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Dr S.BashirDr S.Bashir ##
PlateletsPlatelets ::(thrombocytes)(thrombocytes)
Flattened, disk-like cellFlattened, disk-like cellfra ments .fra ments .
!ssential for "emostasis.!ssential for "emostasis.!ac" #latelet circulates for !ac" #latelet circulates for
$-%2 da s$-%2 da s
'emo(ed ) s#lenic'emo(ed ) s#lenicmacro#"a es.macro#"a es.*"ere are + 3 , uL of *"ere are + 3 , uL of )lood.)lood.
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Dr S.BashirDr S.Bashir $$
SynthesisSynthesis
Produced in t"e )one marro/.Produced in t"e )one marro/.Lar e cells called me akar oc tes releaseLar e cells called me akar oc tes releasefra ments 0#latelets1 into t"e circulation.fra ments 0#latelets1 into t"e circulation.
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Dr S.BashirDr S.Bashir %%
Platelet function:Platelet function:
platelet plug platelet plug
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Dr S.BashirDr S.Bashir ''
11- - Vascular PhaseVascular Phase
*"e smoot" muscle cells in t"e*"e smoot" muscle cells in t"e)lood (essel /all res#ond to)lood (essel /all res#ond todama e. *"edama e. *"e 46N*' 4*46N*' 4* . *"e. *"e
)lood (essel diameter decreases)lood (essel diameter decreasesreduction in )lood loss.reduction in )lood loss.
*"e refle8 is immediate )ut*"e refle8 is immediate )uttransient.transient.9n:ur9n:ur e8#ose t"e rou " & sticke8#ose t"e rou " & stickcolla en fi)ers in t"e )asementcolla en fi)ers in t"e )asementmem)rane of (esselsmem)rane of (essels 0 !8tra 4ell.0 !8tra 4ell.Matri81.Matri81.
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Dr S.BashirDr S.Bashir ((
2 2 - - Platelet plug phasePlatelet plug phase
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Dr S.BashirDr S.Bashir 1*1*
3- oagulation Phase3- oagulation Phase
se
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Dr S.BashirDr S.Bashir 1111
!echanism of oagulation!echanism of oagulation
PhasePhase9n:ured tissues release t"rom)o#lastin,9n:ured tissues release t"rom)o#lastin, PF PF 33 0a #"os#"oli#id10a #"os#"oli#id1
PF PF 33 interacts /it" )lood #rotein clottin factors,interacts /it" )lood #rotein clottin factors,and calcium ions to tri er a clottin cascade.and calcium ions to tri er a clottin cascade.
4lottin factors are4lottin factors are #roen> mes#roen> mes 0inacti(e0inacti(een> mes1 t"at "a(e to )e con(erted to acti(een> mes1 t"at "a(e to )e con(erted to acti(een> mes.en> mes.
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Dr S.BashirDr S.Bashir 1212
!echanism of oagulation!echanism of oagulation
PhasePhase?urin t"e coa ulation?urin t"e coa ulation#"ase en> mes and#"ase en> mes and#roen> mes interact.#roen> mes interact.*"e acti(ation of one*"e acti(ation of one#roen> me#roen> me creates ancreates anacti(e en> me t"at acti(atesacti(e en> me t"at acti(atesanot"eranot"er #roen> me#roen> me t"at /illt"at /illt"en acti(ate a t"ird and sot"en acti(ate a t"ird and soon ieldin a c"ain reactionon ieldin a c"ain reactionoror cascadecascade ..
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Dr S.BashirDr S.Bashir 1#1#
!echanisms of oagulation!echanisms of oagulation
PhasePhase+oagulation can be acti!ate by either+oagulation can be acti!ate by either
-ntrinsic pathway-ntrinsic pathway
Extrinsic pathwayExtrinsic pathway he intrinsic pathway/ all factors foun he intrinsic pathway/ all factors founin bloo .in bloo .
he extrinsic pathway/ re0uires tissue he extrinsic pathway/ re0uires tissuefactors resulting from tissue in ury.factors resulting from tissue in ury.
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E +34 -"5 6E+ 7"-S6
E9 8-"S-+
P'6*H'6M=9N *H'6M=9N
F9='9N6@!N
F9='9N0II1 0III1
0I1V
X
*issue *"rom)o#lastin
VII
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Fi)rino en Fi)rin
*"rom)in
Prot"rom)in
Aaa
99a
*F
!8trinsic Pat"/a
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Fi)rino en Fi)rin*"rom)in
Prot"rom)in
Aaa
99a
*F
!8trinsic Pat"/a
9Aa
999a
A9a
A99a
9ntrinsic #at"/a
A999a
Soft clot
Fi)rin
Hard clot
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Dr S.BashirDr S.Bashir 2*2*
%ntrinsic Path$ay %ntrinsic Path$ay
Begins with the exposure of Begins with the exposure of collagencollagen which starts thewhich starts theactivation cascade of severalactivation cascade of severalproen$ymes eventuallyproen$ymes eventuallyresulting in the production ofresulting in the production ofprothrombin activator ( !)prothrombin activator ( !) ..
Because there are severalBecause there are severalsteps, the intrinsic path doessteps, the intrinsic path does
not ma#enot ma#e ( !)( !) as fast as theas fast as theextrinsic path. %owever,extrinsic path. %owever,multiple steps allows for moremultiple steps allows for moreamplification which meansamplification which meansmoremore ( !)( !) will be madewill be made moremorefibrinfibrin
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Dr S.BashirDr S.Bashir 2222
'-(ibrinolysis'-(ibrinolysis
&s repairs proceeds, the clot gradually dissolves. This&s repairs proceeds, the clot gradually dissolves. Thisdissolution is #nown asdissolution is #nown as fibrinolysis.fibrinolysis. ibrinolysis begins with the activation of the proen$ymeibrinolysis begins with the activation of the proen$yme
plasminogen into plasminplasminogen into plasmin'lasmin digests the fibrin strands and erodes the'lasmin digests the fibrin strands and erodes thefoundation of the clotfoundation of the clot ..
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Dr S.BashirDr S.Bashir 2#2#
HemostasisHemostasis :: summary summary
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Dr S.BashirDr S.Bashir 2$2$
)hy *oesn+t bloo* clot in normal)hy *oesn+t bloo* clot in normalvessels, vessels, "n*ogenous %nhibitors of Hemostasis"n*ogenous %nhibitors of Hemostasis%-%-*"e normal endot"elium*"e normal endot"elium intact & smoot"intact & smoot" ..
2-2- Flo/ of )lood.Flo/ of )lood. StasisStasis clottin tendenc B clottin tendenc B
3-3- !ndot"elium also secretes #roducts /"ic"!ndot"elium also secretes #roducts /"ic"in"i)it #latelet a re ationin"i)it #latelet a re ation nitric o8idenitric o8ide andand#rostac clin.#rostac clin. (antagonists for thromboxane A(antagonists for thromboxane A 2 2 11
5-5- ntit"rom)in 0 *1 0also called ntit"rom)in 0 *1 0also called antit"rom)inantit"rom)in999 ,999 ,from t"e li(er from t"e li(er ,, in"i)itsin"i)its t"rom)in 0factort"rom)in 0factor99a1 .99a1 .-- He#arinHe#arin from mast cells en"ances *from mast cells en"ances * ..
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Dr S.BashirDr S.Bashir 2%2%
)hy *oesn+t bloo* clot in)hy *oesn+t bloo* clot in
normal vesselsnormal vessels
, ,
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Dr S.BashirDr S.Bashir 22
Bleeding Disorders & Coagulopath Bleeding Disorders & Coagulopath
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Dr S.BashirDr S.Bashir 2(2(
Vitamin 0 *ef Vitamin 0 *ef ::
S nt"esi>ed ) )acterial flora in lar eS nt"esi>ed ) )acterial flora in lar eintestine.intestine.
Stimulates li(er s nt"esis of factorsStimulates li(er s nt"esis of factors 99, ,99, ,99 , A.99 , A.?eficienc in?eficienc in
C Ne/)orns, s#eciall #remature ones.Ne/)orns, s#eciall #remature ones.;" B;" B
C Prolon ed use of anti)iotics.Prolon ed use of anti)iotics. ;" B;" B
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Dr S.BashirDr S.Bashir #1#1
hrombushrombus
lar e t"rom)us ma lar e t"rom)us ma)lock a (ein)lock a (ein
.. eepeep V V einein hrombosishrombosis=lood stasis increase risk of=lood stasis increase risk of? *? * ..4auses of stasisB4auses of stasisB C 9mmo)ili>ation after9mmo)ili>ation after
fractures sur er ,fractures sur er ,deli(er , Lon fli "ts.deli(er , Lon fli "ts.
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Dr S.BashirDr S.Bashir ####
"mbolus"mbolus
9f t"e t"rom)us )reaks9f t"e t"rom)us )reaksoff & tra(els in t"eoff & tra(els in t"e
)loodstream, itEs called)loodstream, itEs calledanan em)olus.em)olus.!m)olus )locks an!m)olus )locks anarterarter C =rain stroke.=rain stroke. C Pulmonar em)olism.Pulmonar em)olism. C M ocardial infarctionM ocardial infarction
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Dr S.BashirDr S.Bashir #$#$
reatment of coagulopathiesreatment of coagulopathies
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Dr S.BashirDr S.Bashir #%#%
"#ogenous anti-coagulants"#ogenous anti-coagulants
HeparinHeparin /"ic" /orks ) inacti(atin t"rom)in./"ic" /orks ) inacti(atin t"rom)in.4annt )e taken orall & "as to )e in:ected.4annt )e taken orall & "as to )e in:ected.
ouma*in $arfarinouma*in $arfarin ## /"ic" #re(ents t"e li(er/"ic" #re(ents t"e li(erfrom utili>in (itamin D 0necessar for t"efrom utili>in (itamin D 0necessar for t"e#roduction of clottin factors1. *aken orall .#roduction of clottin factors1. *aken orall .
spirin spirin , /"ic" in"i)its #latelet a re ation and, /"ic" in"i)its #latelet a re ation and#rosta landins s nt"esis#rosta landins s nt"esis 0*"rom)o8ane 2 )ut0*"rom)o8ane 2 )utalso #rostac cline.1also #rostac cline.1
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Dr S.BashirDr S.Bashir #'#'
Prevention of clotting in the labPrevention of clotting in the lab::
He#arini>ed containers.He#arini>ed containers.
7 +a7 +a :::: chelating agentschelating agents // ED 7,ED 7,citratescitrates ..
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Dr S.BashirDr S.Bashir #)#)
han4 5ou han4 5ou
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