Cardio

Question 0

Which is the site of highest resistance in the cardiovascular?

Answer 0

The arterioles

Question 1

Flow is predicted by Reynolds number.how it is determined?

Answer 1

When Reynolds number is increased > ^tedency for turbulence >audible vibrations:bruits

Factors:
#^velocity:narrowing of the vessel>low A>^υ
(υ=Q/A)
#low viscosity :anemia>low hematocrit

Question 2

What’s the site of largest total cross sectional and surface area?

Answer 2

The capillaries

Question 3

What does the capillaries wall consist of?

Answer 3

A single layer of endothelial cells and a basal lamina

No muscle layer

Question 4

Where is the unstressed volume?

Answer 4

It is the blood volume contained in the veins

Question 5

What is the velocity of blood at the wall of the vessel?

Answer 5

Zero

Hence,shear is highest at the wall

Question 6

Where does the largest decrease in pressure occur?

Answer 6

Across the arterioles
Paorta=100mmHg
Parteriol=50mmHg

Question 7

How does elastic tissue affect the compliance of blood vessels?

Answer 7

They are inversely related.
Compliance=capacitance=distensibility
The greater the amount of elastic tissue ,the higher the elastance(STIFFNESS ),the lower the compliance

C=V/P. Capacitance decreases with age

Question 8

How is pulse pressure determined?

Which is its most important determinant?

Answer 8

It is the difference between systolic an diastolic pressure
It is proportional to arterial compliance
The most important determinant of PP is stroke volume

Question 9

Name 5cases in which we have ^pulse pressure…

Answer 9

#hyperthyroidism
#aortic regurgitation
#obstructive sleep apnea
#aortic stiffness
#exercise

Question 10

Name 4cases in which we have low pulse pressure…

Answer 10

#aortic stenosis
#cardiogenic shock 
#cardiac tamponade
#HF

Question 11

Which segment of the ECG is isoelectric?

Answer 11

The ST segment where the ventricles are Depolarized

Question 12

What does T-wave inversion indicate?

Answer 12

Recent MI

Question 13

What does U-wave suggest?

Answer 13

Hypokalemia

Bradycardia

Question 14

The intrinsic rate of phase 4 depolarization is fastest in…

Answer 14

SA>AV>Hiss,Purkinje

Question 15

The speed of conduction is highest in…

Answer 15

Purkinje > atria>ventricles>AV node

Question 16

How is mean arterial pressure determined?

Answer 16

MAP=2/3D+1/3S

Question 17

How is the resistance of blood vessels determined?

How does the pattern of the vessel and it’s branches affect the resistance?

Answer 17

in series:

R=8ηl/πr^4
#in parallel series:
¥the total resistance is less than any individual artery
¥in each parallel ,we have the same pressure,but only a fracture of. blood flow

¥each vessel receives the same blood flow
¥as blood flows the pressure decreases(ΔΡ=Q*R> ΔΡ ^>Ρarterioles is lower)

Question 18

When the heart rate increases which part of the cardiac circle is preferentially shortened?

Answer 18

Diastole because there is less filling time>low CO

Question 19

How can myocardial oxygen demand be increased?

Answer 19

C:contractility
A:afterload
R:heart rate
D:diameter of ventricle(^wall tension)

Wall tension=pressureradius/2wallthichness

Question 20

How is ejection fraction determined?

Which is approximate number?

Answer 20

EF. (Ποσοτικοποιηση του contractility)
EF=SV/EDV=EDV-ESV/EDV
It is approximately 55%

Question 21

How does HF affect EF?

Answer 21

EF is lower in systolic HF

EF is normal in diastolic HF

Question 22

In the myocardial action potential for Hiss/Purkinje/ventricles/atria which ion causes the rapid upstroke and depolarization?

Answer 22

Voltage gated Na channels open

Question 23

In the myocardial action potential for Hiss/Purkinje/ventricles/atria what is the cause of myocyte contraction?

Answer 23

At the plateau phase we have Ca influx(L-channels of dihydropyridine )
And K effluent.myocyte contraction occurs due to Ca-induced-Ca release from the SR through ryanodine receptors.

Question 24

In the pacemaker action potential of the SA and AV nodes what is the cause of spontaneous depolarization during diastole?

Answer 24

It is due to If channels (funny current),responsible for the mixed inward of K and Na at phase 4.Its slope determines HR(chronotropic effect)

Question 25

In the pacemaker action potential of the SA and AV nodes what is the cause of the upstroke?

Answer 25

It is due to the opening of voltage gated Ca channels. The amount of inward Ca molecules determines conduction velocity.in the AV node>PR interval ^inward Ca>^velocity>short PR

Question 26

How is chronotropic effect determined?

Answer 26

Rate of phase 4 depolarization->HR proportional to the number of Ifunny channels +:^HR-sympathetic β1 -:lowHR-parasympathetic M

Question 27

How is dromotropic effect determined?

Answer 27

It determines the conduction velocity(in the AV)->PR It is proportional to Ca inward +:sympathetic,β1>short PR -:parasympathetic ,M2>long PR

Question 28

Which parts of the heart have parasympathetic Vagal innervation?

Answer 28

SA,atria,AV

Question 29

What are the low resistance paths between cells in cardiac muscle?

Answer 29

The gap junctions>rapid electrical spread

Question 30

What are three factors that increase contractility(intotropy)?

Answer 30

#^HR>high rate of firing act.pot.>more Ca is stored in the SR #sympathetic stimulation: ▶️^inward of Ca:keeps Ca channels open for more t at the Plateau phase ▶️phosphorylation of phiospholamban>^CaATPSR #glycocods:inhibit NaKATP>^NAi>lows efflux of Ca

Question 31

Give 5examples that decrease contractility

Answer 31

``` #β1blockers(low cAMP) #HF with systolic dysfunction #Acidosis #Hypoxia/hypercapnia #Non-dihydropyridine Ca channel blocker ```

Question 32

Give two pharmacological examples that decrease afterload and preload

Answer 32

Nitroglycerin>venodilator>low preload | Hydralazine>vasodilato>low afterload

Question 33

Equation of stroke volume SV

Answer 33

SV=EDV-ESV

Question 34

CO equations

Answer 34

CO=SV*HR CO=O2consumption/O2pulm.vein-O2pulm.art CO=MAP/TPR

Question 35

Stroke work equation

Answer 35

Stroke work=Aortic pressure*SV

Question 36

Which are the Jugular venous pulse(JPV) waves?

Answer 36

α:atrial contraction c:RV contraction(closed tricuspid valve bulging into atrium) x:descent,atrial relaxation[absent in tricuspid regurgitation] v:^right atrial pressure due to filling against closed tricuspid valve(billing) ψ:descent,RA emptying into RV

Question 37

What is the Cushing reaction?

Answer 37

^intracranial pressure cause compression of the cerebral blood vessels>cerebral ischemia>^Pco2>vasomotor center increases sympathetic outflow>^perfusion pressure(hypertension)>^stretch>peri feral reflex baroreceptor induced>bradycardia ``` Triad #hypertension #bradycardia #respiratory depression ```

Question 38

What are the factors that increase Pc,favoring filtration?

Answer 38

``` #Arteriolar dilation #venous constriction #increase venous/arterial pressure #HF #NO ```

Question 39

What are the factors that increase πi favoring filtration?

Answer 39

Inadequate lymphatic function

Question 40

What are the factors that increase πc favoring absorption?

Answer 40

Dehydration

Question 41

What are the factors that decrease πc favoring filtration?

Answer 41

``` #liver disease #nephrotic syndrome #malnutrition ```

Question 42

What are the factors that increase Kf favoring filtration?

Answer 42

``` #burn #infections #toxins #histamine(dilation of the arteries,constriction of the veins) #cytocins ```

Question 43

Acts on prostaglandins in the vascular system

Answer 43

Prostacyclin. ➡️vasoconstriction E-prostaglandin Thromboxane A2 ➡️vasodilation F-prostaglandin

Question 44

What are the 2causes of orthostatic hypotension?

Answer 44

``` #volume depletion #impaired baroreceptor reflex(individuals with sympatholytic agents) ```

Question 45

On an ECG with ventricular extrasystoles ,what is the effect on SV?whatis the effect on the next normal ventricular contraction?

Answer 45

Pulse pressure decreases(inadequate ventricular filling time)>decreased stroke volume The next contraction will have an increased pulse pressure due to increased contractility(^Ca!!!)

Question 46

2 P waves preceding each QRS complex at the ECG indicates...

Answer 46

That the conduction velocity through the AV node must be decreased

Question 47

The greatest pressure decrease in the circulation occurs across the arterioles because...

Answer 47

They have the greatest resistance (low r>^R>^ ΔP)

Question 48

What's the act of propranolol?

Answer 48

It is adrenergic antagonist that blocks β1 β2 receptors>low HR+contractility>lowCO