Inspiration and Expiration

I breath so I can hate A&P II.

What stage is happening in 1?

Between breaths

Explain what is happening during stage 1

No muscle movements happen. The intrapulmonary pressure equals atmosphere pressure, so no air movement occurs.

List the pressure values from top to bottom on the chart during stage 1

760, 760, 756 mm Hg

What stage is happening in 2?

Inspiration

Explain what is happening during stage 2

The diaphragm contracts and increases the thorax’s height and diameter to increase its volume. The external intercostal muscles causes the thorax to increase in diameter and increases the volume of the lungs. Intrapulmonary pressure decreases below atmospheric pressure. Air flows into the lungs.

List the pressure values from top to bottom on the chart during stage 2

760, 758, 754 mm Hg

What stage is happening in 3?

Between inspiration and expiration

Explain what is happening during stage 3

The diaphragm and external intercostal muscles remain contracted to hold the thorax at increased diameter and lungs at increased volume. No air movement happens

List the pressure values from top to bottom on the chart during stage 3

760, 760, 754 mm Hg

What stage is happening in 4?

Expiration

Explain what is happening during stage 4

Relaxation of diaphragm muscle decreases the height and diameter of thorax and lungs decrease in volume. Air moves out of the lungs.

List the pressure values from top to bottom on the chart during stage 4

760, 762, 758 mm Hg