lungs, pleura and ventilation

Question 1

what does the lung base rest on

Answer 1

convex surface of diaphragm

Question 2

what does the diaphragm separate from right lung

Answer 2

right lobe of liver

Question 3

what does the diaphragm separate from left lung

Answer 3

left lobe of liver, stomach, spleen

Question 4

how can the capacity of the thoracic cavity be increased

Answer 4

movements of diaphragm, movements of ribs

Question 5

what is the main inspiratory muscle

Answer 5

diaphragm

Question 6

diaphragm mechanism of breathing

Answer 6

contraction causes it to press on abdominal viscera which initially descend → further descent stopped by abdominal viscera, so more diaphragm contraction raises costal margin → increased thoracic capacity produced by diaphragm and rib movements in inspiration, reduces intraplueral pressure, with entry of air and expansion of lungs

Question 7

3 components of thoracic surface of diaphragm

Answer 7

skeletal muscle from costal margin, sheet-like central tendon (section in between contracts), pericardial sac

Question 8

what 4 things is the margin of the diaphragm connected to

Answer 8

costal margin, xiphoid process, ends of ribs 11 and 12, lumbar verterbrae

Question 9

what does the diaphragm, pleura and lung cover and why

Answer 9

high abdominal organs such as liver as dome of diaphragm bulges high inside rib cage despite connection to costal margin

Question 10

why do internal and external intercostal muscles stiffen rib cage

Answer 10

increase efficiency of diaphragm

Question 11

what is the costal margin

Answer 11

attachment of ribs to diaphragm

Question 12

what does the diaphragm consist of

Answer 12

flat central tendon with muscle radiating to costal margin (anteriorly) and crus (posteriorly) and vertebrae

Question 13

diaphragm: first stage of insipiration

Answer 13

dome flattens to inrease vertical diameter of chest

Question 14

diaphragm: second stage of insipiration

Answer 14

pulls costal margin up to increase transverse and antero-posterior diameters

Question 15

where does the oesophagus extend from and to

Answer 15

from pharynx to diaphragm at level T10

Question 16

which division of the mediastinum is posterior to pericardial sac and diaphragm

Answer 16

posterior

Question 17

what does the inferior vena cava enter, from where and through what

Answer 17

right atrium from below through central tendon of diaphragm at T8 (where heart sits)

Question 18

what do sensory and motor phrenic nerves innovate

Answer 18

diaphragm

Question 19

where do the phrenic nerves originate

Answer 19

anterior rami of C3, 4, 5

Question 20

what 4 structures do sensory phrenic nerves innovate

Answer 20

central tendon to diaphragm, mediastinal pleura, pericardium, peritoneum of central diaphragm

Question 21

what 3 things pierce the diaphragm at T8, 10, 12

Answer 21

IVC, oesophagus, descending aorta structure into diaphragm

Question 22

what do phrenic motor fibres supply

Answer 22

skeletal muscle of diaphragm

Question 23

vagi in posterior mediastinum: inferior continuation

Answer 23

posterior oesophageal nerve, taking right vagal fibres through diaphragm to abdominal viscera