Mechanics of breathing

Question 1

how do muscles act to increase and decrease thoracic volume

Answer 1

diaphragm and external intercostal muscles (also scalene and sternocleidomastoids) for inspiration and abdominal muscles and internal intercostal muscles during severe respiration for expiration

Question 2

mechanical factors that affect respiratory minute volume

Answer 2

friction, compliance, elastic recoil, elastance, surface tension, airway resistance,

Question 3

why is intrapleural pressure always less than alveolar pressure

Answer 3

due to boyles law, there is always a volume in intrapleural cavity that is trying to expand and as we expand the volume, the pressure decreases so always negative

Question 4

intrathoracic pressure or alveolar pressure is

Answer 4

pressure inside thoracic cavity (lungs) may be negative or positive compared to atmospheric pressure

Question 5

intra pleural pressure

Answer 5

pressure inside pleural cavity. always negative compared to atmospheric pressure

Question 6

transpulmonary pressure

Answer 6

difference between alveolar and inrapleural pressure. almost always positive