Mechanics & Lung Volume

Question 1

Pressure changes that determine the end-expiratory lung volume (static pressure changes )

Question 2

Pulmonary ventilation

Answer 2

Alternating flow of air & out of the lung due to
Inspiratory muscles: expand the ribcage ; drive airflow into the lungs
Expiratory muscles: depress or compress the rib cage; force air out of the lungs

Question 3

Skeletal portion of the thorax

Answer 3

Thoracic cage: includes the ribs, costal cartilages, thoracic vertebrae, and sternum

Question 4

Respiratory mechanics

Answer 4

Study of now the respiratory muscles move the ribcage
Respiratory pump: respiratory muscles, rib cage, pleural membranes, and lung elastic tissues

Question 5

Inspiratory muscles

Answer 5

• Diaphragm: enlarges the thoracic cavity longitude when contracted primary (quiet and labored breathing)
- external intercostal muscles: mores ribs upward & outward expanding the rib cage (quiet & labored breathing)
• sternocleidomastoid: elevates the sternum (labored breathing)
. Scalenes: elevates the top two ribs ( labored breathing)

Question 6

Expiratory muscles

Answer 6

Internal intercostals muscles pull ribs downwards & inwards, reducing rib cage diameter
O abdominal muscles: depress the lower ribs S elevate the diaphragm by increasing abdominal pressure

REDUCE THORACIC CAVITY VOLUME AND FORCE AIR OUT OF THE LUNGS

Question 7

Respiratory mechanics

Answer 7

Gases more from high to low pressure

Inspiration occurs when pressure in lungs is less/lower than the atmospheric pressure

Expiration occurs when pressure in v lungs is greater/higher than than the pressure in the atmosphere

Pressure changes depends on pleural membrane movements ~ in inspiration parietal pleura is pulled outwards and visceral pleura moves along with it

Question 8

Pressures determining inspiration

Answer 8

Diaphragm contracts which enlarges the thoracic cage
Enlarges the intrapleural space E lowers intra- pleural pressure

Question 9

Pressures determining expiration

Answer 9

As the diaphragm relaxes, elastic tissue in the lung recoil inwards~ they compress air and raise the alholar pressure above the atmospheric pressure

Question 10

Transpulmonary pressure (Ptp)

Answer 10

The difference between the pressure and the pearl oral cavity, which surrounds the lungs, called intrapleural pressure and the pressure inside. The alveoli called the intra-alveolar pressure.

Ptp = Palv -P ip

Palv is also called intrapulmonary pressure. Normally intrapulmonary pressure is higher than intrapleural pressure.

Transpulmonary pressure is a measure of the force being exerted on the lungs to keep them inflated