Week 8

Question 1

4 steps in the transport of O2

Answer 1

1. Pulmonary ventilation
   
   2. Pulmonary diffusion
   3. Gaseous transport
2. Capillary diffusion

Question 2

Define external and internal respiration

Answer 2

External respiration: Pulmonary ventilation and diffusion

Internal respiration: Gas exchange between blood and tissues

Question 3

Define alveoli

Answer 3

Site of gas exchange between lung tissue and blood

Question 4

What are the 2 zones of ventilation

Answer 4

Conducting

Transitional and respiratory

Question 5

Conducting zone function and location

Answer 5

Trachea and terminal bronchioles

- Considered anatomic dead space, contains no alveoli 
- Functions: air transport, warming, particle filtration

Question 6

Transitional and respiratory zone and function

Answer 6

Bronchioles, alveolar ducts and alveoli

- Functions: Gas exchange, surfactant production and molecule activation 
- Largest area, occupies 2.5 - 3L

Question 7

Define Fick’s law of diffusion

Answer 7

Fick’s Law describes the relationship between the rate of diffusion and the three factors that affect diffusion.
States that a gas diffuses through a sheet of tissue at a rate:
1. Directly proportional to the tissue area, a diffusion constant and the pressure differential of the gas on each side of the membrane
2. Inversely proportional to tissue thickness

Question 8

sequence of events in inspiration

Answer 8

Sequence of events:
1. Inspiratory muscles contract
2. Thoracic cavity volume increases
3. Lungs stretched; intrapulmonary volume increases
4. Intrapulmonary pressure drops
Air flows into lungs down its pressure gradient until intrapulmonary pressure is 0

Question 9

Sequence of events in expiration

Answer 9

1. Inspiratory muscles relax
   
   2. Thoracic cavity volume decreases
   3. Elastic lungs recoil passively
   4. Intrapulmonary pressure rises
      Air flows out of lungs down its pressure gradient until intrapulmonary pressure is 0

Question 10

When do the intercostals contract, and when do they relax

Answer 10

Contract = inspiration 
Relax = expiration

Question 11

Define Tidal Volume (TV)

Answer 11

Air moved during the inspiratory or expiratory phase of each breathing cycle

Question 12

Define Inspiratory reserve volume (IRV)

Answer 12

Inspiring as deeply as possible following a normal inspiration

Question 13

Expiratory reserve volume (ERV)

Answer 13

After a normal exhalation, continuing to exhale and forcing as much air as possible from the lungs

Question 14

Forced vital capacity (FVC)

Answer 14

Total volume of air voluntarily moved in one maximal breath

Question 15

Define residual lung volume

Answer 15

Air volume remaining in the lungs after a forced maximal exhalation

Question 16

What does dynamic ventilation depend on

Answer 16

1. Maximum ‘stroke volume ‘of the lungs (FVC)

Speed of moving a volume of air (breathing rate)

Question 17

Define anatomic dead space

Answer 17

Air in each breathe that does not enter alveoli and participate in gaseous exchange with blood

Question 18

Define alveolar ventilation

Answer 18

portion of inspired air reached the alveoli and participating in gas exchange

Question 19

Define the ventilation-Perfusion (V-P) ratio

Answer 19

the ratio of alveolar ventilation to pulmonary blood flow

Question 20

Define physiologic dead space

Answer 20

air that is physiologically inaccessible to the body

Question 21

What 2 things can cause alveoli to not function properly

Answer 21

1. Underperfusion of blood

Inadequate ventilation relative to alveolar surface

Question 22

Define hyperventilation

Answer 22

An increase in pulmonary ventilation that exceeds the O2 consumption and CO2 elimination needs of metabolism

Question 23

Define dyspnea

Answer 23

An inordinate shortness of breath or subjective distress in breathing

Question 24

Define vaslalva manuerver

Answer 24

Closing the glottis following a full inspiration while maximally activating the expiratory muscles, creating compressive forces that increase intrathoracic pressure above atmospheric pressure