Cardiovascular Flashcards
What receptor senses an increase in CO2 in the blood?
Chemoreceptors.
What nerve increases HR?
Accelerator nerve.
What nerve decreases HR?
The Vagous nerve.
What activates the sympathetic/ parasympathetic nervous system?
The Medulla Oblongata.
What is stroke volume?
The volume of blood pumped out of the heart during one contraction.
What is heart rate?
How many times the heart contracts per minute (bpm).
What receptor sense an increase in blood pressure?
Baroreceptors.
What receptor detects an increase in muscle movement?
Proprioceptors.
Blood PH decreases during exercise. What happens?
Chemoreceptors detect > medulla receives signal > medulla activates sympathetic nervous system > increase in HR.
Increase in muscle movement during exercise. What happens?
Proprioceptors detect > medulla receives signal > medulla activates sympathetic nervous system > increase in HR.
Increase in blood pressure. What happens?
Baroreceptors detect > medulla receives signal > medulla activates parasympathetic nervous system > decrease in HR.
Max HR formula?
220 - Age = Max HR.
What is vasodilation?
The widening of the blood vessels to increase the flow of blood.
How is blood flow controlled during exercise?
Increase in CO2 > detected by chemoreceptors > vasomotor centre is stimulated > blood is redistributed via vasodilation/constriction.
What is vasoconstriction?
The narrowing of the blood vessels to reduce blood flow.
What is vascular shunt?
When blood flow/cardiac output is redistributed to the working muscles rather than non-essential organs.
What is the Bohr shift?
When an increase in CO2 and decrease in pH in the blood results in a reduction in affinity of Hb for oxygen.
What is pH?
The measure of acidity. The scale ranges from 1-14, anything below 7 indicates acidity.
What is cardiac output?
The volume of blood pumped from the heart per minute.
What is the formula for cardiac output?
Stroke volume x heart rate.
What is cardiac hypertrophy?
The thickening of the heart’s muscular walls so it becomes bigger and stronger.
What causes cardiac hypertrophy?
Regular aerobic training.
What are the effects of cardiac hypertrophy?
Increased stroke volume > heart has to beat less to supply the same amount of blood > bradycardia > less oxygen is needed for heart contraction > more oxygen goes to working muscles.
Define bradycardia.
A decrease in resting heart rate below 60 bpm.
When does a stroke occur?
When the blood supply to the brain is cut off.
What is systolic pressure and when does it occur?
The pressure in the arteries when the ventricles are contracting. It is high.
What is diastolic pressure?
The pressure in the arteries when the ventricles are relaxing. It is lower.
HowWhat is a typical blood pressure at rest?
120mmHg/80
What is the order of conduction in the heart?
SAN > atrial systole > AVN > Bundle of His > Purkinje fibres > Ventricular systole.
What is ejection fraction?
The percentage of blood pumped out by the left ventricle per beat.
What is Starling’s Law?
Increased venous return > More diastole > Cardiac muscles stretched > More contraction force > Greater ejection fraction.
