lecture 4 - pulmonary ventilation part 2

Question 1

why does O2 in blood drop despite alveolar air increasing

Answer 1

1. inequality in ventilation-perfusion within lungs
2. shunting of blood between venous and arterial circulations
3. failure to achieve end-capillary equilibrium in alveolar blood gases

Question 2

alkalosis

Answer 2

decrease in H+ concentration

Question 3

acidosis

Answer 3

increase in H+ concentration

Question 4

define the term ‘buffering’

Answer 4

chemical and physiologic mechanisms to minimize changes in H+ concentration

Question 5

describe the mechanisms that regulate internal pH

Answer 5

chemical buffers, pulmonary ventilation and renal function

Question 6

what is a chemical buffer

Answer 6

a weak acid and a salt of that acid

Question 7

what are a few types of chemical buffers

Answer 7

bicarbonate buffers, phosphate buffers and protein buffers

Question 8

describe how ventilatory buffers work

Answer 8

when H+ in the extracellular fluid and plasma increases, it stimulates the respiratory centre to increase alveolar ventilation to reduce alveolar Pco2, this causes CO2 to be blown off

Question 9

how does a renal buffer work

Answer 9

regulates acidity through chemical reactions that secrete ammonia and H+ which causes urine secretion and reabsorption of alkali, chloride and bicarbonate

Question 10

describe the effects of intense physical activity

Answer 10

increased H+ concentration from CO2 production and lactate formation during strenuous exercise make pH regulation more difficult

Question 11

what occurs if the plasma pH is above 7

Answer 11

nausea, headaches and dizziness

Question 12

describe what constitutes to airway resistance

Answer 12

1. leukotrines - released during inflammation response to contract bronchiolar smooth muscle
2. epinepherine - relax bronchiolar smooth muscle

Question 13

what are the variation from normal breathing patterns

Answer 13

1. hyperventilation - increase in pulmonary ventilation that exceeds O2 consumption and CO2 elimination needs of metabolism
2. dyspnea - inordinate shortness of breath or subjective breathing distress
3. vascular maneuver - closing mouth after full inspiration, while max contractile expiration

Question 14

what occurs to the respiratory tract during cold weather activity

Answer 14

as cold air in inhaled, the pharynx, larynx and alveoli are warming and humidifying air which increases the air’s capacity to hold moistyre

Question 15

PAO2

Answer 15

partial pressure of O2 in alveolar chambers

Question 16

PaO2

Answer 16

partial pressure of O2 in arterial blood

Question 17

SaO2%

Answer 17

percent saturation of O2 arterial blood with O2

Question 18

PvO2

Answer 18

partial pressure of venous blood

Question 19

PACO2

Answer 19

partial pressure of CO2 in alveolar chambers

Question 20

PaCO2

Answer 20

partial pressure of CO2 in arterial blood

Question 21

PvCO2

Answer 21

partial pressure of CO2 in venous blood

Question 22

SvO2%

Answer 22

percent saturation of venous blood with O2

Question 23

a-vO2 diff

Answer 23

arterial -mixed venous blood with O2

Question 24

v

Answer 24

mixed venous blood

Question 25

what is the atmospheric pressure at sea level

Answer 25

760 mmHg

Question 26

what are the percentages of N, O2 and CO2 in the atmosphere

Answer 26

N: 79.04%, O2: 20.93%, CO2: 0.03%

Question 27

total atmospheric pressure

Answer 27

combined pressure of all gases in the atmosphere

Question 28

describe Dalton's law

Answer 28

each individual gas contributes to a total atmospheric pressure and each individual gas will exert its own partial pressure

Question 29

how to calculate partial pressure

Answer 29

formula barometric pressure multiplied by % of gas in the atmosphere

Question 30

what is the partial pressure of O2 at sea level

Answer 30

159 mmHg

Question 31

what is the partial pressure of O2 at alveoli

Answer 31

100 mmHg

Question 32

what is the partial pressure of carbon dioxide in the atmosphere

Answer 32

0.2 mmHg

Question 33

what is the partial pressure of carbon dioxide in the alveoli

Answer 33

40 mmHg

Question 34

what are the 2 factors that impair the gas transfer capacity at alveolar capillary membrane

Answer 34

1. buildup of pollutant layer that "thicken" alveolar membrane 2. reduction in alveolar S.A

Question 35

describe the gas transfer in tissues

Answer 35

pressure differenced between gases in plasma and tissues establish the diffusion gradients

Question 36

how is oxygen transported in the blood

Answer 36

1. physical solution dissolved in fluid portion of blood 2. loose combination w haemoglobin to make oxyhaemoglobin

Question 37

what are the functions of oxygen transported in physical solution

Answer 37

1. establish Po2 of plasma and tissue fluids 2. helps to regulate breathing, particularly at altitude 3. determines O2 loading of hemoglobin in lungs and subsequent release in tissues

Question 38

anaemia

Answer 38

significant decrease in iron availability to decrease hemoglobin concentration which reduces the content of RBCs that reduce blood's O2 carrying capacity

Question 39

myoglobin

Answer 39

iron-containing globular protein in skeletal and cardiac muscle fibres

Question 40

what are the functions of myoglobin

Answer 40

provides intramuscular O2 storage

Question 41

how does blood carry carbon dioxide

Answer 41

1. physical solution in plasma 2. combined with hemoglobin in RBC --> carbaminohemoglobin 3. as plasma bicarbonate