circulatory system phki [compatibility mode]

8/8/2019 Circulatory System Phki [Compatibility Mode]

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Functions of the circulatory system:

Distribute nutrients,

Transport and exchange oxygen and carbon dioxide,

Remove waste materials,

,

Prevent excessive bleeding,

Prevent infection, and

Regulate body temperature.


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CIRCULATORY SYSTEMCIRCULATORY SYSTEM

BLOOD CIRCULATORY SYSTEM LYMPH CIRCULATORY SYSTEM

HEART BLOOD VESSELS BLOOD LYMPH VESSELS LYMPHLYMPH NODES

ARTERIES VEINS

BLOOD CAPILLARIES

LYMPH CAPILLARIES LYMPH VESSELS

LYMPH DUCTS


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HUMAN BLOOD & LYMPH CIRCULATORY SYSTEM


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BLOODBLOOD

SYSTEMSYSTEM


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HEARTHEART

The human heart is four chambered organ composed of twoThe human heart is four chambered organ composed of twoatria and two ventricles. The walls of ventricles are thickeratria and two ventricles. The walls of ventricles are thickerthan those of the atria.than those of the atria.

The heart acting as aThe heart acting as a pump, supplies the principal propelling, supplies the principal propellingforce for the circulation of the blood in two circuits:force for the circulation of the blood in two circuits:

Systemic circuitSystemic circuitHeart the tissues of the body heartHeart the tissues of the body heart(left ventricle) (right atrium)(left ventricle) (right atrium)

Pulmonary circuitPulmonary circuitHeart lung heartHeart lung heart(right ventricle) (left atrium)(right ventricle) (left atrium)

= oxygen-rich blood= oxygen-poor blood


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HISTOLOGICAL FEATURES OF THE HEART

The walls of the heart are composed of three layers:

1. Epicardium: is covered by simple squamous mesotheliumsupported by connective tissue containing many elastic

fibers. The deepest aspect is composed of adipose tissuethat houses nerves and coronary vessels.

2. M ocardium: consist of 1 contractile fascicle of cardiac

muscle fibers, and (2) noncontractile modified muscle fiberscalled Purkinje fibers. The bundles of cardiac muscle areattached to the thick collagennous connective tissue skeletonof the heart.

3. Endocardium: consist of (1) endothelium, (2) elastic fiberswith a few smooth muscle, and (3) subendocardial zone ofloose connective tissue cotaining small vessels and nerves.


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Layers of heart wall

Outer: Epicardium

Middle: Myocardium

Outer: Endocardium


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Valves of the heart:

tricuspid (between the right atrium and rightventricle)

bicuspid (between the left atrium and leftventricle)

and the pulmonary artery)

aortic semilunar (between the left ventricle and

the aortic artery)

The blood flows only in one direction from an

atrium to a ventricle, then from a ventricle into a blood vessel


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BLOOD VESSELSBLOOD VESSELS

Kind of blood vessels that conduct blood away from theheart and conduct blood back into the heart are as below:


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HISTOLOGICAL STRUCTUREHISTOLOGICAL STRUCTUREOF BLOOD VESSELSOF BLOOD VESSELS

Except for the smallest vessels, blood vessel walls

consist of three-layered structures:

1. Inner layer = tunica intima

2. Middle layer = tunica media

3. Outer layer = tunica adventitia


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Histological Structure of Blood VesselsHistological Structure of Blood Vessels


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A Comparison of a Typical Artery and a Typical Vein


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Arteries are blood vessels that carry blood,

rich in oxygen,

.


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Elastic ArteriesElastic Arteries

Large elastic arteries include the aorta and its large branches

The wall is relatively thin as compared with the wide lumen

Tunica Intima Tunica Media Tunica Adventitia

- rather thick - thick, is composed - relativel thin has no

- endothelial cells:short, polygonal

- subendothelial: fibroelastic connective

tissue, circularlysmooth muscle

- internal elasticlamina not beprominent

mostly of elasticfibers, has numerousfenestrated elasticmembrane

- muscle fibers aregreatly reduced

external elastic lamina

- contain vasa vasorum


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Muscular ArteriesMuscular Arteries

Medium size arteries As distributing vessels; regulate blood flow by constriction or

relaxation of their walls


- thin

- thick

-

- thinner than themedia

- en ot e a ce s:flattened polygonal

- subendothelial:collagenous andelastic fibers,

longitudinally smoothmuscle

- Internal elasticlamina: clearly

evident

circular layer ofsmooth muscle

- some elastic.reticular, and

collagenous fibers- external elastic

lamina is well defined

- is composed mostlyof collagenous fibers


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Muscular ArteryMuscular Artery

CF = Collagenous Fibers

EF = Elastic Fibers

En = Endothelium

iEL = internal Elastic Lamina

xEL = external Elastic Lamina

N = Nuclei

SM = Smooth Muscle Cells

TA = Tunica Adventitia

TI = Tunica Intima

TM = Tunica MediaTI

Muscular Artery


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ArterioleArteriole

The smallest artery, internal diameter of 30 um or less

Act as sphincters for control of blood flow into the capillarybed


- thin - relatively thick - fairly prominent

- endothelial: present- subendothelial

connective tissue:present

- internal elasticlamina: present inlarger arterioles

- one-three layerspirally smoothmuscle fibers

- external elastic

lamina: present inlarger arterioles

- is composed ofcollagenous andelastic connectivetissue


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A = Arteriole

CT = Collagenous Connective TissuesL = Lumen

N = Nuclei

TA = Tunica Adventitia

TM = Tunica Media

Ve = Venule

Arteriole and Venule


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CapillaryCapillary

- Is the site of normal exchange of materialsbetween blood and tissue fluid

- is very thin endothelial lined tubule, with basallamina

- diameter 5-12 m

- is devoid of muscular and connective coat

- is surrounded by pericyte that may contract andperhaps constrict the capillaries.


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Continuous capillary

have relatively thickcytoplasm the capillary wallis continuous.

lateral cell surfaces of cellsare characterized byzonula occludens (tight

junctions), so materialsmove across cells viapinocytosis or diffusion.

these capillaries are found

in most organs.


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Fenestration capillary

has extremely thincytoplasm

the capillary wall isperforated at intervals bypores or fenestrations.

through the fenestrations.

lateral cell surfaces arecharacterized by zonula

occludens (tight junctions). these capillaries are found in

the kidney and in endocrineglands


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Sinusoidal capillaries

are larger in diameterthan the other types

have wide spacesbetween the lateral edgesof the adjacentendothelial cells, so

materials (and somecells) can move freely inand out of the capillary.

are found in the spleen,liver, and bone marrow.


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Capillary Structure


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The Organization of a Capillary Bed


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Veins are the blood vessels thatcollect blood from all tissues and organs and

return t to t e eart


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Veins have one-way valves that keep bloodmoving toward the heart and prevent the bloodfrom reversing flow.

These valves allow for muscle contractions andmovement of body parts.

The valves also assist the return flow of blood tothe heart when blood pressure is low.


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Veins are always larger than the arteries and aresometimes more visible than arteries becausethey are closer to the skin surface.

Most veins eventually empty the un-oxygenatedblood into the vena cavas.

Veins normally accompany arteries and oftenhave similar names.


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VenulesVenules

Sizes varies from 10 um to 1 mm Collect blood from capillaries


- endothelial: present

- ver thin subendothelial

- absent in smallvenules

- consist of collagenous

- 1 or two layers ofsmooth muscle inlarge venules

with fibroblast andsome elastic fibers


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Medium Size VeinsMedium Size Veins

Function to collect blood from smaller venous vessels


-Thin

- endothelial: present

- valve: evident

- much thinner thanthat of the

- is well developed

- is composed ofcollagenous andelastic connectivetissue


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Large VeinsLarge Veins

Large elastic arteries include the vena cava and pulmonaryveins

Function to collect blood from medium size veins and

return it to the heartTunica Intima Tunica Media Tunica Adventitia

- thicker es eciall in - poorly developed -very prominent, make

subendothelialconnective tissue

- smooth muscle largelyreplaced by fibroustissue

up most of the wall

-contain longitudinallyoriented smoothmuscle fiber bundlesamong the thick layer

of collagen and elasticfibers.

-vassa vasorum is bestdeveloped


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Vassa vasorum

= a small system of vessels, arteries branching

profusely in the walls of large artery and vein,because it is too thick to be nourished bydiffussion from the blood in the lumen


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BLOODBLOOD

COMPONENTS OF HUMAN BLOOD


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COMPONENTS OF HUMAN BLOOD

Plasma(50-65%)

- Electrolites and ions: calcium, sodium,potassium, bicarbonate

- Larger molecules: albumins, globulins,fibrinogen

- Organic compounds: amino acids, lipids,vitamins, hormones, cofactors

BLOOD

Non plasma(cellular)(35-50%)

- Erytrhocytes

- Leukocytes- Granulocytes

- Eosinophils- Basophils

- Neutrophils- Agranulocytes- Lymphocytes- Monocytes

- Thrombocytes (platelets)

Structure function and formation place of


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Structure, function and formation place ofhuman blood cells

Type Diameter(m)

Morphology Function Formation place

Erythrocyte 7-8 Biconcave disk;anucleate; filled withhemoglobin; pliable

Transport of O2 and CO2 Myeloid tissue

Eosinophil 11-14 Spherical; largebilobed nucleus; filled

with eosinofilicgranules

Phagocytosis of antigen-antibody complex

Myeloid tissue

Basophil 8-10 Spherical; bilobed - Slighly phagocytic

Myeloid tissue

nuc eus; e wbasofilic granules

- ro uce s am n

Neutrophil 10-14 Spherical; 3-5 lobed

nucleus; filled withsmall uniform specificgranules

Active phagocytosis of

bacteria and cellular debrisin inflammatory cinditions

Myeloid tissue

Lymphocyte Small: 6-8Large: 10-14

Spherical; largenucleus, nearly fills

cell

Active in humoral and cellmediated immune responsel

Myeloid tissue and lymphatic tissue

Monocyte 12-20 Spherical; singlekidney shapednucleus

Phagocytosis as themacrophage of the bloodstream

Myeloid tissue and lymphatic tissue

Platelets 2-4 Biconvex disk;anucleate

Secretes enzymethromboplastin for blood

agglutination and clotting

Myeloid tissue


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agranulocytes

Diagram of human blood cells


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EosinophilBasophil

Erythrocyte

Lymphocyte Monocyte

Neutrophil

HEMOPOIETIC ORGANS


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HEMOPOIETIC ORGANS

Erythrocytes

MYELOID TISSUE

(Red Bone Marrow)

Granulocytes

Thrombocytes

Agranulocytes

LYMPHOID TISSUE(Spleen, tonsil, thymus

gland, lymph nodes)

Agranulocytes

Note: hemopoiesis = the production of blood cells


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DIAGRAM OF HEMOPOIESIS IN RED BONE MARROW


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Components

lymph

lymph capillaries

lymph vessels lymph ducts

THE LYMPHATIC SYSTEM


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THE LYMPHATIC SYSTEM

Lymph flows only toward the heart,

the lymphatic vessels form a one-way

system rather than a full circuit


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LYMPH

a transparent, slightly yellow fluid that flows inthe lymph vessels

did not containing erytrhocytes

contain: tissue fluid, small lymphocytes, fewneutrop s an monocytes, an c y om crons(fat droplets)

lymph drainage is not a circulation but only inone-way flow, from the periphery to the heart. It

begins in tissue spaces and end by emptyinginto large vein in the neck.


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Flow of Blood & Lymph Within Tissue

TRANSPORT OF LYMPH


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Cysterna chili(reservoir)

Thoracic duct

Left brachio-cephalic vein

Blood streamin neck

Lymph nodesBlind beginninglymph capillaries

Heart

TRANSPORT OF LYMPH

Lymph vessel

Right subclavianvein

Right lymphaticduct

Upper rightbody quadrant

LYMPH CAPILLARIES


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LYMPH CAPILLARIES

are thin and blind beginning vessels

consist only of a single layer of endothelium cellsthat overlaps each other, and have intercellular

proteins and other matter from tissue fluid.

Function: to collect excess tissue fluid


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LYMPH DUCTS


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LYMPH DUCTS

there are two lymph duct: the large and longerthoracic duct, and the less extensive rightlymphatic duct. The both are receive lymph from

lymph vessels and conduct its to the heart. have no clearly demarcated between three layer

, ,

have numerous valves in subendothelial layer oftunica intima

tunica media is the thickest layer, has even more

circular smooth muscle than in large vein tunica adventitia is relatively underdeveloped

contain vasa vasorum and a rich neural network

LYMPH NODES (LYMPH GLANDS)


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LYMPH NODES (LYMPH GLANDS)

are oval or bean- shaped bodies that are alwaysinterposed along the course of lymphatic vessels

are surrounded by dense connective capsule devided in three region:

1. cortex com osed of numerous l m hoid nodule

with germinal centers are active site of B cells2. paracortical contain many densely packed primarily

T-lymphocyte, and B- lymphocyte that produce specific

antibodies through plasma cells

3. medulla with lymphocytes arranged in widely

spaced strands called medullary cords, contain

macrophages and reticular cells.


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Locations of Lymph Nodes

lymph nodes aggregate in groups or chains alongthe paths of larger lymphatic vessels; are absent inthe central nervous system

major locations are: cervical, axillary, inguinal,subtrochlear regions, & within the pelvic, abdominal,& thoracic cavities


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Lymph Nodes


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y p

The microscopicanatomy of a lymph

node suggests itsrole as a body filter

The node issurroun e y a

fibrous capsule ofdense connectivetissue

There are about 500lymph nodes in thebody


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In the passage to the heart, the lymphmust be passed through the lymph nodes

The lymph enter lymph node through theafferent lymph vessels, and pass awaythrough the efferent lymph vessel at the

hilum of the node

Function of lymph nodes:


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Function of lymph nodes:

filtration of lymph from microorganisms and theirtoxins.

produce lymphocytes, monocytes, and plasma cells

sites of production antibodies (by plasma cells)

Note:

Cancer cells can be the most problematic and canactually use lymph nodes as a site to metastasizefurther.

circulatory system phki [compatibility mode]

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