a brief information about human body vessels ,, their anatomy function location ,classification by different perspective and abnormalities of vessels ,

1. BLOOD VESSELS
Dr : aasim billal

2. Fun facts
• Chocolate can actually help the circulatory
system. According to the Northwest Health
Sciences University, chocolate contains cocoa
which has antioxidants that help protect the
cardiovascular system. The antioxidants help
lower blood pressure and help reduce deaths
related to cardiovascular disease. A 4-5 gram
serving per day is enough to gain the benefits
from the antioxidants found in cocoa.

3. Blood vascular system
• Also know as (cardiovascular system)
• Entirely lined by a special type of simple
squamous epithelium known as endothelium
• Carries blood in both direction b/w heart and
tissue
• This system consist of heart , arteries capillaries
and veins
• Capillaries having simplest structure

4. Capillaries
• Delicate endothelial tubes that connect
arterial and venous sides of the circulation
• Generally have a luminal diameter of 7 to
9 µm
• Arranged in form of network called capillary
bed
• Capillary wall have a single layer of flat
endothelial cells

5. Classification of capillaries
• On the basis of morphology
• 1:Continuous capillaries
• 2:Fenestrated capillaries
• 3:Sinusoidal capillaries

6. Continuous capillaries
• These capillaries neither show any endothelial
pores nor any large gap or discontinuities in their
wall
• Are typically found in the muscle ,lung ,skin and
central nervous system

7. Fenestrated capillaries
• presence of numerous circular pores (fenestrae)
in the lining endothelium cell.
• Pores range form 60 to 80 µm in diameter .
• Found in those region where rapid exchange of
substance b/w blood and tissue is required e.g
intestinal mucosa , endocrine , brain ventricle and
ciliary body of eye.
• capillaries of glomeruli of kidney are a special
variety of fenestrated capillaries.

8. Sinusoidal capillaries
• Large lumen(30 to 40µm), discontinuous
wall(irregular and tortuous), fenestrated
epithelium (permit a very rapid exchange of fluid
and macromolecule b/w blood and tissue.
• Show pores or wide gapes.
• Found in liver, spleen, and bone marrow .
• Also occur in some endocrine gland( hypopyhsis
cerebri and supra renal gland ).

9. Arteries and veins

10. General structure of arteries and veins
• Tunica externa (adventitia) - outermost layer
made of loose connective tissue. Serves to
anchor, protect and prevent overstretching
• Tunica media - middle layer composed of smooth
muscle; functions in dilation and constriction of
blood vessels
• Tunica interna(intima) - innermost layer made of
endothelium (s. squamous epithelium)

11. Arteries
• To carry blood away from the heart.
• Thick muscular walls.
• Lots of elastic tissue in wall.
• Small lumen.
• Blood flow high pressure.
• Blood flow rapid.
• No valves

12. Types of arteries
1: Arterioles
2: medium-size arteries
3: large arteries

13. Arterioles
• arteries with a diameter of less than 0.3mm
• Due to narrow lumina arterioles function is to
regulate the distribution of blood to different
capillary network by vasoconstriction or
vasodilation.
• Most arterioles can dilate 60 to 100% from their
resting diameter

14. Medium – size arterioles
• Also know as muscular arteries because their
thick walls contain a large amount of smooth
muscle in the tunica media.
• Most of the arteries belong to this group e.g
Axillary, radial femoral, popliteal, and tibial
arteries .

15. Large arteries
• Have a large diameter.
• Also called elastic arteries.
• Presence a large amount of elastic tissue in their
wall.
• Aorta and its main branches( bachiocephalic,
commoncarotid, subclavian, common illiac, and
pulmonary arteries belong to this variety of
arteries .

16. Arteriosclerosis
• with increase age, A pathological alteration in
the lateral wall of the arteries ,which result in
thickening and loss of elasticity.
• Major effect is a decrease in the caliber (i.e
narrowing) of the vessels wall, which result
ischemia ,necrosis .

17. Atherosclerosis
• This condition is characterized by the deposition
of soft, noncellular lipid material in the tunica
intima of arteries of the specific regions, this
leads to the formation of fibrofatty plaque called
antheromas,in the vessel wall that result partial
or complete occlusion of the lumen.
• Coronary, carotid, kidney and lower limb arteries
are most commonly affected.

19. Veins
• Carry blood back to the heart.
• Thin muscular wall.
• Little elastic tissue in the wall.
• Relatively large lumen.
• Blood under low pressure .
• No pulse.
• Valves prevent backflow of blood .

20. Types of veins
1: Venules
2: medium- size veins
3: large veins

21. Venules
• Capillary network are drained into venules ,
which are subclassified ,
• Postcapillary venules (less than 0.2 in diameter)
Also called pericytic venules.
Muscular venule(distal located to the postcapillary
venule ,large diameter up to 1mm)

22. Medium- size veins
• Daimeter from 1 to 10mm,
• Composed chiefly of bundle of collagen fibers
• Some elastic fiber are also present

23. Large veins
• Having daimeter large than 10mm.
• this group include the superior and inferior
vena cava ,pulmonary,portal,illiac, and renal
veins.
• Large vein is inferior vena cava.