Cardiology Flashcards
What is a pulse?
Rhythmic expansion of an artery, which corresponds to each contraction of the left ventricle
What is the heart rate?
Speed of the heart contractions
What is stroke volume?
Volume of blood pumped out of the ventricles with each heart beat
What is total peripheral resistance?
The amount of force exerted on circulating blood by the vasculature of the body
What are the 3 factors that affect TPR/SVR?
Autonomic activity - sympathetic nervous system (vasoconstriction)
Blood viscosity - increased thickness of blood leads to increased TPR
Medications - vasoconstrictor and vasodilator drugs
What is cardiac output and how is it calculated?
The amount of blood the heart pumps each minute
Stroke volume X heart rate
What happens to cardiac output if the body needs more oxygen?
It will increase so that more oxygen is available throughout the body
It does this by increasing HR and SVR through vasoconstriction (this increases blood pressure)
What are the stages of the cardiac cycle?
Atrial systole
Ventricular systole
Diastole
What is an ECG?
A scan that records the electrical signals in the heart
Looks at heart rate, rhythm and electrical activity
Can indicate enlargement of the heart (cardiomyopathy) and evidence of a previous heart attack
Sensors attached to skin detect electrical activity
What can ECGs tell us?
Heart rate and rhythm
Abnormalities such as lack of P wave or arrhythmias (irregular beats)
Evidence of damage (MI/ischemia)
Raised, depressed, flipped or flat ST waves - evidence of ischaemic heart damage
What is blood pressure?
Blood pressure is a measure of the force that moves blood around your body
Generated by the heart beat
The force of blood pushing against the walls of your arteries is what is measured
What factors does blood pressure measurement involve?
Cardiac output
Total peripheral resistance
How is blood pressure controlled in the short term?
Via the baroreceptor receptors found in the carotid sinus and the aorta
Changes in blood pressure, and vasoconstrictor or dilate vessels as required - innervates the parasympathetic nervous system (vasodilation and slow HR) or sympathetic nervous system (vasoconstriction and increase HR)
How is longer term blood pressure controlled?
Renin-Angiotensin-Aldosterone System (RAAS)
A hormonal system that controls BP
What are the stages of the RAAS?
Renin
Angiotensin 1
Angiotensin 2
Aldosterone & ADH
Where is renin released from?
The kidneys into the blood
Where is angiotensin released from?
The liver