Lecture 16: ANATOMY OF THE THORAX AND BREATHING

Question 1

What are our body cavities lined with?

Answer 1

Serous membranes

Question 2

Where is the visceral layer of a serous membrane found?

Answer 2

On the organ

Question 3

Where is the parietal layer of the serous membrane found?

Answer 3

On the body wall

Question 4

What are the serous membranes in the thoracic cavity?

Answer 4

Pericardium (surrounds heart) and pleura (surrounds lungs)

Question 5

What is the serous membrane in the abdominopelvic cavity?

Answer 5

Peritoneum

Question 6

What does the thoracic cavity contain?

Answer 6

Mediastinum in the middle and pleural cavities either side

Question 7

What is in the mediastinum?

Answer 7

Heart, vessels and pericardium

Question 8

What is in the pleural cavities?

Answer 8

Lungs

Question 9

What is the anterior boundary of the thoracic cavity?

Answer 9

Sternum

Question 10

What is the posterior boundary of the thoracic cavity?

Answer 10

Thoracic vertebrae

Question 11

What is the lateral boundary of the thoracic cavity?

Answer 11

Ribs

Question 12

What is the superior boundary of the thoracic cavity?

Answer 12

Base of neck

Question 13

What is the inferior boundary of the thoracic cavity?

Answer 13

Diaphragm

Question 14

What is the relationship between pressure and volume?

Answer 14

Pressure is inversely proportional to volume

Question 15

What happens if we change the volume of the thorax?

Answer 15

We change the pressure

Question 16

What happens to volume and pressure during inspiration?

Answer 16

volume increases and pressure decreases

Question 17

What happens to volume and pressure during expiration?

Answer 17

volume decreases and pressure increases

Question 18

What is Boyles law?

Answer 18

P=1/V

Question 19

What is pressure measured by?

Answer 19

Collisions

Question 20

What does a smaller space mean?

Answer 20

More collisions and increased pressure

Question 21

What does a bigger space mean?

Answer 21

Less collisions and decreased pressure

Question 22

Where will air move?

Answer 22

To a lower pressure space

Question 23

What needs to be established to breathe?

Answer 23

A pressure gradient so air can move

Question 24

What is the pressure between breaths?

Answer 24

Pressure inside cavity is equal to pressure outside cavity so there is no gradient

Question 25

What is the pressure during inspiration/inhalation?

Answer 25

Increased volume of thorax, therefore decrease pressure so pressure outside is greater than pressure inside and air flows in

Question 26

What is the pressure during expiration/exhalation?

Answer 26

Decreased volume of thorax, therefore increased pressure so pressure outside is less than pressure inside and air flows out

Question 27

How does the sternum connect to ribs?

Answer 27

Via costal cartilage (hyaline)

Question 28

How many synovial joints on each side of the sternum?

Answer 28

6

Question 29

How many cartilaginous joints on each side of the sternum?

Answer 29

1

Question 30

What is the joint between the costal cartilage and sternum?

Answer 30

Sternocostal

Question 31

What type of joint is the sternocostal?

Answer 31

Synovial, except the first one is cartilaginous

Question 32

What is the joint between the cartilage and ribs?

Answer 32

Chostochondral

Question 33

What type of joint is the chostochondral?

Answer 33

Cartilaginous

Question 34

What are the joints between cartilage of ribs which don't connect directly to the sternum?

Answer 34

Interchondral

Question 35

What type of joints are the interchondral?

Answer 35

Synovial

Question 36

What are the posterior thoracic joints articulations between?

Answer 36

Thoracic vertebrae and ribs

Question 37

What type of joints are the posterior thoracic joints?

Answer 37

Synovial

Question 38

What is the joint between the rib and transverse process of vertebrae?

Answer 38

Costotransverse

Question 39

What is the joint between the rib and body of the vertebrae?

Answer 39

Costovertebral

Question 40

what do respiratory muscles do?

Answer 40

Move the rib cage to allow us to breathe

Question 41

What are the primary inspiratory muscles?

Answer 41

Diaphragm (needed to survive) and intercostals (not needed to survive)

Question 42

When are the accessory muscles active?

Answer 42

Only when needed

Question 43

What is the diaphragm?

Answer 43

A sheet of skeletal muscle which separates the thorax from the abdomen

Question 44

What is the shape of the diaphragm when relaxed?

Answer 44

Dome shaped

Question 45

What is the shape of the diaphragm when contracted?

Answer 45

Flattened

Question 46

What does contraction of the diaphragm do?

Answer 46

Expands the thoracic cavity and compresses abdominopelvic cavity

Question 47

What travels through the diaphragm?

Answer 47

Inferior vena cava, esophagus and aorta

Question 48

Where do intercostal muscles attach?

Answer 48

Diagonally between neighbouring ribs

Question 49

Where do the external intercostals run?

Answer 49

from up and out to down and in so when they contract they lift the ribcage and expand the cavity

Question 50

What are the external intercostals involved in?

Answer 50

Inspiration - quiet and forced

Question 51

Where do the internal intercostals run?

Answer 51

From up and in to down and out so when they contract they depress the ribcage and decrease the cavity

Question 52

What are the internal intercostals involved in?

Answer 52

Expiration - forced only

Question 53

What are the accessory muscles?

Answer 53

Several muscles that attach to the thoracic cage

Question 54

What are the functions of accessory muscles?

Answer 54

Some increase cavity volume for forced inspiration and some decreased cavity volume for forced expiration

Question 55

How are the muscles of respiration during normal 'quiet' inspiration?

Answer 55

The diaphragm contracts and flattens and external intercostals contract and lift the ribs

Question 56

How are the muscles of respiration during active 'forced' breathing?

Answer 56

The diaphragm contracts, flattens and external intercostals contract and lift the ribs and accessory muscles contract to further expand the thoracic cavity

Question 57

What type of process is normal 'quiet' expiration?

Answer 57

Passive

Question 58

How are the muscles of respiration during normal 'quiet' expiration?

Answer 58

The diaphragm relaxes and becomes dome shaped and the external intercostals relax so the ribs are no longer lifted

Question 59

How are the muscles of respiration during active 'forced' expiration?

Answer 59

The diaphragm relaxes and becomes dome shaped, the external intercostals relax so the ribs are no longer lifted, internal intercostals contract and depress ribs and accessory muscles contract to further decrease cavity volume

Question 60

What is lung tissue?

Answer 60

Elastic and always trying to recoil

Question 61

What does the pleura do?

Answer 61

Make the lungs stick to the thoracic wall

Question 62

What do lungs do during inspiration?

Answer 62

Expand

Question 63

What do lungs do during expiration?

Answer 63

Decrease

Question 64

Where is the visceral pleura?

Answer 64

On the lungs

Question 65

Where is the parietal pleura?

Answer 65

On the thoracic wall

Question 66

What is in between the visceral and parietal pleura?

Answer 66

Pleural fluid

Question 67

What does the pleural fluid do?

Answer 67

Make a slippery surface for frictionless movement against other structures and fluid bond causes lungs to stick to thoracic wall

Question 68

What does thoracic wall movement result in?

Answer 68

Lung movement

Question 69

What happens when there is an increased volume of the thorax?

Answer 69

Increased volume of the lungs, decreased pressure in the lungs and so air flows in

Question 70

What happens when there is a decreased volume of the thorax?

Answer 70

Decreased volume of the lungs, increased pressure in the lungs and so air flows out

Question 71

What level is the diaphragm found at?

Answer 71

The 12th rib