Exam 4 Lecture 1 Flashcards

1
Q

Lower part of the heart, per lecture

A

Ventricles

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2
Q

What is Phase 2 of Cardiac AP

A

Plateau Phase: Ca++ influx via L-Type Ca++ channels; K+ channels still closed/closing [decreased permeability]

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3
Q

What is the Subendocardium
*What could happen here and why

A

Super deep muscle layers where a MI would probably happen [increased wall/chamber pressures]

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4
Q

What is the Epicardium
*What sit on these and go deeper into the heart

A

Outside wall of the heart; most superficial
*Vessels sit here and go deeper into the heart

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5
Q

How do Myocytes communicate with each other?

A

Gap Junctions

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6
Q

How many nuclei/nucleus do each myocyte have?

A

1 nucleus

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7
Q

What is the Parietal Pericardium

A

Inner, stretchy layer

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8
Q

Ionic Current is dependent on? 2 things

A

CG/ electrochemical gradient and Amount of Ion channels

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9
Q

How long is a Cardiac AP

A

around 200 ms

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10
Q

What is the Myocardium

A

Bulk of Muscle Wall

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11
Q

What are the Parts of the Pericardium

A

Epicardium, Pericardial Space, Parietal, Fibrous

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12
Q

What is the Pericardium

A

The connective tissue sac that covers the heart

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13
Q

Are ACE and ARBS safe in pregnant women?

A

No, mess w RAAS system and are teratogenic

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14
Q

What are Cardiac Stem cells?
*Fast or slow process

A

Patching areas of dying cells; slow process

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15
Q

What are cardiac fibroblasts?
*When are they activated?
*What disease process is a result of increase fibroblasts?
*Tx for this disease process

A

Lay down scar tissue
*Activated when stem cells are overwhelmed; can also lay down unnecessary scar tissue
*CHF from increased scar tissue = decreased conductance
*Tx: ACE and ARBS [Teratogenic]

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16
Q

What is a way to cause a AV HB in a pt?
*What type of surgery
*What CN are involved
*Pathophys of this

A

Eye muscle reflex due to eye surgery
*V [trigeminal] + X [vagus]
*Sensory perception in eye socket, sends input to brain, vagus nerve then signals massive vagal output, which prevents AP in AV node [wait 30 sec to get HR back]

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17
Q

Purkinje Fibers
*VRM
*Threshold Potential
*What does it rely on to fire an AP

A

-90 mV; Threshold is -70 mV
*Can SLOWLY fire own AP, but mostly relies on upstream AP to help fire AP

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18
Q

What is Phase 3 of Cardiac AP

A

Increased K+ channel permeability, leading to down slope before Phase 4 [VRM]

19
Q

What are Intercalated Discs
*where are they only located
*What are located here

A

High surface area connection points of the cardiac cell to other cardiac cells
*only in heart
*Gap junctions

20
Q

There is less Ca++ coming in than Na+ in an AP, why?

A

Less Ca++ channels than Na+ channels

21
Q

How many cardiac AP phases do we have?

A

5 total

22
Q

What is Phase 0 of Cardiac AP

A

Na+ rapid upstroke in a fast manner; K+ channels begin closing right at top of Phase 0, before Phase 1

23
Q

What is Phase 1 of Cardiac AP

A

Fast Ca++ influx via T-Type Ca++ Channel; K+ channels begin to close [decreased permeability]

24
Q

In a relaxed state, how does the heart look?
*What about the H-band
*Under or overstretched? Why?

A

not relaxed at optimum degree
*No H-Band
*Understretched to produce more force: Increased EF

25
Q

What is Phase 4 of Cardiac AP
*How to start AP

A

VRM @ around -90 w/ slight slope
*can slowly fire AP by itself over time, but mostly gets AP from Na+ influx via gap junctions in upstream AP

26
Q

Cardiac Muscle Tissue

A

Lots of myofibrils to produce more force

27
Q

Cardiac Conduction Tissue

A

Barely any myofibrils to produce more amount and efficient AP’s

28
Q

Ventricle Muscle
*VRM
*Threshold Potential

A

-80 mV; Threshold is -70 mV

29
Q

What does increase scar tissue cause?

A

No AP and no contraction

30
Q

At rest, how does the Cardiac AP VRM look?
*Why

A

Slight slope due to increased Na+ permeability

31
Q

Superficial to Deep, Layers of the Heart

A

Fibrous Pericardium - Parietal Pericardium - Pericardial Space - Epicardium - Myocardium - Endocardium

32
Q

What are Cardiac Syncytial Connections?
*How many layers of the heart and how do they operate
*Name of the layers, per slide
*Efficiency and how are they connected

A

The Arrangement of heart muscle
*2 Layers: Endocardial and Epicardial Fibers twist/rotate in opposite directions, leading to better force [think wring out a wet towel]
*Highly efficient and connected via electricity

33
Q

What is the threshold potential for Purkinje/ Ventricle

A

-70 mV

34
Q

What is the Pericardial Space

A

Filled with mucus and fluid to help the heart move; painful if you have pericardial rub

35
Q

What is the Endocardium

A

Deep Cardiac Muscle

36
Q

What is the conduction system of the ventricle
*What is their role

A

Purkinje Fibers
*Conduct/Relay AP

37
Q

Deep to Superficial, Layers of the Heart

A

Endocardium - Myocardium - Epicardium - Pericardial Space - Parietal Pericardium - Fibrous Pericardium

38
Q

In Purkinje Fibers, if AV heart block, how is PF effected?
*Think Lag time
*How long is lag time

A

AV heart block blocks conductance signal, so increased lag time of about 30 sec for the PF to fire an AP

39
Q

What is the thickest cardiac tissue?

A

Myocardium

40
Q

What is the Fibrous Pericardium
*What is it similar to

A

Outside, stiff, leathery layer
*Similar to Dura layer; difficult to expand

41
Q

Upper part of the heart, per lecture

A

Atrium

42
Q

What is Ohm’s Law
*What does each thing stand for
*what does i mean?

A

V = IR
V = voltage
I = Current
R = Resistance
i- Ionic current

43
Q

2 Things that cause Cardiac Ischemia

A

Increased wall pressure and clogged vessels