Midterm 2 - Amanda Flashcards
Respiration changes in pH
Increasing CO2 is called respiratory acidosis
Decreasing CO2 is called respiratory alkalosis. Hyperventilation
Metabolic Changes in pH
Metabolic acidosis is build up of lactic acid when compensating for respiratory alkalosis.
Metabolic alkalosis: Side effect of certain drugs but does not arise physiologically.
Large Passageways of Respiration
nasal passages contains conchae and sinuses which moisten, warm and clean the air flowing through. Then pharynx containing MALT. Next, larynx. Next, trachea which leads to the primary bronchus then secondary etc… all the way to ten branchings.
Bronchioles
Airways without cartilage. Terminal bronchioles branch to respiratory bronchioles which doesn’t have a complete epithelium. These leads to alveolar ducts with no epithelium.
Pulmonary Artery
The pulmonary artery follows the branching of the pulmonary bronchi and is visible in a pulmonary angiogram.
Airway Epithelium
ciliated epithelium. Goblet cells and submucosa glands excrete mucus and fluids. Basal cells regenerate the other cells.
Chronic Bronchitis
usually arises in COPD patients and is associated with cigarette smoking. Involves the continual inflammation of the airways. Hypertrophy of submucosa glands, lose ciliated cells and basal cells start dividing uncontrollably.
Regulation of Airway Smooth Muscle
- Parasympathetic: contraction of smooth muscle
- Sympathetic: Dilation of smooth muscle
- Inflammatory paracrine: constrict airways. Examples are histamine, phospholipase A2 and leukotrienes.
- Carbon Dioxide: increase leads to smooth muscle dilation.
- Neural Reflexes: Occurs through the stimulation of afferent neurons by irritants in the airway. Causes constriction of smooth muscle.
Regulation of Submucosa Glands
- Parasympathetic: Stimulates secretion
- Inflammatory paracrine: stimulate secretion
- Neural Reflexes: Irritant stimulates sensory afferents activating the parasympathetic neurons causing secretion.
Ion/Fluid Transport in Epithelium of Airways
Regulated step is the net movement of chloride ions from the interstitial space to the lumen. Chloride channel is opened through cAMP phosphorylation.
Alveolar Cells
type I, type II, endothelial, fibroblasts, macrophages, neutrophils
Atelectasis - definition and causes
Collapse of a lung in which a gap opens in the pleural space.
1- Obstructive atelectasis: caused by a clogged bronchus. May be due to a tumor, mucus or a pea.
2- Absorptive atelectasis: occurs when patient is on oxygen therapy
3- Pneumothorax: air or gas in the intrapleural space. Causes may be a wound to the chest wall, or serious infections like TB.
4- Spontaneous pneumothorax: no obvious cause, the lung simply pulls away from the chest wall.
5- Surfactant problem: less surfactant causes more tension in the alveolar walls which makes the lung easier to collapse.
IRDS
infant respiratory distress syndrome
develops in premature infants because surfactant has not developed yet.
Symptoms include tachypnea (fast breathing) and cyanosis (refers to the blue color of deoxygenated hemoglobin especially under fingernails and in the lips)
Restrictive lung disease.
Surfactant
made of phospholipid and four amphipathic proteins. Responsible for changing surface tension based on surface area. Smaller surface areas have smaller surface tensions.
Law of Laplace and surfactant: if alveoli of different sizes didn’t have similar surface tension they would have different pressures and smaller alveoli would collapse. Problem in IRDS
Muscles used in ventilation
quiet breathing: diaphragm, external intercostals for inhalation. exhalation is passive
exercising: Internal intercostals and abdominal muscles aid in active exhalation. Neck muscles also aid in inhalation.
Total lung capacity
maximum amount of gas in lungs after maximum inhalation
Forced Vital capacity
maximum amount of gas you can exhale
FEV1
Maximum amount you can exhale in the first second
Residual volume
gas left in lung following maximum exhalation
Functional residual capacity
amount of gas in lungs following a normal exhalation. Changes in asthma and COPD
Alveolar Ventilation
defined as the amount of new air entering the alveoli per minute. = f * (Vtv - Vds) where f is the frequency of ventilation
Tidal volume
the amount being inhaled and exhaled at any given time
Alveolar gas
upon inhalation it is the first gas that goes into the alveoli but is not fresh because it was the gas left in the airways from the last exhalation.
anatomical dead space
volume of gas left in the airway and is approximately equal (in mL) to the persons weight in pounds
ARDS - causes, characteristics and pathology
Acute respiratory distress syndrome
epithelial inflammation
Causes: serious infection, sepsis
Characteristics: dyspnea signals the onset. hypoxemia which is inadequate oxygenation of the blood. hypercapnia which is not blowing carbon dioxide off fast enough. Protein rich infiltrates accumulate in the alveoli.
Pathology: Neutrophils join macrophages in the alveoli causing hyper-inflammation
Asthma - epidemiology
prevelance is greater than 20 years ago. Higher prevalence in boys in a younger age but girls in older ages.
Asthma - general
Obstructive disease with inflammation that leads to airway hyper-responsiveness. Is reversible to some extent.
Atopic Asthma
genetic predisposition and environmental factors TH2 cells dominate instead of TH1 which would be a normal response. TH2 cells release cytokines and IgE resulting in high levels of inflammation.
Atopic Asthma sequence
Within the first hour: mast cells release inflammatory paracrines such as histamine and leukotrienes causing smooth muscle contraction, edema and mucus secretion.
After 4-6 hours: cytokines with infiltration of cells. Airways become hyper-responsive.
Weeks to months: airway remodeling. Walls and basement membranes thicken and there is goblet cell hyperplasia (have more goblet cells)
Non-atopic asthma
stimulus (cold air, cigarette smoke, exercise) stimulates afferent neurons in the airways which can begin a reflex that either acts locally or via the CNS to cause smooth muscle contraction and submucosal gland contraction
Asthma - treatments
remove or reduce exposure to the allergen
Inhaled short-acting Beta-2 agonist: first choice.
Inhaled corticosteroid: fluticasone. suppresses inflammation to prevent asthma Inhaled
long-acting beta-2 agonist: salmeterol. always given with a inhaled corticosteroid. Oral drugs are contraindicated.
Leukotriene receptor antagonist or a blocker of lipooxygenase.
Anti-IgE monoclonal antibody
Chronic Bronchitis and Emphysema
COPD or chronic obstructive pulmonary disease. Common in smokers.
High functional residual capacity due to the difficulties with exhalation.
Airway Damage in COPD
- epithelial damage including loss of cilia, degenerative epithelial cells and abnormal repair.
- Submucosal glands hypertrophy and mucus production is over-stimulated
- Small airways thin and lose support which, during exhalation, causes the pressure surrounding the airways to be greater than atmospheric, making it hard to exhale.
Alveolar Damage in COPD
- destruction of alveolar walls leads to abnormally large air spaces within the lung called bullae.
- Neutrophils release proteases, such as neutrophil elastase that break down elastic connective tissue. 3. Phagocytes also release proteases and oxygen radicals that damage surrounding tissue.
- Antiproteases, which are normally released by macrophages as protection, are genetically deficient.
Mismatching of Ventilation and Perfusion
Unequal distribution of blood flow to the lungs due to destruction of capillaries. Lowers the partial pressure of oxygen leaving the lungs and may result in hypoxemia (low oxygen in blood).
Treatment in COPD
- First is smoking cessation
- Inhaled short-acting beta-2 agonist. Albuterol. Rescue inhaler.
- Inhaled short-acting anti-cholinergic. Ipratropium.
- Inhaled long-acting beta-2 agonist. Salmeterol. Improve FEV1 but do not affect course of disorder.
- Inhaled long-acting anti-cholinergic. Tiotropium. Improve FEV1 but do not affect course of disorder.
- Inhaled corticosteroid. Fluticasone. Not used alone but may be combined with inhaled long-acting beta-2 agonist to improve FEV1 but does not affect course of disorder.
- Oxygen therapy. Only used if PaO2 falls below 55 mm Hg.
- Lung Reduction Surgery. Remove the worst part of the lung and allow the rest of the lung to regenerate the area.
Characteristics of Restrictive Lung Disease
Defined by having a normal FEV1/FVC ration. However, have an abnormally low FVC meaning inhalation is very difficult.
Low compliance of lungs (in contrast to asthma and emphysema).
Common symptom is dyspnea (difficulty breathing).
Finally, there is impaired diffusion of oxygen between the alveoli and the capillaries.
Normal Lung healing
Type 1 cells are most commonly damaged and if the connective tissue matrix remains intact type 2 cells will divide and develop into type 1 cells. If the connective tissue matrix is damaged it sometimes can be repaired but beyond a certain amount of damage nonfunctional scar tissue forms.
Occupational Restrictive Disorder
Examples are asbestosis and silicosis.
Macrophages release growth factors which drives processes creating fibrosis of the lungs.
Abnormalities in the replenishment of type I cells and impaired mucosal defense mechanisms are present.
Idiopathic Pulmonary Fibrosis
Unknown cause. Common in people over 50. Extensive fibrosis and low survival rates after a few years.
Sarcoidosis
inflammatory disorder of unknown cause. Characterized by accumulation of macrophages which is called granulomas.
Bronchiectasis
chronic, abnormal dilation of the bronchi. Presents with persistent productive cough and recurrent airway infections
Cystic Fibrosis
Genetic disorder involving defective chloride channels. Mucus clogs the lungs which promotes serious lung infections.
IRDS and Laplace
infant respiratory distress syndrome. In normal alveoli with surfactant, surface tension in small alveoli is reduced more compared to the larger alveoli. Without surfactant the surface tension is the same in both large and small alveoli. According to the Law of Laplace, if tension is the same pressure decreases with increasing radius. Because smaller alveoli have higher pressure, gas will flow from small alveoli to larger alveoli. Blood leaving the lungs contains less oxygen than normal because of collapsed small alveoli, causing cyanosis.
Also, compliance is less with low levels of surfactant causing inhalation to be difficult.
Pneumonia
general term that refers to infection of the lung with subsequent solidification of the tissue. Alveoli fill with edema followed by a rapid accumulation of macrophages and neutrophils. Sometimes damage may cause thickening of the airway causing bronchiectasis
Tuberculosis
Activated macrophages accumulate to form a granuloma. Usually leads to significant necrosis and fibrosis. Secondary tuberculosis develops when the bacteria which were contained in a granuloma emerge
Carcinoma of the lung
most common cause of death from cancer in the US. Caused by smoking 90% of the time.
Common partial pressures
PO2 inhaled = 160 mm Hg. PCO2 inhaled = 0.3
PAO2 (alveolar) = 105 mm Hg. PACO2 = 40 mm Hg.
PvO2 (entering right atria) = 40 mm Hg. PvCO2 = 46 mm Hg but both these values are variable and depend on exercise