Physiology Review (Rogers)

Question 1

Which zone/structures of the airways make up anatomic dead space?

Answer 1

• Conducting zone
• Trachea + Bronchi + Bronchioles + Terminal bronchioles

Question 2

What is responsible for decreasing surface tension within alveoli and helps keep them from deflating?

Answer 2

Surfactant

Question 3

Which type of epithelial cells are the primary lining of the alveoli/provide structure and which cells secrete surfactant?

Answer 3

• Type I cells = structure
• Type II cells = surfactant

Question 4

Although the same volume of blood goes through the right and left heart every minute, which side of circulation has lower pressure and why?

Answer 4

Right side; lower resistance to blood flow

Question 5

If the lungs lose their elasticity what occurs to the chest wall?

Answer 5

Chest expands and becomes barrel-shaped

Question 6

Graphically what occurs to the pressure within the alveoli during inspiration and expiration?

Answer 6

• During inspiration there is negative pressure (i.e., from 0 —> -1 —> 0)
• During expiration there is positive pressure (i.e., from 0 —> +1 —> 0)

Question 7

What is the intrapleural pressure at the base of the lungs at the start of inspiration/end of expiration; what occurs during inspiration?

Answer 7

• Usually -2.5 mmHg
• ↓ to about -6 mmHg

Question 8

Which volume and capacities cannot be measured via spirometry?

Answer 8

• Residual volume (RV)
• Any capacity that includes RV cannot be measured (i.e., FRC and TLC)

Question 9

The fraction of the vital capacity expired during the first second of a forced expiration is referred to as what?

Answer 9

FEV₁ (forced expiratory volume in the first second)

Question 10

Which capacity represents the balancing point between the elastic recoil of the lungs and the recoil of the chest wall?

Answer 10

Functional residual capacity (FRC)

Question 11

How do the static expiratory pressure-volume curves of the lungs of pt with emphysema and fibrosis differ from that of normal lungs?

Answer 11

• Emphysema will have a much LARGER lung volumes
• Fibrosis will show much SMALLER lung volumes

Question 12

What are the components of total (physiologic) dead space?

Answer 12

Anatomic dead space of conducting airways + alveolar dead space

Question 13

Which flow volume parameters are increased in obstructive lung disease?

Answer 13

• RV
• FRC
• TLC

Question 14

Which flow volume parameters are decrease in obstructive lung disease?

Answer 14

• ↓↓ FEV₁
• ↓ FVC
• ↓ FEV₁/FVC

Question 15

Which flow-volume parameter is normal/increased in restrictive lung disease?

Answer 15

Normal or ↑FEV₁/FVC

Question 16

What does alveolar ventilation represent and how is it calculated?

Answer 16

• Volume of gas that reaches alveoli each minute
• V_A = (V_T - V_D) x RR

*V_T = tidal volume and V_D = physiologic dead space

Question 17

What is the effect of increasing temperature and pH on the affinity of Hb for O₂ (oxygen-Hb dissociation curve)?

Answer 17

• ↑ temperature –> ↓ affinity
• ↑ pH —> ↑ affinity

Question 18

List 6 factors which ↓ the affinity of Hb for O₂ and shift the O₂-hemoglobin disscociation curve to the right.

Answer 18

• ↑ H⁺ (↓ pH, Acid)
• ↑ PCO₂
• Exercise
• ↑ 2,3-BPG
• High Altitude
• ↑ Temperature

*ACE BATs RIGHT

Question 19

For each molecule of CO₂ that enters a RBC, which additional ions will be in the cell?

Answer 19

HCO₃^- and Cl^-

Question 20

Retention of CO₂ in the body (hypercapnia) stimulates which physiological adjustments?

Answer 20

• Initially ↑ in respiration
• Large amounts of HCO₃^- are excreted, but more HCO₃^- is reabsorbed

Question 21

Hypocapnia is the result of what?

Answer 21

Hyperventilation

Question 22

Breathing is under what 2 types of control and where in the brain are these centers located?

Answer 22

• Voluntary control –> cerebral cortex
• Autonomic control –> pacemaker cells in medulla

Question 23

Which complex in the medulla contains synaptically coupled pacemaker cells that allow for rhythmic generation of breathing?

Answer 23

pre-Bötzinger complex

Question 24

Slowing adapting receptors in the airways are activated by what?

Answer 24

Lung inflation/hyper-inflation

Question 25

Rapidly adapting receptors in the airways can be activated by what stimuli and can trigger what?

Answer 25

- **Chemicals** (i.e., histamine, prostaglandins) - Trigger **cough** + **bronchoconstriction** + **mucus secretion** and in the lungs, **hyperpnea** = ↑ depth and rate of breathing

Question 26

The peripheral chemoreceptors of the carotic and aortic bodies respond to change in what chemical stimuli?

Answer 26

**P_O2** + **P_CO2** + **H⁺**

Question 27

What is the function of the Type I (glomus) cells found within the carotid body?

Answer 27

Release **catecholamines** upon exposue to **hypoxia**

Question 28

The effects of CO₂ on respiration are mainly due to it's movement into what and are sensed by which chemoreceptors?

Answer 28

Into **CSF** and sensed by **central chemoreceptors** of the **medulla**, which are **sensitive** to ↑ [H⁺]

Question 29

The central chemoreceptors of the medulla are sensitive to which ion?

Answer 29

H+

Question 30

What are the J receptors found within the airways, what are they stimulated by, and what is the response?

Answer 30

- **Unmyelinated** vagal fibers found next to **pulmonary vessles** - Stimulated by **hyperinflation** (or **exogenous** substances including **capsaicin**) - Lead to **pulmonary chemoreflex** = **apnea** followed by **tachypnea** + **bradycardia** + **hypotension**

Question 31

What physiological changes occur during the pulmonary chemoreflex upon stimulation of J receptors?

Answer 31

**Apnea** followed by **tachypnea** + **bradycardia** + **hypotension**

Question 32

The Hering-Breuer inflation and deflation relfexes are mediated by which fibers?

Answer 32

**Slowly** adapting receptors