Lecture 21- Respiratory Control And Lung Disease Flashcards
Ventral respiratory group
Within medulla oblongata
Rhythm generating and integration centre for respiration
Contains peerage groups of neurons; some fire during exhalation and others during inhalation
Dorsal respiratory group
Within medulla oblongata
Integrates input from peripheral stretch and chemoreceptors and communicates with ventral respiratory group
Pontine respiratory group
Within the pons
Modifies breathing rhythm set by ventral respiratory group to smooth out transitions between inspiration and expiration
What are the most important factor that influences breathing rate and depth?
Changing levels of CO2 and O2 and H+ in arterial blood
Central chemoreceptors
In medulla oblongata
Stimulate regulatory respiratory centres to cause increase in breathing rate and depth
Peripheral chemoreceptors
In aortic arch and carotid arteries
Sensitive to arterial Po2 but levels must drop substantially before oxygen levels become a major stimulus for increased ventilation
Hyperventilation
Increase depth and rate of breathing that exceeds body’s need to remove CO2
Leads to decreased blood CO2 levels
What does hyperventilation cause?
Cerebral vasoconstriction and ischemia
Dizziness and fainting
Hypocapnia
Decreased blood CO2 levels
Pulmonary irritant reflexes
Respond to inhaled irritants in the nasal passages or tranches by causing reflexive brochoconstriction in the respiratory airways
Inflation (hearing-Breuer) reflex
Activated by stretch receptors in visceral pleurae and conducting airways, protecting lungs from overexpansion
Hyperpnea
Deeper,more vigorous respirations
What are the three neural factors that contribute to change in respirations?
Psychological stimuli
Stimulate our cortical motor stimulation of skeletal muscles and respiratory centres
Excitatory impulses to respiratory areas from proprioreceptors in muscles, tendons and joints
What happens to neural factors when excessive ends?
They are shut off and there is a gradual decline to baseline
Acute mountain sickness
Result from a. Rapid transition from sea level altitudes to above 8000 feet
Pulmonary function tests
Evaluate losses in respiratory function using a spirometer to distinguish between obstructive and restrictive pulmonary disorders
Obstructive pulmonary diseases
Involve hyperinflation of the lungs
Characterized by increased total lung capacity, functional residual capacity and residual volume
Initially a problem in the tubes along respiratory tract
Restrictive pulmonary disorders
Expansion of lungs is limited, display low vital capacity, total lug capacity, functional residual capacity, and residual volume
chronic obstructive pulmonary diseases (COPD)
Seen in patients with smoking history
Result in progressive dyspnea, coughing and frequent pulmonary infections and respiratory failure
Emphysema
Permanently enlarged alveoli and deterioration of alveolar walls
Chronic bronchitis
Result from inhaled irritants
Causes excessive mucus production in bronchi, inflammations and fibrosis of lower respiratory mucosa
Asthma
Inflammatory disease of airways
Causes coughing, dyspnea, wheezing and chest tightness
Adenocarcinoma
Approx. 40% of cases
Originates in peripheral lung areas as nodules that develop from bronchial glands and alveolar cells
Squamous cell carcinoma
Approx. 20-40% of cases
Arises in the epithelium of the bronchi and tends to form masses that hollow out and bleed
Small cell carcinoma
Approx 20% of cases
Contains lymphocyte-like cells that originate int he primary bronchi, form clusters within the mediastinum and rapidly metasize
