radi 660 gateway 3: respiratory system

respiratory structures involved in air distribution

all but alveoli

respiratory structures involved in gas exchange

alveoli

external respiration

exchange gases with the blood; in the lungs

internal respiration

exchange gases between the blood and the tissue cells; in the body

pressure of air outside the body

atmospheric pressure

pressure inside the alveoli

intraalveolar pressure

pressure in the pleural cavity

intrapleural pressure

purpose of surfactant

reduces the surface tension inside the alveoli so they do not stick together and collapse

what issues do premie babies have in regard to respiration?

immature lungs, lack surfactant, difficult aeration of alveoli

inspiratory capacity =

IRV + TV

functional residual capacity =

ERV + RV; what’s remaining after you push everything out

VC =

TV + IRV + ERV

TLC =

TV + IRV + ERV + RV

respiratory volumes and capacities are dependent on ?

age, gender, body build, conditioning

what is dalton’s law of partial pressures?

total pressure exerted is the sum of the pressures exerted by each gas, and the partial pressure exerted by each gas is proportional to its percentage in the total mixture

rate of gas exchange varies with ?

surface area, thickness of respiratory membrane, solubility of the gas, and the difference in partial pressure of the gas on the two sides of the membrane

if tissue PCO2 is higher than the PCO2 in the tissue capillary, which way will it diffuse?

it will diffuse from the tissue into the blood to be transported to the lungs where it will then diffuse into the alveoli and then be expired

what percentage of oxygen is dissolved in the plasma

3%

what percentage of oxygen is carried by hemoglobin as oxyhemoglobin

97%

what percentage of carbon dioxide is dissolved in the plasma

7%

what percentage of carbon dioxide is carried as carbamino-hemoglobin

23%

what percentage of carbon dioxide is carried as bicarbonate ions in the plasma

70%

main function of the respiratory system

distributes air and exchanges gases

atmospheric pressure changes depending on _

altitude

pressure affects how well a patient can do what?

ventilate/move air in and out

inspiration is a _ process while expiration is a _ process

active; passive

why is expiration a passive process

nerve innervation stops, process is reversed via relaxation; this depends on healthy lungs, expiration will be an active process if the lungs are damaged

the brain has respiratory centers in the _ and _

medulla oblongata and pons

chemoreceptors in the medulla oblongata are sensitive to increases in _ and _, and it’s detected in the _ and _; can respond to oxygen decreases but not as sensitive as with CO2

CO2 and H+; aorta and carotids

initiate Herring-Breuer reflex to prevent overinflation

stretch receptors

voluntary impulses from the higher brain can do what?

temporarily override respiration

temperature does what to breathing rate?

increases

what is needed for ventilation? (moving air in and out)

correctly functioning airway/open airway, partial pressures, working muscles, surfactant levels, neural control, muscle control, pressure gradients, lung compliance

what is needed for gas exchange?

pressure/gas gradients, surface area, functional alveoli, adequate blood supply/perfusion to the lungs

what can affect depth and rate of breathing?

neural control, O2/CO2 concentrations (pH more important), pH, voluntary control, emotions, exercise, brainstem control (medulla oblongata and pons)

what is the primary drive that controls ventilation?

carbon dioxide

increased carbon dioxide levels in the blood

hypercapnia

carbon dioxide easily diffuses into CSF, _ pH and stimulates respiratory center

lowers

how to fix hypercapnia

increased rate and depth of respirations (hyperventilation) to exhale the extra CO2

hypercapnia causes respiratory _

acidosis; nervous system depression

emphysema patients chronically retain _

CO2

marked decrease in oxygen

hypoxemia; chemoreceptors respond; important mechanism in individuals with chronic lung disease, move to hypoxic drive since they chronically retain CO2 they rely on detecting changes in oxygen

what factors affect diffusion of gases?

partial pressure gradient, thickness of respiratory membrane (which is why fluid in alveoli or interstitial tissue impairs gas exchange), total SA available for diffusion (if alveolar wall destroyed, SA reduced, so less exchange), ventilation-perfusion ratio - ventilation (air flow) and perfusion (blood flow) need to match for maximum gas exchange

reflex response to irritation in upper respiratory tract; assists in removing the irritant and is associated with inflammation or foreign material

sneezing

irritation caused by nasal discharge; inflammation or foreign material in lower respiratory tract; caused by inhaled irritants

coughing

thick mixture of mucus and saliva that is coughed up from the respiratory tract, specifically the lungs and airways

sputum

blood-tinged (bright red) frothy sputum, usually associated with pulmonary edema

hemoptysis

often indication of a bacterial infection

yellowish-green, cloudy, thick mucus

usually sign of pneumococcal pneumonia

rusty or dark-colored sputum

may be associated with bronchiectasis

very large amounts of purulent sputum with foul odor

thick, tenacious mucus occurs with what?

asthma or cystic fibrosis, blood-tinged sputum; may result from chronic cough; may also be a sign of tumor or tuberculosis

normal rate of breathing

eupnea

often associated with obstruction of airways

labored respiration or prolonged inspiration or expiration

often indicate obstruction in small airways

wheezing or whistling sounds

high-pitched crowing noise, usually indicates upper airway obstruction

stridor

light bubbly or crackling sounds, with serous secretions

rales

deeper or harsher sounds from thicker mucus

rhonchi

absence of breath sounds indicates what?

nonaeration or collapse of lungs

subjective feeling of discomfort; may be caused by increased carbon dioxide or hypoxemia; often noted on exertion, such as climbing stairs

dyspnea

severe dyspnea is indicative of _

respiratory distress

signs of respiratory distress

flaring of nostrils, use of accessory respiratory muscles, retraction of muscles between or above ribs

occurs when lying down; usually caused by pulmonary congestion

orthopnea

sudden acute type of dyspnea; common in patients with left-sided congestive heart failure

paroxysmal nocturnal dyspnea

bluish coloring of skin and mucous membranes caused by large amounts of unoxygenated hemoglobin in blood

cyanosis

results from inflammation or infection of parietal pleura

pleural pain

soft sound produced as rough, inflamed, or scarred pleural surfaces move against each other

friction rub

results from chronic hypoxia associated with respiratory or cardiovascular diseases; painless, firm, fibrotic enlargement at the end of the digit

clubbed digits

common cold (infectious rhinitis) is a _ respiratory tract infection

upper

viral infection; more than 200 possible causative agents; spread through respiratory droplets; preventable with hand-washing; symptomatic treatment; secondary bacterial infections can occur, usually caused by streptococci

common cold (infectious rhinitis)

usually bacterial infection; purulent exudate; systemic signs such as fever

sinusitis

acute infection, common in children 3-7, usually caused by Haemophilus influenzae type B, rapid onset with fever and sore throat; child in tripod position; drooling and difficulty swallowing; anxiety; may obstruct airway

epiglottitis

common viral infection, particularly in children; infection usually self-limited

laryngotracheobronchitis (croup)

viral infection, constantly mutating; sudden, acute onset with fever, marked fatigue, aching pain in the body; may also cause viral pneumonia; mild case of influenza may be complicated by secondary bacterial pneumonia; deaths in flu epidemics usually result from pneumonia

influenza (flu)

caused by the respiratory syncytial virus (RSV); transmitted by oral droplets; the virus causes necrosis and inflammation in the small bronchi and bronchioles

bronchiolitis

signs of bronchiolitis

wheezing and dyspnea, rapid shallow respirations, cough, rales, chest retractions, fever, malaise

inflammation of mucosa of larynx and trachea obstructs airway

laryngotracheobronchitis

gradual onset with hoarse, barking cough, inspiratory stridor, and restlessness

laryngotracheobronchitis (croup)

supraglottic inflammation and swelling of epiglottis obstructs airway

epiglottitis

rapid onset with drooling, dysphagia, high fever, rapid respirations and pulse, tripod position

epiglottitis

inflammation of mucosa of bronchioles obstructs small passages

bronchiolitis

gradual onset with increasing dyspnea, paroxysmal cough, wheezing, chest retractions, flared nases

bronchiolitis

classification of pneumonias is based on what?

causative agent (bacterial, viral, fungal), anatomical location of infection (both lungs or just in one lobe), pathophysiological changes (with interstitial tissue, alveolar septae, alveoli), epidemiological data (nosocomial or community-acquired)

bacterial pneumonia, community-based often in healthy young adults; usually caused by streptococcus pneumoniae; located in all of one or two lobes

lobar pneumonia

pneumonia with inflammation of alveolar wall and leakage of cells, fibrin, and fluid into alveoli causing consolidation; pleura may be inflamed

lobar pneumonia

pneumonia with sudden and acute onset; high fever and chills, fatigue, leukocytosis, dyspnea, tachypnea, tachycardia, pleural pain, productive cough with rusty sputum, rales progressing to absence of breath sounds in affected lobes, confusion and disorientation

lobar pneumonia

pneumonia that occurs in scattered small patches in both lungs, caused by multiple bacteria; inflammation and purulent exudate in alveoli often arising from prior pooled secretions or irritation

bronchopneumonia

pneumonia with insidious (gradual and secrete) onset; mild to moderate fever, productive cough with yellow-green sputum; dyspnea, cough, rales

bronchopneumonia

pneumonia that occurs in scattered small patches; caused by influenza virus or mycoplasma pneumoniae (bacterial); common in older children and young adults, transmitted by aerosol

primary atypical pneumonia

pneumonia with interstitial inflammation around alveoli; necrosis of bronchial epithelium

primary atypical pneumonia

pneumonia with variable onset with variable mild fever, headache, aching muscles, and a frequent nonproductive hacking cough, hoarseness, sore throat, malaise; varies greatly in severity and is usually self-limiting

primary atypical pneumonia

with lobar pneumonia, inflammation and vascular congestion occurs because what forms in the alveoli?

exudate; exudate contains fibrin and forms a consolidated mass, and also produces a rusty sputum; adjacent pleurae frequently involved

lobar pneumonia infection may spread to the pleural cavity, this is called what?

empyema

tuberculosis cause

mycobacterium tuberculosis transmitted by oral droplets from persons with active infection

why you have to be careful about tuberculosis

somewhat resistant to drying and disinfectants, can survive in dried sputum for weeks, destroyed by UV light, heat, alcohol, glutaraldehyde, formaldehyde; normal neutrophil response does not occur but cell-mediated immunity is normally protection

tuberculosis primarily affects what?

the lungs, however other organs may also be invaded

describe tuberculosis primary infection

organism first enters lungs, engulfed by macrophages causing local inflammation

with primary tuberculosis, if cell-mediated immunity is inadequate, then…

mycobacteria reproduce and begin to destroy lung tissue; this form of disease is contagious

with primary tuberculosis, if cell-mediated immunity is adequate, then…

some bacilli migrate to lymph nodes —> granuloma —> formation of tubercle containing live bacilli —> walled off and calcifying; bacilli may remain viable in a dormant stage for years; if individual resistance and immune response is high then bacilli remain walled off; primary infection is often latent, individual is affected but not active

describe secondary or re-infection with tuberculosis

patient’s cell-mediated immunity is impaired because of stress, malnutrition, HIV infection, or age; mycobacteria begin to reproduce and infect lung; this is active TB which can be spread to others

describe active TB

organisms multiply, forming large areas of necrosis, causing cavitation (large open areas) in the lungs; this promotes spread into other parts of the lung and infection may spread into the pleural cavity; cough and positive sputum, radiograph shows cavitation; this form is highly infectious when there is close personal contact over time