histology of Cardio vascular system 1

1. Histology of Cardiovascular
System
Faseeh

2. Cardiovascular System
• The mammalian blood vascular system consists
of the heart, major arteries, arterioles,
capillaries, venules, and veins.

3. Heart
• The wall of the heart consists of three layers: an
inner endocardium, a middle myocardium, and an
outer epicardium.
• Endocardium
– The endocardium consists of a simple squamous
endothelium and a thin subendothelial connective tissue.
– Deeper to the endocardium is the subendocardial layer
of connective tissue. Here are found small blood vessels
and Purkinje fibers.
– The subendocardial layer attaches to the endomysium of
the cardiac muscle fibers.

4. Heart
• Myocardium
– The myocardium is the thickest layer and consists
of cardiac muscle fibers.
• Epicardium
– The epicardium consists of a simple squamous
mesothelium and an underlying subepicardial
layer of connective tissue.
– The subepicardial layer contains coronary blood
vessels, nerves, and adipose tissue.

5. HEART
• Purkinje fibers
– impulse-conducting fibers, are located in the
subendocardial connective tissue.
– larger in size and lighter-staining properties.

10. Artery
• The wall of a typical artery contains three
concentric layers or tunics.
• Tunica Intima
– This layer consists of a simple squamous
epithelium, called endothelium in the vascular
system, and the underlying subendothelial
connective tissue.

11. Artery
• The middle layer is the tunica media,
composed primarily of smooth muscle fibers.
• Interspersed among the smooth muscle cells
are variable amounts of elastic and reticular
fibers.
• The outermost layer is the tunica adventitia,
composed primarily of collagen
• and elastic connective tissue fibers

13. Types of Arteries
• Elastic arteries
• Muscular arteries
• Arterioles

14. Elastic Artery
• Tunica intima is made up of an epithelium, which
is a single layer of flattened epithelial cells,
together with a supporting layer of elastin rich
collagen.
• Tunica media is broad and elastic with concentric
fenestrated sheets of elastin, and collagen and
only relatively few smooth muscle fibres.
• Tunica adventitia - has small 'vasa vasorum' as
the large arteries need their own blood supply.

19. Muscular artery
• The tunica intima has an endothelium of
flattened endothelial cells.
• The tunica media is primarily a layer of
smooth muscle, with some elastin an collagen.
muscle layer, and is sandwiched between the
IEL and EEL.
• The Tunica Adventitia is very broad, and
mostly contains collagen and elastin.

25. Arterioles
• The tunica intima is very thin, and mostly
consists of a single layer of squamous
epithelium.
• The tunica media consists almost entirely of a
single layer up to five layers of smooth muscle
cells, and there is no EEL.
• The Tunica adventitia is about the same size
as the tunica media layer, merges in with
surrounding tissue.