A&P II Exam 2 - Extra Credit

Chronic Obstructive Pulmonary Disease (COPD)

Exemplified by chronic emphysema and chronic bronchitis; Key feature is irreversible decrease in ability to force air out of lungs; Other common features include history of smoking in 80% of patients, Dyspnea labored breathing (“air hunger”), coughing and frequent pulmonary infections, most patients develop hypoventilation accompanied by respiratory acidosis, hypoxemia

Emphysema

Permanent enlargement of alveoli and destruction of alveolar walls result in decreased lung elasticity, with three consequences: accessory muscles are necessary for breathing, leading to exhaustion from using 10-15% more energy to breathe than normal; trapped air causes hyperinflation, which flattens diaphragm and causes expanded barrel chest, both of which reduces ventilation efficiency; damaged pulmonary capillaries lead to enlarged right ventricle

Chronic Bronchitis

Inhaled irritants cause chronic excessive mucus; Mucosae of lower respiratory passageways become inflamed and fibrosed; results in obstructed airways that impair lung ventilation and gas exchange; symptoms include frequent pulmonary infections; risk factors include smoking and environmental pollutants

Asthma

Sometimes classified as COPD, but episodes are acute, not chronic, with symptom-free periods; characterized by coughing, wheezing, and chest tightness; active inflammation of airways precedes bronchospasms (contraction of the smooth muscle of the bronchioles)

Tuberculosis (TB)

Infectious disease caused by bacterium Mycobacterium tuberculosis; symptoms include fever, night sweats, weight loss, racking cough, coughing up blood; treatment includes 12 month course of antibiotics, antibiotic-resistant strains have been seen, including multidrug-resistant strains

Lung Cancer

Leading cause of cancer deaths in North America; 90% of all cases are a result from smoking; three most common types include adenocarcinoma (~40% of cases) originates in peripheral lung areas and develops from bronchial glands and alveolar cells, squamous cell carcinoma (20-40% of cases) arises in bronchial epithelium and tends to form masses that may hollow out and bleed, small cell carcinoma (~20% of cases) contains lymphocyte-like cells that originate in primary bronchi forming small grape-like clusters and subsequently metastasize

Treatments for lung cancer

Early detection is key to survival; if metastasis has not occurred, surgery to remove diseased lung tissue; if metastasis has occurred, radiation and chemotherapy; several new therapies are on horizon

Incompetent Valve

Blood backflows so heart repumps same blood over and over; severely weakens heart; defective valve can be replaced by mechanical, animal, or cadaver valve

Valvular Stenosis

Stiff flaps that constrict opening; heart needs to exert more force to pump blood; severely weakens heart; defective valve can be replaced by mechanical, animal, or cadaver valve

Angina Pectoris

Thoracic pain caused by fleeting deficiency in blood delivery to myocardium; cells are weakened

Myocardial Infection (Heart Attack)

Prolonged coronary blockage; areas of cell death are repaired with noncontractile scar tissue

Arrhythmias

When defects in intrinsic conduction system cause irregular heart rhythms, and uncoordinated atrial and ventricular contractions

Fibrillation

When defects in intrinsic conduction system cause rapid, irregular contractions; heart becomes useless for pumping blood, causing circulation to cease; may result in brain death; treatment involves defibrillation, which interrupts chaotic twitching, giving heart “clean slate” to start regular, normal depolarizations

Heart Block

AV node is defective; few impulses or no impulses reach ventricles; ventricles beat at their own intrinsic rate, too slow to maintain adequate circulation; treatment involves artificial pacemaker, which recouples atria and ventricles

Rhinitis

Inflammation of nasal mucosa; viral infection or allergies; nasal mucosa is continuous with mucosa of respiratory tract, so infections spread from nose to throat to chest; can also spread to tear ducts and paranasal sinuses, causing blockage of sinus passageways; can lead to absorption of air, producing a vacuum resulting in sinus headache; infected and swollen adenoids can block air passage in nasopharynx, making it necessary to breathe through the mouth; as a result, air is not properly moistened, warmed, or filtered before reaching lungs; when adenoids are chronically enlarged, both speech and sleep may be disturbed

Laryngitis

Inflammation of the vocal folds that causes the vocal folds to swell, interfering with vibrations; results in changes to vocal tone, causing hoarseness; in severe cases, speaking is limited to a whisper; laryngitis is most often caused by viral infections but may also be due to overuse of the voice, very dry air, bacterial infections, tumors on the vocal folds, or inhalation of irritating chemicals

Smoking

Inhibits and ultimately destroys cilia; without ciliary activity, coughing is only way to prevent mucus from accumulating in lungs; reason smokers with respiratory congestion should avoid medications that inhibit cough reflex

Tracheal Obstruction

Life threatening; many people have suffocated after choking on a piece of food that suddenly closed off their trachea

Heimlich Maneuver

Procedure in which air in victim’s lungs is used to “pop out”, or expel, an obstructing piece of food; maneuver is simple to learn and easy to do but is best learned by demonstration; when done incorrectly, may lead to cracked ribs

Pleurisy

Inflammation of pleurae that often results from pneumonia; inflamed pleurae become rough, resulting in friction and stabbing pain with each breath; pleurae may produce excessive amounts of fluid, which may exert pressure on lungs, hindering breathing

Airway Resistance

As airway resistance rises, breathing movements become more strenuous; severe constriction or obstruction of bronchioles can prevent life-sustaining ventilation, and can occur during acute asthma attacks and stop ventilation; epinephrine dilates bronchioles, reducing air resistance; effective thickness of respiratory membrane increases dramatically if the lungs become waterlogged and edematous; seen in pneumonia or left heart failure; the 0.75 seconds that red blood cells spend in transit through pulmonary capillaries may not be enough for adequate gas exchange; results in body tissues suffering from oxygen deprivation

Emphysema

Walls of adjacent alveoli break down, and alveolar chambers enlarge; tumors, mucus, or inflammatory material also can reduce surface area by blocking gas flow into alveoli

Hypoxia (Hypoxemia)

Inadequate O2 delivery to tissues; can result in cyanosis; hypoxia is based on cause

Anemic Hypoxia

Too few RBCs or abnormal or too little Hb

Ischemic Hypoxia

Impaired or blocked circulation

Histotoxic hypoxia

Cells unable to use O2, as in metabolic poisons

Hypoxemic hypoxia

Abnormal ventilation; pulmonary disease

Carbon monoxide poisoning

Especially from fire or engines; hemoglobin has a 200x greater affinity for carbon monoxide than oxygen