1. General Anatomy of Cardiovascular System.By
Dr. Suhail Ahmad.

2. Blood Vascular System.
One of the major and more important systems of the body.
Consists of heart and blood vessels

3. Blood Vascular System.
An efficient mode of transport for oxygen, nutrients, and waste products to and from body tissues.
Heart is the mechanical pump that propels the blood through the vessels.
Heart and blood vessels form a closed-loop system.

7. Blood vessels A closed system of tubes in which the blood circulates.
Arteries
Veins
capillaries
Blood vessels are not rigid and immobile.
Can pulsate and change shape in accordance with the body’s needs.

8. Blood Vessels: Did you know….
Humans have about 60,000 miles of vessels
Vessels reach every millimeter of tissue
We have at least two veins for every artery in our extremities
We have 200 miles of vessels in every pound of adipose tissue

9. Blood vessels
Naming:
Often share names with either the body region they traverse or the bone next to them.
Some are named for the structure they supply.
Arteries and veins that travel together sometimes share the same name.

10. Three Main Classes of Blood Vessels
Arteries convey blood away from the heart to the body tissues.
Arteries branch, or bifurcate, into smaller and smaller vessels (arterioles) until they feed into the capillaries, where gas and nutrient exchange occurs.
From the capillaries, veins return blood to the heart.

11. Three Main Classes of Blood Vessels
Arteries become progressively smaller as they divide and get further from the heart.
Veins become progressively larger as they merge and get closer to the heart.

14. Blood Vessel Tunics Tunica Intima Tunica Media innermost layer
composed of:
an endothelium (simple squamous epithelium)
subendothelial layer (areolar CT)
Tunica Media
middle layer of the vessel wall
circularly arranged smooth muscle cells

15. Blood Vessel Tunics Tunica Externa, or Tunica Adventitia
outermost layer
composed of:
areolar connective tissue that contains elastic and collagen fibers
helps anchor the vessel to other tissues
Term adventitia is used to specify outer layer in blood vessels that are buried in CT
Vasa vasorum : blood vessels that supply large blood vessels
In the externa

16. Arteries
In the systemic circulation, carry oxygenated blood to the body tissues.
Pulmonary arteries carry deoxygenated blood to the lungs.
Three basic types of arteries:
elastic arteries, muscular arteries, and arterioles
as an artery’s diameter decreases
corresponding decrease in the amount of elastic fibers
relative increase in the amount of smooth muscle

17. Arteries Types of arteries Elastic arteries
Contain elastic fibers in the tunica media and interna
Largest arteries

18. Arteries Elastic arteries: act as conduits 1-2.5 cm diameter
Expand with surge
of blood from heart
Recoil and continue
the propagation of blood
Elastin is thick in media:
dampens the surge of blood
pressure
Aorta and its branches

19. Arteries

20. Arteries Muscular arteries Little elasticity
Abundant smooth muscle in tunica media

21. Arteries 2. Muscular arteries: act as distributing arteries
Middle sized .3mm-1cm
Changes diameter to differentially regulate flow to organs as needed
Internal as well as external elastic lamina
Most of what we see as “arteries”
Tunica media larger in proportion to the lumen, thus “muscular”

22. Arteries

23. Arterioles < 1mm in diameter Endothelium and smooth muscle
Metarterioles regulate flow of blood into capillaries
Help regulate blood pressure

26. Capillaries Contain only the tunica intima.
Allow gas and nutrient exchange between the blood and the body tissues to occur rapidly.
Smallest blood vessels, connect arterioles to venules(5-10 micrometer).
Are called the functional units of the cardiovascular system.
A group of capillaries (10–100) functions together and forms a capillary bed.

27. The Three Basic Kinds of Capillaries
Continuous capillaries
the most common type
Fenestrated capillaries
Extensive molecular exchange(kidney, endocrine glands, intestines)
Sinusoids, or discontinuous capillaries
Liver, spleen

30. Veins Drain capillaries and return the blood to the heart.
Walls are relatively thin and the vein lumen is larger.
Systemic veins carry deoxygenated blood to the right atrium of the heart, while pulmonary veins carry oxygenated blood to the left atrium of the heart.

31. Veins
Blood pressure is substantially reduced by the time blood reaches the veins.
Hold about 60% of the body’s blood at rest.
Veins function as blood reservoirs
Venae comitantes
Venous plexuses(Pampiniform)

32. From Venules to Veins Venules merge to form veins.
Venule becomes a “vein” when its diameter is greater than 100 micrometers.
Blood pressure in veins is too low to overcome the forces of gravity.
Veins contain one-way numerous valves
to prevent blood backflow in the veins.
To assist in moving blood back to the heart.

33. Veins

34. From Venules to Veins
Many deep veins pass between skeletal muscle groups.
As the skeletal muscles contract, veins are squeezed to help pump the blood toward the heart.
This process is called the skeletal muscle pump.

36. Small sized veins
Medium sized veins
Large veins

38. Artery/Vein differences
Arteries (aa.)
Veins (vv.)
Direction of flow
Blood Away from Heart
Blood to Heart
Pressure
Higher
Lower
Walls
THICKER: Tunica media thicker than tunica externa
THINNER: Tunica externa thicker than tunica media
Lumen
Smaller
Larger
Valves
No valves

39. Sympathetic innervation:
Increase: vasoconstriction (narrowing of the blood vessel lumen)
Decrease: vasodilation (widening of the blood vessel lumen)

40. Vascular Anastomoses Vessels unite and connect
Anastomosis: Site where two or more vessels communicate to supply the same body region.
Arterial
Venous
Arteriovenous

41. Vascular Anastomoses Arterial Anastomoses
Communication between arteries
Joints, Abdominal Organs, Brain
alternate route
Types of arterial anastomosis:
Heterocladic & homocladic
End to end, convergence, transverse

45. Vascular Anastomoses Functional end arteries(potential anastomosis)
Have small anastomoses at capillary level
E.g.: coronary arteries
End arteries
Arteries that do not form anastomoses
Only one route
E.g.: renal artery, splenic artery, central artery of retina.

46. Vascular Anastomoses Venous Anastomoses Communication between veins
More common
(eg) back of hand
Veins tend to form many more anastomoses than do arteries.

48. Vascular Anastomoses
Arterio-venous anatomoses: blood flows directly from arteries to veins without passing through capillary bed.
Simple A-V anastomosis
Between branches of small arteries and their corresponding veins(skin of nose, lips, external ear)
Preferential thoroughfare channels
Arteriolo-venular with capillaries as side branches(almost everywhere)

50. Complex A-V anastomosis(glomera)
Coiled vessels
Regulate temperature & regional blood flow
Corium of hands, digital pads, nail beds

51. Circulatory systems of the body.
Systemic circulation
consists of the blood vessels that extend to and from the body tissues.
Pulmonary circulation
consists of the vessels that take the blood to the lungs for gas exchange.
Coronary Circulation
Blood flow to and from the myocardial capillaries
Portal circulation

54. Portal System
Special vascular circulation where blood goes through 2 capillary beds before returning to the heart .
Venous portal systems
Hepatic portal
Hypothalamo- hypophyseal
Arterial portal system
Renal

55. Hepatic portal system
Picks up digested nutrients from stomach & intestines and delivers them to liver for processing and storage
Storage of nutrients
Detoxification of toxins, drugs, etc.
Two capillary beds
Route: artery to capillaries of gut to hepatic portal vein to liver’s capillaries to hepatic vein to IVC

59. Renal portal system.

60. Arteriosclerosis
Atherosclerosis
Varicose veins