Exam 3 CVS 1-4 Flashcards
Atria and ventricles are separated by _______.
Atrioventricular Valves
left AV valve
Mitral Valve
Right AV valve
Tricuspid valve
_______ are positioned between the ventricles and the great arteries
Semilunar Valves
What are the two semilunar valves?
Aortic valve and Pulmonary valve
propels blood through the pulmonary circulation
right ventricle
propels blood through the systemic circulation
left ventricle
what are the 3 diff types of cardiac cells
- myocardial cells
- pacemaker cells
- conduction cells
striated muscle specialized for contraction and impulse conduction
myocardial cells
cells that exhibit automatic rhythmical electrical discharge in the form of APs
Pacemaker cells
cells that conduct the APs through the heart providing and excitatory system that controls the rhythmical beating
conduction cells
Fibers remain separate but contract together as a single unit
Syncytium
What are the two types of cell - cell junctions found within intercalated disks
- gap junctions
2. desmosome
What is the purpose of gap junctions?
allow rapid diffusion of ions
what is the purpose of desmosomes?
provide mechanical strength
Where is the main source of energy for cardiac muscle derived from?
oxidative metabolism of fatty acids
The normal pacemaker of the heart
Sinoatrial node (SA node)
where is the SA node located?
Right atrium
_____ initiates the AP that is conducted throughout the heart
SA node
T/F. the Sarcoplasmic reticulum is not well developed in cardiac muscle
T
what are the 2 places where calcium is derived in order to make AP
- Extracellular fluid
2. sarcoplasmic reticulum
What generates the normal heart rythm?
a. Myocardium
b. sinoatrial node
c. atrioventricular node
d. purkinje fibers
B. SA node
delays impulse conduction from the atria to the ventricles
AV node
where is the AV node located?
Behind the tricuspid valve in the R atrium
Why does the AV node delay the impulse from the atria to the ventricles?
to allow time for the atria to empty their blood into the ventricles before ventricular contraction begins
Trace AP through the heart:
- SA node generates impulse
- Impulse pulse at AV node
- AV bundle connects atria to ventricles
- bundle branches conduct impulses thorough the interventricular septum
- purkinje fibers depolarize the contractile cells of both ventricles
Lead the AV node impulse through the AV bundle into the ventricles
Purkinje fibers
______ allows for instantaneous transmission of the cardiac impulse throughout the entire remainder of the ventricular muscle
Purkinje fibers
Is the AP in the SA node fast or slow compared with atrial and ventricular cells?
slow
What are funny sodium channels? and when are they open?
Pacemaker sodium channels
during slow AP:
closed during AP
begin to open spontaneously once an AP has finished
What are fast calcium channels? when are they open?
T-type calcium channels
begin to open near threshold of slow AP
what is the ion primarily responsible for the AP in a pacemaker cell?
Calcium
During slow AP in SA node, the repolarization occurs after the closing of_____ and opening of _______
Closing: L-type calcium channels
Opening: K channels
The myocardium AP (fast AP) is caused by the opening of 2 channels:
- Fast sodium channels
2. L-type calcium channels
Which cells have a shorter AP, atrial or ventricular?
Atrial
Movement away from the baseline in either a positive or negative direction
waveform
a line between waveforms
segment
a waveform and a segment
interval
several waveforms
complex
numbers of heartbeats per min.
HR
inc. in HR
Tachycardia
Dec. in HR
bradicardia
Normal cardiac rhythm where depolarization begins at the SA node
Sinus Rhythm
Abnormal heart rhythm
Arrhythmia
First ECG deflection
P wave
ECG: What is the P wave
Depolarization of atrial muscle
ECG: What are the 2 parts of the P wave?
R. atrial depolarization and L atrial depolarization
ECG: What segment follows the P wave?
P-R segment
ECG: What does the P-R segment correspond to?
AV node conduction
ECG: the ______ is the time from initial depolarization of the atria to initial depolarization of the ventricles
P-R interval
ECG: How does sympathetic and parasympathetic stimulation affect the P_R interval?
S: inc. conduction velocity
P: dec. conduction velocity
ECG: As the impulse activates the His-Purkinje system and ventricular muscle, ________ is generated.
QRS complex
ECG: wave that corresponds to early ventricular depolarization
Q
ECG: wave that corresponds to ventricular depolarization
R
ECG: wave that corresponds to late ventricular depolarization
S
ECG: The ____ interval reflects the approximate duration of ventricular systole and the ventricular refractory period.
Q-T
ECG: The ___ Segment correlates with the plateau of the ventriular AP
S-T
ECG: Represents ventricular repolarization
T wave
Which interval in an ECG can be used to calculate HR?
R-R
The time between one R wave and the next?
Cycle length
a positive and negative charge separated by a small distance
dipole
Where are the electrodes for eithoven’s Triange placed?
RA, LA, LL
ET: What color lead is the RA?
White
ET: what color lead is the LA?
Black
ET: what color lead is the LL?
Red
ET: what color lead is the RL
Green
ET: what does lead 1 connect?
RA and LA
ET: what does lead 2 connect
RA and LL
ET: what does lead 3 connect
LA and LL
ET: Why are standard bipolar leads most extensively used in vet med?
Provides info on the frontal plane of the heart
ET: What are the 3 augmented unipolar leads
aVR
aVL
aVF
ET: Augmented lead that measures the voltage from the RA compared to the sum of the other two leads
aVr
ET: Augmented lead that measures the voltage from the LA compared with the sum of the other two leads
aVL
ET: Augmented lead that measures the voltage from the LA compared with the sum of the other two leads
aVF
What do you use to determine the mean electrical axis(MEA)?
Hexaxial System
Represents the direction of the average direction of the entire ventricular myocardium
MEA mean electrical axis
Contraction and emptying of the heart
Systole
relaxation and filling of the heart
diastole
the total volume of blood ejected by the heart per minute
cardiac output (CO)
the volume of blood ejected by the ventricles on each beat
Stroke volume
Trace the pathway of blood through the heart:
deoxegenated blood> Vena cave> R atrium> R ventricle> Pulmonary arteries> Lungs> Oxygenated> pulmonary veins> L atrium> L ventricle> Aorta> circ.
Prevent backflow of blood from the ventricles to the atria during systole
AV Valves
T/F Valves of the heart open passively
T
When do the AV valves open?
When atrial pressure is greater than ventricular pressure
When do the AV valves close?
When ventricular pressure is greater than Atrial pressure
The AV valves are attached to the papillary muscles by the ________
Chorda Tendinae
T/F the function of the Chorda Tendinae is to help open and close the AV Valves?
F. function to pull the vanes of the valves inward toward the ventricles during systole
Prevent back flow of blood from the aorta and pulmonary arteries into the ventricles during diastole
Semilunar valves
What is the second heart sound?
The closing of the semilunar valves
What causes the semilunar valves to close?
higher pressure in the arteries during systole
What does the A wave of the wiggers diagram correspond to?
Atrial contraction
What does the C wave of the wiggers diagram correspond to?
ventricles begin to contract
What does the V wave of the wiggers diagram correspond to?
End of ventricular contraction
the ventricles fill with blood during systole or diastole?
Diastole
What happens during the first 1/3 of diastole?
pressure inside atria causes AV valves to open and blood to rush into ventricles
What happens during the second 1/3 of diastole?
small amount of blood flows into the ventricles
what happens during the last 1/3 of diastole?
atria contract and give aditonal 20% of blood to ventricles
the outflow of blood from the ventricles during systole begins with _______
isovolumic contraction
what is the ejection fraction?
blood that is ejected during systole (60% of total volume)
what are the 2 parts of the ejection fraction?
- Rapid ejection (70%)
2. Slow ejection (30%)
what is incidura
short period of backwards flow during the end of systole when the AV valves close
What is isovolumic relaxation
when both the AV and semilunar valves are closed following Systole
During diastole, normal filling of the ventricles increases the volume of each ventricle
End diastolic volume
the volume of blood ejected by the ventricle on each beat
stroke volume
the remaining volume in each ventricle
end systolic volume
the total volume ejected by the heart per minute
cardiac output
What are the 4 stages of the volume pressure diagram of the cardiac cycle?
- period of filling
- isovolumetric contraction
- period of ejection
- isovolumetric contraction
What causes the 1st cardiac sound?
closing of the AV valves
What causes the 2nd cardiac sound?
closing of the Semilunar valves
What causes the 3rd cardiac sound?
Rush of blood into the ventricles
What causes the 4th cardiac sound?
The end of diastole during atrial systole
