly (reduced co mpliance). The eustachian tube maintains the optimal comp liance by keeping the air pressure outside the ear the same as air pressure inside the ear. The end result is that the eustachian tube preserves and mainta ins optimal hearing. When new air is unable to enter the eustachian tube, the body will absorb the remaining air in the middle ear creat ing a vacuum (negat ive pressure). This is the same t ype of pressure that keeps a lid on a Mason Jar. When this pressure is mild, the body senses this as stuffiness or pressure in the ear. However, when the negat ive pressure is severe the body senses this as pain. If the negat ive pressure remains for an extended period of time then the body will replace the vacuum wit h fluid. The fluid behind the eardrum can lead to problems with hearing loss and ear infect ion ( otit is ). Treatment for middle ear fluid consists of ways to get the air pressure behind the eardrum equa l to pressure outside the eardrum. These treatments include inflat ion of the middle ear via the eustachian tube or if unsuccessful through the eardrum (see placement of pressure equalizat ion tubes) A pressure equalizat ion tube is placed to allow air pressure in the middle ear to equal air pressure in the outside world. In healt hy ears, the eustachain tube provides the funct ion of pressure equalizat io n. Wit hout pressure equalizat ion, ear diseases can deve lop. These proble ms range fro m mild hearing loss to life threatening disorders. Ear tube (Myringotomy Tubes) Pressure equalizing tubes­ allow air to get into the ear space behind the ear drum. Air is needed in this space to allow the ear drum to move. Parts of the Pharynx Oropharynx • the middle portion of the pharynx containg the opening from the mouth called the fauces. • Serves as a common passageway for air, food, and drink. • Lined with nonkeratinized squamous epithelium that’s more suitable for abrasion from the coarse food particles. • Contains the Lingual and Palatine tonsils Pharyngea l Tonsil Palat ine Tonsil Lingual Tonsils Parts of the Pharynx Laryngopharynx • Extends downward from the hyoid bone and connects with the esophagus (food tube) in back and the larynx (voice box) in front. • Lined with nonkeratinized squamous epithelium. • Has both respiratory and digestive function. Pharyngitis Beefy redness of posterior pharynx, which is the result of infection. Palate Edema Due To Pharyngitis Larynx (Voicebox) • A short passageway that connects the pharynx with the trachea. Anatomy • The walls are composed of nine pieces of cartilage – three single • thyroid, epiglottis, and cricoid cartilage – Three paired (1 pair is the most important) • arytenoid cartilage Laryngeal Cartilages • Thyroid cartilage (Adam’s apple) – consist of hyaline catilage and forms the front of the larynx and gives it its triangular shape. • Epiglottis – large leaf shaped piece of elastic cartilage covered by epithelium lying over the top of the larnyx. – During swallowing, the epiglottis covers the glottis (the passageway leading to the true and false vocal cords) so that food does not enter the lungs, thereby routing it to the esophagus. Laryngeal Cartilages (cont) • Cricoid cartilage – is a ring of hyaline cartilage attached to the first ring of cartilage of the trachea. • Arytenoid cartilage – mostly hyaline cartilage located above the cricoid cartilage – attach the true vocal cords and pharyngeal muscles and function in voice production. Voice Production False vocal cords­ function to hold the breath against pressure in the thorax such as might occur when straining to lift a heavy object. True vocal cords­ produce sound. They contain elastic ligaments stretched between pieces of rigid cartilage via muscle. The muscle tightens and relaxes the cord causing tension variations. Laryngitis­ inflammation of the larynx causing swelling of the cords and a henderance to vibration (hoarseness). Trachea • Extends form the larynx to the upper part of the fifth vertebra, where it divides into right and left primary bronchi. • The wall is lined by pseudostratified ciliated columnar epithelium with goblet and basal cells. • Walls have “C” shaped cartilagenous rings that provides rigid support to prevent collapse. • Tracheostomy­ emergency airway through the trachea • Intubation­ the insertion of a tube through the mouth or nose down through the larnyx and treachea. Tracheostomy Bronchial Tree •Trachea •Primary Bronchi­ right more straight, object caught here. •Secondary Bronchi •Tertiary Bronchi •Bronchioles •Terminal Bronchioles Structural Changes of Bronchioles •no cartilage at bronchioles •increase of smooth muscle at bronchioles •epithelium changes to cuboidal non­ciliated and then to simple squamous in terminal bronchioles. •Muscular contraction controlled by the autonomic nervous system and various chemical (inhaled irritants and chemicals from inflammatory cells) •Asthma­ smooth muscle spasm that closes off the bronchioles •Bronchoscopy­ the visual examination of the bronchi through a bronchoscope. Cilliated ColumnarEpithelium Cartilage ring The smooth, glistening pleural surface of a lung is sho wn here. This patient had marked pulmonary edema, which increased the fluid in the lymphatics that run between lung lobules. Thus, the lung lobules are outlined in white. To each lung To each lung lobe Bronchopulmonar y segment To each lobule Respiratory bronchio les Alvo lar ducts Alveo lus­ a epithelial lined sac where gas exchange occurs. Alveo lar sacs­ two or more alveo li that share a co mmo n opening. Terminal bronchiole Smooth muscle Elastic fibers Lobule Alveolus 1st orde r 2nd orde r 3rd orde r Respiratory Bronchioles Alvolar Ducts Alvolar Sacs & Alveoli Secretes Surfactant Alveolar Capillary Membrane This is normal lung microscopically. The alveolar walls are thin and delicate. The alveoli are well­aerated and contain only an occasional pulmonary macrophage (type II pneumonocyte). External Respiration Hemothorax Chest Drainage Pneumothorax Dynamics of Breathing Diaphragm Vital Capaciaty­ maximal volume that can be inhaled or exhale Alveolar pressure­ the pressure inside the lungs Collapsed Lung The pressure in the pleural cavity is subatmospheric inorder to keep the alveoli slightly inflated after the end of expiration. This negative pressure overcomes the recoil force from the elastic bands around the alveoli. A collapsed lung may be caused by air entering the pleural space from a surgical incision or a chest wound, airway obstruction, or lack of surfactant. Surfactant­ a phospholipid produced by the septal cells that prevents the alveolar walls from sticking together (surface tension) Lung Capacities Spirogram Anatomic dead space­ aprox 30% of inhaled air Minute volume of respiration­ total air taken in during 1 min. The efficiency of external respiration depends on several factors • altitude – high altitude sickness (shortness of breath, nausea, dizziness) • surface area available for O2­CO2 exchange • minute volume respiration – drugs, such as morphine, slow down the respiratory rate • the amount of O2 that reaches the alveoli (plugged passages) CO + H CO 2 2 3 ­ + HCO3 + H The release of O2 fro m hemog lo bin depends on •difference in pO2 between blood and t issue •pH­ increase release •temperature­ increase release •Carbon mo noxide po isoning­ CO has a stronger affinit y for hemog lo bin than oxygen. •Hypoxia­ dific iency o f O2 at the tissues. carbaminohemoglobin •Low pO2 in arterial blood •high alt itude •too litt le funct ioning hemog lo bin (anemia) •inefficient blood transport as in heart failure •inabilit y o f t issue to use O2 properly as in cyanide poisoning •Lobe •bronchopulmo nary segment (supplied by tertiary bronchi •lo bules­ each containing arterio le, venule, and lymphat ic vessel and a branch from a termina l bronchio le, wrapped in elast ic connect ive tissue. •Respiratory bronchio les •Alveo lar ducts •Alveo lar sac­ two or more alveo li, sharing a co mmo n opening •Alveo li Bronchus Bronchiole Respiratory Bronchiole Respiratory Bronchiole Respiratory Bronchiole Respiratory Bronchiole Alveolar Duct Respiratory Bronchiole Alveolus Double Blood Supply •From Pulmonary arteries •From the aorta via bronchial arteries ...
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