cardiovascular Phgy part 3 (from slide 106)

Question 1

What is the normal heart rate (normal sinus rhythm)?

Answer 1

-normal heart rate is about 70 BPM
-anything less than 60 BPM is sinus bradycardia (slow HR)

Question 2

What are the physioligcal explanations for sinus bradycardia and sinus arrhythmia

Answer 2

-sinus bradycardia- when we sleep
-sinus arythmia- occurs in young ppl, old ppl dont have these arythmias anymore

Question 3

what is sinus tachcardia and sinus arrhytmia?

Answer 3

-sinus tachycardia= rate is greater than 100BPM
-sinus arrhythmia- when heart accelerates when breathing in
-when heart decelerates on expiration

Question 4

What is the 2:1 atrioventricular block?

Answer 4

-block of AP going from AV node to ventricular muscles ( no contraction, occurs every other P wave
-AP doesnt get down to the QRS complex since it is blocked

Question 5

What is the location of the 2:1atrioventricular block?
What happens if block is in the right branch?
What is the treatment?

Answer 5

• block is int the AV node, bundle of His, and both bundle branches
  -if block in the right branch then left still flows and AP goes from left cells to right (activation of all cells will sill occur)
  -this can kill you so the treatment is pacemaker (which induces AP in ventricular muscles)

Question 6

What happens when there is no QRS complex?

Answer 6

-there is a complete atrioventricular block (AV block)

Question 7

What is the premature ventricular contraction?

Answer 7

-it comes from a location in the ventricle that is normally silent (called an etopic beat since it comes to early)

Question 8

What is ventricular tachycardia
what is ventricular fibrillation?

Answer 8

-tachycardia= very fast BPM
-ventricular fibrillation= no organized contraction ( onset of fatal arythmia, can be reversed by defibrillator)

Question 9

What does the epicardial sock array do?

Answer 9

-it has electrodes all over the hear and simultaneously records all 64 electrodes electrical activity at once

Question 10

What is the dynamic equilibrium of the heart?

Answer 10

-each group of cells has a diff refractory period, and the activation wavefront makes its way back in a counteclockwise direction (refractory period trails the section that has just been depolalrized)

Question 11

what is pulmonary vein isolation, what is it used to treat?

Answer 11

-Pulmonary vein isolation is when we use a probe and use it to burn/freeze tissue to kill muscle cells in a circle to replace them with fibrous tissue (stop the point of atrial fib in the heart)
-used to treat premature atrial contraction since the burn/freezing of tissue causes scar tissue to form, no AP is formed

Question 12

How do heart cells contract?
What happens during action potential phase?
What is the ryanodine receptor?

Answer 12

-heart cells contract via invasion of action potential which causes an upstroke of potential in cells across the sarcolema membrane
-calcium goes into cytoplasm and diffuse around until it binds to ryanodine receptor on sarcoplasmic reticulum (ryanodine is a calcium channel)

Question 13

What is in the sarcoplasmic reticulum, what happens the channel opens?

Answer 13

-SR is full of calcium and cytoplasm conc. is low, thus when the channel opens Ca2+ flows out into cytoplasm and then Ca2+ binds to troponin, which activates the entire complex

Question 14

What is activation vs excitation in heart contraction?

Answer 14

-activation does not equal contraction
-mechanical activity lags behind electrical activity

Question 15

What occurs during the diastolic period?

Answer 15

-heart fills in diastolic period when everything is resting and nothing is contracting, it happens to be that the atria has a higher BP than ventricles (AV valves open in diastolic period)

Question 16

How long does ventricles contract for right after AV valve opens in diastolic period, and what does this cause?

Answer 16

-ventricles contract for 1/3 of a second and the pressure in ventricle becomes higher than the atrium and the AV valve closes, this is the beginning of systole (period of contraction)

Question 17

When does the AV valve close, when does pressure in ventricles increase?

Answer 17

-AV valves close at low ventricular Pressure,
-pressure in ventricles increase as ventricles contract but the volume of blood is the same (blood has no where to go since AV valve is closed)

Question 18

What happens when ventricular pressure exceeds the Pressure in the aorta and pulmonary trunk?
-What phase does this start?

Answer 18

-the pulmonary valve and aortic valve open
-this starts the phase of ejection (blood leaves ventricle and goes into aorta

Question 19

What happens when ventricles start relaxing?
What closes?
What does this mark?

Answer 19

-When ventricles start relaxing, they reduce ventricular pressure
-eventually the aortic and pulmonay valve will close as P is higher in aorta and pulmonary than ventricles (pressure in aorta stays high due to windkessel effect)
-this marks the end of the ejection phase and start of isovolumetric pressure

Question 20

What happens the entire time the AV valves are closed?
What happens when pressure in ventricle goes down to 0?
-What phase does this start

Answer 20

the entire time AV valve’s are closed blood flows into them
-when ventricle goes down close to 0, the pressure in the atrium is high than pressure in ventricles and the AV valves open so then the filling phase begins (lasts for 2/3 of section)

Question 21

What happens when the sinus node fires, what does this mark the start of?

Answer 21

-sinus node fires to start P wave and atrial contraction to dump more blood into ventricles

Question 22

In diastole what valves are closed in isovolumertic ventricular relaxation?
-What parts of the heart are relaxed?

Answer 22

-AV valves are closed
-Aortic and pulmonary valves are closed
-atria relaxed, and ventricles are relaxed

Question 23

What happens in diastole when ventricular filling blood flows into ventricles, what is closed?
What is relaxed?

Answer 23

Av valves are open, and aortic + pulmonary valves are closed
-atria and ventricles are relaxed

Question 24

What happens before the p wave, and what causes the p wave?

Answer 24

-just before the P wave the sinus node fires
-the P wave is the activation of the atrial muscle

Question 25

What causes the first heart sound?
What causes 2nd heart sound?

Answer 25

-the mitral valve closing, this pushes the cusps up, snapping them causing the vibration in walls of heart generating a sounds
-second heart sound is when the aortic valve closes

Question 26

What is the stroke volume, how do you calculate it?
What is the typical stroke volume?

Answer 26

Stroke volume is the volume of blood in the ventricle when the ventricle is filled and just about to contract (end diastolic volume), minus the blood at the end of the systolic phase once all the blood is ejected
SV=end diastolic volume and end systolic volume
-100mL

Question 27

What is ejection fraction?
What is the typical ejection fraction value?
what is the formula?

Answer 27

-fraction of blood in ventricle at the time the contraction started that got ejected. the stroke volume got ejected at the time on contraction the amount of blood in ventricle is the end diastolic volume
-60% is fraction of blood ejected from stroke volume at end of cycle (each stroke of heart)
-EF=SV/EDV

Question 28

What is the formula for cardiac output (CO)?

Answer 28

-Heart rate*Stroke volume
-typically 5L/min

Question 29

Which side of the heart has a lower pressure?
where does the pressure get trasmitted?
What valve closes this time?

Answer 29

right heart
-pressure developed in the right ventricle is lower thus the P that gets transmitted to big artery (pulmonary tract) is also lower
-instead of mitral valve closing it is the tricuspid valve that closed
-and instead of aortic valve closing it is the pulmonary valve

Question 30

What would happen if we increase the end diastolic volume?
What does stretching the cells more mean?

Answer 30

-the ventricles are more full for the next contraction, so the force of ventricular contraction will be stronger as the extra filling will extend/stretch the cells
-the more stretched the cells are, the more they will contract and thus the greater the force can be generated

Question 31

what happens when stroke volume increases?
What is preload?

Answer 31

-when SV increase the volume increases
-preload is the stretch of the ventricular muscle prior to contraction (SV controlled by amount of stretch)

Question 32

What happens if EDV increases?
How long does the heart fill for and what causes this?

Answer 32

if EDV (end diastolic volume increases) then preload increases
-heart fills for 2/3 of the cycle due to atrial pressure being larger than ventricular pressure, so if atrial pressure increases then it will take more blood filling the ventricle to cause ventricular pressure to rise above atrial/contract

Question 33

What is the function of atria vs ventricles?

Answer 33

-Atria has chambers which blood flows from veins to ventricles, atrial contraction adds to ventricular filling but is not essential for it
-the ventricle has chambers which produce pressure that drive the blood through the pulmonary and systemic vascular systems and back to the heart

Question 34

vascular system, and blood table

Answer 34

Question 35

What are the vital sign measurements?

Answer 35

ROTHB
R-Respiratory rate
O-oxygen saturation
T-temperature
H-Heart rate
B-BP

Question 36

What happens when intraventricular pressure drops during a heart contraction?
-What happens to pressure in the aorta due to this?

Answer 36

-the aortic valve closes
-aortic pressure stays up

Question 37

What is the max pressure vs lowest pressure called?
how do you calculate pulse pressure?

Answer 37

-lowest P is diastolic
-Highest P is systolic
-pulse pressure=systolic-diastolic

Question 38

How do you calculate MAP (mean arterial pressure)
-What is the typical MAP value

Answer 38

MAP=diastolic pressure+1/3 pulse pressure
MAP usually is 100 mmhg

Question 39

What is the the windkessel effect?

Answer 39

When there is still a pressureized source so even when there is no active pressure there is still a force acting on the water

Question 40

What is it called when a ventricle is in contraction?
How long does this last?
What occurs in the heart during this phase/

Answer 40

-systole is the name, and it lasts 1/3 of a second
-during this, the aortic valve is open and blood is ejected into the aorta (pressure increases bc of aorta compliance)

Question 41

What maintains the pressure in the aorta?

Answer 41

-windkessel effect since the volume will still run over the course of the diastolic period when aortic valve is closed

Question 42

What is the definition of the stroke volume?

Answer 42

-when the heart transfers a volume from venous to arterial side

Question 43

What are the 2 main methods of measuring BP and what are the subcategories?

Answer 43

Direct-makes and artery puncture
Indirect-palpation, ausculatation, oscillometry

Question 44

What type of instrument does the palpation method use, and what are the other componenets of the intrument?

Answer 44

-anoeroid sphygomomanometer which has a cuff that inflates using an inflating bulb and the cuff pressure is displayed on the aneroid gauge

Question 45

What artery is used for measurements for palpation?
What can the method of palpation measure?
At what beat is the arteriole pressure higher than cuff pressure, what happens at this point to the artery, at what pressure does this occur?

Answer 45

-the radial artery to feel the pulse
-systolic pressure and BP which is displayed on the gauge
-at the 5th beat the arteriole pressure is higher than cuff pressure, at this point artery will push outward onto the skin (artery transiently opens)
-this occurs at systolic pressure (pressure in artery at its max)

Question 46

What and when can we hear the sound in the method of ascultation?
What causes the sound, and at what pressure?
When does the sound stop, and at what pressure?

Answer 46

-when we pump up the cuff we can hear the korotkoff sounds
-when blood comes out of the constriction to a wide artery area, (turbulent flow) usually at 110mmhg
-sound stops bc the pressure in the arteries at all points in the cycle is higher than the cuff (no more turbulent flow), 80mmhg (diastolic pressure)

Question 47

What machine do we use for oscillometric method?
When can sounds be heard and when do they stop in this method?

Answer 47

-we use an automated pump machine that inflates a cuff
-as we lower P in the cuff we hear sound at 157mmhg and then stops at 83

Question 48

What generates the heart rate to make BP?

Answer 48

-the contraction of the ventricular muscles

Question 49

What has the largest pressure drop in the vascular tree?
What does this large pressure drop mean?

Answer 49

-small arteries and arterioles
-means there is higher resistance in these areas