PULMONARY 2.0 Flashcards
Your tidal volume can increase to …
2.0 L or more
When do respiratory muscles contract
when stimulated by their nerve supply
Where is the primary respiratory control centre
the respiratory centre in the medial medulla
What is the route of impulses to control respiratory muscles
From respiratory centre in medial medulla to motor neurons located in spinal cord to respiratory muscles
What are factors that affect medullary control of pulmonary ventilation
- Peripheral chemoreceptors
- Receptors in lung tissue
- Proprioceptors in joints and muscles
- Core temperature
- Chemical state of blood in medulla
Where is the best peripheral chemoreceptor
in carotid artery
What do chemoreceptors do
sample PO2 and PCO2 in blood as it goes by
When do the receptors in lung tissue send signals to the brain
when they are stretched
When do muscles and joints send signals to the brain
when there is lots of movement - to adjust breathing accordingly
When core temp ____ it ____ breathing regulatory centres in the brain
increases
excites
Upon onset of exercise there is a ____ increase in minute ventilation
sharp
What occurs to breathing as you stop exercising
it gradually comes back down
What occurs to minute ventilation in non-steady-rate exercise from rest to moderate
increases in proportion to oxygen consumption over range from rest to moderate exercise
What occurs to minute ventilation in non-steady-rate exercise from moderate to strenuous
increases disproportionately to oxygen consumption
What occurs when there is inadequate O2 delivery or utilization (series of events)
reliance on anaerobic metabolism -> increase lactate -> production of H2O and CO2 -> Excess, non-metabolic CO2 stimulates increased pulmonary ventilation (additional exhalation of CO2)
What is the reaction from lactate and NaHCO3 to H2O and CO2
lactate + NaHCO3 -> Na lactate + 2CO3 -> H2O + CO2
What is ventilatory threshold
The point at which ventilation increases disproportionately with oxygen uptake during incremental exercise
What are the 2 main factors that determine the energy requirement of breathing
- Compliance of the lung and thorax
- Resistance of airways to smooth flow of air
what is compliance
how easily these tissues stretch
For a healthy individual at rest, what % of total oxygen consumption is to the respiratory muscles themselves
3-5%
For a healthy individual at max, what % of total oxygen consumption is to the respiratory muscles themselves
10-15%
As compliance of respiratory muscels decreases, work of breathing ____
Increases
What is an example of a condition where the compliance or air resistance in the respiratory system is decreased
Chronic Obstructive Pulmonary Disease
for people with COPD, what % of total oxygen consumption is to the respiratory muscles themselves at max
40%
What is the O2, CO2 and N content in ambient air
O - 20.93%
CO2 - 0.03%
N - 79.04%
If air is humidified what occurs to O2
decreases by 10 mmHg
Why is PO2 lower in alveoli air than inspired air ? and what is it>
incoming air mixes with residual air which has already had some of the O2 removed from it 100 mm Hg
What do the partial pressures of O2 and CO2 in alveoli and blood allow
O2 to travel down the gradient into blood. and to CO2 to leave the blood via the gradient
What is the equation for partial pressure
% concentration x Total gas mixture pressure
Inspired air has a PO2 of? CO2?
159 mm Hg
0.2 mm Hg
What is the Po2 and PCO2 of skeletal muscle
46mm Hg
40 mm Hg
How is oxygen carried in blood
dissolved in fluid portion of blood
or
Combined with hemoglobin with red blood cells
How much O2 is dissolved in blood itself
only 1.5%
How much O2 is in bound to hemoglobin
98.5%
What is the oxygen carrying capacity of blood in men and women?
M - 20.1 mL per 100 mL blood
W - 18.8 mL per 100 mL blood
What is the oxygen carrying capacity of hemoglobin
1.34
Do men or women have more hemoglobin
men
What is SaO2
% saturation - how saturated the hemoglobin is with oxygen
How do you measure SaO2
Pulse oxymeter using infrared light
what is SaO2 of hemoglobin in lungs at rest?
98%
what is SaO2 of hemoglobin in tissue at rest?
75%
What is the plateau of the oxyhemoglobin curve consistent with
PO2 at pulmonary capillaries
What are the consequences of alveolar & arterial PO2 falling 40%
- %Hb saturation remains at 90%
- Total O2 content in the blood is only slightly decreased
- even if youa re not airating properly you still have a high oxygen carrying capacity in blood is very high - Safety mechanism!!
The plateau provides …
a significant margin of safety in O2 carrying capacity of blood
The steep portion of the oxyhemoglobin curve occurs where in the body …
systemic capillaries
What does the steep portion of the oxyhemoglobin curve allow for
HbO2 to disassociate and O2 to diffuse to tissue cells
What occurs to PO2during exercise - why is this good?
PO2 at tissues goes even lower - allows more o2 to enter the tissue as needed. Steep curve allows the oxygen to be given to the tissues is a very efficient manor
What is the route of O2 from hemoglobin to tissue
O2 must travel from hemoglobin and dissolve into blood and then to the tissues.
What does Hb saturation drop to at tissues with exercise
30%
What is myoglobin
similar to Hb but at level of mitochondria - iron protein compound found in skeletal and cardiac muscle
What does myoglobin facilitate
mitochondrial oxygen transfer
When does myoglobin bind and retain oxygen
at low pressures
In what 3 ways does blood carry CO2? and what % in each method?
- In physical solution in plasma 7-10%
- Combined with hemoglobin within red blood cell 20%
- As plasma bicarbonate 70%
Does delivering more oxygen improve exercise capacity
No, in healthy respiratory system your arterial blood is almost always fully saturated. Hemoglobin cant take any more. This is maintained even at high exercise levels
Are more red blood cells able to improve exercise capacity?
Yes
- Blood doping, body replaces loss blood and hemoglobin in about 6 weeks. then you put old blood back in and you are performing above average, hemoglobin slowly returns and readjusts to normal levels
With blood doping you can increase hemoglobin levels by how much
8-20%
15 g/dL to 19 g/dL blood
Increasing oxygen carrying capacity from 20.1 to 25.5
Why is blood doping dangerous?
a large increase in cellular concentration leads to an increase in blood viscosity. This in turn
- decreases cardiac output
- increases systolic blood pressure
- causes strain on heart
what is the impact of blood doping on functional capacity
- Increase O2 available to working muscles
- Improved max aerobic performanace (5-13%)
- Reduced submaximal HR and blood lactate for a standard exercise test
What is EPO and what is its purpose
Erythropoietin - inject after removing blood for blood doping to allow athletes to continue to train at high levels
Does regular endurance exercise stimulate large increases in the functional capacity of the pulmonary system
no - minor ability to
Submax training may improve the endurance of the ventilatory muscles by…
16%
How does training increase the endurance of ventilatory muscles
- Increased aerobic enzymes at the level of the ventilatory muscles
- Reduced fatigue of ventilatory muscles
- Lowers oxygen demand from ventilatory muscles and frees up oxygen use by non-ventilatory muscles
- Slower breathing rate for a given submaximal exercise rate, training can extract more oxygen
How does the O2 composition of exhaled air change between trained and non trained individuals
trained - 15%
untrained - 17%
