CVS Flashcards
What is systole
The contraction phase
What is diastole
the relaxation phase
What is the systemic circuit
Peripheral (all around the body)
left ventricle to right atrium
What is the pulmonary circuit
lung circuit
right ventricle to left atrium
Differences in cardiac muscle compared to skeletal muscle
Cardiac muscle has:
Intercalated discs and gap junctions
All electrically coupled cells
What is the foramen ovale what does it turn into
Hole between right and left ventricles in a foetus
turns into fossa ovalis
What causes the foramen ovale to close
Increase in pressure in the left atrium
Layers of the heart from outermost to innermost
Fibrous pericardium Parietal pericardium Pericardial fluid visceral pericardium (aka epicardium) cardiac muscle (myocardium) connective tissue and endothelium (endocardium)
What does the fibrous pericardium do
anchors the heart in the mediastinum and protects heart from trauma
What is the main pathology that affects the pericardium
Pericarditis
What is pericarditis? What does it present as? How to treat it
is: inflammation of pericardium
Present as: sharp, pleuritic (stabbing pain when inhaling/exhaling), usually made worse by lying flat
Treat: non-steroidal anti-inflammatory drugs
What is a common complication with pericarditis
effusion of the pericardial cavity
Where is the mitral valve located
Between the left atrium and left ventricle
What are the atrioventricular valves
Mitral and tricuspid valve between the atrium and ventricles
What are the chordae tendinae
chord like connective tissue and elastin tendons
What are the semilunar valves
Pulmonary and aortic valves (tricuspid valves)
What is S1 and what is it generated by
First heart sound
generated by the closure of atrioventricular valves
What is S2 and what is it generated by
Second heart beat
Generated by the closure of semilunar valves
What is the sinus venosus
Comes before primitive atrium
part of it forms the coronary sinus
also forms the sinoatrial node
What is the coronary sinus
vein that contains deoxygenated blood from the myocardium before draining into the right atrium
What is the primitive ventricle
separated from the primitive atrium by the atrioventricular canal
Gives rise to part of the left ventricle
When are chambers of the heart formed
during the fourth/fifth week after conception
What are intercalated discs
adhering structures that hold individual cardiomyocytes to form functional syncytium
What is a syncytium
single cell containing multiple nuclei
What are t-tubules
inside out bits of sarcolemma which allow depolarisation of the membrane
In a normal heart where does the electrical activity arise from
the sinoatrial node
What is the sinoatrial node known as
the physiological pacemaker
What are the atria and ventricles insulated by
the annulus fibrosus
What does the atrioventricular node act as ? Why?
“a relay station”; has a slow conduction velocity to allow atria to contract
What does the Bundle of His divide into
The right and left bundle branches
What do the bundle branches divide into
the purkinje fibres
what is a moving dipole
a pair of equal and opposite electrical charges separated in space
How to measure heart rate with the RR interval
HR(bpm)=60/RR(s)
How to get the RR value from intervals
RR=TQ + QT
What is the Valsalva manoeuvre
forced expiration against a closed glottis (straining)
What happens to a person doing the Valsalva manoeuvre
face may become red, jugular veins may become exposed, can experience dizziness
Describe where lead I electrodes go
negative electrode: right arm
positive electrode: left arm
earth electrode: right leg
Describe where lead II electrodes go
negative electrode: right arm
positive electrode: left leg
earth electrode: right leg
Describe where lead III electrodes go
negative electrode: left arm
positive electrode: left leg
earth electrode: right leg
What does the TQ interval mean
measure of ventricular diastole
What does the QT interval mean
measure of ventricular systole
What does the P wave represent
atrial depolarisation
What does the QRS complex represent
ventricular depolarisation
What does the T wave represent
ventricular repolarisation
When is your blood pressure lowest? highest?
lowest when you’re asleep
highest when you get up after just waking up
what is dynamic exercise? what happens to BP when doing it
Alternating between contraction and relaxation
systolic pressure increases (cardiac output)
diastolic pressure may decrease (fall in total peripheral resistance)
What is static exercise? What happens to BP when doing it
sustained hand grip
both systolic and diastolic increase
What is autorhythmicity? what has it? what is another name for it
how cardiomyocytes are able to fire action potentials without nervous input
sinoatrial node has it (as the pacemaker)
another name: myogenic
What does sinus rhythm mean
normal heart rhythm
Where is the sinoatrial node located
in the posterior wall of the right atrium
How are the cells specialised in the SAN
less polarised than other cells
What are chronotropic factors
factors that effect heart rate
What do positive chronotropes do
increase heart rate (treat bradycardia)
What is sinus tachycardia
sinus rhythm of more than 100bpm
what can sinus tachycardia be a normal response to
response to exercise, anxiety and pain
what can sinus tachycardia be a sign of
shock, infection or acute respiratory failure
What is sinus bradycardia
sinus rhythm of less than 60bpm
When is sinus bradycardia normal
with trained athletes or during sleep
What is starlings law of the heart
the energy of contraction of a cardiac muscle fibre is proportional to the initial fibre length at rest
How does the sympathetic nervous system control the heart
it accelerates heart rate, speed of conduction and strengthens contractions
postganglionic neurotransmitter is noradrenaline
works via β-adrenoreceptors
How does the parasympathetic nervous system control the heart
Slows the heart rate, and conduction time
postganglionic neurotransmitter acetylcholine
work via muscarinic receptors
What does contractility mean
energy of contraction independent of fibre length at rest
What does positive inotropy mean/give some examples
increased contractility
noradrenaline, adrenaline, digoxin
What does negative inotropy mean/give some examples
decreased contractility
β-blockers, Ca2+ channel blockers
What does positive luisotropy mean
increased rate of relaxation
How do you measure cardiac output (Q) in an equation
(mean arterial pressure (MAP)-central venous pressure (CVP))/total peripheral resistance (TPR)
What is the rate of blood flow directly related to
the pressure difference
What is the rate of blood flow inversely related to
resistance in the system
What is the resistance of a vessel inversely related to
its radius (small radius=large resistance)
When does turbulent blood flow occur
when flow is disrupted
What is a bruit
a vascular sound resembling heart murmurs
Where are common signs for bruits
over the femoral arteries, carotid arteries and renal arteries
What is bolus flow
in capillaries when red blood cells travel with a little bit of plasma (bolus) between them
What are vascular myocytes
vascular smooth muscle cells
Describe vascular myocytes
spindle shaped non-striated involuntary muscle cells joined by gap functions contain a single nucleus
What are caveolae
invaginations (inside out bits) of cell membrane which increase surface area and facilitate movement of calcium from extracellular fluid for contraction
What is vascular smooth muscle contraction reliant upon
rise in intracellular calcium concentration
What is vascular smooth muscle contraction caused by
phosphorylation of myosin
What are the four most important hormones in regulating vascular tone
adrenaline (epinephrine)
Vasopressin (an ADH)
Angiotensin II
ANP
Name a few vasoconstrictors
Noradrenaline/adrenaline Endothelin Angiotensin Vasopressin Thromboxane A2
Name a few vasodilators
Adrenaline/noradrenaline Adenosine Bradykinin Prostacylcin Nitric oxide
What is microcirculation
delivery of oxygen and other nutrients to the tissues and removal of CO2 and other waste products
What are three local factors that affect blood flow at capillary level
autoregulation
metabolic byproduct vasodilators
local vasoactive hormones
What is a haemorrhage
loss of blood from the cardiovascular system
what is hypovolaemia
reduction in blood volume
What does hypovolaemia produce
a decrease in mean arterial pressure
Where are baroreceptors located
in the carotid sinus and aortic arch
Where do baroreceptors relay information
to the vasomotor (central processor) in the medulla
Give two equations for mean arterial pressure
Mean arterial pressure (mmHg)= cardiac output (l/min) x total peripheral resistance (mmHg/l/min)
Mean arterial pressure (mmHg) = diastolic pressure (mmHg) + 1/3 pulse pressure (mmHg)
Equation for pulse pressure
Pulse pressure (mmHg) = systolic pressure (mmHg)-diastolic pressure (mmHg)
Equation for cardiac output
cardiac output (l/min)= heart rate (bpm) x stroke volume (l)
What does HR stand for
heart rate
What does ABP stand for and how is it recorded
arterial blood pressure
recorded from a catheter inserted into a peripheral artery
What does PAP stand for and how is it recorded
pulmonary arterial pressure
recorded by a catheter inserted via venous system through the right side of the heart and into the pulmonary artery
What is CVP and how is it recorded
central venous pressure
recorded from a catheter inserted into the venous system until its tip is situated at the junction of the right atrium and superior vena cava
What is CO and how is it recorded
cardiac output
recorded by a rapid injection of a known amount of cold saline into the right atrium
What are spaces in the body that can hold enough blood to cause death
pleural space
abdominal cavity
mediastinum
retroperitoneum
What are the signs of stage 4 shock
extremities cold to the touch "thready" pulse may be cyanotic due to hypoxemia sweating results in moist, clammy feel digits will have severely slow capillary refill time decrease in urinary output
What is the average life span of a red blood cell
120 days
what’s the other name for a red blood cell
erythrocyte
What is erythropoiesis
production of red blood cells
Where is the site for erythropoiesis in a foetus
the liver
Where are the sites for erythropoiesis in children
all bones with red bone marrow
liver and spleen
Where are the sites for erythropoiesis in adults
ends of long bones skull vertebrae ribs sternum pelvis liver and spleen
what stem cells do red blood cells come from
haemopoietic stem cells
How would you listen to the aortic valve
put stethoscope over second right intercostal space to the right hand side of the sternum
How would you listen to the pulmonary valve
put stethoscope over the second left intercostal space to the left hand side of the sternum
How would you listen to the right tricuspid valve
place stethoscope over the left fifth intercostal space just to the left hand side of the sternum
How would you listen to the mitral valve
place stethoscope over the left fifth intercostal space on the mid-clavicular line
How would you palpate the carotid pulse
in the neck between the anterior border of the sternoclastoid muscle lateral to the thyroid cartilage
How would you palpate the brachial pulse
at the elbow medial to biceps brachii aponeurosis
How would you palpate the radial pulse
at wrist lateral to the flexor carpi radials tendon (in the supinated position)
How would you palpate the ulnar pulse
at wrist lateral to flexor carpi ulnaris tendon (medial aspect of the arm)
How would you palpate the femoral pulse
located at the mid-inguinal point
How would you palpate the popliteal pulse
can be difficult to palpate
located deep in the fossa
best felt with knee passively flexed
How would you palpate the posterior tibial pulse
at ankle posterior and slightly inferior to the medial malleolus
How would you palpate the dorsals pedis pulse
felt on the dorsum of the foot lateral to extensor hallucis longus tendon distal to navicular bone
What us JVP and what is it used to measure
jugular venous pressure
allows us to measure pressure within the right atrium
When taking a pulse measure what four things should you be looking for
rate
rhythm
volume
character
What is meant by rate when measuring a pulse
number of pulses occurring per minute
What is meant by rhythm when measuring a pulse
pattern or regularity of pulses
what is meant by volume when measuring a pulse
perceived degree of pulsation
What is meant by character when measuring a pulse
an impression of the pulse waveform or shape
What artery should you use to measure rate and rhythm when measuring a pulse
radial artery
What arteries should you use to measure volume and character when measuring a pulse
brachial
carotid
femoral
What is the third heart sound caused by
rapid ventricular filling
When does third heart sound occur
0.1 seconds after the first heart sound
When is the fourth heart sound heard
just before the first heart sound
What is the fourth heart sound caused by
caused by stiff ventricles
When listening for murmurs, what side of the stethoscope should you use to listen for high pitched sounds? low pitched?
high pitched: diaphragm
low pitched: bell side
What should you do to help you hear a patient with mitral stenosis
turn them on their left hand side
What should you do to help you hear a patient with aortic regurgitation
sit patient up
ask them to lean forward
breathe out and hold their breath
What are the features of a murmur (SCRIPT)
Site where murmur is loudest Character (soft?crescendo?) Radiation (to carotids?) Intensity (grade of murmur) Pitch (high?low?) Timing (systolic? diastolic?)
Describe the grades of murmurs 1-6
1: difficult to hear
2: quiet
3: easy to hear
4: easy to hear with palpable thrill
5: hear murmur with stethoscope barely touching their chest
6: hear murmur with stethoscope off chest
What is hypertrophy
Where heart muscle thickens into the chambers and outside the heart
What is dilatation
Where heart muscle gets thinner and expands
what is mitral stenosis
Where the mitral valve becomes narrowed
What does mitral stenosis result in
Atrial hypertrophy
What is mitral stenosis caused by
rheumatic heart disease
infective endocarditis
What does mitral stenosis sound like
mid-diastolic low pitched rumbling murmur
get a loud S1 because of thick valves
(Sounds like LUB DUB DRRR)
What is mitral stenosis associated with
with malar flush (flushed cheeks)
and atrial fibrillation
What is mitral regurgitation
incompetent mitral valve allows blood to flow back through during systole
What does mitral regurgitation sound like
high pitched whistling murmur
(Because of high velocity of blood flow through leaky valve)
sounds like BRRRRRRRRR
What are some causes of mitral regurgitation
idiopathic weakening with age ischaemic heart disease infective endocarditis rheumatic heart disease connective tissue disorders
What is aortic stenosis
narrowing of aortic valve
What does aortic stenosis cause
ventricular hypertrophy
slow rising pulse
narrow pulse pressure
exertion syncope (light headed/fainting with exercise)
What are some causes of aortic stenosis
idiopathic age related calcification
rheumatic heart disease
What is aortic regurgitation
where the aortic valve becomes incompetent
What does aortic regurgitation sound like
diastolic soft murmur
LUB TARR
What causes aortic regurgitation
idiopathic age related weakness
connective tissue disorder
