cvs system lecture 01

7/27/2019 CVS system lecture 01

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MIS 264SESSION 1

HISTOLOGY OF THE

CARDIOVASCULAR SYSTEM

2013


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THE VASCULAR SYSTEM


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GENERAL STRUCTURE OF

BLOOD VESSELS

Tunics of the blood vessel wall:

Tunica intima

Tunica media

Tunica adventitia


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BLOOD VESSEL WALLTunica Intima

Endothelial layer

Basal lamina

Subendothelium

Loose connective tissue

Smooth muscle cells

Internal elastic lamina

(Arteries)

Venous valves

(endoteel + bl+

Subendothelium)


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Smooth muscle tissue

Connective tissue (elastic-, reticular-

collagen- fibres) Ground substance

External elastic lamina (larger arteries)

Concentric layers

170 layers

BLOOD VESSEL WALLTunica Media


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Connective tissue Loose- to dense connective tissue

(collagen type I fibres and elastic fibres)

Ground substance

Connective tissue fuse with surrounding connectivetissue

Vasa vasorum

Nervi vascularis

BLOOD VESSEL WALLTunica Adventitia


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GENERAL STRUCTURE OF ARTERIES

AND VEINS


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SPECIFIC HISTOLOGICAL STRUCTURE

OF BLOOD VESSELS

Capillaries

Arteries

Veins


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CAPILLARIES

General structure

COMPOSED OF:

Single layer of endothelial cells, resting on a

Basal lamina

Pericytes are genrally found on the outer surface

of capillares en venules, enclosed in the basal

lamina of the capillaries endothelial cells

Pericytes are able to contract and differentiate

into endothelial cells, smooth muscle cells and

fibroblasts; during repair and growth of

capillaries


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CONTINUOUS CAPILLARIES

FENESTRATED CAPILLARIES WITH A

DIAPHRAGM

FENESTRATED CAPILLARIES WITHOUT

A DIAPHRAGM

SINUSOIDS

TYPES OF CAPILLARIES


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Endothelium:

Continuousno openings between adjacent cells - limitsthe movement of substances between cells

No fenestrae in the capillary wall

Large number of pinocytotic vesicles* (70 nm) present,

responsible for the transport of macro-molecules across the

endothelial cell layer

Basal lamina: Continuous basal lamina

Regulate movement of substances across this lamina



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Occurrence:

Muscle tissue, lung, most connective tissues, exocrineglands and nervous tissue

Remarks:

Pinocytotic vesicles is absent or limited in the capillariesof the Central Nervous System (Blood brain barrier)

limited and regulated transport of macro-molecules across

the endothelium

Pericytes may be present

CONTINUOUS CAPILLARIES (cont.)


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Remarks: It is encountered in tissues where rapid interchange of

larger molecular substances occurs between the tissues and

the blood and/or fluid absorption

Endothelium: Large fenestrae (80100 nm) present in the endothelial

wall - fenestrae covered with a diaphragmregulated

transport of larger molecules

Pinocytotic vesiclestransport of macro-molecules across

the endothelial layer

Basal lamina: Continuous basal lamina

Regulate movement of substances across this lamina


DIAPHRAGM


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Occurrance: It is encountered in tissues where rapid interchange of

larger molecular substances occurs between

the tissues and the blood and/or fluid absorption

Peritubular network and vasa recta of the kidney, smallintestine, endocrine glands and gall bladder

Remarks:

Fenestrae (80100 nm) creates channels across the fullthickness of the edothelial layer

Diaphragm regulates the transport of substances

The number of fenestrae and pinocytotic vesicles correlate

with the functional activity across the capillary wall


DIAPHRAGM


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DIAPHRAGM


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Remarks: Renal glomeruluscontribute to the urinary filtration

barrier

Endothelium: Large fenestrae (80100 nm) present in the endothelial

wall - NO diaphragmtransport of larger molecules

Pinocytotic vesiclestransport of macro-molecules across

the endothelial layer

Basal lamina: Thickend continuous basal lamina

Increased regulation of movement of substances across this

lamina

FENESTRATED CAPILLARIES

WITHOUT A DIAPHRAGM


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Occurrance: Renal glomeruluscontribute to the urinary filtration

barrier

Remarks: Fenestrae (80100 nm) creates channels across the full

thickness of the edothelial layer

Urinary filtration barrier consists of capillary endothelium,

fused basal laminas of the endothelial cells and Podocytes,

and pedicels of Podocytes. The filtration slits between the

pedicels of podocytes are covered b a diaphragm

FENESTRATED CAPILLARIES

WITHOUT A DIAPHRAGM (cont.)


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Remarks:

Lumen has a large diameter, which slow the circulation ofblood

Endothelium: Discontinuousgaps between cellslarge-molecular

substances can cross

Large fenestrae (80100 nm) present in the endothelial

wall - NO diaphragmtransport of larger molecules

Basal lamina: Discontinuous or absenteasy movement substances

SINUSOIDS


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Occurrence:

Liver, spleen and bone marrow

Remarks: Lumen has a large diameter, which slow the circulation of

blood Irregular shapevaries between organs and specialised in

different organs

SINUSOIDS (cont.)


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Regulate blood flow and blood pressure

Arteries are classified based on their size:

Elastic arteries

Aorta, pulmonary a, Renal a, Brachiocephalica, Common carotid a, Subclavian a, andCommon iliac a.

Muscular arteries

Most arteries with names

Arterioles

ARTERIES


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Aorta, pulmonary a, Renal a, Brachiocephalic a,Common carotid a, Subclavian a, and Common iliac a.

Regulate blood flow and blood pressure

ELASTIC ARTERIES


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ELASTIC ARTERIESTunica Intima

Endothelial layer Continuous and with adhesions between cells

Basal lamina

Sub endothelium

Loose connective tissue with collagen and elastic fibres

Smooth muscle cells



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Fenestrated elastic laminae Diffusion of substances

Blood pressure, blood flow,and secondary pump

Connective tissue (elastic-, collagen- fibres

and fibrils)

Ground substance

External elastic lamina

Concentric layers

4070 layers

BLOOD VESSEL WALLTunica Media


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Connective tissue Relatively thin

Loose network of collagen and elastic fibres

Ground substance

Collagenlimits vascular distension

Vasa vasorum* Nutrition of blood vessel wall

Nervi vascularis Sympathetic and Parasympathetic innervations - blood

pressure

BLOOD VESSEL WALLTunica Adventitia


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ELASTIC ARTERIES


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MUSCULAR ARTERIESTunica Intima

Thinner than that of Elastic arteries

Endothelial layer

Basal lamina

Sub endothelium

Thin, Loose connective tissue Smooth muscle cells


PROMINENT


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Thickest layer

Smooth muscle tissue Blood pressure

Connective tissue (elastic-, collagen- fibres)

Ground substance

External elastic lamina (larger arteries)

Concentric layers 740 layers

MUSCULAR ARTERIESTunica Media


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Connective tissue Relatively thick

Loose connective tissue

Fibroblasts, adipocytes

Collagen and elastic fibres

Ground substance

Collagenlimits vascular distension

Vasa vasorum* Nutrition of blood vessel wall

Nervi vascularis Sympathetic and Parasympathetic innervations - blood

pressure

MUSCULAR ARTERIESTunica Adventitia


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MUSCULAR ARTERIES


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MUSCULAR ARTERIES


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SMALL ARTERIES AND ARTERIOLES


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Relatively small lumensdiameter less than 0.5mm.

Arterioles1-2 layers of smooth muscle

Small arteries36 layers of smooth muscle

Regulate blood flow to capillaries

Peripheral resistance Blood pressure

SMALL ARTERIES AND ARTERIOLES


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ARTERIOLESTunica Intima

Endothelial layer

Basal lamina


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Connective tissue

Concentric layers

12 layers

ARTERIOLESTunica Media


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Connective tissue Thin layer

Connective tissue fuse with surrounding connective

tissue

ARTERIOLESTunica Adventitia


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ARTERIOLES

VEINS


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Return blood back to the heart aided by the

action of smooth muscle and specialisedvalves

Veins are classified as: Venules

Small veins

Medium veins Large veins

VEINS

LARGE VEINS


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Tunica adventitia is the thickest layer

Diameter larger than 10 mm

LARGE VEINS


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LARGE VEINSTunica Intima

Endothelial layer

Basal lamina

Sub endothelium

Thin loose connective tissue

Smooth muscle cells

Boundary between Tunica intima and Tunica media

NOT clear

Venous valves

(One directional flow)


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Relatively thin

Smooth muscle tissue Blood pressure

Collagen fibres

A few fibroblasts

Poorly defined

concentric layers

LARGE VEINSTunica Media


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Thickest layer

Connective tissue -prevent over-distension of vein Collagen and elastic fibres

Ground substance Fibroblasts

Smooth muscle -prevent over-distension of vein

Longitudinal bundles

Vasa vasorum

Nervi vascularis

LARGE VEINSTunica Adventitia


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LARGE VEINS

A G S


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LARGE VEINS

VENEOUS VALVES


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VENEOUS VALVES


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DIFFERENCES BETWEEN AN ARTERY

AND A VEIN

ARTERIE VEIN

-ROUNDED - OVALSHAPED

-THICK WALL - THIN WALL

-INTIMA SCALLOPED - INTIMA SMOOTH

-THREE LAYERS ARE - DIFFICULT TO

CLEARLY DISTIN- IDENTIFY THE

GUISHALBE DIFFERENT LAYERS

(T. MEDIA IS (T. ADVENTITIA

PROMINENT) IS PROMINENT)



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AND A VEIN

ARTERY Rounded

Thick wall

Intima scalloped Three layers are

Clearly distinguishable

T. Media is prominent

VEIN Ovalshaped

Thin wall

Intima smooth Difficult to identify the

different layers

T. Adventitia prominent Valves

ARTERIES AND VEINS


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ARTERIES AND VEINS

ARTERIES AND VEINS


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ARTERIES AND VEINS

ARTERIES AND VEINS


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ARTERIES AND VEINS

ARTERIES AND VEINS


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ARTERIES AND VEINS

SUPPLY OF NUTRIENTS AND GASSES TO


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Inner portion of blood vessel wall (T. Intima

and inner 1/3 of T. Media) receives nutrients

and gasses by means of diffusion from theblood vessel lumen

Distance for effective diffusion is limited.

The outer part of the blood vessel wall needs

an alternative mechanism vasa vasorum

SUPPLY OF NUTRIENTS AND GASSES TO

BLOOD VESSEL WALL AND

VASA VASORUM

VASA VASORUM


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Distance for effective diffusion is limited.

The outer part of the blood vessel wall needs

an alternative mechanism vasa vasorum

Blood supply to the outer 2 layers of the

blood vessel wall (T. Media en T. Adventitia)of large blood vessels.

The vasa vasorum penetrates the large blood

vessels from the T Adventitia side andsupply the T. Adventitia and outer 2/3 of T.

Media.

VASA VASORUM

THE HEART


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THE HEART


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THE HEART

THE WALL OF THE HEART CONSIST

OF THE FOLLOWING:

1. Cardiac muscle

2. Fibrous skeleton

3. Impuls conducting system

THE HEART


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THE HEART


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THE HEART

THE WALL OF THE HEART CONSIST

OF THE FOLLOWING LAYERS:

1. Endocardium

2. Myocardium

3. Epicardium

1 ENDOCARDIUM


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1. ENDOCARDIUM

-Endothelium

-Subendothelium

SUBENDOCARDIAL LAYER

-Purkinje fibers

-Veins

-Nerves

2 MYOCARDIUM


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2. MYOCARDIUM

- 3 layers cardiac muscle

SUBEPICARDIAL LAYER

- Loose connective tissue

- Adipose tissue- Blood vessels

- Nerves

3. EPICARDIUM

- Connective tissue

- Mesothelium

THE HEART


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THE HEART

cvs system lecture 01

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