1. Respiratory System
Unit 7:10

2. Introduction
The respiratory system consists of the lungs & air passages. It is responsible for taking in oxygen, a gas needed by all body cells, & removing carbon dioxide, a gas that is a metabolic waste product produced by cells. The body has only a 4 to 6 minute supply of oxygen, so the respiratory system must work continuously or death will occur. Parts of the respiratory system: nose, pharynx, larynx, trachea, bronchi, alveoli, & lungs.

3. Respiratory System

4. Nose
The nose has 2 nostrils (nares) : openings through which air enters. The nasal septum is a wall of cartilage that divides the nose into two hollow spaces called nasal cavities.
The nasal cavities are lined with a mucous membrane & have a rich blood supply. As air enters the nasal cavities, it is warmed, filtered, & moistened. Mucous, produced by the mucous membrane, also helps to trap pathogens & dirt.

5. Nose
Cilia- Tiny hair like structures in the nasal cavity that help trap dirt & pathogens as they enter the nose so trapped particles can be pushed toward the esophagus & be swallowed.
Olfactory receptors for the sense of smell are located in the nose.
Lacrimal ducts drain tears from the eye into the nose to provide additional moisture for the air.

6. Sinuses Cavities in the skull around the nasal area.
They are connected to the nasal cavity by short ducts.
They are lined with mucous membrane that warms & moistens the air.
The sinuses also provide resonance for the voice.

7. Pharynx
Also called the throat, the pharynx begins directly behind the nasal cavities. As air leaves the nose it enters the pharynx.
The 3 sections of the nasopharynx are:
Nasopharynx- the upper portion behind the nasal cavities. The pharyngeal tonsils, & the Eustachian tube openings are located here.
Oropharynx- Middle section located behind the oral cavity. Receives both air from the nasopharynx & food & air from the mouth.
Laryngopharynx-Bottom section of the pharynx It branches into the trachea, which carries air to & from the lungs, & the esophagus, which carries food to the stomach.

8. Larynx
Also called the voicebox. It lies between the pharynx & the trachea. It has a framework of cartilage commonly called the Adam’s apple.
It contains two folds called the vocal cords.
The opening between the vocal cords is called the glottis.
As air leaves the lungs, the vocal cords vibrate & produce sound.
The tongue & lips act on the sound to produce speech.
The epiglottis is a special piece of cartilage. It has a leaflike structure that closes the opening into the larynx during swallowing to prevent food & liquid from entering the respiratory tract.

9. Trachea
Also called the windpipe, it is the tube extending from the larynx to the center of the chest.
It carries air between the pharynx & bronchi.
It is composed of a series of c-shaped cartilage, which are open on the dorsal (back) surface. These structures help keep the trachea open.

10. Bronchi
Two divisions of the trachea near the center of the chest. Each bronchus enters a lung & carries air from the trachea to the lungs.
In the lungs, the bronchi continue to divide into smaller & smaller bronchi. The smallest branches are called bronchioles. The smallest bronchioles end in air sacs called alveoli.

11. Alveoli Air sacs that resemble a bunch of grapes.
The adult lung contains approx. 500 million alveoli.
Alveoli are made of one layer squamous epithelium tissue & contains a rich network of blood capillaries. The capillaries allow oxygen & carbon dioxide to be exchanged between the blood & the lungs.
The inner surface of the alveoli are covered with surfactant. Surfactant is a lipid (fatty) substance that helps prevent alveoli from collapsing.

12. Lungs Organs that contain divisions of the bronchi & alveoli.
The right lung has 3 sections called lobes: the superior, middle, & inferior.
The left lung has only 2 lobes: the superior & inferior. The left lung is smaller because the heart lies more to the left side of the chest.

13. Lungs
The pleura is a membrane or sac enclosing each lung. It consists of two layers:
Visceral pleura attached to the surface of the lung
Parietal pleura attached to the chest wall.
Pleural space: located between the two layers of pleura and filled with pleural fluid the lubricates the membranes.
Both of the lungs, along with the heart & major blood vessels are located in the thoracic cavity.

14. Process of Respiration
There are two phases of respiration: inspiration & expiration.
Inspiration (inhalation) is the process of breathing in air. The diaphragm, a dome shaped muscle between the thoracic & abdominal cavities) & the intercostal muscles (located between the ribs) contract & enlarge the thoracic cavity. This creates a vacuum. Air rushes in through he air tubes to the alveoli, where the exchange of gases takes place.

15. Expiration (exhalation) Process where air leaves the lungs
Expiration (exhalation) Process where air leaves the lungs. The diaphragm & intercostal muscles relax and air is forced out of the lungs & air passages.
The process of respiration is controlled by the respiratory center in the medulla oblongata of the brain. A lack of oxygen or increased amount of carbon dioxide in the blood causes the center to increase the rate of respirations. The process is usually involuntary, but a person can control the rate of breathing by breathing faster or slower.

16. There are two main stages of respiration: External Respiration & Internal Respiration
External respiration is the exchange of oxygen & carbon dioxide between the lungs & blood stream. Oxygen breathed in through the respiratory system, enters the alveoli. The concentration of oxygen in the alveoli is higher than the concentration in the blood capillaries so oxygen leaves the alveoli & enters the capillaries or bloodstream.

17. Carbon dioxide (CO2), a metabolic waste product is carried in the bloodstream. The concentration of carbon dioxide is higher in the capillaries so CO2 leaves the capillaries & enters the alveoli. The alveoli the expel it from the body during exhalation.

18. Internal Respiration
The exchange of carbon dioxide & oxygen between the cells & the bloodstream.
Oxygen is carried to the cells by the blood. The concentration of oxygen is higher in the blood than in the body cells. Oxygen leaves the blood capillaries & enters the body cells.
Cells then use the oxygen & nutrients to produce energy, water, & carbon dioxide, a process called cellular respiration. The level of carbon dioxide is higher in the cells so carbon dioxide leaves the cells & enter the bloodstream to be transported back to the lungs where external respiration takes place.

19. Diseases of the Respiratory System
Asthma
Acute Bronchitis
Chronic Bronchitis
COPD
Emphysema
Epistaxis
Influenza
Laryngitis
Lung Cancer
Pleurisy
Pneumonia
Rhinitis
Sinusitis
Tuberculosis
URI

20. Asthma
A respiratory disorder usually caused by a sensitivity to an allergen such as dust, pollen, animals, or foods. Stress, overexertion, & infections can also cause an attack.
Symptoms: occur when bronchospasms narrow openings of the bronchioles, mucus production increases, & edema develops in the mucosal lining. Dyspnea, wheezing, coughing with expectoration of sputum, tightness in chest.
Treatment: bronchodilators to enlarge the bronchioles, epinephrine & anti-inflammatory meds, oxygen therapy
Identification & elimination of or desensitization to allergens causing the problem is important in preventing asthma attacks.

21. Bronchitis Inflammation of the bronchi & bronchial tubes
Acute Bronchitis is usually caused by an infection. It is characterized by a productive cough, dyspnea, chest pain, & fever. It is treated with antibiotics & expectorants to remove excessive mucus
Chronic Bronchitis occurs after frequent attacks of acute bronchitis & long-term exposure to pollutants or smoking. It is characterized by chronic inflammation, damaged cilia, & enlarged mucus glands. Symptoms include excessive mucus resulting in a productive cough; wheezing & dyspnea; prolonged expiration of air. It can be treated, but not cured. Treatments : antibiotics, bronchodilators, & respiratory therapy.

22. COPD Chronic Obstructive Pulmonary Disease
Any chronic lung disease that results in obstruction of the airways.
Disorders such as chronic asthma, chronic bronchitis, emphysema, and TB lead to COPD.
Smoking is the primary cause, but allergies & chronic respiratory infections are also factors.

24. Emphysema
Noninfectious chronic respiratory condition that occurs when the walls of the alveoli deteriorate & lose their elasticity.
Carbon dioxide remains trapped in the alveoli & there is a poor exchange of gases.
The most common causes are heavy smoking & prolonged exposure to air pollutants
Symptoms: Dyspnea & a feeling of suffocation; pain & a barrel chest; chronic cough, cyanosis, rapid respirations with prolonged expiration; eventual respiratory failure & death.
Treatment: No Cure- but, avoiding smoking, bronchodilators, prompt treatment of respiratory infections, oxygen therapy & respiratory therapy

25. Epistaxis
Commonly called nosebleeds, this occurs when the capillaries in the nose become congested & bleed.
Causes: injury or a blow to the nose, hypertension, chronic infections, anticoagulant drugs, blood diseases such as hemophilia or leukemia
Treatment: Compress the nostrils toward the septum, elevate the head & tilt it slightly forward, & apply cold compresses. At times it is necessary to insert nasal packs or cauterize (burn & destroy) the bleeding vessels. Eliminate the underlying cause (like hypertension) when possible.

26. Influenza
Commonly called the Flu, a highly contagious viral infection of the upper respiratory system with a sudden onset.
Symptoms: chills & fever; cough, sore throat, & runny nose; muscle pain & fatigue
Treatment: Bedrest, fluids, analgesics for pain & fever, antibiotics are NOT effective against viruses, but they are given at times to avoid secondary infections such as pneumonia

27. Laryngitis
Inflammation of the larynx & vocal cords, it frequently occurs with other respiratory infections.
Symptoms: Hoarseness or loss of voice, sore throat, dysphagia or difficulty swallowing
Treatment: rest & fluids, limited use of the voice, medications if an infection is present.

28. Lung Cancer
Leading cause of cancer death in both men & women. It is a preventable disease because the main cause is exposure to carcinogens in tobacco, either through smoking or through exposure to “second hand” smoke. There are 3 types: Small cell, squamous cell, adenocarcinoma

29. Lung Cancer
Symptoms: None in the early stages, then chronic cough, hemoptysis (coughing up blood-tinged sputum), dyspnea & chest pain, fatigue, & weight loss.
The prognosis is poor since the disease is usually advanced before it is diagnosed.
Treatment: Surgical removal of the cancerous sections of the lung, radiation, &/or chemotherapy

30. Pleurisy
Inflammation of pleura or membranes of the lungs that usually occurs with pneumonia or other infections.
Symptoms: Sharp stabbing pain while breathing, crepitation (grating sounds in the lungs), dyspnea, & fever
Treatment: Rest, meds to relieve pain & inflammation, if fluid collects in the pleural space, a thoracentesis (withdrawal of fluid through a needle) is done to remove fluid & prevent compression of the lungs.

31. Pneumonia
Inflammation or infection of the lungs with a buildup of fluid or exudate in the alveoli. It usually is caused by a bacteria, virus, or chemicals.
Symptoms: chills,fever, chest pain, productive cough, dyspnea, & fatigue.
Treatment: Bedrest, fluids, antibiotics if indicated, respiratory therapy, & pain meds.

32. Rhinitis
Inflammation of the nasal mucous membrane resulting in a runny nose, soreness, & congestion. It is commonly caused by infections & allergens
Treatment: fluids & medications to relieve congestion

33. Sinusitis
Inflammation of the mucous membrane lining the sinuses usually caused by a bacteria or virus
Symptoms: headache or pressure, thick nasal discharge & congestion, loss of resonance in the voice
Treatment: analgesics for pain, medications to loosen secretions, moist inhalations, surgery in chronic sinusitis to open the cavities & encourage drainage

34. Tuberculosis (TB)
An infectious disease of the lungs caused by the bacteria Mycobacterium tuberculosis
At times, white blood cells surround invading TB organisms & wall them off creating a nodule called a tubercle. The organisms remain dormant in the tubercle and can cause an active case of TB later if the body resistance is lowered.
Symptoms of active TB are : fatigue, chest pain, fever, night sweats, weight loss, hemoptysis
Treatment: Administration of drugs for one or more years to destroy the bacteria; good nutrition & rest.
In recent years a new strain of the TB bacteria that is resistant to drug therapy has created a concern that TB will become a widespread infectious disease.

35. Upper Respiratory Infection (URI)
An Upper Respiratory Infection, also called the common cold, is an inflammation of the mucous membrane lining the upper respiratory tract. It is caused by viruses & is highly contagious.
Symptoms: fever, runny nose, watery eyes, congestion, sore throat, & hacking cough
There is no cure & minimal treatment. Analgesics for pain & fever, rest & increased fluids, & antihistamines to relieve congestion can help increase comfort.
The symptoms usually last about a week.