CVS pptx - د. حيدر الكفائي

CARDIOVASCULAR SYSTEM HISTOLOGY

HEART ARTERIESVEINSCAPILLARIES100,000 - 150,000 Km

HEARTIs a modified blood vessel, consist of the following layers:

Epicardium
Myocardium
Endocardium

walls of heart chambers consist of three layers:

External Epicardium
Middle Myocardium
Internal Endocardium

Epicardium (visceral pericardium)

Adipose tissue in Epicardium

Blood vessels in Epicardium

EPICARDIUM

FAT
CONNECTIVE TISSUE
NERVE
MYOCARDIUM
MESOTHELIUM
Epicardium

Myocardium

Endocardium
Endothelium & supporting connective tissue
Middle myoelastic layer
Deep layer called the subendocardial layer

ENDOCARDIUM

PURKINJE
MYOCARDIUM
Ventricle
Atrium
ENDOCARDIUM
PURKINJE
MYOCARDIUM

Fibrous skeleton of the heart(Dense fibrous connective tissue)

Endothelium

Connective tissue
Endocardium
Atrium
Ventricle

Conductive system of the heart

Sinoatrial (SA) node (pacemaker)
Located in the right atrial wall near the S.V.C
6- to 7-mm3
Cardiac muscle cells with smaller size, fewer myofibrils and intercalated disks.

Purkinje fibers

Pale-staining fibers
Larger than the adjacent muscle fibers
Sparse, peripheral myofibrils & much glycogen

Vascular system

• Elastic Artery
• Muscular Artery
• Small Artery
• Arteriole
• Capillary
• Venule
• Small vein
• Medium size vein
• Large vein

Tunics(Layers) of the vascular wall

Comparison
Lumen
Media
Adventitia
Valves

Tissues of vascular wall

Endothelium:
• Metabolite exchange
• Nonthrombogenic surface
• Control of Vascular tone and blood flow
• Role in Inflammation
• Growth factors

Smooth muscle

Occur in the walls of all vessels larger than capillaries
Arranged helically in layers
Connected by gap junctions
Permit vasoconstriction & vasodilation

Connective tissue

Variable amounts and proportions
Collagen fibers
Elastic fibers

AORTA

VENA CAVA
INTIMA
MEDIA
ADVETITIA
INTIMA
MEDIA
ADVETITIA

INTIMA

MEDIA
ADVENTITIA
ARTERIOLE
NERVE
VENULE
Vasa vasorum

Elastic Artery

Endothelium

Internal Elastic Lamina
Smooth Muscle
Vasa Vasorum
Muscular artery

VENULE

ARTEIOLE
CAPILLARY

Thoroughfare channel (short circuit bypass channel)

Arteriole

Capillaries
Single layer of endothelial cells rolled up as a tube
Diameter of capillaries varies from 4 to 10 μm
Length not more than 50 μm
90% of the body’s vasculature
Total length of more than 100,000 km
Total surface area of approximately 5000 m2
Cyclical opening and closing of the sphincters
Have thin walls, extensive surface area, and slow pulsatile blood flow