Unit 2: Cardio Mechanical Flashcards by Salina H Huy

Cardiac cycle encompasses the events around ______

2 phases:
Diastole ->
Systole ->

_____ contract-relax cycle

one heartbeat

Diastole -> relaxation
Systole -> contraction

One

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The cardiac cycle is a series of _______ that take place within the heart

pressure changes

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AV valves open when atrial pressure is ______ than ventricular pressure

higher

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The heart contracts and relaxes ______ in one cardiac cycle

ONE TIME

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Which comes first, following atrial filling?

A. Atrioventricular valve opening
B. Atrial contraction

A. Atrioventricular valve opening

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Cardiac Cycle:

1) Late Diastole
Blood from the body enters atrium ______
More blood in atriums = increased _____
Atrium pressure _____ ventricular pressure
_____ open
Blood ______ fills ventricles to 80% full

passively
pressure
Atrium pressure greater than or equal to ventricular pressure
AV valves open
passively

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Cardiac Cycle:

2) Atrial systole
Atrial _____ “kicks” remaining _____ of blood into ventricles
Volume in ventricles = _____
Ventricles start to ______
At the beginning of ventricular contraction, ventricular pressure ______ atrial pressure
Ventricle pressure pushes back on the leaflets of the ____ and forces them close -> ____

contraction, 20%
End Diastolic Volume (EDV)
contract (isovolumic contraction)
is greater than
AV valves (FIRST HEART SOUND)

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Cardiac Cycle:

3) Isovolumic Contraction
Ventricles contract while both ______ remain closed
Ventricle contraction _____ ventricle pressure
Ventricle pressure _____ arteries
______ open

AV valves, SL valves
increases
greater than
SL valves open

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Cardiac Cycle:

4) Ventricular ejection
Blood moves from high pressure in ____ to ____
Ventricles _____ blood
Arteries pressure _____ ventricles pressure
Blood flow push back into cusps of ____ forcing them closed ( )

ventricle, arteries
eject
greater than
SL valves (SECOND HEART SOUND)

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Cardiac Cycle:

5) Isovolumic ventricular relaxation
Blood left in ventricle = ______
Ventricles relax with both _____ closed

End Systolic Volume (ESV)
AV and SL valves

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Heart sounds occur when ______

a valve closes
1st heart sound -> AV valve closes
2nd heart sound -> SL valve closes

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Points A, B, C, and D of cardiac represent (in order)…

AV valve opens, AV valve closes/EDV (1st heart sound), SL valve opens, SL valve closes/ESV (2nd heart sound)

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Stroke volume is the amount of ____ ejected from the left ventricle in one ____

blood, heartbeat

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SV =

EDV - ESV

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Ejection Fraction (EF) =

EF = SV/EDV x 100

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Cardiac output measures the ________ of the heart as a pump

units are

effectiveness

avg = 5L / min

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Cardiac Output (CO) =

CO = HR x SV

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Preload: When blood returns from body (venous return), the degree of _____ in ventricles before contraction begins

muscle stretch

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Frank Starling Law states: the more the ventricle muscle stretch = the _____ a contraction

more forceful

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Preload approximately _____

End Diastolic Volume (EDV)

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Increased preload = ______ venous return

3 factors for venous return:

increased

skeletal muscle pump
respiratory pump
sympathetic on veins (constriction of veins)

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Preload is increased by:

A. Increased contractility
B. Increased skeletal muscle activity
C. Increased heart rate
D. None

B. Increased skeletal muscle activity

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Contractility is directly related to the ______ concentration in contractile cells

intracellular

Contractility is increased/regulated by ______
_____ cAMP

2 sites of regulation:

sympathetic (epinephrine and norepinephrine)
increases

phosphorylates Voltage-gated Ca2+ channels
increases Ca2+ stores in SR

What are the immediate results of low-dose application of an Na/K ATPase inhibitor in contractile cells? A. Higher preload B. Increased contractility C. Reduced stroke volume

B. Increased contractility has nothing to do with 3 determinates of preload (skeletal, respiratory, constriction of veins) INCREASES stroke volume

Afterload is the force ______ the ejection of blood by the heart

resisting

Effect of increased preload on PV loop?

Increases EDV (EDV moves to the right)

Effect of increased afterload on PV loop?

Curve gets skinnier Point 2 moves up because more contraction means more pressure

Effect of increased contractility on PV loop?

Curve widens because there is more blood ejected ESV moves to the left because there is less ESV in ventricles due to how we were able to contract more blood

Venous vasoconstriction _______ SV

increases

A deep inhalation _____ SV

increases

Units for SV?

mL/beat

How does exercise affect the PV loop? A. widens the curve B. Increases peak systolic pressure C. Point C moves up

A. widens the curve B. Increases peak systolic pressure increases preload, increases SV

Upregulation of parasympathetic... A. Increases If activity in contractile cells B. Increase K+ permeability in pacemaker cells C. Lengthens the PR segment D. Decreases the length of R-R interval

B. Increase K+ permeability in pacemaker cells C. Lengthens the PR segment If activity is for PACEMAKER cells, increasing this would increase heart rate parasympathetic INCREASES R-R interval, slows heart rate

Total peripheral resistance (TPR) is regulated by: Local control: 1. Myogenic response 2. Paracrines Metabolic ____ Signal molecules _____ Immune cells ____ Reflex control: 1. Neural Sympathetic on arterioles (____ on ___) 2. Hormonal Epi on beta-2 ADH (vasopressin)

O2, CO2 Nitric oxide (NO) Histamine Norepinephrine, adrenergic receptors

Adrenergic Receptors for Sympathetic Vasoconstriction of arterioles and veins -> Heart rate and contractility -> Vasodilation ->

Vasoconstriction of arterioles and veins -> Norepinephrine on Alpha-1 receptors Heart rate and contractility -> Norepinephrine on Beta-1 receptors Vasodilation -> Epinephrine on Beta-2 receptors

Choose all forms of REFLEX control of vasculature: A. Carbon dioxide B. Histamine C. Norepinephrine D. Vasopressin

C. Norepinephrine D. Vasopressin

Mean arterial pressure (MAP) =

MAP = DBP + 1/3 (DSP - DBP) b/c you spend more time in diastole, closer to diastole

MAP is proportional to

CO x TPR

Baroreceptors are a type of ______

mechanoreceptors (change in pressure)

MAP is increased by... A. upregulation of nitric oxide B. Halving of HR, doubling of TPR C. Increased respiratory pump activity

C. Increased respiratory pump activity increases SV, which increases CO MAP is proportional to CO x TPR

In response to hypertension: A. Baroreceptors increase firing B. Venous return is increased C. If channels are upregulated in pacemaker cells

A. Baroreceptors increase firing

Which is SIMILAR in baroreceptor reflex and fight/flight reflex? A. Stimulus B. Limbic as integrating center C. CVCC as integrating center D. Adrenal medulla as integrating center E. Epinephrine as efferent

C. CVCC as integrating center

When comparing fight/flight to baroreceptor, which is ONLY true for fight/flight? A. Stimulus B. Limbic as integrating center C. CVCC as integrating center D. Adrenal medulla as integrating center E. Epinephrine as efferent

D. Adrenal medulla as integrating center E. Epinephrine as efferent

In congestive heart failure (CHF), hypertension strains the left ventricle so that it begins to weaken. How does hypertension strain the ventricle to the point of failure?

Increased AFTERLOAD hypertension = increased BP, increased resistance in arterioles preload only relates to 3 determinates contractility only relates to Ca2+

If arteriolar radius is significantly reduced: Resistance to flow increases _____ Flow _____ by a factor of r^4

r^4 DECREASES

Arteriosclerosis causes hypertension by _____ total peripheral resistance

INCREASING narrowing of the arterioles

Mr. Williams' systolic pressure was 175 and his diastolic was 120 mm Hg. What was his mean arterial pressure?

MAP = DBP + 1/3 (SBP - DBP) 120 + 1/3 (175-120) = 138.33

Design a drug to increase force in Mr. Williams' weak ventricle. Your new drug should impact a normal contractile cellular mechanism. What would these drugs target?

Regular sites of regulation Phosphorylation (activation) of voltage-gated Ca2+ channels AND increase Ca2+ stores in SR

How would chronic heart failure (CHF) affect Mr. William’s ECG? A. No T wave B. Longer PR segment C. Wider QRS segment D. Longer QRS segment E. No change

E. No change (contractility = mechanical)

Williams’ cardiologist prescribed two major forms of medications to treat his condition. One set of meds were antihypertensives. The other set increased force of contraction. Which of these meds would be a poor choice for Mr. Williams? A. spironolactone—a diuretic B. an ADH antagonist C. beta 1 antagonist D. nitric oxide

C. beta 1 antagonist Norepinephrine on beta-1 effects contractility

You look back in Mr. William’s medical chart and noticed that a few years ago, he was diagnosed with Left Ventricular Hypertrophy (more cardiac muscle mass of his left ventricle). How would Mr. William’s ECG be affected by left ventricular hypertrophy? A. No T wave B. Longer PR segment C. Larger QRS segment amplitude D. No P wave E. No Change

C. Larger QRS segment amplitude Amplitude of waves is determined by MASS of tissue QRS complex -> ventricular depolarization

The primary force responsible for opening the atrioventricular (AV) valves is: A. Increased ventricular pressure B. Increased atrial pressure C. Decreased arterial pressure D. Atrial relaxation

B. Increased atrial pressure

During atrial systole, the ventricles are: A. Completely empty B. Filling with blood C. Contracting D. Relaxed with semilunar valves open

B. Filling with blood

Total peripheral resistance (TPR) is regulated by all of the following EXCEPT: A. Local metabolic factors B. Sympathetic nervous system C. Parasympathetic nervous system D. Hormones like epinephrine

C. Parasympathetic nervous system

Which of the following is a primary site of sympathetic regulation in the cardiovascular system? A. Alpha-1 receptors on arterioles B. Muscarinic receptors on ventricles C. Beta-2 receptors on veins D. Nicotinic receptors on pacemaker cells

A. Alpha-1 receptors on arterioles