A&P - Chapter 28 (Part 3)

Question 1

What are 4 structures that generate strong impulses?

Answer 1

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

Question 2

What is the pacemaker of the heart?

Answer 2

SA node

Question 3

What does the SA node do?

Answer 3

It initiates impulses/heartbeats and sets its pace

Question 4

Where is the SA node?

Answer 4

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

Question 5

Where is the AV node located?

Answer 5

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

Question 6

Where is the AV bundle located?

Answer 6

In the septum of the ventricle

Question 7

Where are the Purkinje fibres located?

Answer 7

In the walls of the ventricles

Question 8

ECG

Answer 8

Electrocardiogram

Question 9

Electrocardiogram

Answer 9

The recording of the electrical impulses of the hearts conduction system

Question 10

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

Answer 10

1. P Wave
2. QRS complex
3. T Wave

Question 11

P wave

Answer 11

Represents depolarization of the atria

- triggers contraction

Question 12

QRS complex

Answer 12

Represents depolarization on the ventricles

Question 13

T wave

Answer 13

Represents re-polarization of the ventricles

- just before relaxation phase

Question 14

What is not shown on an ECG?

Answer 14

Re-polarization of the aorta

- overshadowing by a large QRS complex

Question 15

What will change the ECG?

Answer 15

Damaged heart muscles

- CVD = cardiovascular disease

Question 16

What is each complete heartbeat called?

Answer 16

Cardiac cycle

- regular and rhythmic

Question 17

What is the average beat per minute?

Answer 17

72

- 0.8sec long

Question 18

What is each cycle subdivided into? (2)

Answer 18

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

Question 19

Stroke volume

Answer 19

Amount of blood that one ventricle ejects with each beat

Question 20

Cardiac output

Answer 20

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

Question 21

What are the 5 phases of the cardiac cycle?

Answer 21

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

Question 22

Atrial systole

Answer 22

Atria contracts

- pressure gradient allows blood to flow into relaxed ventricles

Question 23

Isovolumnetric ventricular contraction (2)

Answer 23

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

Question 24

Ejection

Answer 24

SL valves open

- blood leaves the house

Question 25

Isovolumetric ventricular relaxation (2)

Answer 25

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

Question 26

Passive ventricular filling (3)

Answer 26

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

Question 27

What makes the sound of a heartbeat?

Answer 27

Heart valves opening and closing