Thoracic Diaphragm and Respiratory Movement Flashcards
What is the thoracic diaphragm, and what is its primary function?
The thoracic diaphragm is a dome-shaped muscle that separates the thoracic and abdominal cavities and is the primary muscle of respiration.
What are the origins and insertions of the thoracic diaphragm?
It originates from the xiphoid process, lower six ribs, and lumbar vertebrae and inserts into the central tendon.
Which structures pass through the diaphragm, and at what vertebral levels do they pass?
The inferior vena cava passes through at T8, the esophagus at T10, and the aorta at T12.
What are the major openings of the diaphragm, and what structures traverse each?
The major openings are the caval opening (T8, for the inferior vena cava), the esophageal hiatus (T10, for the esophagus and vagus nerves), and the aortic hiatus (T12, for the aorta, thoracic duct, and azygos vein).
What is the innervation of the diaphragm?
The diaphragm is innervated by the phrenic nerve (C3-C5).
What is the blood supply of the diaphragm?
It is supplied by the superior and inferior phrenic arteries, musculophrenic artery, and pericardiophrenic artery.
How does the diaphragm contribute to respiration?
During inspiration, the diaphragm contracts and flattens, increasing thoracic volume and decreasing pressure, drawing air into the lungs.
What are the primary muscles of inspiration?
The primary muscles of inspiration are the diaphragm and external intercostal muscles.
What are the accessory muscles of inspiration, and when are they used?
The accessory muscles of inspiration include the sternocleidomastoid, scalene, and pectoralis muscles, which are used during forced breathing.
What muscles are involved in quiet expiration?
Quiet expiration is passive and occurs due to elastic recoil of the lungs and relaxation of the diaphragm.
What muscles are involved in forced expiration?
Forced expiration involves the internal intercostal muscles and abdominal muscles.
What is the role of the intercostal muscles in respiration?
The intercostal muscles stabilize the rib cage and assist in expanding and compressing the thoracic cavity.
How does the diaphragm move during inspiration?
During inspiration, the diaphragm contracts and moves downward.
How does the diaphragm move during expiration?
During expiration, the diaphragm relaxes and moves upward.
What is the relationship between intra-thoracic pressure and diaphragmatic movement?
When the diaphragm contracts, intra-thoracic pressure decreases, allowing air to enter the lungs. When it relaxes, intra-thoracic pressure increases, expelling air.
What is diaphragmatic paralysis, and what are its causes?
Diaphragmatic paralysis is the loss of diaphragmatic movement due to phrenic nerve injury or neurological disorders.
What are the clinical features of diaphragmatic paralysis?
It presents with dyspnea, paradoxical breathing, and reduced lung volumes, especially when lying down.
What is the significance of the phrenic nerve in diaphragmatic function?
The phrenic nerve (C3-C5) controls diaphragmatic contraction and is essential for breathing.
What is the difference between costal and diaphragmatic breathing?
Costal breathing relies more on rib cage expansion, while diaphragmatic breathing emphasizes diaphragm movement.
How does pregnancy affect diaphragmatic movement?
Pregnancy elevates the diaphragm due to the growing uterus, reducing lung volumes but maintaining tidal volume by increasing respiratory rate.
What is a diaphragmatic hernia, and what are its common types?
A diaphragmatic hernia occurs when abdominal organs protrude into the thoracic cavity; common types include hiatal hernia and congenital diaphragmatic hernia.
What is congenital diaphragmatic hernia (CDH), and how does it present?
CDH is a developmental defect in the diaphragm that allows abdominal organs into the thorax, leading to pulmonary hypoplasia and respiratory distress in newborns.
What is the role of the diaphragm in the Valsalva maneuver?
The diaphragm contracts during the Valsalva maneuver, increasing intra-abdominal and intra-thoracic pressure.
How does the diaphragm contribute to coughing and sneezing?
The diaphragm contracts forcefully during coughing and sneezing to expel air forcefully from the lungs.
What is the role of the diaphragm in speaking and singing?
The diaphragm modulates airflow and pressure for controlled vocalization during speaking and singing.
How does diaphragmatic dysfunction affect respiratory mechanics?
Diaphragmatic dysfunction can lead to respiratory insufficiency, reduced tidal volume, and increased work of breathing.
What are the effects of high-altitude adaptation on diaphragmatic function?
High-altitude adaptation increases diaphragmatic efficiency through hyperventilation and enhanced oxygen utilization.
How does obesity affect diaphragmatic movement and respiratory function?
Obesity limits diaphragmatic movement by increasing abdominal pressure, leading to restrictive lung disease.
What is paradoxical breathing, and what conditions cause it?
Paradoxical breathing is an abnormal movement where the diaphragm moves upward during inspiration, seen in diaphragmatic paralysis and respiratory distress.
How is diaphragmatic function assessed clinically?
Diaphragmatic function is assessed using fluoroscopy, ultrasound, pulmonary function tests, and electromyography.
