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BIEN 140B > Cardiac Bioengineering > Flashcards

Flashcards in Cardiac Bioengineering Deck (26)
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1

What wraps the heart?

a protective sheath called the Pericardium

2

What are the three layers of the heart?

Epicardium - outer layer including connective tissue
Myocardium - the cardiac muscle
Endocardium - endothelium layer

3

What is the cardiac muscle?

myocardium
only found in heart
contracts to pump blood through heart
appears striated, long cells
short branching cell with one or two large nuclei
cardiac fibers join the cells for cellular networks
free passage of ions

4

What are the chambers of the heart?

Two atria- receiving chamber
Two ventricles - discharging chamber

5

How many valves are there?

4 unidirectional valves

6

What are the atriventricular valves?

between atria and ventricles
tricuspid (right atria-ventricular valve)
bicuspid/mitral valve ( left atria-ventricular valve)

7

What are the semilunar valves?

between ventricle and artery
pulmonary valve
aortic valve

8

How are the systems for heart beat?

Sinoatrial Node
Atrioventricular Node
His-Purkinje System

9

What is the SA node?

sinoatrial node
natural pacemaker
contains specialized innervated cells
produces 60-100 electrical signals per minute

10

What is the AV node?

atrioventricular node
located in the bridge between the atria and ventricles
electric signals pass from the atria down to the ventricles through the AV node

11

What is the Purkinje System?

carries electrical signal throughout the ventricles to produced contractions

12

What are the steps for cardiac conduction?

Pacemaker impulse generation
AV node impulse conduction
AV bundle conduction
Purkinje fiber conduction

13

What is an electrocardiogram?

ECG/EKG
measures cell potential
measure of cardiac muscle depolarization followed by depolarization

14

What are the three components of ECG?

P wave: depolarization of atria, pacemaker firing
QRS complex: depolarization of ventricles
T wave: depolarization of ventricles

15

What are the important segments of the ECG?

PR interval: time electrical impulse takes to travel from SA to AV
ST segment: time in which ventricles are depolarized
QT: ventricle contraction until the heart is ready to fire again

16

What is a cardiogram?

graph of voltage v time

17

What is a pacemaker?

electrode device used to imitated a heartbeat when the intrinsic system fails when there is no output or signal is too weak to generate enough

18

What are the components of the pacemaker?

pulse generator
electrode
battery
sensor
leads
can be single or dual chamber

19

What are the types of heart valves?

mechanical: inert and durable
bioprosthetic: animal tissue

20

What is the silastic ball valve?

mechanical heart valve
bulky
not suitable for mitral replacement
induces hemolysis
smaller sizes become stenotic

21

What is the tilting disc valve?

good hemodynamics
excellent durability
central laminar flow
anticoagulation mandatory (therapy)
higher risk of thrombosis

22

What is the St. Jude medical bileaflet valve?

most common
low bulk, light weight
superior hemodynamics
greater opening area
performs well under a range of cardiac pressures

23

What is the trileaflet?

closer mimic of physiological function
even greater hemodynamics
reduced thombosis

24

Describe bioprosthetic heart valves.

xenograft
allograft
stented or stentless
scentless: lower post op gradient, greater flow, earlier regression of LVH, implantation is more complex

25

What is an artificial heart?

duplicates the rate, output and blood pressure of the natural heart

26

What is a ventricular artificial heart?

two heart pumps connected to a power console
each pump is implanted into area left behind from extraction
pneumatic pump