HCR 240 test 3 notes
HCR 240 test 3 notes HCR 240
Popular in Human Pathology
verified elite notetaker
verified elite notetaker
verified elite notetaker
verified elite notetaker
verified elite notetaker
verified elite notetaker
Popular in Department
This 41 page Study Guide was uploaded by Natalie Willins on Monday March 14, 2016. The Study Guide belongs to HCR 240 at Arizona State University taught by Dr. Christodoulakis in Spring 2016. Since its upload, it has received 60 views.
Reviews for HCR 240 test 3 notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 03/14/16
Chapter 35: Structure and function of the Respiratory System ● Ventilation ○ The movement of air between the atmosphere and the respiratory portion of lungs (movement of gases into and out of the alveoli of the lungs) ○ Does not participate in gas exchange ● Perfusion ○ The flow of blood in the adjacent pulmonary capillaries ● Diffusion ○ The transfer of gases between the airfilled spaces in the lungs and the blood (the alveoli and the pulmonary capillaries) ● The respiratory system is divided into 2 parts by function: ○ Conducting airways: through which air moves as it passes between the atmosphere and the lungs ○ Respiratory tissues of the lungs: where gas exchange takes place ● Structure of the lungs ○ Soft, spongy, coneshaped organs located side by side in the chest cavity ○ Mediastinum: separates the lungs ○ Divided into lobes (3 in right lung, 2 in left lung) ○ Apex: upper part of lung; lies against the top of thoracic cavity ○ Base: lower part of lung; lies against the diaphragm ● Structure of larynx ○ Connects the oropharynx with the trachea ○ Located in a strategic position between the upper airways and the lungs ● Functions of larynx ○ Helping to produce speech ○ Protecting the lungs from substances other than air ● Inspiration ○ Air is drawn into the lungs as the respiratory muscles expand the chest cavity ● Expiration ○ Air moves out of the lungs as the chest muscles recoil, and the chest cavity becomes smaller ● Ventilation is dependant on the conducting airways: ○ Nasopharynx and oropharynx ○ Larynx ○ Tracheobronchial tree ● Structures of the airways ○ Conducting ■ Nasal passages ■ Mouth and pharynx ■ Larynx ■ Trachea ■ Bronchi ■ Bronchioles ○ Mucociliary blanket ○ Respiratory tissues ■ Alveolar bundle ■ Respiratory membrane ● Composition of the alveolar structures ○ Type I alveolar cells: flat squamous epithelial cells across which gas exchange takes place ○ Type II alveolar cells: produce surfactant, a lipoprotein substance that decreases the surface tension in the alveoli and allows for greater ease of lung inflation ● Lung circulation ○ Pulmonary circulation ■ Arises from the pulmonary artery ■ Provides for the gas exchange function of the lungs ○ Bronchial circulation ■ Arises from the thoracic aorta ■ Supplies the lungs and other lung structures with oxygen ■ Distributes blood to the conducting airways ■ Temperature and humidity control of incoming air ● Properties of gases ○ Respiratory pressures ○ Atmospheric pressure ■ Partial pressures ○ Humidity ■ Temperature effects ● Q: which of the following is directly responsible for gas exchange? ○ Trachea ○ Bronchi ○ Bronchial circulation ○ Pulmonary circulation ○ Respiratory membrane ● Respiratory pressures ○ Intrapulmonary pressure or alveolar pressure: pressure inside the airways and alveoli of the lungs ○ Intrapleural pressure: pressure in the pleural cavity ○ Intrathoracic pressure: pressure in the thoracic cavity ● Lung compliance ○ C= △V/△P ○ The change in lung volume that can be accomplished with a given change in respiratory pressure ● Airway resistance ○ The volume of air that moves into and out of the air exchange portion of the lungs ○ Directly related to the pressure difference between the lungs and the atmosphere ○ Inversely related to the resistance the air encounters as it moves through the airways ● Lung volumes ○ Tidal volume (TV): amount of air that moves into and out of the lungs during a normal breath ○ Inspiratory reserve volume (IRV): the max amount of air that can be inspired in excess of the normal tidal volume ○ Expiratory reserve volume (ERV): Max amount of air that can be exhaled in excess of the normal TV ○ Residual volume: the air that remains in the lungs after forced respiration ● Lung capacities ○ Vital capacity: IRV + TV + ERV ○ Inspiratory capacity: TV + IRV ■ The amount of air a person can breathe in beginning at the normal expiratory level and distending the lungs to the max amount ○ Functional residual capacity: RV + ERV ■ Volume of air that remains in the lungs at the end of normal expiration ○ Total lung capacity: sum of all volumes in the lungs ● Pulmonary function studies ○ Max voluntary ventilation: the volume of air a person can move into and out the lungs during max effort lasting for 1215 seconds ○ Forced expiratory vital capacity (FVC): involves full inspiration to total lung capacity, followed by forceful max expiration ○ Forced expiratory volume (FEV): expiratory volume achieved in a given time period ○ Forced inspiratory vital flow (FIF): the respiratory response during rapid max inspiration ● Types of air movement in the lung ○ Bulk flow ■ Occurs in the conducting airways ■ Controlled by pressure differences between the mouth and that of airways in the lung ○ Diffusion: the movement of gasses in the alveoli and across the alveolar capillary membrane ● Types of dead space ○ Anatomic dead space: that contained in the conducting airways ○ Alveolar dead space: that contained in the respiratory portion of the lung ○ Physiologic dead space: the anatomic dead space plus alveolar dead space ● Types of shunts ○ Anatomic: blood moves from the venous to the arterial side of the circulation without moving through the lungs ○ Physiologic: mismatching of ventilation and perfusion with the lung ■ Results in insufficient ventilation to provide the oxygen needed to oxygenate the blood flowing through the alveolar capillaries ● Matching ventilation and perfusion ○ Required for exchange of gasses between the air in the alveoli and the blood in pulmonary capillaries ○ Factors that interfere with the process: dead air space and shunt ○ The blood oxygen level reflects the mixing of blood from the alveolar dead space and physiologic shunting areas as it moves into the pulmonary veins ● Factors affecting alveolarcapillary gas exchange ○ Surface area available for diffusion ○ Thickness of the alveolarcapillary membrane ○ Partial pressure of alveolar gases ○ Solubility and molecular weight of the gas ● Oxygen and Carbon dioxide transport ○ PO2 of arterial blood normally is above 80 mm Hg ■ In chemical combination with hemoglobin ● 9899% ● Oxyhemoglobin ● Binding affinity of hemoglobin for oxygen ■ In the dissolved state ○ The PCO2 is in the range of 3545 mm Hg ■ Dissolved in CO2 (10%) ■ Attached to hemoglobin (30%) ■ Bicarbonate (60%) ● The acidbase balance is influenced by the amount of dissolved carbon dioxide and the bicarbonate level in the blood ● Breathing control ○ Respiratory center ■ Pacemaker center (pneumotaxic center and apneustic center) ■ Phrenic nerve ○ Automatic regulation of ventilation ■ Controlled by 2 types of sensors/receptors: ● Chemoreceptors: monitor blood levels of oxygen and carbon dioxide adjust ventilation to metabolic needs ● Lung receptors: monitor breathing patterns and lung function ○ Voluntary regulation of ventilation ■ Integrates breathing with voluntary acts such as speaking, blowing, and singing ■ These acts, initiated by the motor and premotor cortex, cause a temporary suspension of automatic breathing ● Cough reflex ○ Neurally mediated reflex that protects the lungs ○ Accumulation of secretions ○ Entry of irritating and destructive substances ● Mechanisms involved in dyspnea ○ Stimulation of lung receptors ○ Increased sensitivity to ventilation changes ○ Reduced ventilatory capacity or breathing reserve ○ Stimulation of neural receptors in muscle fibers of intercostals and diaphragm, and of receptors in skeletal joints ○ Associated conditions: ■ Primary lung diseases ■ Heart disease ■ Neuromuscular disorders ● Q: Which of the following accurately describes your breathing pattern after running to class? ○ Cheynestrokes ○ Normal ○ Dyspnea: dyspnea is labored breathing (not necessarily pathological in nature) ○ Eupnoea ○ Hypoxemia Chapter 36: Respiratory tract infections, neoplasms, and childhood disorders ● Areas involved in respiratory tract infections ○ Upper respiratory tract: nose, oropharynx, and larynx ○ Lower respiratory tract: lower airways and lungs ○ Upper and lower airways ● Common respiratory infections ○ Common cold ○ Influenza ○ Pneumonia ○ Tuberculosis ○ Fungal infections of the lung ● Factors affecting respiratory tract infections ○ Function of the structure involved ○ Severity of the infectious process ○ Person’s age and general health status ● Transmission of the common cold ○ Viral infection of the upper respiratory tract ■ Rhinoviruses, parainfluenza viruses, respiratory syncytial virus, corona viruses, adenoviruses ○ Fingers are the greatest source of spread ○ Cough, sneeze ■ Nasal mucosa and conjunctival surface of the eyes are the most common portals of entry of the virus ● Q: the most common port of entry for cold viruses is ○ Inhalation ○ Small cuts ○ Food ○ Conjunctival surface of the eyes ○ Fingers ○ Inhalation and conjunctival surface of the eyes: conjunctival surface of the eyes and the nasal mucosa are the most common portals of entry for cold viruses ● Rhinitis and sinusitis ○ Rhinitis: inflammation of the nasal mucosa ○ Sinusitis: inflammation of the paranasal sinuses ● Types of sinuses ○ Paranasal sinuses: air cells connected by narrow openings or ostia with the superior, middle, and inferior nasal turbinates of the nasal cavity ○ Maxillary sinus ■ Inferior to the bony orbit and superior to the hard palate ■ Opening is located superiorly and medially in the sinus ○ Frontal sinuses ■ Open into the middle meatus of the nasal cavity ○ Sphenoid sinus ■ Just anterior to the pituitary fossa behind the posterior ethmoid sinuses ■ Its paired openings drain into the spenoethmoidal recess at the top of the nasal cavity ○ Ethmoid sinuses: comprise 315 air cells on each side, with each maintaining a separate path to the nasal chamber ● Classifications of rhinosinusitis ○ Acute rhinosinusitis ■ May be of viral, bacterial, or mixed viralbacterial origin ■ May last from 57 days up to 4 weeks ○ Subacute rhinosinusitis: lasts from 4 weeks to less than 12 weeks ○ Chronic rhinosinusitis: lasts beyond 12 weeks ● Allergic rhinosinusitis ○ Occurrence ■ Occurs in conjunction with allergic rhinitis ■ Mucosal changes are the same as allergic rhinitis ○ Symptoms ■ Nasal stuffiness ■ Itching and burning of the nose ■ Frequent bouts of sneezing ■ Recurrent frontal headache ■ Watery nasal discharge ○ Treatment: oral antihistamines, nasal decongestants, and intranasal cromolyn ● Types of influenza viruses ○ Type A ■ Most common ■ Can infect multiple species ■ Causes most severe disease ■ Further divided into subtypes based on 2 surface antigens: hemagglutinin (H) and neuraminidase (N) ○ Type B ■ Hasn’t been categorized into subtypes ● Antiviral drugs ○ Amantadine ○ Rimantadine ○ Zanamivir ○ Oseltamivir ● Types of influenza vaccinations ○ Trivalent inactivated influenza vaccine (TIIV) ■ Developed in the 1940s ■ Administered by injection ○ Live, attenuated influenza vaccine (LAIV) ■ Approved for use in 2003 ■ Administered intranasally ● Pneumonia ○ Respiratory disorders involving inflammation of the lung structures (alveoli and bronchioles) ○ Causes ■ Infectious agents: such as bacteria and viruses ■ Noninfectious agents: such as gastric secretions aspirated into the lungs ● Factors facilitating development of pneumonia ○ Exceedingly virulent organism ○ A large inoculum ○ Impaired host defenses ● Classifications of pneumonias ○ According to the source of infection ■ Communityacquired ■ Hospitalacquired ○ According to the immune status of the host ■ Pneumonia in the immunocompromised person ● Tuberculosis ○ Caused by mycobacterium, M. Tuberculosis: outer waxy capsule that makes them more resistant to destruction ○ Infect practically any organ of the body, the lungs are most frequently involved ○ Macrophagedirected attack, resulting in parenchymal destruction ○ Cellmediated immune response ■ Confers resistance to the organism ■ Development of tissue hypersensitivity ● Forms of tuberculosis ○ M. tuberculosis hominis (human tuberculosis) ■ Airborne infection spread by minute droplet nuclei harbored in the respiratory secretions of persons with active tuberculosis ■ Living under crowded and confined conditions increases the risk for spread of the disease ○ Bovine tuberculosis ■ Acquired by drinking milk from infected cows; initially affects the GI tract ■ Has been virtually eradicated in North America and other developed countries ● Positive Tuberculin (TB) skin test ○ Results from cellmediated immune response ■ Implies that a person has been infected with M. tuberculosis and has mounted a cellmediated immune response ■ Doesn’t mean the person has active tuberculosis ● Classification and spread of fungi ○ Yeasts: are round and grow by budding ○ Molds: ■ Form tubular structures called hyphae ■ Grow branching and forming spores ○ Dimorphic fungi: grow as yeasts at body temperatures and as molds at room temperatures ○ Mechanisms of fungal spread: inhalation of spores ● Lung cancer ○ Causative factors ■ Smoking ■ Asbestos ■ Familial predisposition ○ Manifestations ■ Primary lung tumors (95%) versus bronchial, glandular, lymphoma ■ Secondary via metastasis ● Categories of bronchogenic carcinomas ○ Squamous cell lung carcinoma (2540%) ■ Closely related to smoking ○ Adenocarcinoma (2040%) ■ Most common in North America ○ Large cell carcinoma (1015%) ■ Large polygonal cells, spread early in development ○ Small cell carcinoma (2025%) ■ Small round to oval cells, highly malignant ● Q: the lungs are a common sight for secondary tumor development. Why? ○ Due to the highly vascular nature and small capillaries ○ Due to the fragility of the cells ○ Due to the rapid replication of type I alveolar cells ○ Due to dumb luck ● Categories of the manifestations of lung cancer ○ Those due to involvement of the lung and adjacent structures ○ The effects of local spread and metastasis ○ The nonmetastatic paraneoplastic manifestations involving endocrine, neurologic, and connective tissue function ○ Nonspecific symptoms such as anorexia and weight loss ● Q: which of the following involves infection of the entire respiratory tract ○ Common cold ○ Pneumonia: it can involve all respiratory tissues, and due to its virulence, is a major health risk ○ Tuberculosis ○ Cancer ● Stages of lung development ○ Embryonic period: bronchial bud formation ○ Pseudoglandular period: conducting airways ○ Canalicular period: primitive alveoli ○ Saccular period: terminal alveolar sacs, surfactant ○ Alveolar period: alveolar maturation and expansion ● Respiratory disorders in the neonate ○ Respiratory distress syndrome ○ Bronchopulmonary dysplasia ● Respiratory disorders in children ○ Upper airway infections ■ Viral croup ■ Spasmodic croup ■ Epiglottitis ○ Lower airway infections ■ Acute bronchiolitis ● Impending respiratory failure in infants and children ○ Rapid breathing ○ Exaggerated use of the accessory muscles ○ Retractions ○ Nasal flaring ○ Grunting during expiration Chapter 37: disorders of ventilation and gas exchange ● Gases of respiration ○ Primary function of respiratory system ■ Remove CO2 ■ Addition of O2 ○ Insufficient exchange of gasses ■ Hypoxemia ■ Hypercapnia ● Hypoxemia ○ Results from ■ Inadequate O2 in the air ■ Disease of the respiratory system ■ Dysfunction of the neurological system ■ Alterations in the circulatory function ○ Mechanisms ■ Hypoventilation ■ Impaired diffusion of gasses ■ Inadequate circulation of blood through the pulmonary capillaries ■ Mismatching of ventilation and perfusion ● Manifestations of hypoxemia ○ Mild hypoxemia ■ Metabolic acidosis ■ Increase in HR ■ Peripheral vasoconstriction ■ Diaphoresis ■ Increase in BP ■ Slight impairment of mental performance ○ Chronic hypoxemia ■ Manifestations may be insidious and attributed to other causes ● Compensation masks condition ■ Increased ventilation ■ Pulmonary vasoconstriction ■ Increased production of RBCs ■ Cyanosis ● Hypercapnia ○ Increased arterial PCO2 ○ Caused by hypoventilation or mismatching of ventilation and perfusion ○ Effects ■ Acidbase balance (decreased pH, respiratory acidosis) ■ Kidney function ■ Cardiovascular function ● Disorders of the pleura ○ Pleural effusion: abnormal collection of fluid in the pleural cavity ■ Transudate or exudate, purulent (containing pus), chyle, or sanguineous (bloody) ○ Empyema ○ Chylothorax ○ Hemothorax ○ Pleuritis ○ Atelectasis ● Types of pneumothoraxes ○ Spontaneous pneumothorax: occurs when an airfilled blister on the lung surface ruptures ○ Traumatic pneumothorax: caused by penetrating or nonpenetrating injuries ○ Tension pneumothorax: occurs when the intrapleural pressure exceeds atmospheric pressure ● Diagnosis and treatment of pleural effusion ○ Diagnosis ■ Chest radiographs, chest ultrasound ■ Computed tomography (CT) ○ Treatment: directed at the cause of the disorder ■ Thoracentesis ■ Injection of a sclerosing agent into the pleural cavity ■ Open surgical drainage ● Q: which of the following is a disorder caused by abnormal accumulation of fluid in the pleural space? ○ Pneumothorax ○ Pleural effusion: can be caused by transudate, exudate, chyle, or other fluid ○ Atelectasis ○ Hypercapnia ● Physiology of airway disease ○ Upper respiratory tract: trachea and major bronchi ○ Lower respiratory tract: bronchi and alveoli ○ Creation of negative pressure ○ Effects of CO2/pH ○ Role of inflammatory mediators ○ Increase airway responsiveness by: ■ Producing bronchospasm ■ Increasing mucus secretion ■ Producing injury to the mucosal lining of the airways ● Functions of bronchial smooth muscle ○ The tone of bronchial smooth muscles surrounding the airways determines airway radius ○ The presence or absence of airway secretions influences airway patency ○ Bronchial smooth muscle is innervated by the automatic NS ■ Parasympathetic: vagal control ● Bronchoconstrictor ■ Sympathetic: B2adrenergic receptors ● Bronchodilator ● Factors contributing asthmatic attack ○ Allergens ○ Respiratory tract infections ○ Exercise ○ Drugs and chemicals ○ Hormonal changes and emotional upsets ○ Airborne pollutants ○ Gastroesophageal reflux ● Factors involved in pathophysiology of asthma ○ Genetic: atopy ○ Environmental ■ Viruses ■ Allergens ■ Occupational exposure ● Classifications of asthma severity ○ Mild intermittent ○ Mild persistent ○ Moderate persistent ○ Severe persistent ● Q: which of the following hasn’t been implicated in the development of asthma? ○ Allergens ○ Respiratory tract infections ○ Diet: diet doesn’t affect the respiratory tract other than via allergic reactions ○ Drugs and chemicals ○ Hormonal changes and emotional upsets ○ Airborne pollutants ○ Gastroesophageal reflux ● Types of chronic obstructive pulmonary disease ○ Emphysema (Type A) ■ Enlargement of air spaces and destruction of lung tissue ■ Types: centriacinar and panacinar ○ Chronic obstructive bronchitis (type B): obstruction of small airways ● Characteristics of Type A pulmonary emphysema ○ Smoking history ○ Age of onset: 4050 years ○ Often dramatic barrel chest ○ Weight loss ○ Decreased breath sounds ○ Normal blood gases until late in disease process ○ Cor pulmonale only in advanced cases ○ Slowly debilitating disease ● Characteristics of type B chronic bronchitis ○ Smoking history ○ Age of onset 3040 years ○ Barrel chest may be present ○ Shortness of breath, a predominant early symptom ○ Rhonchi often present ○ Sputum frequent, an early manifestation ○ Often dramatic cyanosis from hypercapnia and hypoxemia ○ Frequent cor pulmonale and polycythemia ○ Numerous lifethreatening episodes due to acute exacerbations ● Bronchiectasis ○ Permanent dilation of the bronchi and bronchioles ○ Secondary to persisting infection or obstruction ○ Manifestations ■ Atelectasis ■ Obstruction of the smaller airways ■ Diffuse bronchitis ■ Recurrent bronchopulmonary infection ■ Coughing; production of the copious amounts of foulsmelling, purulent sputum, and hemoptysis ■ Weight loss and anemia are common ● Cystic fibrosis ○ An autosomal recessive disorder fluid secretion in exocrine glands and epithelial lining of respiratory, GI and reproductive tracts ○ Cause: single gene mutations on long arm chromosome 7 that encodes for cystic fibrosis transmembrane regulator (CFTR), which functions as a chloride (Cl) channel in epithelial cells ● Manifestations of cystic fibrosis ○ Pancreatic exocrine deficiency ○ Pancreatitis ○ Excess loss of sodium in sweat ○ Nasal polyps ○ Sinus infections ○ Cholelithiasis (gall stones) ● Diffuse interstitial lung diseases ○ A diverse group of lung disorders that produce similar inflammatory and fibrotic changes in the interstitium or interalveolar septa of the lung ○ Types: ■ Sarcoidosis ■ Hypersensitivity pneumonitis ■ Lung diseases caused by exposure to toxic drugs ■ The occupational lung diseases ● Occupational lung diseases ○ Pneumoconioses : the inhalation of inorganic dusts and particulate matter ○ Hypersensitivity diseases: the inhalation of organic dusts and related occupational antigens ○ Byssinosis: cotton workers; has characteristics of pneumoconioses and hypersensitivity lung disease ○ Toxic drug exposure ■ Chemotherapy ■ Treatment of arrhythmia ● Pulmonary embolism ○ Development: bloodborne substance lodges in a branch of pulmonary artery and obstructs flow ○ Types: ■ Thrombus: arising from DVT ■ Fat: mobilized from the bone marrow after a fracture or from a traumatized fat depot ■ Amniotic fluid: enters the maternal circulation after rupture of the membranes at the time of delivery ● Pulmonary hypertension ○ A disorder characterized by an elevation of pressure within the pulmonary circulation ○ Pulmonary arterial hypertension ○ Signs and symptoms of secondary pulmonary hypertension: ■ Dyspnea and fatigue ■ Peripheral edema ■ Ascites ■ Signs of right heart failure (cor pulmonale) ● Cor pulmonale ○ Right heart failure resulting from primary lung disease and long standing primary or secondary pulmonary hypertension ○ Involves hypertrophy and the eventual failure of the right ventricle ○ Manifestations include the signs and symptoms of the primary lung disease and the signs of rightsided heart failure ● Acute respiratory distress syndrome (ARDS) ○ A number of conditions may lead to acute lung injury/ ARDS ○ All produce similar pathologic lung changes including diffuse epithelial cell injury with increased permeability of alveolarcapillary membrane ● Causes of ARDS ○ Aspiration of gastric contents ○ Major trauma (with/without fat emboli) ○ Sepsis secondary to pulmonary or nonpulmonary infections ○ Acute pancreatitis ○ Hematologic disorders ○ Metabolic events ○ Reactions to drugs and toxins ● Causes of respiratory failure ○ Impaired ventilation ■ Upper airway obstruction ■ Weakness of paralysis of respiratory muscles ■ Chest wall injury ○ Impaired matching of ventilation and perfusion ○ Impaired diffusion ■ Pulmonary edema ■ Respiratory distress syndrome ● Treatment of respiratory failure ○ Respiratory supportive care directed toward maintenance of adequate gas exchange ○ Establishment of an airway ○ Use of bronchodilating drugs ○ Antibiotics for respiratory infections ○ Ensure adequate oxygenation ● Q: which of the following has been implicated as a causative factor in right ventricular failure? ○ Cor pulmonale: will result in RV failure due to the increase in workload that will result ○ Pneumothorax ○ Cystic fibrosis ○ ARDS Chapter 38: structure and function of the kidney ● Kidney structure and location ○ Structure ■ Paired, beanshaped organs ■ Multilobular structure, composed of up to 18 lobes ■ Each lobule is composed of nephrons, the functional units of the kidney ○ Location ■ Outside the peritoneal cavity in the back of the upper abdomen ■ One on each side of the vertebral column at the level of the 12th thoracic to 3rd lumbar vertebrae ● Nephron ○ The functional unit of the kidney ○ Regulates blood volume and blood pressure, controls levels of electrolytes and metabolites, and regulates blood pH ○ Regulated by the endocrine system by hormones such as antidiuretic hormone, aldosterone, and parathyroid hormone ● Function of the nephron ○ Glomerular filtration: 3 layers of filtration ○ Reabsorb water, electrolytes, and other substances to maintain consistent concentrations in the ECF ○ Secrete unneeded materials into tubular filtrate for elimination ● Capillary systems supplying the nephron ○ Glomerulus capillary system ■ Highpressure capillary filtration system located between the afferent and efferent arterioles ■ Selectively dilates or constricts to regulate pressure ○ Peritubular capillary system ■ Lowpressure reabsorptive system originating from efferent arteriole ■ GFR ● Segments of nephron tubule ○ Proximal convoluted tubule: coiled segment; drains into Bowman capsule ○ Loop of Henle: thin looped structure ○ Distal convoluted tubule: distal coiled portion ○ Collecting tubule: joins with several tubules to collect the filtrate ● Tubular filtration ○ The urine filtrate flows through the tubular component of the nephron ○ As the filtrate flows through the tubule, the concentration of water and electrolytes in the filtrate changes due to ■ Reabsorption of water and solutes by tubular cells into the peritubular capillary blood ■ Secretion from the blood into the tubular lumen ● Na+ transport driving force ○ Na+/K+ ATPase ■ Maintains concentration gradient ○ Symport ○ Antiport ● Q: which of the following best describes the function of the nephron ○ Detoxification of blood ○ Retention of important organic materials found in the filtrate ○ Reabsorption of water, electrolytes, and other substances from the bloodstream: reabsorption is the main function of the nephron ○ Synthesis and storage of urine ● 3 processes of urine formation ○ Glomerular ○ Tubular reabsorption: process by which solutes and water are removed from the tubular fluid and transported into the blood ○ Tubular secretion: transfer of materials from peritubular capillaries to renal tubular lumen. Caused mainly by active transport ● Regulation of urine concentration ○ Response to changes in interstitial osmolarity: 1200 mOsm normal ○ ADH changes the permeability of the tubules of the collecting duct ○ Regulation of blood flow: ■ Neural and humoral control (sympathetic NS, angiotensis II, ADH, endothelins) ■ Autoregulatory (juxtaglomerular complex) ○ Endothelins produce vasoconstrictions ○ Dopamine and nitric oxide produce vasodilations ● Urine pH regulation ○ The kidney regulates the composition and pH of body fluids through absorption and elimination or conservation of sodium, potassium, hydrogen, and bicarbonate ions ○ Kidneys eliminate H ions (acid base balance) from the body and conserving base bicarbonate thus regulating pH ○ The ability of the kidney to excrete H ions depends on buffers in the urine that combine with the hydrogen ion. The 3 major urine buffers are bicarbonate (HCO3), phosphate (HPO4) and ammonia (NH3) porth p1011 ● Elimination functions of the kidney ○ Renal clearance ○ Regulation of sodium ○ Potassium elimination ○ pHdependent elimination of organic ions ○ Uric acid elimination ○ Urea elimination ○ Drug elimination ● Juxtaglomerular complex ○ Thought to be a feedback control system linking changes in GFR with renal blood flow ● Endocrine functions of the kidney ○ Juxtaglomerular complex ○ Reninangiotensinaldosterone mechanism ■ Plays important part in regulation of BP ○ Erythropoietin: regulates the differentiation of RBCs in bone marrow ○ Vitamin D: ■ Increases calcium absorption from the GI tract ■ Helps regulate calcium deposition in bone ● Q: which of the following hormones is produced in the kidney ○ ADH ○ Erythropoietin: formed in the kidney in response to decreased blood oxygenation ○ Aldosterone ○ Angiotensin ● Action of diuretics ○ Loop diuretics: exert their effect in the thick ascending loop of Henle ○ Thiazide diuretics: prevent the reabsorption of NaCl in the distal convoluted tubule ○ Aldosterone antagonists (potassiumsparing diuretics): reduce sodium reabsorption and increase potassium secretion in the late distal tubule and cortical collecting tubule site regulated by aldosterone ● Characteristics of normal urine ○ A clear or ambercolored fluid ○ Approximately 95% water and 5% dissolved solids ○ Kidneys normally produce approximately 1.5 L of urine each day ○ Contains metabolic wastes and few or no plasma proteins, blood cells, or glucose molecules ● Renal clearance ○ Volume of plasma that is completely cleared each minute of any substance that finds its way into urine ○ Determining factors: ■ The ability of the substance to be filtered in the glomeruli ■ Capacity of renal tubules to reabsorb or secrete the substance ● Renal function tests ○ Urinalysis ○ Glomerular filtration rate ○ Blood tests ■ Serum creatinine ■ Blood urea nitrogen ○ Cystoscopy ○ Ultrasonography ○ radiologic/imaging studies ● Q: normal urine should ○ Be cloudy ○ Have a pH of 7.0 or greater ○ Have a specific gravity of 1.0 ○ Be sterile: there will be no bacteria present in a healthy urinary tract ● Renal casts ○ Molds of the distal nephron lumen ○ Casts develop when protein concentration is high (as in nephrotic syndrome), urine osmolality is high, and urine pH isn’t balanced ● Specific gravity ○ The specific gravity of urine varies with its concentration of solutes. The urine specific gravity provides a valuable index of the hydration status and functional ability of the kidneys ○ Healthy kidneys can produce concentrated urine with a specific gravity of 1.0301.040. During periods of marked hydration, the specific gravity can approach 1.000. ● Factors affecting glomerular filtration rate ○ Glomerular capillary hydrostatic pressure ○ Glomerular capillary osmotic pressure ○ Hydrostatic and osmotic pressures in the Bowman capsule ● Serum creatinine levels ○ In addition to its use in calculating GFR, the serum creatinine level is used in estimating the functional capacity of the kidneys ○ If the value doubles, the GFR (and renal function) probably has fallen to one half of its normal state ○ A rise in the serum creatinine level to 3 times its normal value suggests that there’s a 75% loss of renal function ○ With creatinine values of 10 mg/dL or more, it can be assumed that approximately 90% of renal function has been lost ● New methods of investigation ○ Cystoscopy provides a means for direct visualization of the urethra, bladder, and ureteral orifices. It relies on the use of a cystoscope, and instrument with a lighted lens ○ Ultrasonographic studies use the reflection of ultrasonic waves to visualize the deep structures of the body. The procedure is painless, noninvasive, and requires no patient preparation ○ Radiologic studies include a simple flat plate of the kidneys, ureters, and bladder that can be used to determine the size, shape, and position of the kidneys and observe any radiopaque stones that may be in the pelvis or ureters ○ Urography is used to detect spaceoccupying lesions of the kidneys, pyelonephritis, hydronephrosis, vesicoureteral reflux, and kidney stones ○ Other diagnostic tests include computed tomography (CT) scans, magnetic resonance imaging (MRI), radionuclide imaging, and renal angiography Chapter 39: disorders of fluid and electrolyte balance ● Functions of body fluids ○ Transport gases, nutrients, and wastes ○ Generate electrical activity to power body functions ○ Take part in the transformation of food into energy ○ Maintain the overall function of the body ● Distribution of body fluids ○ Intracellular compartment (ICF) ■ Fluid contained within billions of cells in the body ■ Larger compartment, approximately, ⅔ of body water in healthy adults ■ High concentration of K+ ○ Extracellular compartment (ECF) ■ Remaining ⅓ of body water ■ All fluids outside the cells, including the interstitial or tissue spaces and blood vessels ■ High concentration of Na+ ● Composition of fluids ○ Extracellular, interstitial, plasma ■ Large amounts of sodium and chloride ■ Moderate amounts of bicarbonate ■ Small quantities of potassium, magnesium, calcium, and phosphate ○ Intracellular ■ Almost no calcium ■ Small amounts of sodium, chloride, bicarbonate, phosphate ■ Moderate amounts of magnesium ■ Large amounts of potassium ● Q: which ion is in the highest concentration in the ICF ○ Na+ ○ K+: most abundant ion of the ICF and is responsible for the regulation of the resting membrane potential ○ Cl ○ Ca2+ ● Diffusion and osmosis ○ Concentration gradient:difference in concentration over a distance ○ Diffusion: the movement of charged or uncharged particles along a concentration gradient from an area of higher concentration to one of lower concentration ○ Osmosis: movement of water across a semipermeable membrane from the side of the membrane with the lesser number of particles and greater concentration of water to the side with the greater number of particles and lesser concentration of water ● Tonicity ○ The tension that effective osmotic pressure of a solution with impermeable solutes exerts on cell size because of water movement across the cell membrane ○ Isotonic: neither shrink nor swell ○ Hypotonic: swell ○ Hypertonic: shrink ● Mechanisms protecting Extracellular fluid volume ○ Alterations in hemodynamic variables: vasoconstriction and an increase in HR ○ Alterations in sodium and water balance ■ Isotonic contraction or expansion of ECF volume ■ Hypotonic dilution or hypertonic concentration of extracellular sodium brought about by changes in extracellular water ● Edema ○ Accumulation of fluid in extracellular space ■ Pitting edema ■ Nonpitting edema: brawny edema ● Edema formation ○ Physiologic mechanisms of edema ■ Increased capillary filtration pressure ■ Decreased capillary colloidal osmotic pressure ■ Increased capillary permeability ■ Obstruction to lymph flow ○ Types of edema ■ Localized ■ General ■ Dependent ● Methods for assessing edema ○ Daily weight ○ Visual assessment ○ Measurement of the affected part ○ Application of finger pressure to assess for pitting edema ● Physiologic mechanisms regulating body water ○ Thirst: primarily a regulator of water intake ○ Antidiuretic hormone: regulator of water output ○ Both mechanisms respond to changes in extracellular osmolality and volume ● Water and Na+ balance ○ Baroreceptors regulate effective volume ○ Modulating sympathetic NS outflow and ADH secretion ○ Atrial natriuretic peptide ○ Renin angiotensin aldosterone system ■ Angiotensin II ■ Aldosterone ○ Gain: ■ Water oral and oxidative (metabolic) ■ Na+ ○ Loss: ■ Kidneys ■ Skin ■ Lungs ■ GI tract ● Regulation of sodium ○ Kidney ■ Retains sodium when arterial pressure is decreased; eliminates it when arterial pressure is increased ■ Rate coordinated by sympathetic NS and renin angiotensinaldosterone system (RAAS) ■ Atrial natriuretic peptide (ANP) may also regulate sodium excretion by the kidney ● Assessment of body fluid loss ○ History of conditions predisposing sodium and water loss, weight loss, and observed altered physiologic function indicative of decreased fluid volume ■ HR ■ BP ■ Venous volume/filling ■ Capillary refill rate ● Psychogenic polydipsia ○ Compulsive water drinking ○ Psychiatric disorders ○ Schizophrenia ○ Drinking large amounts of water and excrete large amounts of urine ○ Cigarette smoking interferes with water excretion by the kidneys ○ Antipsychotic medications increase ADH levels ● ADH and aquaporin2 channels ○ ADH ■ V1 receptors: vasoconstriction ■ V2 receptors: control water reabsorption and aquaporins ● Disorders of ADH expression ○ Diabetes insipidus ■ Deficiency of/decreased response to ADH ■ Patients unable to concentrate urine during periods of water restriction and excrete large volumes of urine ○ SIADH: failure of negative feedback system that regulates the release and inhibition of ADH ● Types of diabetes insipidus ○ Central or neurogenic diabetes insipidus: occurs because of a defect in the synthesis or release of ADH ○ Nephrogenic diabetes insipidus: occurs because the kidneys don’t respond to ADH ● Causes of fluid volume excess ○ Inadequate sodium and water elimination ○ Excessive sodium intake in relation to output ○ Excessive fluid intake in relation to output ● Isotonic fluid volume excess ○ Isotonic expansion of the ECF compartment with increases in both interstitial and vascular volumes ○ An increase in total body sodium that is accompanied by a proportionate increase in body water ○ Causes of decreased sodium and water elimination ■ Renal function ■ Heart failure ■ Liver failure ■ Corticosteroid excess ● Potassium distribution and regulation ○ Intracellular concentration 140150 mEq/L ○ Extracellular concentration 3.55.0 mEq/L ○ Potassium stores related to body size and muscle mass ○ Normally derived from dietary sources ○ Plasma potassium regulated through: ■ Renal mechanisms to conserve or eliminate potassium ■ Transcellular shift between ECF and ICF compartments ● Abnormal potassium ○ Hypokalemia: plasma potassium levels below 3.5 mEq/L ■ Inadequate intake ■ Excessive GI, renal, and skin losses ■ Redistribution between the ICF and ECF compartments ○ Hyperkalemia: plasma potassium over 5.0 mEq/L ■ Decreased renal elimination ■ Excessively rapid administration ■ Movement of potassium from ICF to ECF ● Diagnosis and treatment of potassium disorders ○ Diagnosis based on: history, physical examination to detect muscle weakness and signs of volume depletion, plasma potassium levels, and ECG findings ○ Treatment ■ Calcium antagonizes the potassiuminduced decrease in membrane excitability ■ Sodium bicarbonate will cause K+ to move ICF ■ Insulin will decrease ECF K+ concentration ■ Curtailing intake or absorption, increasing renal excretion, and increasing cellular uptake ● Q: disorders of which ion will have the greatest effect on the membrane potential ○ Bicarbonate ○ K+: slight deviations in concentration of K+ will directly change the membrane potential ○ Cl ○ Mg2+ ● Vitamin D, calcitonin, and parathyroid hormone ○ Calcium, phosphate, and magnesium are the major divalent cations in the body ○ Vitamin D acts to sustain normal plasma levels of calcium and phosphate by increasing their absorption from the intestine ○ Calcitonin acts on the kidney and bone to remove calcium from the extracellular circulation ● Mechanisms regulating calcium, phosphate, and magnesium balance ○ Ingested in diet ○ Absorbed from intestine ○ Filtered in the glomerulus of the kidney ○ Reabsorbed in the renal tubules ○ Eliminated in the urine ● Physiological calcium ○ ECF calcium exists in 3 forms: ■ Protein bound: 40% of ECF calcium is bound to albumin ■ Complexed: 10% is chelated with citrate, phosphate, and sulfate ■ Ionized: 50% of ECF calcium is present in the ionized form ● Calcium gain and loss ○ Gain ■ Dietary dairy foods ■ PTH, vitamin D stimulate calcium reabsorption in nephron ○ Losses ■ Dietary intake (and calcium absorption) less than intestinal secretion ● Causes and symptoms of hypocalcemia ○ Causes ■ Impaired ability to mobilize calcium from bone stores ■ Abnormal losses of calcium from kidney ■ Increased protein binding or chelation such that greater proportions of calcium are in the nonionized form ■ Soft tissue sequestration ○ Symptoms ■ Increased neuromuscular excitability ■ Cardiovascular effect ■ Nerve cells less sensitive to stimuli ● Causes and symptoms of hypercalcemia ○ Increased intestinal absorption ■ Excessive vitamin D and calcium ■ Milkalkali syndrome ○ Increased bone resorption ■ Increased parathyroid hormone ■ Malignant neoplasms ■ Prolonged immobilization ○ Decreased elimination ■ Thiazide, lithium therapy ○ Symptoms ■ Changes in neural excitability ■ Alterations in smooth and cardiac muscle function ■ Exposure of the kidneys to high concentrations of calciums ● Q: alterations in ______ may result in hypercalcemia ○ ADH ○ Na+ ○ Vitamin D: when increased will result in higher retention of calcium ○ K+ ● Role of phosphate ○ Bone formation ○ Essential to certain metabolic processes: formation of ATP and enzymes needed for metabolism of glucose, fat, and protein ○ Incorporated in nucleic acids, phospholipids or cell membrane ○ Serves as acidbase buffer in ECF and renal excretion of hydrogen ions ○ Necessary for delivery of oxygen by the RBCs ○ Needed for normal function of other blood cells ■ WBCs and platelets ● Hypophosphatemia ○ Depletion of phosphate because of insufficient intestinal absorption ○ Transcompartmental shifts ○ Increased renal losses ● Hyperphosphatemia
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'