Download cvs -UMK 2011 - UMK CARNIVORES 3

HISTOLOGY OF CVS
PROF. DR. FAUZIAH OTHMAN
DEPT OF HUMAN ANATOMY
CONTENT
Histological features of cardiac muscles,
epicardium, endocardium,
 Histological features of the Purkinje fibres.
 Histological features of the elastic artery,
muscular artery and arteriole
 Histological features of the large and medium
vein, venule.
 Histological features of capillaries.

Cardiac muscle
Striated
Involuntary
single, centrally placed nucleus
COVERING OF THE HEART
Pericardium
 The membrane surrounds to protects heart.
 Consist 2 principal portions:

• fibrous pericardium
• Serous pericardium
Fibrous Pericardium
Serous pericardium
•Superficial
•Tough
•Inelastic
•Dense irregular connective tissue
•Deeper
•Thinner
•More delicate membrane that
form double layer round the heart
Fx: prevent overstretching of
heart, provide protection & anchor
of the heart to mediastinum.
•Outer parietal of serous
pericardium –fused to fibrous
pericardium
Visceral layer of serous
pericardium--epicardium
HEART WALL

1.
2.
3.
Heart comprises of three layers;
Epicardium( external layer)
Myocardium ( middle layer)
Endocardium (inner layer)
Epicardium (epi= on top of)




Visceral layer of the serous pericardium
Thin, transparent outer layer of the wall
Composed mesothelium & CT

Myocardium (myo = muscle)




Composed cardiac muscle tissue
Responsible for pumping action.
Stratified, involuntary & intercalating bundles
Endocardium (endo= within)
thin layer of endometrium
 Smooth muscle
 The outmost layer is composed of irregularly
arranged collagen fibres that merge with collagen
surrounding adjacent cardiac muscle fibres. This
layer may contain some Purkinje fibres, which are
part of the impulse conducting system .

PURKINJE FIBERS (OR PURKYNE TISSUE)

are located in the inner ventricular walls of the
heart, just beneath the endocardium. These
fibers are specialized myocardial fibers that
conduct an electrical stimulus or impulse that
enables the heart to contract in a coordinated
fashion.
PURKINJE FIBERS
SPECIALIZED CARDIAC MUSCLE FIBERS
Heart: contracting cardiac muscle fibers and impulse-conducting
Purkinje fibers. Stain: Mallory-azan
5 MAIN TYPES OF BLOOD VESSELS
1.
2.
3.
4.
5.
Arteries (ar= air; ter= to carry)
Arterioles
Capillaries
Venules
Veins
TYPE OF ARTERIES

There are 3 types of arteries
Elastic arteries
 Muscular arteries
 Arterioles


The luminal diameter of artery gradually
decrease with each branching.
ARTERY

Wall have 3 tunics:
Tunica interna (intima)
 Tunica media
 Tunica externa

Tunica
interna (intima)
composed simple squamous epithelium (endothelium)
& layer elastic tissue (internal elastic lamina)
 Closest to lumen


Tunica media
Thickest layer
 Elastic fiber & smooth muscle fibers arranged in ring
around lumen


Tunica Externa

Composed principally of elastic & collagen fibers
Elastic arteries/ conducting
arteries
Muscular arteries/ distributing
arteries
Largest blood vessel in the body
Larger-diameter
Tunica media contain high
proportion of elastic fiber
Most numerous vessels in the
body.
Medium size
Tunica media contain high
proportion of smooth muscle fiber
Eg: brachial artery or popliteal
artery
Eg: aorta & pulmonary trunk
ARTERIOLE (= SMALL ARTERY)



The smallest branches of arterial system.
The wall of arteriole consist of one to five layers
of smooth muscle fibers.
Arteriole deliver blood to the capillaries, which
are microscopic blood vessels that connect
arteriole with the venules.
DIFERRENCES BETWEEN ARTERY & VEIN
Artery
Vein
•Thick and elastic muscular walls
•No valves
•carriers of oxygenated blood
(exception: pulmonary arteries
which carry de-oxygenated blood
from the heart to the lungs).
•Thin and slightly muscular walls.
•internal valves (to prevent back
flow of blood)
•veins carry de-oxygenated blood
(exception: pulmonary veins which
carry oxygenated blood from the
lungs to the heart)
Artery and vein in connective tissue of the vas deferens. Stain: iron
hematoxylin and alcian blue
Muscular artery and vein (transverse section). Stain: elastic stain
Blood and Lymphatic vessels stain with H&E
Wall of large vein: portal vein(tranverse section). Stain:H&E
Heart: right ventricle, pulmonary trunk, and pulmonary valve. Stain:
H&E
CAPILLARIES


Microscopic vessel that connect arteriole to
venule.
Capillary wall composed of ONLY a single layer
of endothelial cell & a basement membrane.

NO tunica media & NO tunica externa

Perculiar- protuding nucleus in the lumen.
Type of
Capillaries.
Continuous
Fenestrated
Discontinuous/
Sinusoidal
Plasma membrane of
endothelial cells form
are continuous tube
Plasma membrane of
endothelial cells have
many small pores,
ranging from 70-100nm
in diameter
Wider & more winding
than other capillaries
Found in skeletal
muscle, central nervous
system, skin, gonads,
connective tissue and
lungs
Found in
endocrine glands,
intestines, pancreas
and glomeruli of kidney
Large pores
Primarily located in the
liver, spleen, bone
marrow, lymph nodes,
and adrenal cortex.
VASA VASORUM


network of small blood vessels that supply large
blood vessels.
This is because:

The wall of larger arteries and vein are too thick to
receives nourishment direct diffusion from their
lumina .
VENULES


Several capillaries form small vein
The smallest venules, those closest to the
capillaries, consist of a tunica interna of
endothelium & tunica media that has only a few
scattered smooth muscle fiber & fibroblast.
VEINS
Same as tunica in arteries BUT different in
thickness.
 Tunica interna more thinner (little SM & elastic
fiber)
 Tunica externa of veins is thickest layer (collagen
& elastic fibers)
 Vena cava- longitudinal fiber of smooth muscle.


Veins LACK external or internal elastic lamina
found in arteries
CLINICAL CORRELATION

Congestive heart failure occurs when the heart is unable
to adequately pump blood. Because of this the body's
tissues don't receive enough blood to function properly.
Congestive heart failure can be a devastating disease for
both dogs and cats, striking primarily older and obese
animals