BIOL 208 Lecture Notes - Lecture 22: Latissimus Dorsi Muscle, Thoracic Cavity, Pectoralis Minor Muscle
19 May 2018
School
Department
Course
Professor
Anatomy 2
Lecture 22
April 24th, 2018
Transpulmonary
- * diff b/w intrapulmonary and intrapleural/intrathoracic pressure (4 mmHg)
Boyle’s Law
- * pressure of gas in closed container is inversely proportional to volume of that container
Inspiration
- Rise in sz of thoracic cavity
- Only muscles involved
- External intercostals
- Thoracic cavity
- Intrapulmonary pressure (lungs) drops to 757 mmHg; outside pressure does not change
and pressure gradient happens from air to lungs
Recruit additional muscles in forced inspiration
- Scalenes
- Attach to vertebral column ( pull up 1st 2 ribs)
- Sternocleidomastoid
- Pectoralis minor
Expiration
- Return of muscles to normal component
- External intercostals and diaphragm have elastic component and rebound to slightly
higher pressure than before
- Passive mechanism
Forced expiration
- Force thoracic cavity to become smaller (757 to 763 mmHg)
- Pressure gradient goes ou
- Muscles recruited
- Latissimus dorsi
- Internal intercostals
- Flank muscles
- Reduce sz of thoracic cavity
Document Summary
* diff b/w intrapulmonary and intrapleural/intrathoracic pressure (4 mmhg) * pressure of gas in closed container is inversely proportional to volume of that container. Intrapulmonary pressure (lungs) drops to 757 mmhg; outside pressure does not change and pressure gradient happens from air to lungs. Attach to vertebral column ( pull up 1st 2 ribs) External intercostals and diaphragm have elastic component and rebound to slightly higher pressure than before. Force thoracic cavity to become smaller (757 to 763 mmhg) Ability of lungs to go with the flow. * refers to ease w/ which lungs and thorax can be expanded (their distensibility) Related to elasticity of alveolar wall and bronchioles. Water surface tension results in decrease in compliance. * occurs when air presence is allowed into pleural cavity bringing about collapsed lung. Volume: tv - 500 ml, irv - 3,000 ml, erv - 1,200 ml, rv - 1,200 ml, mv - 500 ml.
