First Aid Physiology

Question 1

What structures make up the conducting zone?

Answer 1

• Large Airways
  
  • Nose
  • Pharynx
  • Larynx
  • Trachea
  • Bronchi
• Small Airways
  
  • Bronchioles
  • Terminal bronchioles

Question 2

How far do the cartilage and goblets cells extend?

Answer 2

To the end of the bronchi

Question 3

How far does the pseudostratified, ciliated, columnar cells extend?

Answer 3

To the beginning of the terminal bronchioles

Question 4

What epithelium is found in the terminal bronchioles?

Answer 4

Cuboidal cells

Question 5

What structures make up the respiratory zone?

Answer 5

• Lung parenchyma
  
  • Respiratory bronchioles
  • Alveolar ducts
  • Alveoli

Question 6

What type of epithelium is found in the respiratory bronchioles? Alveolar ducts and Alveoli?

Answer 6

Cuboidal

Simple squamous

Question 7

What defense mechanism is found in the respiratory zone?

Answer 7

Alveolar Macrophages

NO cilia

Question 8

What are the 3 types of pneumocytes found in the lung? Which is most numerous? Which have a proliferative capacity? Which are involved in surfactant production?

Answer 8

1. Type I - most numerous
2. Type II - stem cells/surfactant
3. Club (Clara) - granules/secrete component of surfactant

Question 9

What is the equation for collapsing pressure?

Answer 9

CP = 2(surface tension)/radius

Question 10

When does surfactant synthesis begin? When is it considered adequate?

Answer 10

Week 26

Week 35 or L:S ratio of > 2 in amniotic fluid

Question 11

Where does a peanut go when you’re standing? Lying down?

Answer 11

Lower portion of R inferior lobe

Superior portion of R inferior lobe

Question 12

What inervates the diaphragm?

Answer 12

C3, 4, and 5 - Phrenic Nerve

Question 13

What structures perforate the diaphragm?

Answer 13

IVC - T8

Esophagus and Vagus - T10

Aorta, Thoracic Duct, and Azygos Vein - T12

Question 14

Where is pain from the diaphragm referred to? What might cause it?

Answer 14

Shoulder (C5), trapezius ridge (C3, C4)

Air or blood in peritoneal cavity

Question 15

What does inspiratory reserve volume represent?

Answer 15

Air that can still be breathed in after a normal inspiration

Question 16

What does expiratory reserve volume represent?

Answer 16

Air that can still be breathed out after a normal expiration

Question 17

What does tidal volume represent?

Answer 17

Air that moves into the lung w/ each inspiration ~500 mL

Question 18

What does residual volume represent?

Answer 18

Air remaining in lung after maximal expiration - cannot be measured w/ spirometry

Question 19

What determines inspiratory capacity?

Answer 19

TV + IRV

Question 20

What determines Vital Capacity?

Answer 20

ERV + TV + IRV

Question 21

What determines Total Lung Capacity?

Answer 21

RV + ERV + TV + IRV

Question 22

What determines Functional Residual Capacity?

Answer 22

RV + ERV

Question 23

How do you calculate the physiologic dead space (V_D)?

Answer 23

**V_D= V_T [(Pa_CO2 - P_ECO2) / Pa_CO2] **

Taco, Paco, PEco, Paco

Peco = expired air

Question 24

Minute Ventilation (V_E)

Answer 24

Total volume of gas entering lungs/min

V_T * RR

Question 25

Alveolar ventilation (V_A)

Answer 25

Volume of gas/unit time that reaches the alveoli ## Footnote **(V_T - V_D) \* RR**

Question 26

At FRC, what are the airway and alveolar pressure? Intrapleural pressure?

Answer 26

Airway and alveolar pressure = 0 Intrapleural pressure = negative

Question 27

Compliance

Answer 27

Δ lung volume / Δ pressure ↑ compliance → ↑Δ lung volume for a given ΔP

Question 28

Which disease processes ↑ compliance?

Answer 28

Obstructive diseases i.e. emphysema \> asthma \> bronchiectasis Normal aging

Question 29

What diseases ↓ compliance?

Answer 29

Restrictive: Pulmonary fibrosis Pneumonia Pulmonary Edema

Question 30

What form of Hb has a _lower affinity_ for O₂? Where is it found? What induces this?

Answer 30

**T (taut)** - tissues ↑Cl, H, CO₂, 2,3-BPG, temperature "Right" shift

Question 31

What is methemoglobin? How does it present? How do you treat it?

Answer 31

Oxidized Hb (Ferric/Fe³⁺) — Doesn't bind O₂ - binds cyanide Cyanosis and chocolate colored blood Methylene blue

Question 32

How do you treat cyanide poisoning?

Answer 32

1. **Nitrites:** oxidize Hb → bind cyanide 2. **Thiosulfate: **​bind cyanide → thiocyanate (renally excreted)

Question 33

What is carboxyhemoglobin?

Answer 33

Hb bound tight to CO - locked in R state Left Shift

Question 34

True or False: O₂ content of arterial blood _decreases_ as Hb falls, but O₂ saturation and arterial P_O2 do not.

Answer 34

True

Question 35

What is perfusion limited? How do you increase diffusion?

Answer 35

O₂ normal health Gas equilibrates early along length of capillary Inc. blood flow

Question 36

Diffusion limited

Answer 36

Gas does not equilibrate by the time blood reaches the end of the capillary O₂ (emphysema, fibrosis)

Question 37

How do you calculate pulmonary vascualr resistance?

Answer 37

(P_{pulm artery} - P_{L atrium}) / CO

Question 38

What is another word for P_{L atrium}?

Answer 38

Pulmonary wedge pressure

Question 39

What is a normal A-a gradient? What would cause an increase?

Answer 39

10-15 (PA_O2 - Pa_O2) Hypoxemia: shunting, V/Q mismatch, fibrosis

Question 40

Does all hypoxemia cuase an ↑ A-a gradient?

Answer 40

No. High altitude and hypoventilation

Question 41

What is the significance that the apex of the lung has a V/Q of 3

Answer 41

Over-ventilated/Under-perfused TB likes it here

Question 42

What is the signficance that the base of the lung has a V/Q of .6?

Answer 42

Under ventilated/over-perfused

Question 43

When does the V/Q = 0?

Answer 43

**Airway obstruction** - shunt i.e. 100% O2 won't help P_O2

Question 44

When does the V/Q = ∞?

Answer 44

Blood flow obstruction - physiologic dead space 100% O₂ will improve P_O2

Question 45

Where are ventilation and perfusion greatest?

Answer 45

Base of the lung

Question 46

In what 3 forms is CO₂ transported to the lungs from the tissues? Which is the most abundant?

Answer 46

1. HCO₃^- | 90% 2. Carbaminohemoglobin | 5% 3. Dissolved CO₂ | 5%

Question 47

In peripheral tissue, ↑H+ from tissue metabolism shifts curve to the right, unloading O2. What is this known as?

Answer 47

Bohrn Effect

Question 48

In the lungs, oxygenation of Hb promotes Hb dissociation of H+ from Hb. This shifts equilibrium toward CO₂ formation; therefore CO₂ is released from RBCs. What is this known as?

Answer 48

Haldane Effect

Question 49

What is the enzyme that converts CO₂ and H₂O → H₂CO₃?

Answer 49

Carbonic anhydrase

Question 50

What is the response to high altitude?

Answer 50

↑ ventilation → resp. alkalosis ↑ erythorpoietin ↑2,3-BPG ↑ mitochondria ↑ renal excretion of HCO3 to compensate for the **respiratory alkalosis**

Question 51

Response to exercise?

Answer 51

**↑ CO2 production, O2 consumption** — _No change_ in PaO2 and PaCO2 ↑ venous CO2 content & ↓ venous O2 content ↑ ventilation to meet demand V/Q ratio become more uniform ↑ pulmonary blood flow ↓ pH during strenuous exercise