A&P - Chapter 28 (Part 3) Flashcards Preview

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Flashcards in A&P - Chapter 28 (Part 3) Deck (27)
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1
Q

What are 4 structures that generate strong impulses?

A
  1. SA nodes
  2. AV nodes
  3. AV bundle
    - bundle of His
  4. Aubendocardial branches
    - Purkinje fibres
2
Q

What is the pacemaker of the heart?

A

SA node

3
Q

What does the SA node do?

A

It initiates impulses/heartbeats and sets its pace

4
Q

Where is the SA node?

A

In the wall of the RA near the opening of the superior vena cava

5
Q

Where is the AV node located?

A

In the right atrium along the lower part of the interatrial septum

6
Q

Where is the AV bundle located?

A

In the septum of the ventricle

7
Q

Where are the Purkinje fibres located?

A

In the walls of the ventricles

8
Q

ECG

A

Electrocardiogram

9
Q

Electrocardiogram

A

The recording of the electrical impulses of the hearts conduction system

10
Q

What kind of waves/deflections are on a normal ECG? (3)

A
  1. P Wave
  2. QRS complex
  3. T Wave
11
Q

P wave

A

Represents depolarization of the atria

- triggers contraction

12
Q

QRS complex

A

Represents depolarization on the ventricles

13
Q

T wave

A

Represents re-polarization of the ventricles

- just before relaxation phase

14
Q

What is not shown on an ECG?

A

Re-polarization of the aorta

- overshadowing by a large QRS complex

15
Q

What will change the ECG?

A

Damaged heart muscles

- CVD = cardiovascular disease

16
Q

What is each complete heartbeat called?

A

Cardiac cycle

- regular and rhythmic

17
Q

What is the average beat per minute?

A

72

- 0.8sec long

18
Q

What is each cycle subdivided into? (2)

A
  1. Systole
    - contraction (lub)
  2. Diastole
    - relaxation (dub)
19
Q

Stroke volume

A

Amount of blood that one ventricle ejects with each beat

20
Q

Cardiac output

A

Volume of blood that flows out of a ventricle per unit of time
- mL/min

21
Q

What are the 5 phases of the cardiac cycle?

A
  1. Atrial systole
  2. Isovolumetric ventricular contraction
  3. Ejection
  4. Isovolumetric ventricular relaxation
  5. Passive ventricular filing
22
Q

Atrial systole

A

Atria contracts

- pressure gradient allows blood to flow into relaxed ventricles

23
Q

Isovolumnetric ventricular contraction (2)

A
  1. Intraventricular pressure begins to increase
  2. AV vales close
    - hearts first sound (lub)
24
Q

Ejection

A

SL valves open

- blood leaves the house

25
Q

Isovolumetric ventricular relaxation (2)

A
  1. Ventricles begin to relax
  2. SL valves close and AV valves open
    - second heart sound (dub)
26
Q

Passive ventricular filling (3)

A
  1. Intraventricular pressure drops and intra-artial pressure rises
  2. AV valves open
  3. Blood enters in
27
Q

What makes the sound of a heartbeat?

A

Heart valves opening and closing

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