Case 13 Flashcards
Respiratory changes which occur during exercise?
Increased ventilation rate
Increased respiratory rate
Increased tidal volume
Increased O2 consumption
What is oxygen debt?
When body does intense exercise, it undergoes anaerobic respiration
This causes lactic acid build up
Oxygen debt is the amount of oxygen needed to break down the lactic acid produced by anaerobic respiration
What are the 2 methods of ventilatory response during exercise?
Increased tidal volume
Increased respiratory rate
Why does increased ventilation during exercise not cause ventilation perfusion mismatch?
Vasodilation means more blood reaches alveoli
What is respiratory exchange ratio?
Ratio between CO2 produced and O2 consumed during metabolism
How does respiratory exchange ratio change during exercise?
Higher rate of CO2 production than O2 consumption
What is alveolar capillary gradient?
Difference in O2 conc between alveoli and pulmonary capillaries
How does pO2 in pulmonary capillaries and alveolar capillary gradient change during exercise?
Decreased pO2 in capillaries
Higher alveolar - capillary gradient.. (pO2 in air in alveoli remains same)
What control mechanisms increase rate of ventilation during exercise?
-NEURAL CONTROL - peripheral receptors detect changes in blood O2 and CO2 levels, which trigger increased neural impulses to respiratory muscles
-CHEMICAL CONTROL - increased CO2 levels stimulates chemoreceptors which send signals to respiratory centres
Cardiovascular changes during exercise?
Increased heart rate
Increased stroke volume
Increased cardiac output
Peripheral vasodilation (increase blood flow to muscles)
Redistribution of blood flow (to where it is needed most)
Increased blood pressure (due to increased cardiac output)
Increased proportional O2 uptake
How to calculate maximal heart rate using Karvonen formula?
220-age
Explain Starling’s law ( how force of heart contraction changes with blood vol inside heart) ?
Greater volume of blood in heart
Increased load on muscle fibre
Meaning they stretch
This increases their contractility, so contraction force increases.
What is Fick equation ( calculates cardiac output) ?
Cardiac output = O2 consumption / (Arterial O2 content - Venous O2 content)
What is haemoconcentration?
Increase in conc of blood compentents (particularly rbc and plasma proteins)
Effects of training on respiration?
Increased maximal O2 uptake due to many factors
Increased lung capacity
Improved ventilation
Enhanced O2 transport
Reduced resp rate
Adaptions to lung and alveoli can make gas exchange more efficient
Effects of training on cardiovascular system?
Increased cardiac output (mainly due to incr hr and stroke vol)
Increased stroke vol
Reduced resting heart rate ( due to increased cardiac efficiency)
Improved performance of cardiac muscle
Enhanced blood volume
Lower blood pressure
More ‘good’ cholesterol and less ‘bad’ cholesterol in blood
What is hypertension?
High Blood pressure
Relationship between blood pressure, cardiac output and total peripheral resistance?
Blood pressure = cardiac output x total peripheral resistance
What is cardiac output?
Vol of blood expelled by heart per min
What is stroke volume?
Volume of blood expelled by heart per beat
Relationship between cardiac output, stroke vol and heart rate?
Cardiac output = stroke volume x heart rate
Factors which cause increased heart rate?
Epinephrine and Norepinephrine
Increased temp
Thyroid hormone
Caffeine
Factors which cause decreased heart rate?
Acetylcholine
Decreased temp
Intense visceral pain
What is visceral pain ?
Pain originating from internal organs
What is total peripheral resistance?
Overall resistance to blood flow encountered by systemic circulation outside of heart and lungs
Factors which affect total peripheral resistance?
Blood viscosity (minimal change)
Blood vessel length (no change)
Blood vessel radius (causes the most change)
How is vessel radius controlled?
Sympathetic nervous system
Vasoconstriction vs Vasodilation?
Vasoconstriction - decreased vessel radius
Vasodilation - increased vessel radius
4 types of receptors in blood?
Baroreceptors
Volume receptors
Chemoreceptors
Osmoreceptors
Describe neural control of blood pressure?
Uses autonomic nervous system
Directly influences heart and blood vessels
Short term mechanism of change
Describe numeral control of blood pressure?
Uses circulating factors and hormones
Directly influences heart and blood vessels, or alters blood volume
Intermediate and long term mechanism of change
What is vasomotor centre?
It regulates blood vessel diameter, so controls peripheral vascular resistance, impacting blood pressure.
It is a group of sympathetic neurones in medulla
What is cardiac accelerator centre?
Regulates heart rate and contractibility
A group of sympathetic neurones in medulla