30 Questions
Which part of the respiratory system allows gas exchange between blood and air?
Bronchioles
What is the normal respiratory rate during rest?
12-16 cycles/minute
Which nerve arises from the cervical neurons and supplies the diaphragm?
Phrenic nerve
Where does gas exchange occur within the respiratory system?
In the alveoli
Which part of the respiratory system has a thick wall and no gas exchange occurs in it?
Trachea
In rapid respiration, which characteristic found in normal respiration is absent?
Respiratory pause
What is the name of the center in the lower part of the pons that is involved in the cough reflex?
Apneustic center
Which of the following is NOT a medullary center involved in the cough reflex?
Pneumotaxic center
What is the primary function of the cough reflex?
To protect the lungs from the accumulation of secretions
Where are the receptors for the cough reflex located?
In the tracheobronchial wall
What is the afferent pathway for the cough reflex?
Vagus nerve
What is the stimulus that triggers the cough reflex?
Irritating substances and excess secretions
What happens to the chest diameter when the diaphragm contracts?
Increases vertically
Which muscle contraction is responsible for increasing the anteroposterior and transverse diameters of the chest?
Diaphragm
What is the intrapulmonary pressure reduced to during inhalation?
-1mmHg
What is the process of exhalation primarily driven by?
Elastic properties of the lung
In which conditions does deep expiration become an active process?
During asthma and emphysema
Which muscles are considered accessory inspiratory muscles during deep inspiration?
Scapular elevators and rib elevators
What is the physiological significance of pulmonary surfactant?
Helping to prevent pulmonary edema
Which factor accelerates the maturation of surfactant?
Thyroid hormone
What causes impaired cough reflex according to the text?
Presence of a nasogastric tube
Which condition leads to a serious lung disease due to deficient formation of surfactant?
Respiratory distress syndrome
How do glucocorticoids affect surfactant maturation?
Increase lung surfactant
What factor decreases lung surfactant according to the text?
Smoking
Which of the following is NOT a recommended long-term medication for persistent asthma?
Short-acting β2 agonists
What is the primary cause of emphysema?
All of the above
Which of the following statements about the pathogenesis of emphysema is NOT true?
Inflammation in the lungs leads to the release of proteases that cause emphysema.
What is the primary function of α1-antitrypsin in the lungs?
To protect the lung from injury by proteases
Which of the following is a characteristic of emphysema?
All of the above
What is the primary goal of patient and family education in asthma management?
To avoid exposure to irritants and allergens that trigger asthma attacks
Study Notes
Respiratory System Introduction
- The respiratory system provides a continuous supply of oxygen to the body's tissues and removes carbon dioxide produced by aerobic metabolism.
- The respiratory system consists of the air-conducting part (no gas exchange) and the respiratory part (gas exchange occurs).
- The respiratory part includes respiratory bronchioles, alveolar ducts, and alveoli.
Normal Respiration (Eupnoea)
- Normal respiratory rate: 12-16 cycles per minute.
- Inspiration is an active process, while expiration is a passive process.
- Mechanism of inspiration: signals from the brain stimulate the diaphragm and external intercostal muscles to contract.
Brain Stem Respiratory Centers
- Medullary centers: inspiratory center (dorsal part of medulla oblongata) and expiratory center (ventral part of medulla oblongata).
- Pontine centers: apneustic center (lower pons) and pneumotaxic center (upper pons).
Cough Reflex
- Coughing is a neurally mediated reflex that protects the lungs from secretions and irritating substances.
- Stimulus: irritating substances and excess secretions.
- Response: rapid inspiration, closure of the glottis, and forceful contraction of abdominal and expiratory muscles.
Respiratory Muscles and Mechanism
- Inspiration: diaphragm and external intercostal muscles contract, increasing chest volume and decreasing intrapulmonary pressure.
- Expiration: relaxation of inspiratory muscles, aided by the elastic property of the lung and the weight of the thoracic cage.
- Deep inspiration and expiration: accessory inspiratory and expiratory muscles are activated.
Respiratory Centers and Cough Reflex Impairment
- Respiratory centers control breathing involuntarily.
- Causes of impaired cough reflex: weak abdominal or respiratory muscles, limited chest expansion, disease conditions, and depressed medullary center function.
Surfactant
- Definition: a lipoprotein mixture produced by type II alveolar cells, decreasing surface tension in the alveoli.
- Physiological significance: keeps alveoli open, reduces ventilation effort, and prevents pulmonary edema.
- Factors affecting surfactant: thyroid hormone, glucocorticoids, smoking, insulin, and pulmonary circulation cessation.
Respiratory Distress Syndrome (RDS) and Emphysema
- Respiratory distress syndrome (RDS or hyaline disease): a serious lung disease due to deficient surfactant formation.
- Emphysema: characterized by lung elasticity loss, air space enlargement, and alveolar wall destruction.
- Causes of emphysema: inherited α1-antitrypsin deficiency and smoking.
Learn about the importance of the respiratory system in providing oxygen to the body's tissues and removing carbon dioxide. Explore the components of the air conducting part and the respiratory part of the respiratory system.
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