2/25- Heart Continuation (Exam 2) Flashcards Preview

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Flashcards in 2/25- Heart Continuation (Exam 2) Deck (42)
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1
Q

What is a extended refractory period?

A

Period of time where new action potential cannot occur

Allows heart to keep the regular steady heart beat without going into fibrillation

2
Q

What happens with summation and tetanus?

A

Is impossible to have in heart because it’s already at rest

Can kill you because the heart is a pump that needs to contract and relax fully

3
Q

What is the nodal system?

A

Wiring of the heart

4
Q

What is the fibrous skeleton of heart?

A

Disc of CT

Goes from one side of heart to other

Separates electrical events between atriums and ventricles as separate ones

Electrical events cannot go through

5
Q

What is automaticity or autorhymicity?

A

Ability for cardiac muscle cells to spontaneously depolarize and then contract

6
Q

What is a Sinoatrial Node (SA Node)?

A

Pacemaker of the heart

Depolarizes faster

After it depolarizes atriums depolarize then contracts

7
Q

What is Atrioventricular Node (AV Node)?

A

Captures depolarization before being lost at the fibrous skeleton

Rapidly transmits depolarization to wires connected to it (atrioventricular bundle)

8
Q

What is the Atrioventricular bundle or bundle of his?

A

Wire that passes through fibrous skeleton of heart

Depolarization comes here then sent to right and left bundle branches

9
Q

What happens to the depolarization after the right and left bundle branches?

A

Goes to Purkinje Fibers

Then sweeps up ventricles causing them to contract and blood goes through circuit

Then depolarization is lost at fibrous skeleton of heart

10
Q

What is the Electrocardiogram (EKG or ECG)?

A

Recording of electrical occurrences

11
Q

What is a Electrocardiograph?

A

Machine that records recording

12
Q

What causes the P wave?

A

Depolarization of Atriums

13
Q

What causes the QRS complex?

A

Depolarization of the ventricles

14
Q

What causes the T wave?

A

Ventricular repolarization

15
Q

Why can’t you see the atriums repolarize in the recording by the EKG?

A

It happens simultaneously of the QRS complex

16
Q

What is the Magnitude of Waves?

A

Direct measure of the voltage (millivolts)

17
Q

What happens when the magnitude of wave forms is large?

A

Hypertension (high blood pressure)

Can lead to enlarged heart

18
Q

What happens when the magnitude of wave forms are smaller?

A

Cardiac tamponade

19
Q

What is a lead?

A

Combos of electrodes

12 different combos (12 angles)

Each lead gives some version of PQRST

20
Q

What are the first 3 leads of a 12 lead?

A

Standard leads

  • simple 2 electrode combos
  • written as Roman numerals (1, 2, 3)
21
Q

What is the middle 3 leads in a 12 lead?

A

Augmented leads
- 3 electrode combos

  • aVR (right wrist)
  • aVL (left wrist)
  • aVF (left ankle)
22
Q

What are the last 6 leads in a 12 lead?

A

Chest leads or precardial leads

V1- V6

23
Q

What are the 3 influences how fast a heart beats?

A

1) rate of pacemaker (SA Node)
2) autonomic innervation
3) atrial reflex or brainbridge reflex

24
Q

What is the autonomic innervation?

A

Nervous system

Sympathetic

  • nonepinepheine
  • increases fire rate of SA Node

Parasympathetic

  • hyperpolarize SA Node
  • more difficult for action potential to occur so heart slows down
25
Q

What is Atrial Reflex or Bainbridge Reflex?

A

Triggered if too much blood from systemic circuit enters the heart from the right atrium at once

Heart speeds up

26
Q

What is in the medulla oblongata?

A

Cardiac control centers

27
Q

What is a cardiac control center?

A

Controls heart pace when it increases or decreases from normal rate

Have parasympathetic and sympathetic connections to the heart

28
Q

What are the 2 inputs for the cardiac control centers?

A

1) Baroreceptors

2) Chemoreceptors

29
Q

What are Baroreceptors?

A

Measure blood pressure

Speed of gears affects BP

Raise pressure- sympathetic
Lower pressure- parasympathetic

30
Q

What are Chemoreceptors?

A

Blood gases (oxygen and carbon dioxide)

Low O2 and high CO2= faster heart beat (sympathetic)

High O2 and low CO2= lower heart beat (parasympathetic)

31
Q

Where are Baroreceptors and chemoreceptors found?

A

Aorta

Carotid Arteries (in neck)

32
Q

What is cardiac rate?

A

How fast the heart is beating

Beats per min

Beats/ min

To figure out:

  • pulse
  • stethoscope
  • EKG
33
Q

What is bradycardia?

A

Heart rate is too slow

Lower than 60

Lower than 50 feel symptoms

34
Q

What is tachycardia?

A

Heart rate is too fast

100 or more

35
Q

What is End Diastolic Volume (EDV)?

A

Volume of blood in left ventricle after it is done filling up

36
Q

What is Stroke Volume (SV)?

A

How much blood comes out if left ventricle when it contracts a moment later

mL/ beat

37
Q

What is the ejection fraction?

A

Comparing Stroke volume to end diastolic volume

What percentage of blood is left in the left ventricle

Never 100%

SV/ EDV x 100

38
Q

What is cardiac output?

A

Volume of blood ejected by left ventricle over one minute

SV x cardiac rate = cardiac output

mL/ min

39
Q

What are 3 things that affect SV?

A

1) End Diastolic Volume
2) contractility
3) Total Periphereal Resistance

40
Q

What is contractility?

A

How hard the ventricle squeezes when if contracts

41
Q

What is the Total Peripheral Resistance?

A

Resistance blood meets when trying to squeeze the blood out of the ventricle

Force to push blood out

More force = less blood
Less force = more blood

42
Q

What is Frank Starling Law of Heart?

A

When total peripheral resistance is more and less blood is out there is more contractility

In healthy hearts