3. Learning objectives are:
Classify the circulatory system.
a)Cardiovascular system:
•Define cardiovascular system and its main components Blood, Heart & Blood vessels.
•Describe blood and its composition.
•Explain the classifiaction & structure of different types of blood vessels.
•Define and classify the anastomosis with their clinical correlates.
•Describe different types of circulatory routes.
b) Lymphatic System:
Define and describe the components of lymphatic system.
Comprehend the mechanism of production and circulation of lymph
Describe the function of lymphatic system and its role in spread of infection annd cancer.
7. Red blood cells/ Erythrocytes
• Most numerous
• 4-6 millions per microliter
of blood
• Non-nucleated, biconcave
disc
• 8µm and 2µm
• Iron containing
pigment…… hemoglobin
• Colour
8. White blood cells/ Leukocytes
• Count………4000-11,000 cells
per microliter of blood
• Contain nuclei
• Function ……… destroy
microorganism at infection
sites
• Act as scavengers
• 2 types
– Granulocytes
– Agranulocytes
9.
10. Platelets
• Small, flat cytoplasmic fragments
• Count ……… 150,000 -400,000 per microliter of
blood
• 2-4 µm
• Do not contain nucleus
• Function …… blood clotting
11. Layers of the Heart
• There are 3 layers
1. Endocardium
2. Myocardium
3. Epicardium ( visceral layer of serous
pericardium)
12. 1- Endocardium
• The innermost layer is called the endocardium.
• It corresponds to the tunica intima of blood vessels.
• The endocardium is a thin layer of connective tissue
lined by simple squamous endothelium.
• Between the endocardium and myocardium is a
layer of variable thickness called the subendocardial
layer containing small nerves and in the ventricles
the conducting (Purkinje) fibers
13. 2- Myocardium
• The myocardium is the thickest of the tunics of the
heart and consists of cardiac muscle cells
• Consists of anastomosing network of branching
cardiac muscle fibers,which are arranged in layers
separated from one another by slender connective
tissue
• Cardiac muscle is striated but the striation are faint,
has intercalated disks.
• Each cell has a elongated oval nucleus which is
centrally located
15. 3- Epicardium
• Simple squamous epithelium (mesothelium) supported by
a thin layer of connective tissue.
• A subepicardial layer of loose connective tissue contains
coronary veins, nerves, nerve ganglia.
• The adipose tissue that generally surrounds the heart
accumulates in this layer.
• The epicardium corresponds to the visceral layer of the
pericardium
• Between the visceral layer (epicardium) and the parietal
layer is a small amount of fluid that facilitates the heart's
movements
17. 1. The tunica intima is the
inner lining
2. The tunica media is the
middle layer
3. The tunica adventitia is
the outer layer.
STRUCTURAL PLAN OF BLOOD VESSELS:
18.
19. • Vasa Vasorum :
o These are the vessels supplying the vessels
o They are present in the adventitia and media of
large vessels
o Supply the outer 2 layers as blood cannot diffuse
from the lumen to them.
24. • Arterioles
• Are the smallest arteries
– The term arterioles stand for
terminal arterial vessels
having a caliber of 0.2 -
0.4mm
– They do not have an internal
elastic lamina and only few
layers of smooth muscle in
the media
25. Capillaries
• Small vessels, diameter 7-
9µm.Only the tunica intima is
present, which typically only
consists of the endothelium
• The wall of capillary is formed
by a single endothelial cell
28. • Venules
o The smallest veins, into which
capillaries drain are called Venules
o They are 20-30 micro meter in
diameter
o It consists of endothelium, basal
lamina and thin adventitia
o Venules having pericytes outside
basal lamina are called Post-capillary
venules .
o Venules with some muscle are called
Muscular venules
o Site for exchange of white blood cells
and lymphocytes.
29. Edema:
junctions between
endothelial cells of post
capillary Venules are the
loosest of the
microvasculature. This
facilitates trans endothelial
migration of leucocytes at
these locations during
INFLAMMATION.As well as
loss of fluid leading to tissue
edema.
30. o Their thickness is typically
much less than the diameter
of the lumen
o A wall similar to that of
arteries but with a thinner
tunica media
o Tunica media contains much
larger quantity of collagen and
less elastic tissue and muscle
o With such relatively thin walls,
veins tend to appear flattened
or collapsed in cross-section in
histological preparations
o Adventitia of veins is thicker
than media.
Veins
33. • Formed by reduplication of
Tunica Intima.
• Prevent backward flow of
blood.
• Are most numerous in the veins
of the limbs
• It consists of fibroelastic tissue
lined on both sides by
endothelim.
Venous valves
35. Structure of microvasculature
• Consists of blood vessels of less than 0.5
mm diameter.
• Include arterioles and their smaller
branches metarterioles in which the
layer of smooth muscle cells is dispersed
as bands of cells that act as precapillary
sphincters.
• The distal portion of the metarteriole,
sometimes called a thoroughfare
channel.
• The wall of capillaries lacks smooth
muscle cells altogether.
• Capillaries and the metarteriole
converge as postcapillary venules,the
last component of the microvasculature
36.
37.
38. Capillary with pericyte.
• Capillaries are normally
associated with
perivascular contractile
cells called pericytes
39. Pericytes
o Located along the long axis of
continuous capillaries
o Elongated cell with long
cytoplasmic processes
o Contain myosin, actin and
tropomyosin. have contractile
properties and can regulate
blood flow in capillaries
o They can also differentiate into
endothelial and smooth muscle
cells
40. Diabetic microangiopathy
The hyperglycemia that occurs with
diabetes commonly leads to Diabetic
microangiopathy,a diffuse thickening
of the capillary basal laminae and
decrease in metaboloic exchange at
tissue vessels particularly in kidneys
and retina.
44. Anastomosis Of Blood Vessels:
A union between the distal ends of blood vessels
permitting free communication between arterioles and
venules.
Anastomosis serve to equalize pressure differences
It provide an alternative route of blood flow.
45. Collateral Circulation
• The alternative route of blood to a body part
through an anastomosis is called a collateral
circulation.
52. Arteriovenous Anastomosis
These channals serve as a pathway for shunting arterial blood directly into
venous system.
Like preferential channels they play an important role in regulating the blood
flow in specific regions of body according to functional requirements.
Those found in skin serve to regulate the body temperature.
Location: lips, external ear ,nose
64. Lymph:
The TISSUE FLUID formed at the arterial end of capillaries and most of it
is returned to the circulation via the venous end of capillaries,but 10-20%
of tissue fluid passes into blind ending lymphatics known as Lymph
Chyle is lymph collected from GIT .
All the tissues of body drained by lymphatic vessels Except CNS,
Bonemarrow ,COATS of eyeball
65.
66. Lymph Capillaries
• Originate in various tissue as thin
close ended vessel
• Consisting of single layer of
endothelium
• Incomplete basal lamina
• Intercellular clefts allow access of
macromolecules to the capillary
lumen.
• Anchoring filaments of elastic fibers
bind the vessels firmly to the
surrounding connective tissue.
• Abundant near the inner and
outermost surfaces of bodye.g
• Dermis of skin,Mucosa of respiratory
and digestive system
Millary
TrichomeX200
67. Lymphatic Vessels
o Lymphatic capillaries converge to
form large lymphatic vessels.
o Vessels have thin walls.
o Lack of clear cut demarcation
between tunics.
o Numerous internal valves.
.
.
Millary trichomeX200
68. Tunics of lymphatics
• Tunica intima : Lined by endothelium,
underneath which is present a delicate
network of elastic and collagen fibers
• Tunica media :Is composed of smooth
muscle fibers with few elastic fibers.
• Tunica adventatia :Thickest coat consist of
longitudinally running collagenous ,elastic
fibers and few smooth muscle cells.
69. Lymphatic Ducts
Lymphatic vessel end up into two large trunks
1-Thoracic duct
2-Right lymphatic duct.
Structure is similar to large vein except the presence of great amount of smooth muscles in
the media.
Tunica Intima: Endothelium and subendothelial layer of delicate connective tissue with few
smooth muscle fibres.
Tunica media: Logitudional and circular bundles of smooth muscles and collagen fibres
Tunica adventatia: poorly developed contains collagen fibres,few smooth muscle cells,vasa
vasorum and vasa nervi.
70. Lymph Nodes:
Kidney/ bean shaped structure present along the pathways of lymphatic
vessels.
1-25mm in length
Grouped as Superficial and Deep lymph nodes
They filter out the harmful microorganism and other foreign substances
from the lymph.
They also add lymphocytes to the lymph which is eventually delivered to
the blood
