lecture 3 - dynamics of pulmonary ventilation

Question 1

what are the conducting zone functions

Answer 1

airflow, inflammation and allergens, protection, warm and humidify air, phonation

Question 2

describe the types of cells in an alveoli

Answer 2

1. type 1 epithelial cells - gas exchange
2. type 2 epithelial cells - secrete pulmonary surfactanjt
3. pulmonary capillaries
4. intersitial space - diffusion distance for O2 and CO2

Question 3

pulmonary ventilation

Answer 3

movement of air in and out of the lungs

Question 4

pulmonary diffusion/ external respiration

Answer 4

exchange of CO2 and O2 between lungs and blood

Question 5

capillary gas exchange / internal respiration

Answer 5

exchange of O2 and CO2 between blood and tissues

Question 6

define Boyle’s Law

Answer 6

there is an inverse relationship between volume and pressure

Question 7

what occurs during inspiration

Answer 7

diaphragm lowers, pressure decreases, volume increases

Question 8

what occurs during expiration

Answer 8

diaphragm recoils, rib cage falls, pressure increases, volume decreases

Question 9

what is the oxygen cost per litre of ventilation during low intensity exercise

Answer 9

3-6% of total VO2

Question 10

what is the cost of ventilation per litre during high intensity exercise

Answer 10

10-15% of total VO2 max

Question 11

what are the three different indicators of lactate threshold

Answer 11

1. fixed blood lactate concentration, 2. ventilatory threshold, 3. blood lactate

Question 12

why should one measure lactate threshold

Answer 12

1. sensitive indicator of aerobic training status
2. predicts endurance performance, often with greater accuracy than VO2
3. establish effective training intensity for active muscle’s aerobic metabolic dynamics

Question 13

explain the factors that impact lactate threshold

Answer 13

1. imbalance between rate of glycolysis and mitochondrial respiration
2. decreased redox paradox
3. lowered blood O2 content
4. lowered blood flow to muscles

Question 14

what is the relationship between OBLA and VO2 max

Answer 14

OBLA increase = VO2 max increase

Question 15

define the term ‘lactate threshold’

Answer 15

highest VO2 or exercise intensity before 1.0mM increase in blood lactate concentration above pre-exercise level

Question 16

describe the two thresholds when determining lactate threshold

Answer 16

1. increase in blood lactate that is more rhan 0.4mmol
2. modified Dmax method

Question 17

define the term ‘ventilatory threshold’

Answer 17

point where pulmonary VE increases disproportionately to VO2 during graded exercise

Question 18

what does excess ventilation come from

Answer 18

stimulating effects of CO2, release from buffering of accumulating lactate and H+

Question 19

where is the point of lactate threshold

Answer 19

point where you can no longer clear out lactate as fast as it is produced

Question 20

what are the 2 thresholds of pulmonary ventilation

Answer 20

1. start to reach threshold but cannot sustain if forever
2. you cannot sustain the threshold any longer

Question 21

what are 2 factors that impact the abrupt decline in ventilation when exercise ceases

Answer 21

1. removal of central command drive
2. decreased sensory input from previously active muscles

Question 22

slower recovery phase results from 2 factors, what are they?

Answer 22

1. gradual diminution of short term potentiation of respiratory centre
2. re-establishment of body’s normal metabolic, thermal and clinical milleu