Major Determinants Of Ventricular Function Lecture

Front 1

What is the fundamental morphological unit of cardiac muscle?

Back 1

Sarcomere

Front 2

TRUE/FALSE - The heart generates tension via the shortening of its muscular fibers, which is manifest as the ejection of a volume of blood.

Back 2

False - heart generates pressue not tension

Front 3

Describe the concept of Preload.

Back 3

Preload is the force necessary to stretch the relaxed muscle to its initial length.

Front 4

Why is Preload important?

Back 4

The degree of initial stretch effects the muscle's ability to stretch upon stimulation.

Front 5

TRUE/FALSE - Maximal Resting Sarcomere length is around 2.2 microns

Back 5

True

Front 6

Diastolic ventricular function can be thought of as chamber compliance or distensibility. What are the major determinants of compliance?

Back 6

The active process of muscular relaxation and the passive elastic properties of the left ventricle which define the intrinsic stiffness of cardiac muscle are the major determinants.

Front 7

Describe isotonic contractions.

Back 7

An isotonic contraction is a contraction which occurs with no load on the muscle in which developed force is negligible and velocity of shortening is maximal.

Front 8

Describe isometric contractions.

Back 8

An isometric contraction occurs when the muscle is stimulated to contract against a load and no shortening occurs so that developed force is maximal and velocity of shortening is negligible

Front 9

Afterload is determined largely by (blank) and impedance to (blank).

Back 9

PVR and ventricular ejection

Front 10

TRUE/FALSE - Contractility is a change in cardiac function independent of variation in AL & PL.

Back 10

True

Front 11

Describe the concept of Afterload.

Back 11

The tension, force or stress (force per unit of cross-sectional area) acting on the fibers in the ventricular wall after the onset of shortening.

Front 12

Cardiac Output = HR x ?

Back 12

Stroke Volume