Pathophysiology II Study Guide, Composite Exam 2 PDF

- How does the body physiologically respond to a respiratory acidosis? - From a neurological perspective: - The medulla, which serves as the central chemoreceptor, receives afferent (incoming) information from peripheral chemoreceptors (aorta, carotid sinu...

- How does the body physiologically respond to a respiratory acidosis? - From a neurological perspective: - The medulla, which serves as the central chemoreceptor, receives afferent (incoming) information from peripheral chemoreceptors (aorta, carotid sinus); induces forced expiration in an effort to reduce serum CO2 levels, normalizing blood pH - From a renal perspective: - The kidneys (specifically the proximal convoluted tubule) increases its reabsorption of bicarbonate from the glomerular filtrate (urine) back into the bloodstream, effectively normalizing blood pH - What are some factors which can result in a right shift of the hemoglobin-oxygen dissociation curve? - Sepsis - Hyperinflammation/SIRS (systemic inflammatory response syndrome) - Hypoxia - Hypotension, Hypovolemia - Hyperthermia/Fever - Causes of acidosis - What is Boyle's Law? - Boyle's Law states that pressure and volume are INVERSELY proportional---as one factor increases, the other decreases - Critically important since the pressure gradient between the atmospheric pressure (the pressure OUTSIDE the body) and intrapulmonary pressure aids in establishing a basis for the movement of air - ALSO the reason why smaller alveoli cannot participate equally in gas exchange with larger ones unless surfactant is present - What are the two subtypes of alveoli normally found in the pulmonary system? - Type I Alveoli---directly participate in gas exchange; highly vascularized - Type II Alveoli---produce and secrete surfactant; not as highly vascularized - What is the purpose of surfactant? - Surfactant lowers surface tension by equally distributing water molecules across the inner alveolar wall---allows for smaller alveoli to overcome higher pressure gradient and participate in gas exchange - What effect does increased elevation have on respiratory function? - Atmospheric pressure at sea level = 760 mmHg - At higher elevations atmospheric pressure drops (REMEMBER: PARTIAL PRESSURE OF OXYGEN ITSELF DOES NOT DROP; THE CONCENTRATION OF O2 MOLECULES AT HIGHER ELEVATIONS IS STILL 21%); as atmospheric pressure drops, the driving force for oxygen also drops, meaning that inspiration will be much more difficult. - What is lung compliance? - Lung compliance = elasticity of the lung; very important in terms of measuring the ability of the lung to expand during inspiration, recoil during expiration - Decreased lung compliance decreased elasticity of the lung - HALLMARK OF RESTRICTIVE LUNG DISEASE - What factors increase airway resistance? - Parasympathetic Nervous System Vagus Nerve releases acetylcholine bronchoconstriction - Inflammation, especially due to mast cells and basophils degranulation of immune cells histamine release bronchoconstriction - What common pharmacologic agents can be utilized to counteract the bronchoconstriction associated with obstructive lung diseases? - Beta-2 agonists (e.g., albuterol) sympathomimetic; bind to beta-2 receptors, promoting bronchodilation - Anti-cholinergics (e.g., Ipratropium) counteracts the effects of acetylcholine-mediated bronchoconstriction from the vagus nerve - Which two brainstem components are involved in the mechanics of breathing? - Pons controls the respiratory rate and rhythm of breathing - Medulla central chemoreceptor; mediates the "drive" for breathing by increasing respiratory rate in response to increasing serum CO2 levels - What is the pathophysiologic basis of obstructive lung disease? - Obstructive lung disease due to increased airway resistance; results in mild hypoxia, significant retention of CO2 due to inability to fully expire - "Big 3" Asthma, COPD, Emphysema - Asthma largely genetic, though epigenetic factors involved as well; bronchoconstriction secondary to presence of allergens or environmental stimuli (exercise, cold weather) - COPD largely due to smoking - Emphysema irreversible destruction of alveoli, resulting in decreased gas exchange and, if untreated or poorly managed, pulmonary fibrosis - Pathophysiologic hallmarks of obstructive lung disease: - Asthma Hyper-eosinophilia, increased IgE levels, increased histamine levels secondary to mast cell and basophil degranulation; decreased FEV1/FVC ratio - COPD increased macrophage+neutrophil+fibroblast activation, resulting in bronchial airway edema + increased thickness of alveolar membrane secondary to collagen production (fibroblasts), bronchoconstriction, increased mucus production; decreased FEV1/FVC ratio - Emphysema widespread destruction of Type I and II alveoli, increased fibrosis - What is the most common cause of pneumonia in COPD patients? - Community-Acquired Pneumonia (CAP) caused by streptococcus pneumoniae - What is cor pulmonale? - Cor Pulmonale = right sided heart failure; occurs as a result of pulmonary hypertension - Bilateral lower extremity edema occurs FIRST (due to right sided heart failure) if prolonged, will eventually lead to left sided heart failure - What is the pathophysiologic basis for restrictive lung disease? - Hyperinflammation increased activation of macrophages and neutrophils release of pro-inflammatory cytokines which activate fibroblasts pulmonary fibrosis decreased lung compliance, decreased lung expansion - NORMAL FEV1/FVC because BOTH inspiration and expiration are adversely affected! - What are some causes of restrictive lung disease? - Exposure-Induced Pneumoconiosis due to exposures to either noxious gases or heavy metals - Berylliosis - Silicosis - Asbestosis - Coal Miner's pneumoconiosis---most common - Hypersensitivity Pneumonitis - REMEMBER: TYPE III HS REACTION! - Antigen-Antibody complex formation between IgG and antigens immune complex deposition into lung parenchyma inflammation, pulmonary fibrosis - Sarcoidosis - More common in African-American females - Multi-organ disease can affect skin, lungs, brain, heart, kidneys - Macrophages accumulate, form granulomas - Granulomas produce large amounts of vitamin D hypervitaminosis D, resulting in hypercalcemia - Treatment: Corticosteroids - ARDS acute respiratory distress syndrome - Hallmark pathophysiologic findings? - Alveolar wall fibrosis, resulting in impaired gas exchange between the alveoli and pulmonary capillaries - Surfactant inactivation, resulting in decreased alveolar recruitment - Significantly increased vascular permeability, resulting in significant pulmonary edema - Causes of ARDS? - Primary conditions that affect the lungs (chest wall trauma, pneumothorax, severe pneumonia, acute exposure to noxious gases/heavy metals - Secondary SEPSIS, SIRS (systemic inflammatory response syndrome), acute pancreatitis/appendicitis - Pneumothorax presence of air, fluid, resulting in increased intrapleural pressure - Tension Pneumothorax\-- Results in mediastinal shift of the heart cardiac arrest, hemodynamic instability - What neuromuscular diseases are most highly associated with pulmonary disease? - Myasthenia Gravis anti-nicotinic acetylcholine receptor antibodies - Guillain-Barre Syndrome ascending demyelinating disease; look for loss of reflexes + muscle weakness - Muscular dystrophies, kyphoscoloiosis DO NOT WORRY ABOUT THESE FOR THE EXAM! - Dermatologic Pathophysiology: - What are the 3 primary histologic components of the skin, from superficial to deep? - Epidermis---LACKS BLOOD SUPPLY; therefore, often does not bleed in the case of small splinters, paper cuts - Dermis - Subcutaneous layer (hypodermis) - What are the 5 layers of the epidermis, from superficial to deep? - REMEMBER: "CHEETAHS LOVE GOOD SPAGHETTI, BRO" - "Cheetahs" Stratum Corneum - most superficial layer of the epidermis; consists almost exclusively of dead, keratinized epithelium (keratinocytes, or skin cells) with no nuclei - "Love" Stratum Lucidum - only found in places of thickened skin (palms of the hand, soles of the feet); in terms of functionality and histology, similar to the stratum corneum - "Good" Stratum Granulosum - histologically, contains lamellar granules granules which contain hydrophobic biomolecules which aid in sealing moisture within the skin; some nucleated keratinocytes can be seen - "Spaghetti" Stratum Spinosum - contains Langerhans Cells (intra-epidermal macrophages) which are involved with the immune protection of the skin from infectious pathogens, foreign debris; multitude of keratinocytes with dark nuclei - "Bro" Stratum Basale - deepest layer of the epidermis; contains a significant number of mitotically active keratinocytes; also contains melanocytes, which produce melanin involved with protection against UV radiation - KNOW THE DEFINITIONS AND THE LISTED EXAMPLES OF EACH OF THE FOLLOWING TERMS: - Macule - well-circumscribed, flat skin lesion which typically results in a change in the color of the skin in a certain location; usually less than 1 cm in diameter - EXAMPLE: petechiae - Papule - small, elevated skin lesion which is less than 1 cm in diameter. - EXAMPLE: Warts - Patch - macular lesion which is greater than 1 cm and/or is irregular in terms of its appearance (i.e., not well circumscribed) - EXAMPLES: Vitiligo, Port-Wine Stains, Café-au-lait spots - Wheal - elevated, irregularly shaped area of cutaneous edema [ ] which is typically solid; think ALLERGY (therefore, associated with Type I Hypersensitivity Reactions) or INSECT BITE - most of the time, these are transient and go away once the offending event/agent is discontinued - Urticaria - Hives - Vesicle - elevated, well-circumscribed lesion which is superficial (does not extend to the dermis in terms of its depth), and may be filled with serous fluid - Commonly painful to touch - EXAMPLE (ABOUT 99% OF THE TIME) HERPESVIRUSES (HSV-1, HSV-2, HERPES ZOSTER, VARICELLA (CHICKENPOX)) - Telangiectasia- fine, irregular skin lesion characterized by areas of capillary dilation, sometimes in a "spider" like pattern - KNOW APPEARANCE! - Telangiectasia (broken capillaries \... - What type of skin infections are typically transmitted due to animal/insect bites? - Zoonotic Infections! - Rocky Mountain Spotted Fever, Lyme Disease, Spider bites, Mosquito-borne infections