lecture 1 - the cardiovascular system Flashcards
blood pressure
force of blood against arterial wall during cardiac cycle
formula for blood pressure
cardiac output x total peripheral resistance
systolic blood pressure
work of heart and force blood exerts against arterial wall during systole
diastolic blood pressure
work of heart and blood that flows throughout the heart during diastole
mean arterial pressure
average force exerted by blood against arterial wall during cardiac cycle
formula for mean arterial pressure
DBP +[0.333 (SBP - DBP)]
what regulates an individuals blood pressure?
the medulla oblongata
how does the body respond to a rise in blood pressure
- increased parasympathetic activity
- decrease sympathetic activity
- decrease heart rate
- increase arterial diameter
how does the body respond to a drop in blood pressure
- baroreceptors inbilited
- increase parasympathetic activity
- increase heart rate and contractile rate
- vasoconstriction
- adrenal gland increase epinephrine secretion
long term regulation of blood pressure
- renin activates angiotensin = aldosterone release
- aldosterone increase sodium absorption and water retention
- ADH released, which causes water retention
blood pressure response to resistance training
an increase in demands of the body = increased blood pressure
What is the heart’s blood supply
Coronary Circulation
What is the heart’s blood supply while at rest
myocardium extracts 70-80% of oxygen from the blood
what fuels myocardial energy
glucose, fatty acids and lactate
myocardial fuel at moderate intensity
glucose more heavily
myocardial fuel at intense exercise
lactate increases as it is produced and broken down for energy
steps of the cardiac cycle
- impulse originate from SA node in RA and spread across atria
- impulse pass through atrioventricular node to 2 branches; right and left crus, then into ventricles
- dissipation of impulse cause atria and ventricles to relax or dilate
explain the steps of an ECG
- P wave - atrial depolarisation
- P-R interval - impulse moves from atria to ventricles
- QRS - ventricular depolarisation
- S-T segment - ventricular repolarisation
- T wave - ventricular repolarisation
describe the physical factors that affect blood flow
capillaries that are open during exercise and rest
what occurs during the opening of closed capillaries during exercise
- increase total muscle blood flow
- deliver large blood volume with only minimal increase in flow velocity
- increase surface area and nutrient exchange
