Following our way through the Cardiac Cycle:

Step by step…

Atria and ventricles at

rest

Atrial Systole: 20% of

ventricular filling

Early ventricular contraction Obtain first heart sound: AV valves close “lub”

EDV

Isolvolumic ventricular contraction

Ventricular Ejection

Our second heart sound:

semilunar valves close

“dup”

ESV

Isovolumetric relaxation

Ventricular relaxation

We’re back to atrial and ventricular relaxation

Wiggers Diagram

Ausculation

Can we measure how much blood your heart pumps?

CO=SV X Heart Rate

What determines our stroke volume?

Stroke volume influenced by

Length of muscle fiber

contractility

Frank-Starling Law(length of muscle fiber)

Contractility influence by Norepinephrine

Drugs: in the news today! digitalis

Chapter 15 Blood Flow

Blood Pressure and Control of blood pressure

Picture 15-3

Then, how then does blood from your extremities get back to heart from these low pressure veins?

Skeletal and respiratory pumps

Varicose Vein Disorders

Spider VeinsDr. Berman

Measurements of blood pressure

•Systolic between 90 and 135 mmHg

Diastolic between 50 and 90 mmHg

NORMAL BP RANGES

1. Pulse pressure Systolic pressure-Diastolic pressure

measures strength of pressure wave

2. MEAN ARTERIAL PRESSURE MAP=1/3 Pulse Pressure + Diastolic pressure

MAP provides a single value that does not show aall the changes of arterial pressure.

Blood Pressure Day 1 Day 2

120/90 160/70

Now by calculating the mean arterial pressure, on which day is blood flow greatest to the tissues?

Local Controllers of Blood pressure

Myogenic autoregulation

Paracrines and smooth muscle

Chemical affects on our blood vessels

Norepinepherine Serotonin

NO Histamine Epinephrine

Vasocontriction

Vasodilation

Migraines: inappropriate vasodilation

Sumatriptan Serotonin agonist

Affect of some paracrines Active hyperemia

Reactive hyperemia

Coordination of blood pressure Control

Baroreceptors stretch

Action potentials to CNS

ANS