PBL Flashcards
what initiates the excitement of the heart
sino-atrial node
what does stroke volume respond to changes in
pre-load and after load (frank-starling curve)
what heart conditions can inherited
cardiomyopathies, inherited arrhythmias (LQTS, brugada), very high cholesterol levels
what should waist circumference be for men and women
men less than 94cm
women less than 80 cm
what should BMI be
18.5-24-9 healthy
more than 30 = obese
what are the three layers of the pericardium and which one is in contact with the heart
outermost- fibrous, parietal serous, visceral serous- innermost in contact with the heart
what is between the serous layers of the pericardium
pericardial space filled with pericardial fluid
where are the semilunar valves of the heart
at the base of the great vessels
where do most of the coronary veins drain into
the coronary sinus which drains into the right atrium
where are baroreceptors located and what are they sensitive to
located in the walls of the large arteries and are stretch receptors which are sensitive to changes in pressure
how do baroreceptors respond to changes in blood pressure
cause reflex changes to bring blood pressure back to normal
how does an increased arterial BP affect the medulla
an increased arterial BP causes an increase in action potential frequency to the cardio-regulatory centres in the medulla, causing an increase in parasympathetic activity to the heart, decreasing HR and force of contraction
how do chemoreceptors maintain BP
by monitoring blood oxygen, CO2 and pH. if decreased O2 or pH or increased CO2 or pH the chemo-receptors will cause a decrease in para symp stim
what are the natural mechanisms for long term BP maintenance
pressure natriuresis, RAA mechanism, ADH mechanism and natriuretic peptide hormone
what is pressure diuresis
increased urine output due to high arterial pressure- decreases blood volume
what is pressure natriuresis
increased sodium output due to high BP- decreases blood volume
what is the RAA mechanism and how does it control BP
renin-angiotensin-aldosterone
regulates kidney function which affects peripheral resistance, blood volume and blood pressure
when is renin secreted and from where
released from kidney when BP is reduced
what is the role of renin
cleaves protein angiotensin to angiotensin 1 which is later cleaved to angiotensin 2
also acts on adrenal cortex to secrete aldosterone which acts on kidney tubules to increase reabsorbtion of sodium- increasing blood volume
what does angiotensin 2 do
constricts arterioles and veins to increase venous return to the heart and increase arterial BP
what is ADH and when is it released
anti-diuretic hormone
when baroreceptors detect decrease in arterial blood pressure
what does ADH do
acts directly on blood vessels causing vasoconstriction and increases water absorption by the kidneys - increasing BP
what releases natriuretic peptides and when
synthesised by the heart, brain and other organs
released in response to cardiac distension or neurohormonal stimuli
what do natriuretic hormones do
cause excretion of salt and water in the kidneys - reducing blood volume
also decrease renin release and act as vasodilators
what are ‘gallop’ heart sounds
low frequency sounds associated with diastolic filling
where do you measure waist circumference and what does it show
between lower rib and iliac spine
distribution of fat
what are the normal ranges for cholesterol
LDL below 5
HDL above 1
what are the clinical signs of hypertension
loud aortic second sound, prominent left ventricular impulse, fourth heart sound, hypertensive retinopathy
describe the grading of hypertensive retinopathy
grade 1 slight narrowing
grade 3 exudates or flame haemorrhages
grade 4 optic nerve oedema
why is being female important in CV history
menopause, combined oral contraceptive pill