lecture 16 - anatomy of the thorax and breathing

Question 1

what is the mediastinum region

Answer 1

the heart, vessels + pericardium

Question 2

what are the anterior and posterior boundaries of the thorax

Answer 2

the sternum and the vertebrae

Question 3

what are the superior and inferior boundaries of the thorax

Answer 3

the base of the neck and the diaphragm

Question 4

what is the pleural cavity

Answer 4

the space between the pleura

Question 5

what is the function of parietal pleura

Answer 5

• slippery surface for frictionless movement against other structues
• fluid bond causes lungs to ‘stick’ to thoracic wall

Question 6

where is the parietal pleura

Answer 6

on the outer

Question 7

where is the visceral pleura

Answer 7

directly on the lungs

Question 8

what is the diaphragm

Answer 8

sheet of skeletal muscle

Question 9

what does the diaphragm seperate

Answer 9

the thorax from abdomen

Question 10

when is the diaphragm dome shaped

Answer 10

when it is relaxed

Question 11

when is the diaphragm flattened

Answer 11

when contracted

Question 12

what does contraction of the diaphragm cause

Answer 12

expansion of the thoracic cavity and compression of the abdominopelvic cavity

Question 13

where do intercostal muscles attach

Answer 13

attach diagonally between neighbouring ribs

Question 14

what do the external intercostal muscles do

Answer 14

lift ribcage and expand cavity
- inspiration = quiet and forced

Question 15

what do the internal intercostal muscles do

Answer 15

depress ribcage and decrease cavity
- expiration = forced only

Question 16

what are the accessory muscles of the thorax

Answer 16

several muscles that attach to the thoracic cage

Question 17

what are the functions of the accessory muscles

Answer 17

• some increase cavity volume for forced inspiration
• others decrease cavity volume for forced expiration

Question 18

how is pressure related to volume in the lungs and what does this mean during inspiration and expiration

Answer 18

• pressure inversely related to volume

inspiration = volume increases
expiration = volume decreases

Question 19

what needs to be established in order for us to be able to breathe

Answer 19

a pressure gradient

Question 20

what is the pressure like in the lungs between breaths

Answer 20

pressure inside the cavity = pressure outside
- no gradient

Question 21

what occurs in the lungs when there is an increase in volume

Answer 21

decrease in pressure, therefore air flows in

Question 22

what occurs in the lungs when there is an decreases in volume

Answer 22

increase in pressure, therefore air flows out

Question 23

what connects the sternum to the ribs

Answer 23

costal cartilage

Question 24

what is sternocostal cartilage and what type of joint is there

Answer 24

against the sternum = synovial joint

Question 25

what is the costochondral cartilage and what type of joint is here

Answer 25

against the ribs = cartilaginous

Question 26

what is the interchondral cartilage and what type of joint is here

Answer 26

connects interchondral joints which are below the sternum = synovial

Question 27

what are the prosterior thoracic joints

Answer 27

the costotransverse and the costovertebral joints

Question 28

what does the costotransverse joint connects

Answer 28

between rib and transverse process of vertebrae

Question 29

what does the costovertebral joint connect

Answer 29

between rib and body of vertebrae

Question 30

what are the muscles that are used during 'quiet inspiration'

Answer 30

diaphragm contracts = flattens external intercostals contract = lifts ribs

Question 31

what are the muscles that are used during 'forced' inspiration

Answer 31

diaphragm contracts = flattens external intercostals contract = lifts ribs accessory muscles contract = to further expand the thoracic cavity

Question 32

what are the muscles that are used during normal 'quiet' expiration

Answer 32

diaphragm relaxes = dome shaped external intercostals relax = ribs no longer lifted

Question 33

what are the muscles that are used during 'forced' expiration

Answer 33

diaphragm relaxes = dome shaped external intercostals relax = ribs no longer lifted accessory muscles contract to further decrease cavity

Question 34

what is the lung tissue like

Answer 34

elastic = always trying to recoil

Question 35

what pleura is on the lungs

Answer 35

visceral pleura

Question 36

what pleura is on the thoracic wall

Answer 36

parietal pleura

Question 37

what is the function of the pleural fluid in between lungs and thoracic wall

Answer 37

slippery surface for frictionless movement fluid bonds causes lungs to stick to thoracic wall