CVS Flashcards
Cardiovascular risk assessment
QRISK
risk of having a cardiac event in the next 10 years
Used for those up to 84 years old
Shouldn’t be used in those with CVD already or those over 85 or high risk of developing CVD
repeat every 5 years
which details are needed for QRISK assessment?
age sex ethnicity postcode clinical info - smoking status, medical and family history, systolic BP, height, weight and total cholesterol/ HDL-cholesterol ratio
what are cardiac enzymes?
released into the circulation when myocardial necrosis occurs - e.g. MI
what are the cardiac enzymes?
myoglobin
troponin
creatine kinase
myoglobin
non-specific because come from skeletal muscles
troponin
important in the contractile apparatus of cardiac myocytes
released between 3-4 hours after MI
other non-related causes of raised troponin
remains in blood for 10 days
creatine kinase
muscle enzyme that exists as isoenzymes
specific to myocardial cells
better for detection of re-infarction as remains in blood for 3-4 days but released 3-4 hours after event
regulation of BP
short term and long term
long-term regulation of BP
renin-angiotensin-aldosterone
ADH
Natriuretic peptides
prostaglandins
renin
peptide hormone released by granular cells in juxtaglomerular apparatus in kidney
what is renin released in response?
sympathetic stimulation
reduced sodium-chloride delivery to DCT
decreased blood flow to kidney
what does renin do?
converts angiotensinogen to angiotensin I which is converted to angiotensin II using angiotensin-converting enzyme -ACE.
what does angiotensin II do?
a potent vasoconstrictor that acts directly on the kidney to increase sodium reabsorption in PCT. Sodium is reabsorbed via a sodium-hydrogen exchanger
promotes the release of aldosterone
what does ACE do?
converts angiotensin I to II
breaks down bradykinin which is a potent vasodilator - potentiates constricting effects
what does aldosterone do?
promotes salt and water retention by acting at DCT to increase expression of epithelial sodium channels
increases activity of basolateral sodium-potassium ATP-ase, increasing the electrochemical gradient for movement of sodium ions
more sodium collects in kidney tissue and water follows by osmosis cause decreased water excretion and increase blood volume and BP
where is ADH released?
organum vasculosum of lamina terminalis
why is ADH released?
in response to thirst or increased plasma osmolarity
what does ADH do?
increases permeability of collecting duct to water by inserting aquaporin channels into apical membrane
stimulates sodium reabsorption from thick ascending limb of loop of Henley which increases water reabsorption which increases plasma volume and decreases osmolarity
what is another control of BP?
natriuretic peptides
Natriuretic peptides
atrial natriuretic peptide
Atrial natriuretic peptide
synthesised and stored in cardiac myocytes
released when atria are stretched which indicates a high BP
secretion is low when BP is low
what does Atrial natriuretic peptide do?
promotes sodium excretion
dilates afferent arteriole of glomerulus increasing blood flow
inhibits sodium reabsorption along nephron
Prostaglandins
act as local vasodilators to increase glomerular flow rate and reduce sodium reabsorption
act to prevent excessive vasoconstriction triggered by sympathetic nervous and renin-angiotensin-aldosterone systems
what is the pericardium?
fibroserous membrane covering the heart and parts of great vessels
composition of pericardium
closed sac
2 layers
what are the layers of the pericardium?
fibrous pericardium
serous pericardium
what are the layers of the serous pericardium?
parietal
visceral
pericardial sinuses
transverse pericardial sinus
oblique pericardial sinus
heart wall layers
endocardium
myocardium
epicardium - visceral pericardium
what are the surfaces of the heart?
anterior
diaphragmatic
right pulmonary
left pulmonary
what are the borders of the heart?
right
inferior
left
superior
what does the right atrium do?
receives deoxygenated blood from superior and inferior vena cava and coronary veins
pumps blood through right atrioventricular orifice - tricuspid valve
what is the right auricle?
right atrial appendage
what is the coronary sinus?
receives blood from coronary veins, opens between the inferior vena cava and right atrioventricular orifice.
What is the interatrial septum?
solid muscular wall separates the 2 atria.
what does the left atrium do?
receives oxygenated blood from 4 pulmonary veins and pumps through left atrioventricular orifice - mitral valve
anatomy of left atrium
left auricle extends from superior aspect of chamber
inferior surface is divided into 2
what are the divisions of the inferior surface of the left atrium?
inflow portion
outflow portion
inflow portion of left atrium
receives blood from pulmonary veins
internal surface is smooth
outflow portion of left atrium
includes left auricle
lined with pectinate muscles
what does the right ventricle do?
pumps blood through pulmonary orifice - pulmonary valve into pulmonary artery
structure of right ventricle
triangular
can be divided into inflow and outflow portions which are separated by a muscular ridge - supraventricular crest
inflow portion of right ventricle
interior part covered by irregular muscular elevations - trabeculae carnae
what are the different types of trabeculae carnae
ridges
bridges
pillars
ridges
attached along their entire length on one side to form ridges