Muscles and Mechanics of Ventilation Practice Flashcards

A set of practice flashcards covering the primary and accessory muscles of ventilation, the mechanics of inspiration and expiration, and abnormal breathing patterns associated with COPD.

How is ventilation defined?

The movement of air into and out of the lungs.

Which muscle is the primary muscle of inspiration?

The diaphragm.

What are the two parts that make up the diaphragm?

The right and left hemidiaphragms.

Which nerve innervates the diaphragm?

The phrenic nerve.

From which spinal levels does the phrenic nerve originate?

$$C3, C4, C5$$

What is the mnemonic used to remember the spinal levels of the phrenic nerve?

“C3, 4, and 5 keep the diaphragm alive.”

How far does the diaphragm descend during quiet breathing?

Approximately $1.5\,cm$.

How far does the diaphragm descend during heavy exercise?

$6-10\,cm$.

Why is inspiration classified as an active process?

Because it requires muscle contraction.

Which accessory muscles are involved in inspiration?

External intercostals, Scalenes, and Sternocleidomastoids (SCMs).

What are the two specific movements that increase thoracic volume during inspiration?

Bucket-handle and pump-handle movements.

How does the increase in thoracic volume facilitate air entry into the lungs?

It creates negative pressure that pulls air into the lungs.

Is quiet expiration an active or passive process?

A passive process.

What physical property does quiet expiration rely on?

The elastic recoil of the lungs.

When is forced expiration used?

During exercise or respiratory distress.

Which accessory muscles are involved in forced expiration?

Internal intercostals, Rectus abdominis, External obliques, Internal obliques, and Transverse abdominis.

How do the abdominal muscles assist in forced expiration?

By compressing the abdomen and pushing the diaphragm upward.

What occurs during paradoxical breathing?

The abdomen moves inward during inspiration.

What conditions does paradoxical breathing suggest?

Diaphragmatic fatigue, weakness, or obstruction.

What is the tripod position in the context of COPD breathing strategies?

A position where the patient leans forward on their arms to engage the pectoralis major and neck muscles.

What are the three benefits of pursed-lip breathing for COPD patients?

It creates back pressure, helps prevent airway collapse, and improves airflow during exhalation.