cardiovascular physiology Flashcards
what is the stroke volume?
a) blood remaining the ventricle after systole
b) blood in the ventricle at end diastole
c) blood volume at end diastole+ blood volume at end systole
d) blood volume at end diastole- blood volume at end systole
C. the amount of blood ejected from the heart
what is the ejection fraction?
a) (stroke volume/ end diastolic volume) x100
c) blood volume at end diastole+ blood volume at end systole
d) blood volume at end diastole- blood volume at end systole
the amount of blood ejected compared to the amount that was there in the first place
XX% of ventricular filling occurs due to atrial contraction.
a) 10%
b) 20%
c) 30%
d) 50%
B.
There is continuous flow of blood into the atria from the great veins, 80% of which passes
straight into the ventricles. Only 20% of ventricular filling results from atrial contraction.
blood flows due to XXX from areas of high pressure, to areas of low pressure
pressure gradients
momentum is also important for the third stage of systole, where there is reduced ejection – pressures drop off as blood is ejected as they pass their peak systolic values.
Ventricular pressures actually fall below aortic but blood still flows due to
momentum
match up the pressures with the most correct values:
a) systolic aortic pressure
b) diastolic aortic pressure
c) systolic pulmonary artery pressure
1) 120mmHg
2) 3mmHg
3) 60mmHg
4) 80mmHg
5) 98mmHg
6) 130mmHg
– Systolic aortic pressure – 120 mmHg
– Diastolic aortic pressure – 80 mmHg
– Mean aortic pressure – 98 mmHg
– Pressure in CVC – 3 mmHg
– Systolic pulmonary artery pressure – 20 mmHg
– Diastolic pulmonary artery pressure – 8 mmHg
– Mean pulmonary artery pressure – 13 mmHg
– Pulmonary vein pressure – 5 mmHg
what is isovolumetric relaxation?
a) when the aortic valve remains closed until the pressure in the left ventricle exceeds that in the aorta during systole
b) when systolic pressures rise above aortic pressures the aortic valves open and
there is a rapid ejection of blood.
c) when pressures in the LV fall below LA opening the mitral valve and starts
ventricular filling - rapid ventricular filling
d) when the Mitral valve remains closed during early diastole, and no filling occurs until the LV pressures drop below LA
D
A is isovolumetric contraction
what is diastasis?
a) reduced passive ventricular filling as LV pressure increases
b) when systolic pressures rise above aortic pressures the aortic valves open and
there is a rapid ejection of blood.
c) when pressures in the LV fall below LA opening the mitral valve and starts
ventricular filling - rapid ventricular filling
d) when the Mitral valve remains closed during early diastole, and no filling occurs until the LV pressures drop below LA
A
regarding the electrocardiography, what occurs during the p wave?
represents atrial depolarisation therefore occurs in mid to late diastole and
precedes atrial contraction.
regarding the electrocardiography, what occurs during the qrs complex?
represents ventricular depolarisation therefore immediately
precedes ventricular contraction and hence systole (this tends to obscure evidence of
atrial repolarisation). as the qrs occurs, that is the end of diastole
regarding the electrocardiography, what occurs during the t wave?
represents ventricular repolarisation hence occurs in the second half of
systole.
which phrase describes preload?
a) the load against which the muscle exerts its force
b) the degree of tension on the muscle when it starts to contract
c) the volume of blood pumped out of the heart’s left ventricle during each systolic cardiac contraction
B. the amount of blood in the ventricles at the end of diastole (before contraction), essentially the stretch on the heart muscle before it contracts. It’s one of the three main factors influencing stroke volume (along with afterload and contractility) and is directly related to venous return.
a is after load
c is stroke volume
systole occurs…
a) when you hear s1
b) between s1 and s2 heart sounds
c) when you hear s2
d) between s2 and s1
B
s1- closure of AV valve then ventricles start to contract
s2- closure of semilunar valves at the end of sytole
Murmurs due to mitral valve disease are..
a) continuous with varying intensity
b) holosystolic
c) mid diastolic
d) early diastolic
B
left apical
murmurs due to a PDA are…
a) continuous with varying intensity
b) holosystolic
c) mid diastolic
d) early diastolic
A- left heart base As the pressure within the aorta always exceeds that within the PA, this condition results in a continuous murmur – however with variable pressures during the cardiac cycle the murmur will vary in intensity (machinery murmur)
Later in the disease course, the diastolic component of the murmur may decrease or
disappear due to the development of pulmonary hypertension
a systolic murmur loudest on the right is most compatible with…
a) MVD
b) HCM
c) tricuspid regurgitation
d) pulmonic stenosis
C
what changes are expected on radiographs in a case of PDA?
- left to right shunt
-enlarged pulmonary arteries and pulmonary veins due to increased volume and pressure in the pulmonary circulation- vascular pattern
-increased size of the LA (eccentric due to volume) and LV (eccentric and concentric due to volume and increased work due to low systemic perfusion) - MPA bulge
- prominent aortic arch
- possible pulmonary oedema due to volume overload
- triple knuckle appearance.
right to left shunting (reversed PDA)
- pulmonary hypertension
In severe cases may give peritoneal as well as pleural effusion.
– an anomaly where blood flows from the right to the left side of the heart, thus failing to flow through the pulmonary circulation.
– Typically these result in early cyanosis, due to lack of oxygenation of the blood
what changes are expected on radiographs in a case of Pulmonic stenosis?
- dilated MPA bulge
- enlarged RV caused by hypertrophy related to increased resistance associated with blood ejection
pulmonary vessels normal, or small in very severe cases with hyperlucent lungs
possible signs of right sided heart failure- enlarged liver, ascites, pleural effusion
which type of PDA is most commonly associated with pulmonary hypertension/ eisenmengers sydrome?
Type I- gradually tapering from the aorta to the pulmonic trunk
type II- abrupt narrowing prior to the pulmonic trunk (IIA and IIB- slight variation)
type III- tubular/ cylindrical
type III
aortic stenosis/ regurgitation:
a) reduces stroke volume
b) increases stroke volume
A
-In stenosis this allows the ventricle to develop a much increased internal
pressure, and hence a much increased pressure difference across the stenosed
valve, helping to maintain flow initially.
- In regurgitation the LV chamber also dilates, which combined with the
hypertrophy allows for a much greater stroke volume (though as much as ¾
of this may regurgitate)
which if these is not a predisposed breed to aortic stenosis?
a) boxer
b) GSD
c) Irish wolfhound
d) golden retriever
C
other predisposed dogs- dogue de bordeaux, Newfoundland, bull terriers
aortic stenosis is usually…
a) subvalvular
b) valvular
c) supravalvular
A- subaortic stenosis
the disease progresses as they grow and so at risk breeds should not be screened till 12 months old. but can be diagnosed earlier if clinical
pulmonicic stenosis is usually…
a) subvalvular
b) valvular
c) supravalvular
B
what radiographic changes can be seen with more severe aortic stenosis
mild form- no changes as concentric hypertrophy of the ventricle rarely alters the silhouette
moderate and severe cases- aortic bulge or prominent ascending aorta, cardiomegaly, occasional left atrial enlargement, if severe this suggests concurrent mitral regurg/ dysplasia. pulmonary edema and pulmonary venous congestion if in heart failure
what is the most common congenital cardiac disease in cats?
endocardial cushion defects- VSD. also common in dogs
mitral valve dysplasia is also seen commonly in cats
atrial septal defects are almost always…
a) right to left shunting
b) left to right shunts
B unless there is another reason for flow reversal.
most are insignificant and treatment is not usually necessary.
show can mitral valve dysplasia and mitral valve stenosis look different radiographically
in MS the LA will be big but the LA will be normal. in dysplasia both will be big.
the most common cause of cyanotic cardiac disease in young dogs and cats is?
a) mitral valve dysplasia
b) tetralogy of fallot
c) pulmonic stenosis
d) PDA
B
D- caudal preferential cyanosis
what are the primary abnormalities in tetralogy of fallot
pulmonic stenosis (failure of development of the conotruncal septum, leading to hyperplasia or atresia of the pulmonic trunk) and a supracristal VSD which enters the RV at the RVOT, but is beneath the aortic valve leaflets on the left side.
dextroposition/ overriding aorta
which way does blood shunt in tetralogy of fallot?
right to left through the vsd due to pulmonic stenosis
what are the radiographic features of tetralogy of fallot?
small to normal sized heart, rv concentric hypertrophy occasionally seen, possible prominent aorta, hypervascularity of the lungs, hyperinflation of the lungs
where do the coronary arteries drain in to?
a) left atrium
b) right atrium
c) azygous vein
d) right ventricle
B (mostly) from the coronary sinus
a persistent left vena drains in to the coronary sinus
an accessory right coronary artery is preseent in how many dogs?
a)15%
b) 20%
c) 40%
d) 45%
B
which branch of the coronary arteries is this?
a) left circumflex
b) right
c) paraconal
C
which part of the coronary anatomy is this?
a) left circumflex
b) right
c) paraconal
d) coronary sinus
D
circumflex is smaller below it
heart rate has what effect on coronary blood flow
increase
or decrease?
decrease, as most supply is in diastole
using starlings law, the greater the preload of the heart, the XXX force of contraction?
greater.
Energy of contraction is proportional to the initial length of the cardiac muscle fibre - in the heart, the length of the muscle fibres (i.e. the extent of the preload) is proportional to the end-diastolic volume. In fact, under most conditions (i.e. up to a physiological maximum), the amount of blood pumped by the heart is determined almost entirely by the rate of
venous return into the heart.
Stretch of the RA wall also serves to directly increase the HR by 10-20% (via effects
on the SA node), also increasing CO - however this is of lesser importance than the Frank-Starling mechanism)
which chamber is the sinoatrial node in?
right atrum
for mitral inflow, the E to A wave ratio should be…
a) less than 1
b) 1
c) more than 1
d) more than 2
C
can become like this in supernormal state too, LA will most likely be big in this case.
more than 2- bad disease
if a small sample gate is used to assed portal velocity, you need to multiply the velocity by XX to get the mean portal velocity?
0.57.
a small gate in the middle gives the Max velocity.
how do you calculate the portal vein congestive index?
CI = portal vein cross sectional area (cm2) by average blood flow
velocity (cm/sec)
* Normal value in unsedated dogs = 0.04 ± 0.015 cm x sec
what is the most common cause of small volume pericardial effusion in cats?
a) FIP
b) lymphoma
c) CHF
C
the primary type of failure with HCM in cats is…
a) systolic failure
b) diastolic failure
c) volume overload
B but there is also systolic failure and can be some volume overload in some cases)
MMVD causes
a) volume overload, leading to LA and LV eccentric hypertrophy
b) volume overload, leading to LA and LV concentric hypertrophy
c) pressure overload, leading to LA and LV eccentric hypertrophy
d) pressure overload, leading to LA and LV concentric hypertrophy
A
continue from 82 lymph
whic of the following contain lymph vessels?
a) brain
b) skeletal muscle
c) spinal cord
d) mucus membranes
D only.
none within the other organs mentioned
does the lymphatic system contain valves?
yes
where does the thoracic duct most commonly enter the venous system (2)?
a) coronary sinus
b) junction of the jugular and subclavian veins
c) confluence of the internal and external jugular veins
d) caudal vena cava
B and C
massive variation and should be assessed in each dog prior to sx tx of chylothorax
which vein are the mandibular lymph nodes closest to
linguofacial vein
the lateral retropharyngeal lymph node is present in what proportion of dogs?
a) 10%
b) 30%
c) 50%
d) 85%
B around 30%
lymph from the right thoracic limb and right side of the head and neck usually joint the XX before entering the XXX
a) left lymphatic duct
b) right lymphatic duct
c) thoracic duct
d) vena cava
e) heart
f) right subclavian vein
B, C/F
It receives efferent
lymph vessels from the right superficial cervical, axillary and thoracic lymph nodes. The right tracheal trunk drains into the right lymphatic duct 20-30 mm from the first rib. right lymphatic duct empties into the right subclavian vein or the angle formed by the merging of the right subclavian and right external jugular veins. The right lymphatic duct drains into the thoracic duct in 50% of dogs
the left tracheal trunk drains in to the thoracic duct.
