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The Cardiac Cycle
Physiology Test 3
66
Physiology
Graduate
10/25/2011

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Term
Cardiac cycle
Definition
a set of specific events that begins with the initiation of propagated electrical activity in the SAN & includes all the events until the next action potential occurs.
Term
T/F The heart may need to pump as much as 100-150ml blood/kg body weight against pressure as high as 300mm Hg
Definition
T
Term
A unique feature of mammalian cardiovascular system is that blood is pumped through the heart __ before being distributed to the body.
Definition
twice
Term
T/F the left and right sides of the heart pump at different times to ensure cardiac cycle continues
Definition
F
Term
When the hydrolic pressure on the AV valve leaflets is higher than that on the ventricles the valves will __
Definition
open
Term
Can have some backwards flow in the __ because there is no valve here.
Definition
Vena cavae
Term
Jugular pulse
Definition
backwards flow of blood into the vena cavae during atrial contraction
Term
ventricles will contract immediately following __
Definition
atrial systole
Term
For a brief period of time at the beginning of __ the ventricular chambers are closed off at both inlets and outlets
Definition
ventricular systole
Term
You can assess the cardiovascular status in an animal by recording an ECG an preforming __
Definition
auscultation
Term
The QRS recording is triphasic because of changes in the predominate __ throughout the ventricles.
Definition
vectors
Term
QRS masks ___
Definition
repolarization of the atria
Term
It Does/Doesn't matter with phase of the ECG cycle is counted as first.
Definition
Doesn't
Term
The job of the (left/right) ventricle is to push blood at a pressure that will ensure runoff
Definition
left
Term
About how far into the P wave on an ECG will the atria contract?
Definition
three fourths
Term
The atria contract during ventricular diastole allowing them to act as __
Definition
primer pumps
Term
When pressure in the ventricles becomes greater than that of the atria the valves will __
Definition
close
Term
C wave
Definition
is sometimes seen. It is seen sometime when the AV valve closes
Term
The first phase of ventricular systole
Definition
isovlumic contraction
Term
The first phase of ventricular diastole
Definition
isovolumic relaxation
Term
Able to deliver a large amount of volume under high pressure
Definition
left ventricle
Term
The first fibers to contract in the ventricles
Definition
papillary muscles
Term
Papillary muecles pull the __ when they contract which will pull on the leaflets of the AV valve hlping to approximate them.
Definition
chordae tendineae
Term
Although the volume of the ventricle does not change during isovolumetric contraction, the __ of te ventricle does
Definition
geometric configuration
Term
The period of rapid ejection
Definition
when the ventricles are contracting they will convert some of that energy of contraction into kinetic energy and blood flow rapidly increases in botht he aorta and PA.
Term
period of rapid ejection reaches its peak just prior to the peak of __
Definition
aortic blood pressure
Term
75% of the blood leaves the ventricles during this __
Definition
period ofrapid ejection
Term
If the sympahetic system is active, this is prolonged & stores more energy in the roots of the aorts & the PA
Definition
pase of reduced ejection
Term

In the dog the pulmonary valves __ just prior to the aortic & __ just after the aortic

A. open; close

B. close; open

C. close; close

Definition
A
Term
The phase of isovolumetric relaxation begins st about the time of the aortic __ & lasts until the opening of the AV valves
Definition
incisura
Term
The phases __ & __ blend together and compromise a time during which the ventricles fill without assistance of atrial contraction
Definition

rapid ventricular filling

reduced ventricular filling

Term
reduced ventricular filling is also known as __
Definition
diastasis
Term
end-diastolic pressure
Definition
the pressure recorded just before ventricular systole
Term
The end diastolis pressure determines __
Definition
the resting tension of the ventricular musculature (& thus the force of its contraction)
Term
Sounds in the heart ar produced by __
Definition
vibrations
Term
Two most significant components of audible heart sounds
Definition
opening and closing of valves; acceleration of blood through valves
Term

Normally, mammals have __ heart sounds, as well as __ additional sounds which can be recorded.

A. 2, 3

B. 2, 2

C. 3, 2

D. 1, 4

Definition
B
Term
Allows some recorded assesment of mecanical heart events
Definition
phonocardiography
Term
First heart sound (S1)
Definition
begins with the closure of the AV valves & by the ejection of blood through the opening of the semilunar valves. The "lub"
Term
Where is it best to hear the first heart sound?
Definition
over the mitral & tricuspid areas
Term
If the first heart sound is split into two sounds, the first comes from the blood turbulence hitting which valve?
Definition
mitral
Term
If the first heart sound is split into two sounds, the second comes from the blood turbulence hitting which valve?
Definition
tricuspid
Term
Second heart sound (S2)
Definition
a short-duration high-frequency thump that occurs almost simultaneously with isovolumetric relaxation period. The "dub"
Term
Two sounds can be heard of the S2 in a dog when?
Definition
inspiration, more pressure on the thorax increases cardiac return
Term
During inspiration in a dog, the right ventricle receives extra volume which makes its ejection take longer, thus prolonging the __ to remain open longer
Definition
pulmonic valve
Term
Ventricular systole lies during what period of time when considering heart sounds
Definition
between S1 & S2
Term
Occurs as the atrial pressure begins to rise during rapid filling & thought to be due to vibration in the ventricular walls as they are streched.
Definition
third heart sound (S3)
Term
This sound is almost always inaudible in dogs, but may be seen in phonocardiogram.
Definition
fourth heart sound (S4)
Term
Fourth heart sound (S4)
Definition
associated with the vibrations from the filling of the ventricles by the acceleration of blood into them by atrial contraction
Term
Stenosis & velvular insufficiency commonly produce what?
Definition
abnormal sounds or murmurs
Term
Stenosis
Definition
narrowing of te valvular orifice
Term
Insufficiency exhists __
Definition
when the valves do not completely close
Term
___ is used to divide the cardiac cycle into 7-8 periods
Definition
ventricular vloume curve
Term

Place the periods in the right order following atrial contraction:

2. isovolumetric relaxation

3.rapid ejection

4.diastases (reduced filling)

5. isovolumetric contraction

6. reduced ejection

7. rapid filling

 

 

Definition
5. isovolumetric contraction, 3.rapid ejection, 6.reduced ejction,2. isovolumetric relaxation, 7.rapid filling, 4.diastasis (reduced filling)
Term
With __ the period of diastais become disproportionally shortened
Definition
increased
Term
Atrial contraction contributes to how much of ventricular volume?
Definition
20-30%
Term
Animals that exhibit exercise intolerance are more dependent on what?
Definition
atrial contraction to fill the ventricals
Term
The divisions of systole
Definition

isovolumetric contraction

rapid ejection

reduced ejection

Term
T/F the clinical definition of systole differs from the physiological
Definition
T
Term
Th begining of reduced ejection is see by what wave?
Definition
t
Term
Isometric contraction and relaxation is shorter on which side of the heart?
Definition
right side
Term
Type of action used by the heart that is very efficient mean of pumping large and varied volumes of blood against a low resistance (i.e.pulmonary circuit)
Definition
bellows type action
Term
Why will death occur from a pulmonary embolism & not from a gradual increased pulmonary circulatroy pressure change?
Definition
In a sudden change the right ventrical will not have time to adapt and sustain the higher pressure, whereas in a slow change it can adapt.
Term
Why is the left ventricle not as adaptable as the right ventricle in handlinglarge volumes?
Definition
tougher walls
Term
In aortic regurgitation, the heart adapts how?
Definition
for the ventricle to compensate for the increased amount of blood it's thickness will increase resulting in CO increase, but the delivery of blood to the perifery remains near normal.
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