Cardiovascular System I: Heart Anatomy and Physiology
 Cardiovascular System Defined
 Gross Anatomy of the Heart
 Operation of Heart Valves
 Cardiac Cycle and Heart Sounds
 Cardiac Cycle and the EKG (ECG)
 Electrical Conduction in the Heart
The Cardiovascular System Defined
 What it is:
• A closed system of the
heart and blood vessels
o The heart pumps blood
o Blood vessels allow
blood to circulate to all
parts of the body
 Function:
• Deliver oxygen and
nutrients and to remove
carbon dioxide and
other waste products
Heart Gross Anatomy
•
Location: Mediastinum of the thorax
•
Size: As big as your fist
•
Serous Membrane Coverings:
1.
Epicardium (= visceral pericardium) innermost
2.
Parietal pericardium outermost
3.
Mediastinal pleura outside that
The Heart Wall: Three Layers
Visceral
Parietal
Myocardium
Endocardium
Pericardium
Pericardium
(Epicardium)
Parietal
= visceral
pericardium
Exception: In the heart layers, peri- is outside of epi-
Corornal Section of Human Heart
Operation of Heart Valves
AV valves
Semilunar
valves
Stenotic and Regurgitant Valve Conditions
Heart sounds movie online
Flow of Blood Through the Heart
Coronary Circulation: Blood Feeding the Heart
Blockage of these vescles causes ischemia (lack of O2), causing muscle death (myocardio
infarct), and chest pain (angina pectoris)
Posterior View of Real Heart
Auscultation of Heart Sounds
Sounds 1
PCG: Phonocardiograph
lub
dup
“S1”
“S2”
Split S1
Heart sound talk
Auscultation
Split S2
The Heart: Conduction System

Intrinsic conduction system
(nodal system)
•

Heart muscle cells
contract, without nerve
impulses, in a regular,
continuous way
Special tissue sets the pace
1.
Sinoatrial node
a.
Pacemaker
2.
Atrioventricular node
3.
Atrioventricular bundle
4.
Bundle branches
5.
Purkinje fibers

Contraction is initiated by the
sinoatrial node

Sequential stimulation occurs at
other autorhythmic cells
Exterior conduction
Pacemaker with electrode in right ventricle
Filling of Heart Chambers – the Cardiac Cycle
 1. Atria contract simultaneously
 2. Atria relax, then ventricles contract
 Systole = contraction (can be subdivided into atrial and ventricular contraction
but otherwise refers to ventricular systole)
 Diastole = relaxation (ventricular)
Figure 11.6
Cardiac Cycle and Electrocardiography
P
Q
R
S
T
U
Note that an
ECG does not
show actual
contractions
but excitation
and
depolarizations
Cardiac cycle – events of one complete heart beat
•
Mid-to-late diastole – blood flows into ventricles
•
Ventricular systole – blood pressure builds before ventricle
contracts, pushing out blood
•
Early diastole – atria finish re-filling, ventricular pressure is low
Pressure, ECG,
and Heart online
EKG, Heart
contractions,
conduction online
Heart Voltages and the ECG
Arrhythmias
Heart block
Hookups for the ECG