Blood Notes Final

8/19/2019 Blood Notes Final

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BLOODDefinitionBlood is a connective tissue.

• Composed of a straw-coloured transparent fluid called plasma, in which

different types of cells are suspended.

• Blood constitutes 55% plasma and 45% cells.• The volume of blood in the body is: 4-5 litres in a woman and 5- litres in

a man.

• Blood ma!es up about "% of body wei#ht.

Function of blood$. Transportation. &aintenance'. (rotection

Transportation$. Carries o)y#en in the form of o)y-haemo#lobin from the lun#s to the

tissues.. Carries nutrients in the form of amino acids, #lucose, fatty acids,

vitamins, minerals and water to the cells.'. Carries away waste products from the tissues to be e)creted* +)ample:

carries carbon dio)ide from the tissues to the lun#s for e)cretion.4. nternal transport, +)ample: itamin from the s!in is carried by the

blood to the liver and !idney to be chan#ed to active itamin and isthen to the small intestines for absorption of calcium.

5. Carries hormones and en/ymes to their tar#et #lands and tissues.

MaintenanceBlood plays a bi# part in maintainin# homeostasis.$. Blood consists of hormones and en/ymes that control the body

processes. t also contains chemicals that maintain the p0 of the bloodbetween ".'5-".45.

. The osmotic pressure of plasma also maintains the fluid and electrolytebalance.

'. &aintains body temperature.

Protection

$. 1hite blood cells and chemicals li!e antibodies and anti-to)ins areimportant immunolo#ical substances in the prevention of infection bymicroor#anisms and to)ins.

. ia the clottin# mechanisms that coa#ulate blood, loss of blood cells andbody fluids is prevented.

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COMPOSITION OF PLASMA

SN Component Percentage

$. 1ater 23-2%

. (lasma (rotein .%• lbumin 55%

• 6lobulins '%

• 7ibrino#en 4%

• 88888 $%

'. &ineral salts $%

• 9odium

• (otassium

•

Calcium• &a#nesium

• Chlorides

• ron

• (hosphates

• 0ydro#en

• 9odium Bicarbonates

4. 7ood utrients 3.'%

• 6lucose

• mino acids

• itamins

• Cholesterol

5. 6as 3.$%

• Carbon dio)ide

• ;)y#en

• itro#en

. 1aste (roducts 3.$%

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TP!S OF BLOOD C!LLS

SN Component

$. +rythrocytes - >BC

. =eucocytes - 1BC

$. 6ranulocytes

• eutrophils

• +osinophils

• Basophils

. #ranulocytes

• &onocytes

• =ymphocytes

'. Thrombocytes - (latelets

PLASMA P"OT!INS&a!e up "% of plasma.#$ Serum Albumin

• 7ormed in the liver.

• &ost abundant plasma protein.

Function

• 7unction is to maintain the osmotic pressure.

• >esponsible for osmotic pressure of blood ? 5mm0#.

• ;smotic pressure !eeps fluid in the blood.

• f osmotic pressure is low, fluids move into the tissues and cause

oedema and also into body cavities.

%$ Serum &lobulin

• &ost are formed in the liver and the rest in the lymphoid tissue.

Function

• Causes immune reactions on forei#n materials such as anti#ens.

• Transportation of hormones such as thyro)ine and mineral salts such as

iron.

• nhibition of proteolytic en/ymes such as trypsin.

'$ Serum Prot(rombin

• 9ynthesi/ed in the liver and is essential for coa#ulation of blood.

)$ Serum *eparin• (roduced in the liver.

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• (revents coa#ulation of blood by preventin# prothrombin from chan#in#

to thrombin.

MIN!"AL SALTS

nvolved in a wide ran#e of activities such as:$. 7ormation of cells such as iron.. &uscle contractions.'. Transmission of nerve impulses.4. 7ormations of secretions.5. &aintenance of balance betweens acids and al!alis.

N+T"I!NTS

• 7ood is di#ested in the alimentary tract.

• The nutrients such as monasaccharides, amino acids, fatty acids,

#lycerol and vitamins are then absorbed.• The nutrients are then used to provide ener#y, heat and materials for

repair and replacement.

• The nutrients are also used for the synthesis of other blood components

and body secretions.

O"&ANIC ,AST! P"OD+CTS

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There are three types of blood cells:$. +rythrocytes or red blood cells.. =eucocytes or white cells.'. Thrombocytes or platelets.

!"T*"OCT!S O" "!D BLOOD C!LLS$

• &ost abundant red blood cell.

• ormal ran#e is about 5 million mm' of blood.

• The erythrocyte count is low in females @4.5-5million mm'A than males

@5.3-5.5 mm'A.

• +rythrocytes cannot move by themselves but are pushed alon# by the

flow of blood.

Structure of !r0t(roc0tes

•>ed blood cells or erythrocytes are circular biconcave in shape.

• 0ave a diameter of " microns.

• on-nucleated.

• The circular biconcave shape increases surface area of cell and able

more #as to attach to it.

• The shape also decreases the si/e and helps the cell to move into small

blood vessels.

Composition of er0t(roc0tes

• =ipids

• denosine triphosphate @T(A• +n/yme Carbonic nhydrase

• &ost important component is the protein pi#ment called haemo#lobin.

• 0aemo#lobin covers $' of the volume of the cell.

*aemoglobin$

• comple) protein consistin# of #lobin and an iron-containin# substance

called haem.

• s synthesised inside developin# erythrocytes in red bone marrow.

• 0aemo#lobin combines with o)y#en to form o)yhaemo#lobin, #ivin#

arterial blood its red colour.• The normal haemo#lobin level in male is in the ran#e of $4-$#m% and

females is $-$#m%.

Formation of er0t(roc0tes

• 7ormed in red bone marrow: in ends of lon# bones and in flat and irre#ular

bones.

• =ife span is $3 days.

• evelopment of erythrocytes depends upon the presence of:

$. itamin B$

. ron'. (rotein

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4. 7olic acid

5. itamin C

. 0ormone +rythropoietin

!r0t(ropoiesis$

• The process of development of >BC is called erythropoiesis.

• t ta!es about " days.

• The process of development of >BC start from pluripotent stem cells.

• fter under#oin# sta#es of mitosis, some of them differentiate into

(roerythroblast and they form erythroblasts.

• They be#in synthesi/in# haemo#lobin.

• fter several cell divisions, the erythroblasts loses its nucleus and is now

an immature >BC called reticuloyte.• The reticulocytes leave the bone marrow and enter the blood stream.

• fter or ' days, the reticulocytes matures into an erythrocytes.

• &aturation of cell depends on the presence of itamin B$ and folic acid.

Dietar0 Iron Folic acid

1itamin B#% Iron

Control of er0t(ropoiesis• Bone marrow produces erythrocytes at the rate which they are destroyed.

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Pluripotent stem cell

Proer0t(roblast

!r0t(roblast

"eticuloc0te

Mature !r0t(roc0te

Diet

Decrease in si2e3loss of nucleus

S0nt(esis of (aemoglobin

*aemol0sis

Iron Bilirubin


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• ue to ne#ative feedbac! mechanism.

• 0ypo)ia @ o)y#en ?carryin# power of blood is reduced by haemorrha#e or

haemolysisA increases erythropoiesis.

• This is done by stimulation of the production of the hormone erythropoietin

by the !idneys.

• +rthropoietin stimulates increase of proerythroblasts and the release of

erythroblast, which increases o)y#en carryin# capabilities ?o)yhaemo#lobin and thus reverses hypo)ia.

• 1hen erythropoietin levels are low, >BC is not formed and anaemia

develops.

Destruction er0t(roc0tes

• =ife span of erythrocytes is $3 days.

• Brea!down of >BC is called haemolysis.

• 0aemolysis is carried out by macropha#es.

• 0aemolysis occurs in the spleen, bone marrow and the liver.

• 6lobin is bro!en down to amino acid and used in the formation of new

>BC.

• 0aem part releases iron and bilirubin.

• ron is retained in the body and reused to form haemo#lobin.

• Biliverdin is formed from the protein part of the erythrocytes.

• t is reduced to bilirubin, bound to plasma #lobulin and transported to the

liver.

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Tissue *0po4ia

5idne0s secreteer0t(ropoietin into t(e

Bone marro6 increaseser0t(ropoiesis

"ed blood cell numbers rise

Increased blood o40gen.carr0ing capacit0re7erses tissue


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• n the liver it chan#ed from fat-soluble to water-soluble and e)creted as

bile.

Small amount is reabsorbed

Measure Definition Normal 7alues

+rythrocyte count umber of erythrocytes perlitre or cubic millimeter@mm'Aof blood.

Male8 4.5 - .5millionmm'

Female8 4.5 - .5millionmm'

(ac!ed cell volume@(CAor haematocrit

olume of red cells per litre or $ mm' of whole blood.

43-53mm'

&ean cell volume @&CA vera#e volume of cells,measured in femtolitres

3-2fl

0aemo#lobin @0bA 1ei#ht of haemo#lobin inwhole blood, measured in#rams per $33ml

Male8 $' -$#$33mlFemale8 $$.5 ? $.5#$33ml

&ean cell haemo#lobin vera#e amount ofhaemo#lobin in each cell,

" ? 'p#cell

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*aemoglobin from 6ornout er t(roc tes

*aem &lobin

Bilirubin Amino acids

Li7er

Intestines 5idne0s

!4creted in urineas urobilino en

!4creted in faecesas stercobilino en


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measured in pico#rams.

&ean cell haemo#lobinconcentration

mount of haemo#lobin in$33ml of red cells.

'3 ? '5#$33ml of cells

BLOOD &"O+PS

• >ed blood cells have different anti#ens on their surface.

• nti#ens determine blood #roups.

• ntibodies are made a#ainst anti#ens e)cept their own.

• This prevents transfusion reactions caused when donor and recipient

blood types are incompatible..

• &ain si#ns of transfusion reactions are clumpin# of >BC, haemolysis,

shoc! and !idney failure.

T(e ABO s0stem• 7our main types of blood #roup:

#$ : nti#en %$ B : nti#en B'$ B : nti#en and B)$ ; : either nor B nti#en ? +ni7ersal donor$

• Correspondin# antibodies are called anti- and anti- B:

#$ Blood #roup : nti-B%$ Blood #roup B : nti-'$ Blood #roup B : either - +ni7ersal recipient)$ Blood #roup ; : Both nti- and nti-B

BloodT0pe

Antigenon "BC

Antibodies inplasma

Can donate bloodto

Can recei7e bloodfrom

nti-B , B , ;

B B nti- B, B B, ;

B B one B , B, B, ;

; one nti- and nti-B , B, B, ; ;

T(e "(esus s0stem

• 1ith the >h factor ? >h positive.• 1ithout >h factor ? >h ne#ative.

• f blood from >h positive person is transfused to a >h ne#ative person, the

>h ne#ative person will develop antibodies a#ainst the >h positive >BC.

• ntibodies will build up in the >h ne#ative plasma.

• f the person receives additional >h positive blood, the newly formed

antibodies will a##lutinate the >h positive >BC.

L!+5OCT!S 9,*IT! BLOOD C!LLS:

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Structure of Leu;oc0tes

• 0as a nucleus without haemo#lobin.

• 0ave #ranules in their cytoplasm.

• 1hite in colour.

• 9i/e of -2um diameter.

• ormal rate is between 5333-$3333 mm'.

Function

• efend a#ainst microbes and other forei#n materials.

T0pes of leu;oc0tesThere are two main types:$. 6ranulocytes:

• eutrophils

• +osinophils

• Basophils

. #ranulocytes:

• &onocytes

• =ymphocytes

&ranuloc0tes

• 7ormation of #ranulocytes is !nown as #ranulopoiesis.

• They develop from myeloblast to myelocyte before differentiatin# to

eutrophils, +osonophils and Basophils.

• 0ave multilobed nuclei.

• 9ome have #ranules in their cytoplasm.

Neutrop(ils

• &ost in number.

• &a!e up about 5-"5% of total leu!ocytes.

• &ain function is to protect a#ainst any forei#n materials, mainly microbes

and to remove waste materials, +)ample: cell debris.

• ttracted to area of infection by chemical substances, called chemota)ins.

• Chemota)ins are released by dama#ed cells.

• (ass throu#h the capillary walls by amoeboid movement called

diapedesis.

• They en#ulf and !ill microbes by pha#ocytosis.

• The #ranules or lysosomes contain en/ymes that di#est the en#ulfed

materials.

• (us that form in the affected area consists of dead tissues cells, dead and

live microbes and pha#ocytes !illed by microbes.

• eutrophils are increased in:

$. 9trenous e)ercise. &icrobial infection'. Tissue dama#e - inflammation, myocardial infarction, burns, crush inuries.

4. &etabolic disorders ? diabetic !etoacidosis, acute #out.5. =eu!aemia

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. 0eavy smo!in#".


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L0mp(oc0tes

• 9mallest of all leu!ocytes.

• 0as a diameter of 2um.

• 0as a lar#e round nucleus that occupies most of the cell.

• They circulate in the blood.

• (resent in lymph nodes and the spleen.

• evelop in red bone marrow and then travel in blood to lymphoid tissues.

T6o different t0pes of l0mp(oc0tes are8$. T-lymphocytes. B-lymphocytes

T.l0mp(oc0tes

• (rocessed by the thymus #land.

• 7ree to circulate in the blood.

• >eco#nise only one !ind of anti#en, +)ample: pro#rammed to reco#ni/e

chic!enpo) virus and will not reco#ni/e a measles virus.

• (rovide cell-mediated immunity.

• ble to respond to anti#ens includin#:

$. Cells invaded by virus, cancer cells, tissue transplant cells. (ollen from flowers and plants'. 7un#i4. Bacteria5. ru#s such as penicillin and aspirin

Cell.mediated immunit0• 9ensitive to anti#en when encounter for the first time.

• nti#en presented on the surface of an anti#en-presentin# cell-

macropha#es.

• fter di#estin# anti#en, they display the anti#en on their own surface

membrane.

• Come in contact with T-lymphocyte that is processed to tar#et that anti#en.

• 9timulates division and proliferation of T-lymphocyte and differentiation

into ' main types:#$ Memor0 T.cells

(rovide immunity to the anti#en by respondin# rapidly to the same typeof

anti#en.

%$ C0toto4ic T.cells Bind to anti#en and release to)ins and destroy it.

'$ *elper T.cells>elease cyto)ines to support cytoto)ic T-lymphocytes and cooperatewith B-lymphocytes to produce antibodies.

B.l0mp(oc0tes• (rocessed in the bone marrow.

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• 7i)ed in lymphoid tissue such as spleen and lymph nodes.

• >ole is to produce antibodies @immuno#lobulinsA.

• ntibodies @immuno#lobulinsA are proteins desi#ned to bind to and cause

the destruction of an anti#en.

• +ach B-lymphocytes tar#ets one spesific anti#en.

• (rovide antibody-mediated immunity.

Antibod0.mediated immunit0

• >eco#nise and bind anti#en without bein# presented by anti#en-

presentin# cell.

• +nlar#es and divides into two types of cell:

#$ Plasma cell(roduce and release antibodies that bind to the anti#en and destroys it.

%$ Memor0 B.cells>espond to another encounter by production of antibody-secretin#plasma cells.

T*"OMBOCT! 9PLAT!L!TS:

Structure

• is!-shaped.

• 9maller than >BC.

•

o nucleus and are incapable of cell division.• iameter of -4um.

• erived from red bone marrow.

• 0as a life span of -$$ days.

• estroyed by macropha#es in the spleen.

• ormal rate is 53,333-'53,333mm'.

• Contains substances that promote blood clottin# ? haemostasis.

*aemostasis0ealin# of blood vessel occurs in 4 processes:

#$ 1asoconstriction• 9urface of platelet becomes stic!y when in contact with dama#ed vessel.

• They adhere to dama#e wall.

• >elease serotonin which constricts the vessel.

• This reduces blood flow.

• Thrombo)ane, which causes vasoconstriction is also released by

dama#ed vessel. %$ Platelet plug formation

• The adhered platelet clump to each other.

• >elease adenosine diphosphate @(A, which attracts more platelets.• &ore platelets adhere and Euic!ly form a temporary sealt ? platelet plu#.

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'$ Coagulation8 blood clotting

• This involves a positive feedbac! system involvin# clottin# factors.

• Blood clottin# results in formation of an insoluble, thread-li!e mesh of

fibrin.

• 7ibrin traps blood cells.

• (rothrombin activator acts on the plasma protein prothrombin convertin#

it to thrombin.

• Thrombin acts on plasma protein fibrino#en and converts it to fibrin.

• (rothrombin activator can be formed by ways:

a: !4trinsic pat(6a0

• ;ccurs within seconds when there is tissue dama#e outside circulation.

• ama#ed tissue releases a chemical called thromboplastin which

initiates coa#ulation.b: Intrinsic pat(6a0

• ;ccurs slower- ' to minutes.

• Tri##ered by dama#e to blood vessel linin# and the effects of platelets

adherin# to it.

• fter a time, the clot shrin!s, sEuee/in# out a serum, which is plasma

without the clottin# factors.

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T(romboplastin released b0damaged tissue cells enters t(e

blood

Platelets ad(ere to damageblood 7essel lining

!4trinsic pat(6a0 Intrinsic pat(6a0

Prot(rombin acti7ator

Prot(rombin

T(rombin

Fibronogen

Loose fibrin t(reads

Stabilised fibrin clot


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Factor Number

PlasmaCoagulation Factor

Description and Origin Function

7ibrino#en (lasma protein synthesi/ed inliver

(recursor of fibrin,converted to fibrin in finalsta#e of clottin#. 9erumis plasma minusfibrino#en.

(rothrombin (lasma protein synthesi/ed inliver. 9ynthesis reEuires vitaminD.

(recursor of thrombin,the en/yme thatconverts fibrino#en intofibrin.

Thromboplastin Comple) lipoprotein formedfrom disinte#ratin# platelets ortissues.

Combines with calciumto convert prothrombininto active thrombin.

Calcium ions nor#anic ion in plasma,acEuired from bones and diet.

ecessary for formationof thrombin and for allsta#es of clottin#.

ccelerator6lobulin

(lasma protein synthesi/ed inliver.

ecessary for e)trinsicand intrinsic pathways.

The same as factor .

9erum(rothrombinconversionaccelerator@9(CA

(lasma protein synthesi/ed inliver. 9ynthesis reEuires vitaminD.

ecessary for first phaseof e)trinsic pathways.

ntihemophilicfactor @07A

(lasma protein @#lobulinAsynthesi/ed in liver. 9ynthesisreEuires vitamin D.

ecessary for first phaseof intrinsic pathways.eficiency causes

hemophilia , a #eneticdisorder.

F (lasmaThromboplastincomponent@(TCA

(lasma protein synthesi/ed inliver. 9ynthesis reEuires vitaminD.

ecessary for first phaseof intrinsic pathways.eficiency causeshemophilia B.

F 9tuart factor (lasma protein synthesi/ed inliver. 9ynthesis reEuires vitaminD.

ecessary for earlyphases of e)trinsic andintrinsic pathways.

F (lasmaThromboplastin

ntecendent@(TA

(lasma protein synthesi/ed inliver.

ecessary for first phaseof intrinsic pathways.

eficiency causeshemophilia C.

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F 0a#eman factor (lasma protein* sourceun!nown.

ecessary for first phaseof intrinsic pathways*activates plasmin*activated by contact with#lass, probably involved

with clottin# outsidebody.

F 7ibrin-stabili/in#factor @797A

(rotein present in plasma andplatelet* source un!nown.

ecessary for finalphase of clottin#.

)$ Fibrinol0sis

• n inactive substance called plasmino#en is present in the clot.

• (lasmino#en is converted to plasmin.

• (lasmin brea!downs the fibrin to soluble products.

• This is treated as waste materials and removed by pha#ocytosis.

• s clot is removed, healin# ta!es place.

Plasminogen Plasmin Brea;do6n of Fibrin Clot remo7ed

*ealing Integrit0 of blood 7essel 6all restored$

Control of coagulation

• (rocess of clottin# needs to be controlled as once started, it would

spread throu#hout the circulatory system.

• The main controls are:

$. 9mooth surface of normal blood vessel ? platelet do not adhere.. Bindin# of thrombin to a thrombin receptor ? thrombin is inactivated.'. (resence of natural anticoa#ulants such as 0eparin ? inactivates clottin#

factors.

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T*! CA"DIO1ASC+LA" SST!MT(e cardio7ascular s0stem is di7ided into t6o main parts:$. The Circulatory system

• Consists of the heart and the blood vessels.

. The =ymphatic system

• Consists of lymph nodes and lymph vessels.

T(e (eart pumps blood into t6o s0stems of blood 7essels8$. The (ulmonary circulation. The systemic circulation

BLOOD 1!SS!LS

The types of blood vessels are:$. rteries. rterioles

'. enules4. eins5. Capillaries

A"T!"I!S AND A"T!"IOL!SFunctionTransport blood away from the heart.

Structure1alls of arteries consists of three layers of tissue:

#$ Tunica ad7entitia• ;uter layer of artery.

• Consists of colla#en fibers and elastic tissues.

• erves and lymphatic vessels are also found within this layer.

• ourished by small blood vessels called vaso vasorum.

• 6ives protection to the artery.

• Thic! elastic walls allows the arteries to withstand the hi#h pressure of

arterial blood.

%$ Tunica media

•Thic!est layer.

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• Composed mainly of colla#en fibres, connective tissue, smooth muscle

cells and elastic fibres.

• n the orta, the tunica media has more elastic fibres than smooth

muscles.

• This helps to contract and rela).

• n the arterioles, it has more smooth muscles than elastic fibres because

it only helps to brin# blood from the orta to the whole body.

• Contraction and rela)ation of the artery is controlled by the symphathetic

nerve.

'$ Tunica intima

• 0as an inner linin# of simple sEuamous epithelium called endothelium, a

thin subendothelial layer of fine connective tissue and an e)ternal elastic

layer called the internal elastic lamina.• This layer can cause hardenin# and become thic!.

• =oss of elasticity can cause arteriosclerosis.

• 0ardenin# of the walls by fat deposits can cause artherosclerosis.

Blood 9nutrient: suppl0 to t(e arteries

• By small blood vessels called vaso vasorum.

• lso by blood that flows throu#h the layers by diffusion.

ANASTOMOS!S AND !ND.A"T!"I!S

• nastomoses are arteries that form lin! between main arteries.• f one artery is occluded, anastomotic arteries provide a collateral

circulation.

• +)ample: The heart muscles.

• +nd-arteries are arteries with no anastomoses.

• f one is occluded, the tissues it supplies die because there is no

alternative blood supply.

• +)ample: The central artery to the retina of the eye.

VEINS AND VENULES

FunctionBlood vessels that return blood at low pressure to the heart.

Structure

• Thinner walls than arteries.

• Consists of three layers of tissue:

#$ Tunica ad7entitia

• ;uter layer.

• 7ibrous tissue, much thinner than artery.

• The veins collapse when cut but arteries remain open.

%$ Tunica media

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• =ess elastic fibre and smooth muscles.

• 0as a steady flow of blood compared to artery, easier to stop bleedin#.

'$ Tunica intima

• 0as an inner linin# of simple sEuamous epithelium called endothelium.

• (ossess valves.

• 7ormed by a fold of tunica intima.

• =ayer of connective tissue stren#thens it.

• Cusps are semilunar in shape with the concavity towards the heart.

1al7es

• alves are abundant in the veins of the limbs.

• Blood in lower limbs must flow a#ainst #ravity when the person is

standin#.

• alves are absent in very small and very lar#e veins in the thora) and

abdomen.• (oolin# of blood in the veins due to prolon# standin# can cause

con#estion in the vein.

• This causes varicose veins.

Function of 7al7es$. (revent bac!flow of blood ? ensures blood flows

towards the heart.

Difference bet6een arteries and 7eins

NO A"T!" 1!IN$. 7unction Transport blood away from the

heart.>eturn blood at lowpressure to the heart.

. 1alls Thic!, stron# and elastic Thin

'. Tunica media &ore smooth and elastic musclefibres

=ess smooth and elasticmuscle fibres

4. 9hape &aintains walls and remain openwhen cut

1alls collapse when cut

5. Bleedin# Blood spurts and difficult to stopbleedin#

9lower steady flow ofblood and easy to stopbleedin#

. alves o valves 0as valves

Capillaries9mallest arterioles that brea! up into minute vessels.

Structure

• iameter of "um.

• 1alls consists of sin#le layer of endothelial cells.

• +nables water and small molecules to pass throu#h.

• Capillaries lin! the smallest arterioles to the smallest venules.

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Sinusoids7ound in bone marrow, endocrine #lands, spleen and the liver.

Structure

• 1ider than capillaries.

• Thin walls that separates blood from other cells.• ue to lar#e lumen, blood pressure in sinusoids are lower - slow rate of

blood flow.

Control of blood 7essel diameter

• 9mooth muscle fibres in the tunica media are supplied by nerves of the

autonomic nervous system - sympathetic nerves.

• iameter of blood vessels are chan#ed by these nerves which arise

from the vasomotor center in the medulla oblon#ata.

• This is done by controllin# the volume of blood they contain.

1asodilatation

• ecrease nerve stimulation causes the smooth vessel to rela), thinnin#

the vessel wall, enlar#in# the lumen and causin# vasodilation.

• This causes increased blood flow under less resistance.

1asoconstriction

• ncrease nerve stimulation causes the smooth vessel to contract,

thic!enin# the vessel wall and the lumen and causin# vasoconstriction.

• This causes decreased blood flow under more resistance.

Perip(eral resistance

• The walls of small arterioles consists mainly of smooth vessel.

• Chan#e in their lumen alters blood flow.

• rterioles provide the peripheral resistance to the flow of blood

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S0mpat(etic Ner7es

Increase stimulation Decrease stimulation

Contract"ela4

T(ic;ening of 7essel 6all T(inning of 7essel 6all

1asoconstriction1asodilation

Lumen becomes smallLumen enlarges


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• This is called resistance vessels and is important for maintainin#

homeostasis.

• >esistance to the flow of blood is determined by:

aA diameter of tubebA len#th of tube

cA viscosity of blood.

CI"C+LATO" SST!Mivided into two parts:$. (ulmonary circulation. 9ystemic circulation

P+LMONA" CI"C+LATION

• Circulation of blood from the ri#ht ventricle of the heart to the lun#s and

bac! to the atrium.

• Carbon dio)ide is e)creted in the lun#s and o)y#en is absorbed.

A"T!"• The pulmonary artery carries deo)y#enated blood, leaves the upper part

of the ri#ht ventricle.

• ivides into left and ri#ht pulmonary arteries.

• The left pulmonary arteries divides into two, one passin# into each lun#.

• The ri#ht pulmonary artery divides into two and supplies the ri#ht lobes

of the lun#s.

• They divide into smaller arteries, arterioles and capillaries.

• +)chan#e of #as ta!es place between capillary and the alveoli.

1!INS• n each lun# the capillaries oin up and eventually form two veins.

• The pulmonary veins leave each lun#s, brin#in# o)y#enated lun#s to the

left atrium of the heart.

SST!MIC CI"C+LATION

• The blood pumped out from the left ventricle is carried by the branches

of the aorta around the body.

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• t is returned to the ri#ht atrium of the heart by the superior and inferior

vena cava.

AO"TAThe aorta is divided into two:

$. Thoracic aorta. bdominal aorta

T*O"ACIC AO"TA=ies above the diaphra#m and is described in three parts:$. scendin# aorta. rch of aorta'. escendin# aorta in the thora)

#$ Ascending aorta

• Branches are the ri#ht and left coronary arteries.

• 9upplies blood to the tissues of the heart.

%$ Arc( of aortat is a continuation of the ascendin# aorta. t branches into three:$. Brachiocephalic artery. =eft common carotid artery'. =eft subclavian artery

Circulation of blood to t(e (ead and nec;a: Carotid arteries

• The arteries supplyin# the head and nec! are the common carotidarteries.

• The ri#ht common carotid artery is a branch of the brachiocephalic

artery.

• The left common artery arises from the arch of aorta.

• They divide into two:

#$ !4ternal carotid arter0 9upplies the head and nec!.%$ Internal carotid arter0 9upplies the #reater part of the brain, eyes, forehead and nose.

b: Circle of ,illis

• t is an arran#ement of arteries which supplies the #reater part of the

brain.

• 7ormed by:

anterior cerebral arteries internal carotid arteries $ anterior communicatin# artery posterior communicatin# artery posterior cerebral arteries $ basilar artery

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Function$. Balance the blood pressure to the brain and to pressure.. +nsure adeEuate blood supply to the brain when a contributin# artery is

dama#ed.'. +nsure adeEuate blood supply to the brain durin# e)treme movements of

the head and nec!.

Circulation of blood to t(e upper limb$. The ri#ht subclavian artery from the brachiocephalic artery.. The left subclavian artery from the arch of the aorta.

Before entering t(e a4illa3 eac( subcla7ian arter0 gi7es off t6obranc(es8$. ertebral artery ? supplies the brain. The internal thoracic artery ? supplies the breast and structures in the

thoracic cavity.

• )illary artery is a continuation of the subclavian artery.

• Brachial artery is a continuation of the a)illary artery.

• >adial artery and the ulnar artery.

'$ Descending aorta in t(e t(ora4

• Continuous with the arch of the aorta.

• t #ives off many paired branches which supply the walls of the thoracic

cavity and the or#ans within the cavity includin#:$. Bronchial arteries which supplies the bronchus and their branches,

connective tissue in the lun#s and the lymph nodes of the lun#s.. ;esopha#eal arteries that supply the oesopha#us.

'. ntercostal arteries that supply the intercostals muscles, muscles of thethora), the ribs, the s!in and connective tissues.

ABDOMINAL AO"TA

• Continuation of the thoracic aorta.

• ivides into ri#ht and left common iliac arteries.

• &any branches arise from the abdominal aorta, some paired and some

unpaired.

Paired branc(es

•nferior phrenic arteries which supply the diaphra#m.

• >enal arteries which supply the !idneys and branch into suprarenal

arteries to supply the adrenal #land.

• Testicular arteries supply the testes in the male.

• ;varian arteries which supply the ovaries in the female.

+npaired branc(es

• The coeliac artery which divides into three branches:

$. =eft #astric artery which supply the stomach.. 9plenic artery which supply the pancreas and the

spleen.

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'. 0epatic artery which supplies the liver, #all bladder andparts of the stomach, duodenum and pancreas.

• The superior mesenteric artery which supplies the small intestine and

the pro)imal half of the lar#e intestine.

• The inferior mesenteric artery which supplies the distal half of the lar#e

intestine and part of the rectum.

Circulation of blood to t(e pel7is and lo6er limb

• The abdominal aorta divides into the ri#ht and left common iliac arteries.

• The ri#ht and left common iliac arteries each divide into the internal and

e)ternal iliac arteries.

• The internal iliac artery supplies the or#ans within the pelvic cavity. The

lar#est branch is the uterine artery which supplies the femalereproductive or#ans.

• The e)ternal iliac artery runs into the thi#h where it becomes the femoral

artery.• The femoral artery and the popliteal artery supplies to the structures of

the thi#h and some superficial pelvic and in#uinal structures.

• The anterior tibial artery supplies the structures in the front of the le#.

• The dorsalis pedis artery is a continuation of the anterior tibial artery and

supplies the dorsum of the foot.

• The posterior tibial artery supplies the bac! of the le#.

• The peroneal artery supplies the lateral aspects of the le#. The plantar

artery supplies the structures in the sole of the foot.

1!NO+S "!T+"N

1enous return from t(e (ead and nec;

• The venous blood is returned by the deep and superficial veins.

• 9uperficial veins return venous blood from the face and scalp and unite

to form the e)ternal u#ular vein.

• The venous blood from the deep areas of the brain is collected into

channels called the dural venous sinuses.

• The main sinuses are:

$. $ superior sa#ittal sinus. $ inferior sa#ittal sinus'. $ strai#ht sinus4. transverse or lateral sinuses5. si#moid sinuses

• The internal u#ular veins run downwards in the nec! and unite with the

subclavian veins, carryin# blood from the upper limbs.

• They then form the brachiocephalic veins which are situated one on

each side in the root of the nec!.

• The superior vena cava drains all the venous blood from the head, nec!

and upper limbs. t ends in the ri#ht atrium of the heart.

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1enous return from t(e upper limbThe veins of the upper limb are divided into two #roups:$. eep veins follows the course of the arteries.

• (almar metacarpal veins

• eep lamar venous arch

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$. 9plenic vein drains blood from the spleen, pancreas and part ofthe stomach.

. nferior mesenteric vein returns blood from the rectum, pelvicand descendin# colon.

'. 9uperior mesenteric vein drains blood from the small intestine

and parts of the lar#e intestine.4. 6astric veins drain blood from the stomach and the distal end of

the oesopha#us.5. Cystic vein drains blood from the #all bladder.1enous return from t(e pel7is and lo6er limb

• There are both deep and superficial veins in the lower limb.

• &ovement of blood towards the heart is depended on contraction of

s!eletal muscles.

• Bac!ward flow is prevented by valves.

Deep 7einsThey are:$. i#ital veins. (lantar venous arch'. posterior tibial vein4. nterior tibial vein5. (opliteal vein. 7emoral vein". +)ternal iliac vein. nternal iliac vein2. Common iliac vein

Superficial 7einsThe two main superficial veins drainin# blood from the lower limbs are:$. 9mall saphenous vein be#ins behind the an!le oint.. 6reat saphenous vein is the lon#est vein in the body.

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T(e Aorta and main arteries of t(e bod0

27

HEARTLEGEND

P = Paired

U = Unpaired

AORTA

ABDOMINAL

AORTA

THORACIC

AORTA

Brachiocephalic arer!

Ri"h Ri"h

Co##on S$%cla&ian

Caroid Arer!

Arer! 'Ri"h Ar#(

'Head )

Nec* )

• Coronar! Arerie+ 'Hear, P(

• Le- S$%cla&ian Arer! 'Le- Ar#(

• Le- Co##on Caroid Arer! 'Head

• Bronchial Arerie+ 'L$n"+, P(

• Oe+opha"eal Arer! 'Oe+opha"$+, P(

• Inerco+al Arer! 'Ri%+ ) Ti++$e+ o-

• Phrenic Arerie+ 'Diaphra"#, P(

• Coeliac Arer! 'So#ach, Li&er,

Spleen ) Pancrea+, U(

• S$perior Me+eneric Arer!

'Ine+ine+, U(

• Renal Arerie+ '/idne!+, P(

• Te+ic$lar0O&arian Arerie+

'Gonad+, P(

• In-erior Me+eneric Arer! 'Lar"e


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Ri"h Co##on Iliac Arer!

Ri"h Inernal Ri"h E.ernal

Iliac Arer! Iliac Arer!

'Pel&i+ and 'Le"(

Pel&ic Or"an+(

Le- Co##on Iliac Arer!

Le- Inernal Le- E.ernal

Iliac Arer! Iliac Arer!

'Pel&i+ and 'Le"(

Pel&ic Or"an+(

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Blood Notes Final

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