Download Ch 21: Cardiovascular System - The Heart -

Ch 21: Cardiovascular System
- The Heart -
Pulmonary & Systemic Circuits
artery
vein
capillaries
Location of Heart within
Thoracic Cavity
Pericardium

serous membrane (serosa) lines pericardial cavity
– visceral pericardium
– parietal pericardium
10-20 ml of
pericardial fluid
Structure of the Heart Wall



Epicardium = visceral Pericardium (serosa)
Myocardium: muscle tissue + c.t. + blood vessels + ?
Endocardium: simple squamous epithelium continuous
with endothelia
of blood vessels
Cardiac Muscle
difference to skeletal muscle??
Intercalated Discs
• Desmosomes &
• Gap Junctions
functional syncytium
= fused mass of cells
Fibrous Skeleton
Lots of collagen and elastic fibers in the
connective tissue of the heart.
function:?
 support (eg: fibrous rings supporting valves)
 prevents over-expansion
 elasticity helps to return to original shape
 physical separation of atria from ventricles
Fibrous skeleton
= internal c.t. network
Surface Anatomy of Heart

Auricle of atria (expandable)

Coronary sulcus (between atria &
ventricles)

Ant. & post. interventricular sulcus

Base (3rd costal cartilage) vs. apex (5th intercostal
space)

Vessels entering & leaving the heart
Sectional (Internal) Heart
Anatomy

Atria & ventricles

Interatrial & interventricular septae

Valves (fibrous tissue)

Pectinate muscles (auricles & ant. atria)

Trabeculae carneae (ventricles)

Chordae tendinae & papillary muscles
Left vs. Right Ventricle

Left: high
pressure pump

Right: low
pressure pump

ventricular
contraction also
functions as
“suction pump”
4 Sets of Valves
= Mitral valve
Mitral Valve Prolapse

Most common cardiac variation (~ 10% of
population)

Mitral valve cusps do not close properly

Regurgitation during left ventricular systole
How can you diagnose?
Not life threatening; may be life-stile threatening
Ventricular Systole:
function of valves: ??
Ventricular Diastole:
Auscultation of Heart Sounds:
1st HS: at beginning of ventricular contraction, due to?
2nd HS: at beginning of ventricular diastole, due to?
Coronary Blood Vessels
Coronary arteries: first branches off the ascending aorta.
coronary veins
post. view
coronary sinus
right atrium
(inferior to opening
of inferior vena cava)
Coronary Artery Disease (CAD)
due to ?
consequences ?
PET scan
the brighter the color the greater the blood flow through tissue
Myocardial Infarction (MI)
= Heart attack

Ischemic tissue degenerates
area = infarct
nonfunctional

Most commonly due to severe CAD
(coronary thrombosis)

~ 1.3 Mio MIs / year in US

Predisposing factors?
Conducting System of Heart
(= bundle of His)
Cardiac Cycle, EKG,
Autonomic Control of Heart
Rate covered in Physiology
the end