Chapter 4 Flashcards
Respiratory
Increased ventilation
Increased tidal volume
Increased respiratory rate
Increased diffusion
Cardiovascular
Increased heart rate Increased stroke volume Increased cardiac output Increased systolic blood pressure (diastolic stays the same) Increased venous return Decreased blood volume Increased a-VO2 difference Increased oxygen consumption
Muscular
Increased motor unit recruitment Increased blood flow to working muscles Increased body temperature Decreased energy substrate levels Increased lactate production
What are acute responses?
Short term changes the body needs to make to accommodate the energy required for the activity.
Respiratory system
Responsible for the delivery of oxygen and removal of carbon dioxide from the cells of the body. Oxygenates blood
Increased respiratory rate
Breathing rate.
Usually 12 breaths per minute at rest.
35-50 during exercise.
Increased tidal volume
The death of your breathing.
Increases from 0.5 l per breath at rest, to a max of 3-5l per breath.
Measured by a spirometer.
Increased ventilation
TVXRR=V.
Increased volume of oxygen in lungs to be diffused to blood to be transported to the working muscles.
V low-moderate exercise
TV and RR increase to increase V.
V sub maximal
V increases rapidly then slows to plateau. Takes 4-5 minutes
Maximal exercise
V increases until exercise is stopped. TV plateaus and further increases in V is needed to increase RR.
At higher intensities V is no longer proportional to oxygen consumption
Increased diffusion
Occurs in the alveoli of the lungs and the muscle capillaries.
During exercise diffusion increases to make more oxygen available and to get rid of more carbon dioxide
Diffusion in the lungs
Oxygen concentration is high, so oxygen diffuses from the alveoli into the bloodstream.
Carbon dioxide levels in the blood are high, so carbon dioxide moves from the blood into the alveoli via a diffusion path.
Diffusion at the muscles
Opposite occurs as blood oxygen leve,s are high and muscle oxygen levels are low.
Exercise- diffusion increased due to increase surface area of alveoli and muscle tissue.
Carbon dioxide by product of aerobic energy production that needs to be removed.
Carbon dioxide levels in the muscles is high, so carbon dioxide moves from the muscles into the blood stream.
Cardiovascular system
Comprised of the blood, heart and blood vessels.
During exercise the central nervous system needs to deliver feud and oxygen to the working muscles. Focuses on getting more blood to the working muscles and speeds up removal of carbon dioxide and waste products.
Increased heart rate
Increase of oxygenated blood flow to working muscles.
Heart rate has a max, calculated by: max HR =220-age.
Heart rate increases anticipation to exercise.
Increased stroke volume
Increases with exercise but only up to 40-60% of maximum intensity of exercise, then it plateaus.
Males generally have higher stroke volumes due to their increased heart size.
Untrained individual SV
Rest: 60-80 ml
Exercise: 80-110ml
Trained individual SV
Rest: 80-110ml
Exercise: 160-200ml
Increased cardiac output
Q=SVXHR
so that more blood can be ejected out of the heart per minute and therefore more oxygen can be delivered to the muscles.
Average adult at rest: 4-6l per min and at exercise 20-25l.
Trained athlete: can get up to 35-40l per minute
Increased venous return
More blood delivered back to the heart to reoxygenate
-muscle pump
-respiratory pump
-venoconstriction (constriction of veins)
Rate of venous return increases as intensity increases
Muscle pump
Contracts/squishes veins
Venoconstriction
Shrinking/tightening of veins
Respiratory pump
Pressure gradient
Increased blood pressure (systolic)
The blood pressure recorded as blood is ejected during contraction phase of the heart cycle. Will be the higher value
Increased blood pressure (diastolic)
Is the blood pressure recorded during the relaxation phase of the heart cycle. Will always be the lower value
Increased blood pressure
More blood is being pumped out per beat/minute and therefore it causes an increase in pressure.
Increased Q equals an increase in blood pressure.
Arteries vasodilate= more blood draining from arteries into the capillaries.
Redistribution of blood flow
The redirection of blood away from areas where it’s not needed (kidney) to areas where it is needed (working muscles)
Rest: 15-20% goes to working muscles 75-80% goes to vital organs
Exercise: 80-90% goes to working muscles 10-20% goes to vital organs
Decreased blood volume
The amount of volume of blood decreases a a consequence of sweating.
Caused by a decrease in plasma volume due to sweating, depends on intensity, duration and environmental factors
Increased a-VO2 difference
To increase amount of oxygen that is delivered and used by the working muscles to produce energy aerobicaly.
Physical exercise leads to increase in a-VO2 difference. As exercise intensities increase the muscles increase the amount of oxygen they extract from the blood and this results in further increase in a-VO2 difference.
A trained athlete has a lower a-vo2 difference at rest and exercise.
Muscular system
Where muscle contractions occur which allow movement of the skeleton.
For exercise to begin the muscular contractions are responsible for movement and need to increase.
The type of contraction, the force and the speed are controlled by central nervous system.
Increased muscle unit recruitment
Increased motor neurone firing and the muscle fibres it stimulates.
Exercise= increase in amount of force dev.oped in working muscles. To do this more motor units need to be recruited.
Strength and speed dictate the amount of motor units required.
Motor units will contract maximally or not at all.
Acute responses to exercise
Respiratory
Cardiovascular
Muscular
Increased temperature
Heat is the By-product of converting chemical energy (fuel) to mechanical energy (movement).
An increase in the rate of reactions= heat production= body temperature increase.
Body stimulates sweat glands and increase blood flow to skin to keep body at a constant temperature.
Decreased energy substrate levels
ATP- immediate source of all muscular contractions.
Short supply so muscles them rely on energy substrates for fuel.
During exercise PC donates a P to ADP to resynthesise ATP.
During exercise: decrease in fuel levels within the muscle.
Glycogen decreases faster with endurance activities compared to high intensity activities due to these activities relying on more ATP AND PC for fuel.
Increased lactate production
At sub maximal exercise sharp increase in lactate, until oxygen can meet demand of the muscle and lactate removed.
At greater intensities blood lactate levels increases beyond removal lactate inflection point.
Oxygen is used to clear lactate.
Increased oxygen uptake
VO2 max= oxygen uptake
Determined by cardiac output and a-VO2 difference.
VO2= QXaVO2 difference
Arteriovenous oxygen difference
Difference in oxygen concentration in the arteries compared to the venuoles.
Body temperature
A change in the internal temperature in the body
Blood pressure
The pressure exerted by the blood against the walls of the arteries.
Cardiac output
The amount of blood pumped out of the heart in one minute
Diastolic blood pressure
Pressure in the arteries when the heart relaxes and ventricles fill with blood.
Diffusion
The movement of molecules from an area of higher concentration to one of a lower concentration.
Heart rate
The number of times the heart beats in one minutes.
Lactate inflection point (lactate threshold)
The exercise intensity beyond which lactate production exceeds removal.
Motor unit
A motor neuron and the muscle fibres it stimulates
Oxygen uptake
The amount of oxygen transported to, taken up by and used by the body for energy production.
Respiratory rate
The number of breaths taken in one minute
Stroke volume
The amount of blood ejected by the left ventricle per beat
Systolic blood pressure
Pressure in the arteries following contraction of ventricles as blood is pumped out of the heart.
Tidal volume
How much air is inspired and expired in one breath.
Vasoconstriction
A decrease in the diameter of the blood vessel, resulting in a decrease in blood flow to the area supplied by the blood vessel.
Vasodilation
An increase in the diameter of the blood vessel, resulting in an increase in blood flow to the area supplied by the blood vessel.
Venous return
The amount of blood that is returned back to the heart via the veins
Ventilation
How much air is breathed in or out in one minute
VO2 Max
The maximum amount of oxygen transported to, taken up by and used by the body for energy production.
