lecture 17 & 18

Question 1

When someone changes from standing to supine, how do lung volumes and capacities change?

Answer 1

VC and TLC is unchanged.
FRC is reduced as a product of ERV decrease
IRV increases

Question 2

There is a slight slope to a normal capnograph… why is this?

Answer 2

Over the course of the 2s of expiration CO2 continues to get unloaded from the pulmonary capillaries into the lung air

Question 3

On average what is our PCO2? How much does it fluctuate with normal TVs?

Answer 3

40mmHg, it fluctuates with each TV. When we bring a fresh TV PCO2 is slightly lower (35.8mmHg)

Question 4

What would cause an inverted slope on a capnograph? Why?

Answer 4

Late stage emphysema (lung compliance is really high, prone to small airway collapse, which occurs at the base of the lung first, so more of the air is coming from the top of the lung during expiration which is lower in CO2)

Question 5

What could you use as a gauge for alveolar dead space?

Answer 5

The difference between ETCO2 and arterial PCO2

Question 6

What equation can you use to find the physiologic dead space (total DS)?

Answer 6

The Bohr equation

Question 7

What is the Bohr equation?

Answer 7

Volume of dead space/TV = PaCO2-PECO2 / PaCO2
ex.) VDS/500mL = 40mmHg-27mmHg/40mmHg = 162.5mL

Question 8

Why do we see barrel chests with patients with emphysema/ COPD?

Answer 8

As we lose elastic tissue in the lungs and elastic recoil there is less counterpressure and the chest wall protrudes outwards.

Question 9

What doe emphysema do to intrapleural pressure?

Answer 9

The pleural pressure is more positive, so it takes less negative pressure to achieve higher lung volumes

Question 10

At rest what is our pleural pressure? At the end of inspiration, what is our pleural pressure?

Answer 10

-5cmH2O to -7.5cmH2O

Question 11

What is the value of pulmonary compliance for our class at FRC?

Answer 11

0.2 L/cmH2O

Question 12

How do we calculate pulmonary compliance at FRC?

Answer 12

compliance = change in volume/ change in pressure
0.5 L / (-5cmH2O - -7.5cmH2O) or
0.5L / 2.5cmH2O = 0.2 L/cmH2O

Question 13

List some key differences between the right and left lung lobes…

Answer 13

L lung: taller and has only 2 lobes
R lung: larger, heavier, more volume has 3 lobes

Question 14

How many bronchopulmonary segments does the R lung have? The L lung?

Answer 14

R lung: 10
L lung: 8

Question 15

Where is the most likely space for a pocket of air or vacuum in the diaphragm?

Answer 15

at the costodiaphragmatic recess

Question 16

Which muscles hold the thorax in place when the diaphragm contracts?

Answer 16

scalene muscles
sternocleidomastoid muscle

Question 17

What are the internal intercostal muscles used for?
What are the external intercostals used for?

Answer 17

Internal: forced expiration
External: helps with inspiration

Question 18

Which muscles are attached to the shoulders and can help with breathing when the upper body is supported (bent over breathing/ tripoding)

Answer 18

Pectoris minor and pectoris major

Question 19

Where does the superior and middle conchae project off of?

Answer 19

ethmoid bone

Question 20

Where does the inferior conchae project from?

Answer 20

maxillary bone

Question 21

What part of the ethmoid bone protrudes up into the cranium? What purpose does this protrusion serve?

Answer 21

Crista galli. It serves as an attachment point for the falx cerebri

Question 22

Which nerve provides the majority of the sensory function to the face? What are the three divisions?

Answer 22

Trigeminal nerve (CN V)
1. ophthalmic
2. maxillary
3. mandibular

Question 23

What are the three sets of tonsils?

Answer 23

pharyngeal (adenoids)
palatine
lingual

Question 24

What are the three sets salivary glands?

Answer 24

parotid
submandibular
sublingual

Question 25

What is the name of the space immediately in front of the epiglottis posterior to the lingual tonsils?

Answer 25

The vallecula

Question 26

Which bone is the floating bone that is porous and breakable?

Answer 26

hyoid bone

Question 27

What are the three unpaired cartilages in the trachea?

Answer 27

1. epiglottis
2. thyroid cartilage
3. cricoid cartilage

Question 28

What are the two paired cartilages in the trachea we talked about in class?

Answer 28

1. arytenoid cartilages
2. corniculate cartilages

Question 29

What is the narrowest part of the airway in adults? In kids?

Answer 29

Adults: space between the vocal cords (transglottic space)
Kids: cricoid cartilage (up until age 10)

Question 30

What are the two movements during swallowing that prevents gastric contents from entering the airway?

Answer 30

1. epiglottis shifts downwards to cover the larynx
2. larynx gets pulled upward

Question 31

What does applying cricoid pressure do? What is the potential complication of this?

Answer 31

Shifts the cricoid posterior to obstruct the esophagus which prevents gastric contents from entering the larynx
complication: pressure blows out the esophageal sphincter and can cause permanent damage