Thorax 2 - Lungs & Pleura

Question 1

how do the lungs facilitate gas exchange?

Answer 1

deliver oxygen from inhaled air into pulmonary capillaries to oxygenate blood & removing carbon dioxide from the blood

Question 2

what structure separates the thoracic cavity from the abdominal cavity and forms the inferior border of the lungs?

Answer 2

diaphragm

Question 3

where are the lungs located in relation to the mediastinum?

Answer 3

the lungs are located on either side of the mediastinum, flanking the heart

Question 4

what is the functional unit of respiration in the lungs?

Answer 4

alveoli - allows oxygen to diffuse into the blood & CO2 to diffuse out)

Question 5

how far does the apex of the lungs extend?

Answer 5

extends above the 1st rib into the root of the neck

Question 6

what are the two layers of the pleura? how do they differ?

Answer 6

visceral pleura - adheres close to the lung surface

parietal pleura - lines the ribcage & diaphragm (internal surface of the thoracic cavity)

Question 7

what are the 4 divisions of the parietal pleura? where are they located?

Answer 7

1. diaphragmatic - covers the superior surface of the diaphragm
2. cervical - extends above the 1st rib into the root of the neck
3. costal - lines the inner surface of the ribs
4. mediastinal - covers the lateral surface of the mediastinum (near the heart)

Question 8

what is the thickened portion of the cervical parietal pleura called? what is its significance?

Answer 8

suprapleural membrane - provides structural support and protection to the cervical parietal pleura as it extends into the root of the neck

Question 9

why is the pleural cavity important for lung function?

Answer 9

pleural cavity is the small space between the two pleural layers - allows the lungs to expand and contract smoothly during breathing

reduces friction between the lungs & thoracic cavity by secreting lubricating pleural fluid - allows lungs to slide freely

Question 10

what would happen if the pleural cavity were compromised (e.g., due to a pneumothorax)?

Answer 10

the lungs may collapse due to the loss of negative pressure that allows them to inflate - impairs gas exchange

Question 11

what is a haemothorax?

Answer 11

when blood enters the pleural cavity - causes loss of negative pressure & lungs may collapse

Question 12

what are the two recesses of the pleural cavity?

Answer 12

costomediastinal recess
costodiaphragmatic recess

Question 13

what are pleural recesses? why do they form?

Answer 13

pleural recesses areas of the pleural cavity not completely filled with lung tissue

form due to differences in the attachment of the visceral and parietal pleura

Question 14

when do pleural recesses become occupied by lung tissue?

Answer 14

occupied with lung tissue during INSPIRATION - remain empty during expiration

Question 15

where is the costomediastinal recess located in relation to the lungs & heart?

Answer 15

lies near the ANTERIOR border of the lungs
CLOSE to the heart - beneath the lingula

Question 16

what happens to the costomediastinal recess during inspiration?

Answer 16

becomes occupied by lung tissue (especially the anterior border of the lungs)

Question 17

where is the costodiaphragmatic recess located?

Answer 17

at the base of the pleural cavity - where the diaphragm meets the thoracic wall

Question 18

primary function of pleural recesses?

Answer 18

provide additional space for lung expansion during deep inspiration

Question 19

how are the pleural recesses affected during pleural effusion? which recess is more clinically significant in this case?

Answer 19

accumulate excess fluid - costodiaphragmatic recess is a common site for fluid accumulation & can be accessed for treatment

Question 20

how are the pleural recesses affected during a pneumothorax?

Answer 20

pleural recesses accumulate air - leads to lung collapse & impaired gas exchange and resp function