Respiratory System Flashcards
gas exchange occurs within the (3 respiratory system parts)
gas exchange occurs within respiratory bronchioles, alveolar ducts, and alveoli
describe alveoli
alveoli are thin-walled, balloon-like structures surrounded by pulmonary capillaries.
describe the alveolus’ role in gas exchange
air enters the alveolus on inspiration, air moves across the alveolar membrane to the capillaries to the RBCs where CO2 is exchanged from the RBCs to the alveolus and expired out of the body
if the PO2 (pressure of oxygen in the arterial blood) is between 90-100 mmHg, how oxygenated is the body?
If the pressure of oxygen in the arterial blood (PO2) is within 90-100 mmHg, Hgb is maximally saturated with oxygen therefore the tissues remain oxygenated
describe ventilation
ventilation is the process of inspiring and expiring air via the pulmonary airways
describe perfusion
perfusion is the movement of blood through the pulmonary circulation providing oxygen to all parts of the body (between the alveoli and the capillaries!)
describe the ventilation-perfusion (V-Q) ratio
the ratio of the amount of air reaching the alveoli to the amount of blood reaching the alveoli; ideal is that they are equal
describe a shunt
an area with perfusion but NO ventilation = no O2 exchange for the increasing amount of CO2 in the alveoli
usually caused by respiratory issues, anything that prevents the oxygen from the outside to reach the blood vessels
describe a dead space
an area with ventilation but NO perfusion = breathing in oxygen but no capillaries to pick it up to take it to places like brain, foot
most common example is a pulmonary embolism
what is hypercapnia
the main stimulus to breathing, an increased level of CO2 in the blood tells us to breath - this is NORMAL
what is hypoxic drive
hypoxic drive is when the peripheral chemoreceptors sense low levels of O2 and take over as the stimulus of breathing - this is due to chronic elevation of CO2
ex: patient with COPD
where are the central chemoreceptors located
the central chemoreceptors are located near the respiratory center in the medulla
where are the peripheral chemoreceptors located
the peripheral chemoreceptors are located in the common carotid arteries
what are baroreceptors and where are they found
baroreceptors are located in the aortic arch and the carotid artery
baroreceptors can send signals to (1) ANS if the systolic BP drops then (2) stimulates the SNS to increase heart rate and respiratory rate
describe dyspnea
perceived or feeling of SOB or difficulty breathing, labored breathing
describe coughing
a neurally-mediated reflex that protects the lungs from accumulation of secretions and entry of irritating substances
describe hemoptysis
bloody sputum but different from hematemesis which is vomiting blood
describe atelectasis
collapse of the alveoli = affects perfusion
describe hypoxia
insufficient oxygen levels in the blood to meet the needs of the tissues
describe pneumonia
inflammation of the lung tissues (alveoli and bronchioles)
name the 4 classifications of pneumonia
- community-acquired (CAP)
- hospital-acquired (HAP)
- ventilator-associated (VAP)
- within those who are immunocompromised
name the 5 etiologic causes of pneumonia
- bacteria
- viral
- inhalation of chemicals
- aspiration of oropharynx contents
- other infectious agents like fungi
what is considered a major risk factor to developing pneumonia?
the flu = the virus can alter pulmonary immune defenses (lowering the resistance) leading to the development of secondary pneumonia
describe the pathway of pneumonia attacking the respiratory system
causative agent enters the upper airways (nose, pharynx, larynx) = reaches the lungs/URT = causative agent adheres to respiratory epithelial cells then 1 of the 3 things happen:
- stimulates inflammatory response = typical s/s of inflammation
- resp cells secrete mucus = in hopes to cough up mucus with bacteria
- resp cells are irritated by foreign substance = dry cough
THEN the mucus plus the inflammatory response = exudative fluids and accumulate in the alveoli = hear crackles through stethoscope b/c alveoli are drowned = s/s: SOB (hypoxia)
at what time is it considered HAP and not CAP (2)
hospital-aqcuired =
- 48 hours after hospital admission
- if someone has been in a long-term care facility for 14 days or more prior to hospital admission
what is the most common causative agent for CAP?
Streptococcus pneumoniae
what is the most common causative agent for HAP?
Staphylococcus aureus; particularly MRSA
what is the most common causative agent for VAP?
MRSA and VRE (vancomycin-resistant enterococcus)
what is the most common causative agents for pneumonia within immunocompromised people?
- S. aureus
- Aspergillus
- Candida
what are examples of obstructive lung disorders?
- asthma
- COPD
- bronchiectasis
obstructive lung disorders are caused by conditions that limit which kind of airflow?
expiratory airflow
what are examples of restrictive lung disorders?
- pulmonary fibrosis
2. thoracic cage deformities
restrictive lungs disorders are caused by conditions that limit which kind of airflow?
limits lung expansion (inspiratory airflow)
indicator of hypercapnia
PCO2 is greater than 45 mmHg
usual cause of hypercapnia…
bradypnea, asphyxiation, aspiration, pneumonia, pulmonary edema
how does someone get chronic hypercapnia
develops over period of time to individuals with progressive hypoxic lung disease
describe chronic hypoxia
aka hypoxemia, diminished level of oxygen in the blood
major cause of COPD plus others
smoking
others:
- genetic predisposition
- IV drug users
- exposure to occupational dusts and chemicals
what is the stimulus to breathing for someone with COPD
low level of O2
3 manifestations of COPD (s/s)
- absent during the early phase
- dyspnea - usually the 1st symptom
- cough or wheezing
what are the 3 types of COPD?
- chronic bronchitis
- emphysema
- chronic asthma
etiology of chronic bronchitis
- smoking & recurrent respiratory infections = hypersecretion of mucus in large airways leads to…
- sputum over production
- affectation of small airways
THEN from (2) affectation of small airways
- -> increased mucus production = plugging of the airways resulting in hypoxia which leads to…
- cyanosis (BLUE BLOATER)
- stimulation of pulmonary arterial vasoconstriction
THEN from (2) stimulation of pulmonary arterial vasoconstriction --> increased resistance to pulmonary artery --> affectation of the R ventricle (can't excrete blood) --> R ventricle hypertrophy = affectation of R atrium, SVC, IVC --> congestion & edema = R VENTRICLE HEART FAILURE (cor pulmonale)
etiology of emphysema
SIMPLY: smoking and inherited deficiency of a1 antitrypsin
smoking =
- attraction of inflammatory cells = release of elastase
- diminishes a1 antitrypsin activity (normally antitrypsin inhibits the release of elastase)
= end result: elastase –> destroys elastic fibers in the lungs –> loss of lung elasticity –> alveoli permanently become hyperinflated –> remain oxygenated –> PINK PUFFER
note: in late-stage emphysema, patient may become cyanotic
etiology of chronic asthma
allergy triggers immune response/reaction
= bronchial constriction (dyspnea; chest tightness)
= inflammation (bronchial edema)
= increase size of goblet cells (increase mucus production = cough)
THEN narrowing of the airway s/s = wheezing, dyspnea, chest pain, use of accessory muscles, increase resp rate
