Lesson 3: Respiratory System: Structure and Function 2

Question 1

what is the pleural sac?

Answer 1

a double-walled, closed sac that separates each lung from the thoracic wall

Question 2

where is the pleural cavity?

Answer 2

interior of pleural sac

Question 3

what is intrapleural fluid secreted by?

Answer 3

surfaces of the pleura

Question 4

what does intrapleural fluid do?

Answer 4

lubricates pleural surfaces

Question 5

where are the lungs found?

Answer 5

in the thoracic cavity

Question 6

what is the lungs divided into?

Answer 6

several lobes, each supplied by one of the bronchi

Question 7

what does lung consist of?

Answer 7

a series of highly branches airways, the alveoli, the pulmonary blood vessels, the large quantities of elastic connective tissue

Question 8

what form does the lung want to be?

Answer 8

deflated
- because the elastic tissue allows us to not have to use muscles to breathe out

• this allows us to manage our chest and the volume of air we allow in

Question 9

what are airways?

Answer 9

tubes that carry air between the atmosphere and the air sacs

Question 10

what are our airways?

Answer 10

• nasal passages
• pharynx (common passageway for respiratory and digestive systems)
• larynx
• trachea
• right and left bronchi
• bronchioles

Question 11

what is the tracheas structure?

Answer 11

• fairly rigid, non-muscular tubes
• rings of cartilage preventing collapse from large pressure
• very stiff, very hard to make it wider or narrower

Question 12

does the bronchioles have cartilage to hold them open?

Answer 12

no

Question 13

bronhiole walls contain smooth muscle innervated by the ______________________________.

Answer 13

autonomic nervous sytem

Question 14

where are alveoli clustered?

Answer 14

at ends of terminal bronchioles

Question 15

why do we have smooth muscles in the small areas of our airways (bronchioles)?

Answer 15

• to be involuntary
• allows for them to dilate or constrict for air

Question 16

are the bronchioles sensitive to certain hormones and local chemicals?

Answer 16

yes

Question 17

why does air sacs constrict?

Answer 17

• protective mechanism to avoid the alveoli from getting exposed to extreme temperatures, chemicals, etc.
• size of airway can change (critical to have efficient breathing)

Question 18

what is critical to have effective breathing?

Answer 18

size of airway can change

Question 19

what does the puffer do?

Answer 19

its a bronchiole dilator to open up the airways
- relaxes smooth muscle to open the airways by targeting beta receptors in the airways

Question 20

what is the scientific name of a puffer?

Answer 20

ventolin inhaler salbutamol
- short acting beta agonist

Question 21

what is targeted when taking a puffer?

Answer 21

smaller airways like the bronchioles

Question 22

** what are alveoli?

Answer 22

• thin-walled, inflatable sacs that function in gas exchange
• walls consist of single layer of flattened type 1 alveolar cells
• pulmonary capillaries encircle each alveolus
• type 2 alveolar cells secrete pulmonary surfactant (located in the lumen of the alveolus)
• alveolar macrophages guard lumen
• pores of Kohn permit airflow between adjacent alveoli (maintain tone)

Question 23

where are type II alveolar cells located?

Answer 23

in the lumen of the alveolus

Question 24

what is the surface of an alveoli?

Answer 24

a single, flattened layer of Type 1 alveolar cells

Question 25

what does pulmonary surfactant do?

Answer 25

- secreted into the alvelous for decreasing surface tension of the type 1 wall - this is to help the pressure be equal in each of the alveolar sacs

Question 26

why does the pressure have to be equal in each of the alveolar sacs?

Answer 26

the alveolus will collapse

Question 27

what happens if too many alveolus collapse?

Answer 27

becomes really hard to breath

Question 28

what does alveolar macrophages do?

Answer 28

guard the lumen

Question 29

what does the pores of Kohn do?

Answer 29

they permit airflow between adjacent alveoli to help maintain tone across alveoli, within and between sacs (communication to make sure everything is properly inflated)

Question 30

the wall of the alveolus is?

Answer 30

one type 1 cell that is stretched across, very thinly

Question 31

what is a single alveolus?

Answer 31

a bulb in the sac

Question 32

how big is the space in the alveolus?

Answer 32

300 micrometers (um) - very very very small

Question 33

what is elastic fibre?

Answer 33

helps us get the elastic, stretchiness of the lung

Question 34

why do we need to have thin walls in the alvelus?

Answer 34

for gas exchange

Question 35

where is the type 2 cells?

Answer 35

a cluster somewhere in the lumen and secretes the surfactant into the lumen

Question 36

the distance between pulmonary capillary and the alveolar wall is? (air and blood barrier)

Answer 36

very thin (0.5um) - this is to maximize gas exchange - allows for easy O2 in and CO2 out diffusion - interstitial space is the small space in between them. can have interstitial fluid that leaks into the space (minimally because it is very small)

Question 37

where may the interstitical space be widened?

Answer 37

- high altitude pulmonary edema - leads to fluid accumulation in the interstitial space. causes fluid leakage a little in the alveoli but mostly in the interstitial space

Question 38

what is the issue with having a widened interstitial space between alveoli and capillaries?

Answer 38

there is going to be more resistance and there is going to be issues getting the oxygen across which will affect gas exchange (because the space is now thicker)

Question 39

example of disease where there is an accumulation of something in the interstitial space?

Answer 39

pulmonary fibrosis

Question 40

what is a disease where the interstitial space is compromised?

Answer 40

interstitial lung disease - like pulmonary fibrosis

Question 41

does the chest wall move air and out?

Answer 41

no, but it facilitates the lung changing its shape to help move the hair

Question 42

what does the outer chest wall (thorax) consist of?

Answer 42

- formed by 12 pairs of ribs that join sternum anteriorly and thoracic vertebrae posteriorly

Question 43

what contains muscles involved in generating pressure that cause airflow?

Answer 43

chest wall

Question 44

what protects lungs and heart?

Answer 44

rib cage

Question 45

what pulls the lung walls open when it stretches?

Answer 45

the chest wall - they are very dependent on each other

Question 46

the chest wall is an opposing force to?

Answer 46

the lung tissue - ribs want to go out and lungs want to go in

Question 47

key muscles in the chest wall?

Answer 47

- diaphragm for inspiration - sternocleidomastoid - external intercostals that slope towards sternum - parasternal intercostals

Question 48

what is the most important key muscle for inspiration?

Answer 48

the diaphragm

Question 49

what muscles are used for inspiration?

Answer 49

- sternocleidomastoid - scalenes - external intercostals - parasternal intercostals - diaphragm

Question 50

what muscles are used for expiration?

Answer 50

- internal intercostals - external abdominal oblique - internal abdominal oblique - transversus abdominis - rectus abdominis

Question 51

when we do not contract any muscles in our chest wall, why does air leave?

Answer 51

because the lungs want to be deflated, they are only inflated because of the inspiration muscles

Question 52

what are the key muscles for expiration in resting breathing?

Answer 52

- it is passive so none

Question 53

when is the only time we do not use our expiration muscles?

Answer 53

when we are rest breathing

Question 54

what is 75% of the enlargement of the thoracic cavity during quiet respiration is due to?

Answer 54

the contraction and flattening of the diaphragm

Question 55

***** onset of expiration begins with?

Answer 55

relaxation of inspiratory muscles

Question 56

what decreases intra-alveolar pressure to a level below atmospheric pressure?

Answer 56

the expansion of the chest wall - allows for air to enter the lungs

Question 57

what is the pleural sac?

Answer 57

double-walled, closed sac that separates each lung from the thoracic wall - both the visceral and parietal pleaura and the fluid in between them

Question 58

what is the intrapleural fluid secreted by?

Answer 58

surfaces of the pleura

Question 59

what does intrapleural fluid do?

Answer 59

lubricates pleural surfaces

Question 60

where is the pleura space?

Answer 60

space between chest wall and lung

Question 61

what is the visceral pleura?

Answer 61

where the pleura is attached to the lungs outer space

Question 62

what is the parietal plerua?

Answer 62

where the pleura is attached to thoracic wall and diaphragm

Question 63

when we open the lungs, what happens to the pressure in the lungs?

Answer 63

decreasing pressure in the lung, the intrathoracic space, and the pressure will be lower than atmospheric, so it will draw air in

Question 64

are the pleura attached?

Answer 64

no, they are very close to each other

Question 65

what does the pleural sac compose of?

Answer 65

the visceral and parietal pleura and the intrapleural fluid

Question 66

there is pressure in the pleura, what is it called?

Answer 66

the intrapleural pressure