Cardiovascular and Respiratory Systems Flashcards
What is the equation for Cardiac Output?
SV x HR = Q
At submaximal levels HR will … when a steady state is reached and O2 demand is met.
Plateau
What is Bradycardia?
Having a heart rate of <60bpm
What is the resting stroke volume for a trained heart?
90-110ml
‘Relaxation of the atria and ventricles’, is the definition of what?
Diastole
What is the average resting stroke volume?
72ml
Explain what happens to your heart rate after exercise
- There is an initial rapid drop due to less O2 demand
- Gradual decrease to repay oxygen debt
Define Stroke Volume
The volume of blood pumped out of the left ventricle of the heart during each contraction of the heart.
What is the average resting heart rate?
72bpm
… is the return of blood to the right side of the heart via the vena cava
Venous return
‘The contraction of the heart, pushing blood out and into the large blood vessels of the cardiovascular system?’, is the definition of what?
Systole
Define Starling’s Law
A decrease in Venous Return = A decrease in stroke volume, which = a decrease in Q
AND
An increase in Venous Return = An increase in stroke volume, which = an increase in Q
What is the resting stroke volume for an untrained heart?
60-90ml
What is an ejection fraction?
An ejection fraction of X% means that there is X% of blood remaining in the heart after a contraction.
What happens to heart rate during steady state exercise?
It Plateaus
Describe the changes in heart rate experienced after exercising.
Initial steep drop due to less oxygen demand
Followed by a gradual decrease to repay the oxygen debt.
What does a motor unit consist of?
A motor neuron and muscle fibers
Put the following in order:
AV Node,Purkinje fibers, SA Node, Bundle of HIS
SA,AV,Bundle Of HIS, Purkinje Fibers
What sends a wave of polarisation to the AV node?
SA node
What are the 5 mechanisms assisting venous return?
Gravity, Pocket Valves, Smooth Muscle, Respiratory Pump, Skeletal Muscle pump
At rest, how much blood is distributed to the muscles?
15-20%
What do chemoreceptors control?
Blood chemistry (PH levels, CO2, Lactic acid)
During exercise, how much blood is distributed to the muscles?
80%
What does VCC stand for and where is it located?
Vasomotor Control Centre
Medulla Oblongata
What are the breathing rates of a trained and untrained athlete?
Trained: 11/12
Untrained: 12-15
What do baroreceptors control?
Blood Pressure, Temperature
What do proprioceptors control?
Detect movements in joints and muscles, leading to an increased O2 demand.
During Exercise, working muscles undergo vaso…
dilation
During rest, other organs undergo vaso…
dilation
What circular muscles constrict to cause the vascular shunt mechanism?
pre-capillary sphincters
What does the following describe:
Veins run through skeletal muscles, when muscles contract, more blood is pumped through the veins and venous return is increased.
A skeletal Muscle Pump
Explain the function of the respiratory Pump
Respiratory Muscles contract, this increases pressure and squeeze blood back to the heart.
How does gravity impact venous return?
Blood from superior vena cava (upper body), will fall back to heart with support of gravity.
Same process applied to lower body if body inverted
What mechanism helps venous return by pulsing and hence increasing blood pressure?
Smooth Muscle
Two ways oxygen can be transported
Through Haemoglobin
Through Plasma
3 ways CO2 can be transported
Plasma
Water
Haemoglobin
What is gaseous exchange?
The movement of gases across a membrane
The pressure a gas exerts within a mixture of gases is referred to as…
Partial pressure
Gases always move from… areas of PP to … areas of PP
High to Low
Where is PP02 high and low?
High in Alveoli
Low in Muscles
Where is PPCO2 high and low?
Low in Alveoli
High in Muscles
Explain how the diffusion gradient changes in exercise?
More CO2 in muscles
Less 02 IN muscles
Concentration Gradient increases
What is the BOHR effect?
Shift of Dissociation curve to the right.
What is dissociation?
The detachment of Hb from O2 when oxygen is provided to muscle tissues