As a speed skater finishes the last lap of a race: a. his...

Name: Problem 6, Chapter 46: Biology: The Dynamic Science
Uploaded: 2021-07-17T07:54:39-08:00
Duration: 2 min 6 s
Channel: Joanna Quigley
Description: As a speed skater finishes the last lap of a race: a. his diaphragm and rib muscles contract when he exhales. b. positive pressure brings air into his lungs. c. his lungs undergo an elastic recoil when he inhales. d. his tidal volume is at vital capacity. e. his residual volume momentarily reaches zero.

As a speed skater finishes the last lap of a race: a. his diaphragm and rib muscles contract when he exhales. b. positive pressure brings air into his lungs. c. his lungs undergo an elastic recoil when he inhales. d. his tidal volume is at vital capacity. e. his residual volume momentarily reaches zero.

As a speed skater finishes the last lap of a race:
a. his diaphragm and rib muscles contract when he exhales.
b. positive pressure brings air into his lungs.
c. his lungs undergo an elastic recoil when he inhales.
d. his tidal volume is at vital capacity.
e. his residual volume momentarily reaches zero.

Key Concepts

Elastic Recoil

Elastic recoil refers to the inherent ability of lung tissue to return to its original shape after being stretched during inspiration. This passive force is a major contributor to expiration, as it helps push air out of the lungs without the need for active muscle contraction under normal breathing conditions.

Pressure Changes in Respiration

This concept covers the mechanism by which pressure differences between the atmosphere and the thoracic cavity drive the movement of air. During inspiration, the expansion of the chest cavity decreases internal pressure relative to the atmosphere, allowing air to flow into the lungs. Conversely, during expiration, the reduction in thoracic volume and the elastic recoil of the lungs increase internal pressure, which helps expel air.

Respiratory Muscle Function

This concept involves the roles of muscles such as the diaphragm and intercostal muscles in breathing. During inspiration, the diaphragm contracts and moves downward while the rib muscles elevate the rib cage to increase thoracic volume, lowering the internal pressure and drawing air into the lungs. In contrast, passive expiration relies mainly on the elastic recoil of lung tissues, though under conditions of increased respiratory demand, other muscles may contribute to forceful exhalation.

Lung Volumes and Capacities

Lung volumes and capacities are measurements that describe the amounts of air within the respiratory system during different phases of the breathing cycle. Tidal volume is the amount of air inhaled or exhaled in a normal breath, vital capacity is the maximum volume of air that can be exchanged in a single breath cycle, and residual volume is the amount of air that remains in the lungs after a forceful exhalation, preventing lung collapse.

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