Pathophysiology of Respiratory system Lecture # 6

What is the respiratory system? Respiratory system is made up of the organs in your body that help you to breathe. Remember, that Respiration = Breathing. The goal of breathing is to deliver oxygen to the body and to take away carbon dioxide. Daily 10,000 liters of air - filtered..!

Organs of the Respiratory System

Respiratory Passages I)Upper respiratory passages -Include: nose, nasal cavity, sinuses and pharynx. -They warm and humidify air :II)Lower respiratory passages A)Conductive portion: -Include: larynx, trachea, bronchi, bronchioles. -Conduct air to respiratory surfaces, also warm and humidify air. B)Respiratory portion: -Include lungs, respiratory lobules, and alveoli -Undergo gas exchange between air and blood

Functions of respiratory system 1) Breathing– movement of air in and out of the lungs Inhalation (inspiration) draws gases into the lungs. Exhalation (expiration) forces gases out of the lungs. 2) Gas Exchange 3) Body temperature regulation 4) Voice production (Vocalization) 5) Site for olfactory sensation 6) Regulation of the pH of the blood 7) Defensive Functions :This occurs through: 1- Hairs 2-Sneezing reflex. 3- Cough Reflex 4-Secretion of immunoglobulins.

Gas Exchange in respiratory system

The process of respiration is divided into: 1) External Respiration: Which consists of: a- Pulmonary Ventilation: means the exchange of air between the lungs and atmosphere. b- Pulmonary Perfusion: means the flow of blood through the pulmonary capillaries. c- The Pulmonary Respiration: means exchange of gases between alveolar air and blood 2) Transport of oxygen and carbon dioxide by the blood. 3) The internal respiration: means exchange of gases between tissues and systemic blood vessels

Symptoms of respiratory disturbances: Include: I) Hypoxia II) Cyanosis III) Dyspnea IV) Orthopnea V) Clubbing

I)Hypoxia Definition: Oxygen deficiency at the tissues. Types: A) Hypoxic Hypoxia: Resulting from an inadequate saturation of blood oxygen due to a reduced supply of oxygen in the air, decreased lung ventilation or respiratory disease. PO2 of arterial blood is lower than normal→hypoxia of the tissues. B) Anemic Hypoxia: In which the PO2 of arterial blood is normal, but the amount of hemoglobin to carry oxygen is decreased.

C) Stagnant Hypoxia Or Ischemic Hypoxia: In which the PO2of arterial blood is normal and the amount of hemoglobin to carry oxygen is normal, but the blood flow to the tissues is so reduced . Heart attack, heart failure, or cardiac arrest, for example, can slow the circulation of blood . D) Histotoxic Hypoxia: Here the amount of oxygen delivered to the tissues is normal, but because of toxic agent, they fail to utilize it effectively because the cells are damaged and cannot extract and absorb oxygen from circulating blood.

Effect Of Hypoxia: A) Severe Hypoxia: →Loss of awareness in about 20 seconds and death within 4 - 5 minutes. B) Less Severe Hypoxia: Like alcoholism → headache, impaired judgment and other symptoms; nausea, vomiting, tachycardia and hyperventilation .

II) Cyanosis Definition: Cyanosis is defined as a bluish discoloration, especially of the skin and mucous membranes, due to excessive concentration of deoxyhemoglobin in the blood caused by deoxygenation. Clinical Causes Of Cyanosis: Asphyxia: lack of oxygen or excess of carbon dioxide in the body caused by obstruction of respiratory passages. 2) Some types of hypoxia: hypoxic hypoxia, and stagnant hypoxia.

III) Dyspnea: Definition: subjective sensation of uncomfortable breathing, feeling “short of breath” Ranges from mild discomfort after exertion to extreme difficulty breathing at rest. Normal person is not aware of breathing .

Causes Of Dyspnea: Bronchial asthma Disease that causes the airways of the lungs to swell and narrow, these airways are sensitive to stimulation by a number of things, such as infection, cold air, exercise, pollens, etc. leading to wheezing, shortness of breath, chest tightness, and coughing

Emphysema Is a type of chronic obstructive pulmonary disease (COPD) involving damage to the air sacs (alveoli) in the lungs., lung fibrosis Pneumonia is an infection that inflames the air sacs in one or both lungs.

Dyspnea (cont. ) Left sided heart failure Acidosis (is an increased acidity in the blood and other body tissue ) Thyrotoxicosis: (is a disease caused by excessive concentrations of free thyroid hormones (most often T4) Oxygen lack: e.g. at high altitudes.

:IV)Orthopnea Definition: form of dyspnea in which the person can breathe comfortably only when standing or sitting straight It occurs in left sided heart failure accompanied with pulmonary congestion.

V) Clubbing The selective bulbous enlargement of the end of a digit (finger or toe). Usually painless Commonly associated with diseases that cause decreased oxygenation Lung cancer Cystic fibrosis Lung abscess Congenital heart disease

Clubbing of the finger

Lung diseases

Obstructive lung diseases People with obstructive lung disease have shortness of breath due to difficulty exhaling all the air from the lungs. Because of damage to the lungs or narrowing of the airways inside the lungs, exhaled air comes out more slowly than normal. There are two main forms of COPD: Chronic bronchitis, which involves a long-term cough with mucus Emphysema, which involves damage to the lungs over time Most people with COPD have a combination of both conditions.

Causes Smoking is the main cause of COPD. The more a person smokes, the more likely that person will develop COPD. But some people smoke for years and never get COPD. In rare cases, nonsmokers who lack a protein called alpha-1 antitrypsin can develop emphysema Exposure to certain gases or fumes in the workplace

Symptoms Symptoms may include any of the following: Cough, with or without mucous Fatigue Many respiratory infections Shortness of breath that gets worse with mild activity Wheezing Treatment There is no cure for COPD. But there are many things can do to relieve symptoms and keep the disease from getting worse

2) Restrictive lung diseases: Is associated with a reduced total lung capacity, i.e., the lungs are unable to expand fully. People with restrictive lung disease cannot fully fill their lungs with air. Restrictive lung disease most often results from a condition causing stiffness in the lungs themselves. In other cases, stiffness of the chest wall, weak muscles, or damaged nerves may cause the restriction in lung expansion. Causes : Obesity, Neuromuscular disease, such as muscular dystrophy or amyotrophic lateral sclerosis (ALS)

Respiratory failure Is a condition in which the lungs becomes unable to oxygenate blood sufficiently or remove CO2. Diseases and conditions that affect your breathing can cause respiratory failure. -Lung diseases such as COPD: prevents enough air from flowing in and out of the airways. -Conditions that affect the nerves and muscles that control breathing, such as spinal cord injuries -Damage to the tissues and ribs around the lungs. An injury to the chest can cause this damage.

-Drug or alcohol overdose -Injuries from inhaling smoke or harmful fumes

Tuberculosis (TB): Cause Tuberculosis (TB) is caused by Mycobacterium tuberculosis, slow-growing bacteria that thrive in areas of the body that are rich in blood and oxygen, such as the lungs Transmitted through inhalation of infected droplets. TB primarily affects the lungs, but it can also affect organs in the central nervous system, lymphatic system, kidney, and circulatory system among others.

Symptoms of active TB in the lungs Symptoms of active TB in the lungs begin gradually and develop over a period of weeks or months. Common symptoms include: A cough with thick, cloudy, and sometimes bloody mucus from the lungs (sputum) for more than 2 weeks. Fever, chills, and night sweats. Fatigue and weakness. Loss of appetite and unexplained weight loss. Shortness of breath and chest pain.

Diagnosis Blood tests a chest X-ray or a CT scan. Sputum tests Treatment With tuberculosis, you must take antibiotics for at least six to nine months. The exact drugs and length of treatment depend on your age, overall health

Pneumonia Is an inflammatory condition of the lung—affecting the microscopic air sacs known as alveoli. It is usually caused by infection with viruses(Influenza virus) or bacteria (Streptococcus pneumoniae) and less commonly other microorganisms, and other conditions such as autoimmune diseases. Typical symptoms include a cough, chest pain, fever and difficulty breathing

Diagnostic Chest X-ray and culture of the sputum. Vaccines to prevent certain types of pneumonia are available. Treatment depends on the underlying cause. . Pneumonia presumed to be bacterial is treated with antibiotics. If the pneumonia is severe, the affected person is, in general, admitted to hospital.

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