Respiratory

Question 1

primary muscle of respiration

Answer 1

diaphragm –> 75% of change in chest volume

Question 2

Tracheobronchial tree

Answer 2

conduit for ventilation & clearance of secretions

- C-shaped cartilage rings

Question 3

Narrowest part of the airway?

Answer 3

cricoid cartilage in adults

Question 4

Main stem bronchi orientation?

Answer 4

R-main stem is more vertical –> aspiration

Question 5

Type I pneumocyte

Answer 5

prevent passage of fluid/material into lungs

Question 6

Type II pneumocyte

Answer 6

prominent cytoplasm

• produce surfactant –> can divide
• resistant to O2 toxicity

Question 7

Pulmonary Circulation

Answer 7

1. Bronchial circulation –> from left side (sustains metabolic requirements of lungs)
2. Pulmonary capillaries –> incorporated into walls of alveoli, large junctions allow passage of albumin

Question 8

Innervation of lungs

Answer 8

• diaphragm is phrenic (C3-5)
• intercostal muscles –> thoracic nerve roots
• vagus –> sensory innervation of tracheobronchial tree
• sympathetics –> bronchodilation

Question 9

Spontaneous respirations

Answer 9

1. Diaphragm and intercostals activate –> chest expansion
2. Drop in intrapleural pressure –> (-) pressure gradient for air into lungs
3. Diaphragm relaxation and chest recoil –> passive expiration

Question 10

Transplumonary pressure?

Answer 10

P(alveolar) - P(intrapleural)

Question 11

Compliance?

Answer 11

deltaV/deltaP

Question 12

Dynamic compliance

Answer 12

measure of overall resistance

- peak pressures (bronchospasm)

Question 13

Static compliance

Answer 13

measure of overall lung stiffness

- plateau pressure (measured at fixed lung volume)

Question 14

Surface tension forces?

Answer 14

LaPlace’s Law

Pressure = 2*surface tension / radius

Question 15

What does pulmonary surfactant do to surface tension?

Answer 15

it decreases alveolar surface tension, to reduce pressure

Question 16

What happens to chest wall compliance in supine position?

Answer 16

Chest wall compliance is reduced in supine position compared to upright

Question 17

Functional Reserve Capacity

Answer 17

lung volume @ end expiration

- at FRC, inward lung elastic recoil is opposed by outward chest recoil –> equals out

Question 18

What makes FRC decrease?

Answer 18

1. Supine vs Sitting
2. Obese
3. Short stature
4. Lung Disease (fibrosis)

Question 19

Closing capacity

Answer 19

volume at which volume in the airways begin to close (below FRC)
- small airways w/o cartilage depend of radial traction to keep them open

Question 20

What makes FRC increase?

Answer 20

1. Height
2. Old age –> loss of elastic recoil
3. Obstructive lung disease

Question 21

Gas flow in lungs equation?

Answer 21

Flow = Pressure gradient / Resistance

Question 22

Resistance equation

Answer 22

R = 8Lviscosity / (pi)R^4

Question 23

Reynolds Number

Answer 23

Rey = diameter * velocity * density / viscosity

Question 24

Reynolds >1500

Answer 24

Turbulent Flow

Question 25

Reynolds <1000

Answer 25

Laminar flow

Question 26

Volume related airway collapse

Answer 26

at low lung volumes --> lose that radial traction --> airway collapse due to increased resistance - use PEEP to decrease resistance and keep airways open

Question 27

Breathing pattern of patients with reduced compliance

Answer 27

rapid, shallow breaths

Question 28

Breathing pattern of patients with increased resistance

Answer 28

slow, deep breaths

Question 29

Effects of anesthesia on pulmonary mechanics

Answer 29

1. Sitting --> supine: decrease FRC, reduced diaphragm excursion 2. Inducing GA --> further reduces FRC and causes atelectasis 3. Steep Trendelenburg --> further reduces FRC and diaphragm excursion

Question 30

Ventilation

Answer 30

~ 5 L/min | MV = RR * Tv

Question 31

Alveolar ventilation

Answer 31

actual gas taking part in gas exchange

Question 32

Dead space ventilation

Answer 32

portion of Tv that fills airway but does not exchange gas

Question 33

Bohr Equation

Answer 33

Vd/Vt = PaCO2 - EtCO2 / PaCO2

Question 34

Which lung receives more ventilation?

Answer 34

R > L - lower lungs receive more ventilation - upper lungs under more negative pressure

Question 35

Pulmonary Perfusion

Answer 35

~5 L/min - only 70-100 cc actually participate in gas exchange at any one time - low pressure system --> can accommodate fluid

Question 36

5 mechanisms of hypoxia

Answer 36

1. Hypoventilation 2. Low FiO2 (altitude) 3. diffusion limitation 4. V/Q mismatch 5. Shunt

Question 37

What hypoxia causes A-a gradient

Answer 37

1. V/Q mismatch 2. Shunt 3. diffusion limitation

Question 38

Wide A-a gradient that responds to O2

Answer 38

1. V/Q mismatch | 2. diffusion limitation

Question 39

Wide A-a gradient that doesn't respond to O2

Answer 39

Shunt!!!!

Question 40

Calculate A-a gradient

Answer 40

PAO2 = PiO2 - PaCO2/Rq

Question 41

Central center of respiration

Answer 41

MEDULLA - dorsal = inspiration - ventral = expiration

Question 42

Central sensors of respiration

Answer 42

chemoreceptors respond to changes in [H+] in the CSF - CO2 crosses BBB and is converted to H+ - HCO3 CANNOT cross BBB

Question 43

Peripheral sensors of respiration

Answer 43

GLOSSOPHARYNGEAL NERVE 1. Carotid body = primary sensor - most sensitive to PaO2 2. Aortic body - secondary sensor

Question 44

Depressants of response to hypoxia and respiration?

Answer 44

Acidosis, hypoxia, and anesthetic agents

Question 45

Hering-Bruer Reflex

Answer 45

lung stretch receptors inhibit inspiration when stretched by too much volume