A&P i2 iLab i4
Circulatory iSystem-Blood iFlow iTracings
Circulatory isystem- ihow ithe iblood ifrom ithe iheart iis icirculated ithroughout ithe ibody.
General iblood iflow ithrough ithe ibody iafter iit ileaves ithe iheart ifollows ia imapping isystem. iFrom ithe
iheart, iit iflows ithrough iarteries, ithen icapillaries, iand icomes iback ito ithe iheart iby iway iof iveins.
BLOOD iVESSELS iIN iTHE iCIRCULATORY iSYSTEM:
•Arteries- ireferred ito ias iefferent iblood ivessel iin ithe icirculatory isystem
oThey ialways icarry iblood iaway ifrom ithe iheart.
oTypically icarry ioxygenated iblood. i(except iin ithe ipulmonary iartery)
o1. iConducting iarteries:
▪very ilarge iarteries iand itypically iexit ifrom ithe iheart
▪They ihave ithe ineed/ability ito iexpand iwhen ithe iheart ibeats iso ithey iwithstand ithe isplurge. iSo, iwith ievery iheartbeat, iblood isurges iout iof ithe
heart iinto ithese ilarge ivessels.
•To ido ithis, ithey imust ihave ia ilayer iof ielastic itissue ithat igives iit ithe iability ito istretch iand irecoil iwhen ithe iheart iis irelaxing.
▪EX: iaorta iand ipulmonary itrunk
oAtherosclerosis- iwhen iarteries iage iand istiffen ibecause iplaque ibuilds iup iin ithe
arteries, ithey iloose ithat ielasticity iand ithe iability ito istretch iwhen iblood isurges iinto ithem.
▪It iresults iin ian iincrease iin ipressure iin ithose ivessels iwhich ican ilead ito ian ianeurism- ia iweak ipoint iin ia iartery iand iwith ieach iheartbeat, ithat ilittle
thin iwalled iarea iwill ipulsate iand iit ican ifurther iand ifurther iweaken iand ieventually irupture iwhich ican ilead ito ideath ior istroke.
o2. iDistributing iarteries:
▪A.k.a. imedium ior imuscular iarteries
▪They iare idirect ibranches ifrom ithe iconducting iarteries
▪Have ia ivery ithick imuscular iwall i(up ito i40 ilayers iof ismooth imuscle)
▪The imuscular iwall iin ia idistributing iartery imakes iup i75% iof ithe iarterial iwall iitself.
•EX: ibrachial iartery, ifemoral iartery i(named ifor iarea iwhere ithey iare idistributing itheir iblood)
o3. iResistance iarteries:
▪A.k.a. ismall iarteries
▪Too inumerous ito iname
o4. iMetarterioles:
▪Very ishort ivessels ithat iwill ilink ithe iarteriole isystem ito ithe icapillaries.
•AFTER iBLOOD iFLOWS iTHROUGH iTHE iARTERIAL iSYSTEM, iIT iTHEN iFLOWS iINTO iA iSERIES iOF iCAPILLARY iBEDS. o5. iCapillaries:
▪Known ias ithe iexchange ivessels ibecause ithey ihave ivery ithin iwalls ithat iexchange ioxygen, iglucose, iand iother inutrients iin ithe ibody.
▪They iconnect ithe ismallest iarteries ito ithe ismallest iveins.
•Veins- iafferent iblood ivessels ibecause ithey ibring iblood iback ito ithe iheart
oThey itypically icarry ideoxygenated iblood i(except ithe ipulmonary ivein)
oThey iare icalled iCapacitance iVessels ibecause ithey itypically icontrol ia ilarge iamount iof ivolume.
oCan istretch imore ieasily ithan iarteries iand ihave ithin, iflaccid iwalls iand ican itherefore iaccommodate ia ilarger ivolume iof iblood.
oComparing iarteries ito iveins:
▪In ia iresting iperson, iabout i11% iof ithe iblood iis ifound iin ithe iarteries iwhile i54% iis ifound iin ithe iveins.
▪Veins iare isubject ito imuch ilower iblood ipressure ibecause ithey iare ifurther iaway ifrom ithe iheart. iBecause iof ithat, ithey ican ihave ithinner iwalls icompared ito ithe iarteries ithat ineed imore imuscular isupport.
▪In ithe iarteriole isystem, iwe igo ifrom ilarge ito ismall ivessels iand ithe ivenous isystem iis iopposite.
o6. iPost icapillary ivein:
▪Very ismall iveins icalled ivenules.
o7. iMuscular iVenules:
▪Very ismall iand itoo inumerous ito iname
o8. iMedium iveins:
▪They idrain iblood ifrom ispecific iareas iof ithe ibody, iorgans iand imuscles.
▪EX: iradial iand iulnar iveins i(drain iblood iout iof ithe iforearm)
▪Unique: ithey icontain ivalves- iflaps iof itissue ithat iextend iinto ithe ilumen iand ipoint iupwards itowards ithe iheart.
•Because iveins ihave ia ivery ilow iblood ipressure, ithey idon’t ihave ithe istrength ito ipump ithe iblood iback ito ithe iheart iagainst ithe ipull iof igravity.
•Skeletal imuscles ithat isurround ithe iveins ialso ihelp ito ipump ithe iblood
oEX: iwhen icalve imuscles icontract, ithey isqueeze iaround ithe ivein iand ipush iblood iup ithrough ithe ivalve.
oKind iof ilike ia i“milking iaction” iknown ias ithe iskeletal imuscle ipump.
•When ithe ivalves iweaken iand ican’t iperform itheir ijob, ivaricose iveins iwill iresult. iThey iare ivisible ithrough ithe iskin idue ito ithe iblood
pooling iand ibackflowing iinto ithe ivenous isystem.
o9. iVenous iSinuses:
▪Large ivessels iwith ivery ithin iwalls iand ivery ilarge ilumens ▪EX: icoronary isinus iof ithe iheart iwhere iblood ithat iflows ithrough ithe iheart, iwill idump iinto ithe icoronary isinus ibefore ientering iback iinto ithe ivena icava.
▪EX: iDural isinuses iin ithe ibrain. iThey icollect ithe iblood iflow ifrom ithe ibrain ibefore ithey ireturn ito ithe iheart.
o10. iLarge iveins
▪EX: iSuperior/Inferior iVena iCava- iwill ibring iblood iback ito ithe iheart iand ifinally istart ithe isystem iall iover iagain.
REVIEW iOF iBLOOD iFLOW iTHROUGH iTHE iHEART
•Inferior iVena iCava: idrains ifrom ianywhere ibelow ithe idiaphragm
•Superior iVena iCava: idrains ifrom ianywhere iabove ithe idiaphragm
•They iboth ibring iblood iinto ithe iright iatrium iof ithe iheart
•Tricuspid ivalve
•Right iventricle
•Pulmonary isemilunar ivalve----pulmonary itrunk-----left iand iright ipulmonary iarteries-----
flow ito ithe ilungs
•Blood ipicks iup ioxygen iin ithe ilungs iand ithen ito ithe
•Pulmonary iveins
•Left iatrium
•Bicuspid ivalve
•Left iventricle
•Aortic isemilunar ivalve
•Ascending iaorta:
•Off iof ithe iascending iaorta, ithe ibranches ifor ithe iLeft iand iright icoronary iarteries ibranch ioff iinto ithe iheart ito isupply ithe iheart imuscle iwith iblood.
•Once ithe iheart iuses ithe ioxygen iin ithe iblood, iit iwill iflow iinto ithe ivenous isystem iinto ithe icoronary isinus iwhich iwill idump iinto ithe iright iatrium ito istart ithe iprocess iagain
BLOOD iTRACINGS iTHROUGH iTHE iBODY
•How iblood igets ito ispecific iorgans iand iregions.
•Aorta iis ithe istarting ipoint.
• iASCENDING iAORTA • AORTIC iARCH
• DESCENDING: iTHORACIC iAORTA
• iDESCENDING: iABDOMINAL iAORTA
•From ithe iaortic iarch, ithere iare i3 ivessels ithat ibranch ioff iand idistribute iblood ito ithe ibrain iand ihead iand ineck iregion.
Circulatory iSystem-Blood iFlow iTracings
Circulatory isystem- ihow ithe iblood ifrom ithe iheart iis icirculated ithroughout ithe ibody.
General iblood iflow ithrough ithe ibody iafter iit ileaves ithe iheart ifollows ia imapping isystem. iFrom ithe
iheart, iit iflows ithrough iarteries, ithen icapillaries, iand icomes iback ito ithe iheart iby iway iof iveins.
BLOOD iVESSELS iIN iTHE iCIRCULATORY iSYSTEM:
•Arteries- ireferred ito ias iefferent iblood ivessel iin ithe icirculatory isystem
oThey ialways icarry iblood iaway ifrom ithe iheart.
oTypically icarry ioxygenated iblood. i(except iin ithe ipulmonary iartery)
o1. iConducting iarteries:
▪very ilarge iarteries iand itypically iexit ifrom ithe iheart
▪They ihave ithe ineed/ability ito iexpand iwhen ithe iheart ibeats iso ithey iwithstand ithe isplurge. iSo, iwith ievery iheartbeat, iblood isurges iout iof ithe
heart iinto ithese ilarge ivessels.
•To ido ithis, ithey imust ihave ia ilayer iof ielastic itissue ithat igives iit ithe iability ito istretch iand irecoil iwhen ithe iheart iis irelaxing.
▪EX: iaorta iand ipulmonary itrunk
oAtherosclerosis- iwhen iarteries iage iand istiffen ibecause iplaque ibuilds iup iin ithe
arteries, ithey iloose ithat ielasticity iand ithe iability ito istretch iwhen iblood isurges iinto ithem.
▪It iresults iin ian iincrease iin ipressure iin ithose ivessels iwhich ican ilead ito ian ianeurism- ia iweak ipoint iin ia iartery iand iwith ieach iheartbeat, ithat ilittle
thin iwalled iarea iwill ipulsate iand iit ican ifurther iand ifurther iweaken iand ieventually irupture iwhich ican ilead ito ideath ior istroke.
o2. iDistributing iarteries:
▪A.k.a. imedium ior imuscular iarteries
▪They iare idirect ibranches ifrom ithe iconducting iarteries
▪Have ia ivery ithick imuscular iwall i(up ito i40 ilayers iof ismooth imuscle)
▪The imuscular iwall iin ia idistributing iartery imakes iup i75% iof ithe iarterial iwall iitself.
•EX: ibrachial iartery, ifemoral iartery i(named ifor iarea iwhere ithey iare idistributing itheir iblood)
o3. iResistance iarteries:
▪A.k.a. ismall iarteries
▪Too inumerous ito iname
o4. iMetarterioles:
▪Very ishort ivessels ithat iwill ilink ithe iarteriole isystem ito ithe icapillaries.
•AFTER iBLOOD iFLOWS iTHROUGH iTHE iARTERIAL iSYSTEM, iIT iTHEN iFLOWS iINTO iA iSERIES iOF iCAPILLARY iBEDS. o5. iCapillaries:
▪Known ias ithe iexchange ivessels ibecause ithey ihave ivery ithin iwalls ithat iexchange ioxygen, iglucose, iand iother inutrients iin ithe ibody.
▪They iconnect ithe ismallest iarteries ito ithe ismallest iveins.
•Veins- iafferent iblood ivessels ibecause ithey ibring iblood iback ito ithe iheart
oThey itypically icarry ideoxygenated iblood i(except ithe ipulmonary ivein)
oThey iare icalled iCapacitance iVessels ibecause ithey itypically icontrol ia ilarge iamount iof ivolume.
oCan istretch imore ieasily ithan iarteries iand ihave ithin, iflaccid iwalls iand ican itherefore iaccommodate ia ilarger ivolume iof iblood.
oComparing iarteries ito iveins:
▪In ia iresting iperson, iabout i11% iof ithe iblood iis ifound iin ithe iarteries iwhile i54% iis ifound iin ithe iveins.
▪Veins iare isubject ito imuch ilower iblood ipressure ibecause ithey iare ifurther iaway ifrom ithe iheart. iBecause iof ithat, ithey ican ihave ithinner iwalls icompared ito ithe iarteries ithat ineed imore imuscular isupport.
▪In ithe iarteriole isystem, iwe igo ifrom ilarge ito ismall ivessels iand ithe ivenous isystem iis iopposite.
o6. iPost icapillary ivein:
▪Very ismall iveins icalled ivenules.
o7. iMuscular iVenules:
▪Very ismall iand itoo inumerous ito iname
o8. iMedium iveins:
▪They idrain iblood ifrom ispecific iareas iof ithe ibody, iorgans iand imuscles.
▪EX: iradial iand iulnar iveins i(drain iblood iout iof ithe iforearm)
▪Unique: ithey icontain ivalves- iflaps iof itissue ithat iextend iinto ithe ilumen iand ipoint iupwards itowards ithe iheart.
•Because iveins ihave ia ivery ilow iblood ipressure, ithey idon’t ihave ithe istrength ito ipump ithe iblood iback ito ithe iheart iagainst ithe ipull iof igravity.
•Skeletal imuscles ithat isurround ithe iveins ialso ihelp ito ipump ithe iblood
oEX: iwhen icalve imuscles icontract, ithey isqueeze iaround ithe ivein iand ipush iblood iup ithrough ithe ivalve.
oKind iof ilike ia i“milking iaction” iknown ias ithe iskeletal imuscle ipump.
•When ithe ivalves iweaken iand ican’t iperform itheir ijob, ivaricose iveins iwill iresult. iThey iare ivisible ithrough ithe iskin idue ito ithe iblood
pooling iand ibackflowing iinto ithe ivenous isystem.
o9. iVenous iSinuses:
▪Large ivessels iwith ivery ithin iwalls iand ivery ilarge ilumens ▪EX: icoronary isinus iof ithe iheart iwhere iblood ithat iflows ithrough ithe iheart, iwill idump iinto ithe icoronary isinus ibefore ientering iback iinto ithe ivena icava.
▪EX: iDural isinuses iin ithe ibrain. iThey icollect ithe iblood iflow ifrom ithe ibrain ibefore ithey ireturn ito ithe iheart.
o10. iLarge iveins
▪EX: iSuperior/Inferior iVena iCava- iwill ibring iblood iback ito ithe iheart iand ifinally istart ithe isystem iall iover iagain.
REVIEW iOF iBLOOD iFLOW iTHROUGH iTHE iHEART
•Inferior iVena iCava: idrains ifrom ianywhere ibelow ithe idiaphragm
•Superior iVena iCava: idrains ifrom ianywhere iabove ithe idiaphragm
•They iboth ibring iblood iinto ithe iright iatrium iof ithe iheart
•Tricuspid ivalve
•Right iventricle
•Pulmonary isemilunar ivalve----pulmonary itrunk-----left iand iright ipulmonary iarteries-----
flow ito ithe ilungs
•Blood ipicks iup ioxygen iin ithe ilungs iand ithen ito ithe
•Pulmonary iveins
•Left iatrium
•Bicuspid ivalve
•Left iventricle
•Aortic isemilunar ivalve
•Ascending iaorta:
•Off iof ithe iascending iaorta, ithe ibranches ifor ithe iLeft iand iright icoronary iarteries ibranch ioff iinto ithe iheart ito isupply ithe iheart imuscle iwith iblood.
•Once ithe iheart iuses ithe ioxygen iin ithe iblood, iit iwill iflow iinto ithe ivenous isystem iinto ithe icoronary isinus iwhich iwill idump iinto ithe iright iatrium ito istart ithe iprocess iagain
BLOOD iTRACINGS iTHROUGH iTHE iBODY
•How iblood igets ito ispecific iorgans iand iregions.
•Aorta iis ithe istarting ipoint.
• iASCENDING iAORTA • AORTIC iARCH
• DESCENDING: iTHORACIC iAORTA
• iDESCENDING: iABDOMINAL iAORTA
•From ithe iaortic iarch, ithere iare i3 ivessels ithat ibranch ioff iand idistribute iblood ito ithe ibrain iand ihead iand ineck iregion.
