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
Our second heart sound:
semilunar valves close
“dup”
ESV
Isovolumetric relaxation
Ventricular Ejection
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 Veins
Dr. Berman
Measurements of blood pressure
NORMAL BP RANGES
•Systolic between 90 and 135 mmHg
Diastolic between 50 and 90 mmHg
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 a
all 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