Circulation and Immunity A) The Circulatory System SCHOOL HOUSE ROCKS ~THE BODY MACHINE
Circulation and ImmunityA) The Circulatory System
SCHOOL HOUSE ROCKS ~THE BODY MACHINE
A) The Circulatory System
I) COMPARATIVE CIRCULATORY SYSTEMS
I) COMPARATIVE CIRCULATORY SYSTEMS
I) COMPARATIVE CIRCULATORY SYSTEMS
Circulations Place in our Biology 20 World
In ecology you learn how organisms interact with their environment to maintain a balance of energy.
In metabolism we learned how organisms harness the energy of the sun and transform it.
In adaptations we learned how organisms adapt to be better energy users.
In digestion we learned how we catabolize matter to extract energy.
In circulation we will learn how the materials needed to make the human machine efficient energy users are carried around the body.
II) CIRCULATION OVERVIEW
The$key$parts$of$the$circulatory$system$are:
• The$Heart$
~$the$muscular$pump$that$circulates$blood.
• Blood$Vessels$
~$a$system$of$closed$tubes$used$to$transport$blood.
• Blood
~$the$carrier$of$gases,$nutrients,$wastes,$hormones$and$cells$of$the$immune$system$throughout$the$body.
II) CIRCULATION OVERVIEW
The$blood$of$the$circulatory$system$performs$the$following$functions$for$the$cells$of$your$body:
~$Carries$food$and$oxygen$to$cells.
~$Removes$wastes$from$cells$and$carries$them$to$“disposal”$organs.
~$Helps$maintain$body$temperature.
~$Carries$infection$Fighting$cells$and$proteins.
II) CIRCULATION OVERVIEWA) BLOOD
~"Removes"wastes"from"cells"and"carries"them"to"“disposal”"organs.
~"Helps"maintain"body"temperature.
~"Carries"infection">ighting"cells"and"proteins.
~"Preserves$pH$of$tissues,$they$are$normally$slightly$alkaline.
~$Transports$hormones
~$Closes$cuts$to$minimize$bleeding$(hemorrhaging),$and$therefore$decrease$the$loss$of$blood$pressure.
II) CIRCULATION OVERVIEWA) BLOOD
Vessels$function$to:
Transport$blood$and$its$contents
Carry$out$gas$exchange
Regulate$blood$pressure
Direct$blood$Flow
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
Arteries"and"Arterioles
Transport"blood"away"from"the"heart
Thick,"strong"walls"composed"of:
• Tunica"interna""""~"endothelium
• Tunica"media""""""~"smooth"muscle"and"elastic"<ibres
• Tunica"externa"""~"outer"connective"tissue"layer
Designed(to(withstand(high(pressure(from(the(heart
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
• Tunica"interna""""~"endothelium
• Tunica"media""""""~"smooth"muscle"and"elastic">ibres
• Tunica"externa"""~"outer"connective"tissue"layer
Designed(to(withstand(high(pressure(from(the(heart
Elasticity"allows"an"artery"to"expand"and"recoil
Arterioles"are"small"arteries
• Constriction"and"dilation"affect"blood"distribution"and"blood"pressure
• Autonomic"nervous"system"regulates"the"number"of"arterioles"that"are"contracted
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
Arterioles"are"small"arteries
• Constriction"and"dilation"affect"blood"distribution"and"blood"pressure
• Autonomic"nervous"system"regulates"the"number"of"arterioles"that"are"contracted"
• Arterioles$have$precapillary$sphincter$muscles$that$can$constrict$or$dilate$to:
~$regulate$blood$Flow$to$organs
~$maintain$blood$pressure
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
Atherosclerosis( ~(a(condition(in(which(fatty(material(( collects( along( the( walls( of( arteries.(( This(fatty(material(thickens,(hardens(( (forms( calcium( deposits),( and( may(( eventually(block(the(arteries.
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
Can produce:
• high blood pressure (tough on the heart)
• coronary artery blockage (heart attack)
• stroke (blockage of blood to brain)
• in a balloon angioplasty (or coronary angioplasty) a balloon-tipped catheter (thin tube) is inserted into a diseased, narrowed blood vessel; inflation of balloon stretches vessel opening, improving blood flow through it.
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
Capillaries
• Microscopic$blood$vessels
• One$layer$of$endothelial$cells
• Site$of$nutrient$and$gas$exchange
• Not$all$capillary$beds$are$in$use$at$the$same$time
• Most$have$a$shunt
• Precapillary$sphincters$control$the$entrance$of$blood$into$capillaries
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
Capillaries
• run through all tissues.
• all cells sit beside a capillary so nutrients can enter the cell from the blood and wastes can move out of the cell into the blood.
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
WALLS ARE ONE CELL THICK FOR EASY EXCHANGE.
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
Capillary"Exchange• Takes$place$across$thin$capillary$walls
• Most$cells$of$the$body$are$near$a$capillary
• Oxygen$and$nutrients$leave$a$capillary
• Cellular$wastes$enter$a$capillary$
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
• Most(cells(of(the(body(are(near(a(capillary
• Oxygen(and(nutrients(leave(a(capillary
• Cellular(wastes(enter(a(capillary
• Three$processes$inFluence$capillary$exchange:
• Blood$pressure$–$pushes$blood$through$the$capillary
• Diffusion$–$movement$of$a$substance$from$an$area$of$higher$concentration$to$an$area$of$lower$concentration
• Osmotic$pressure$–$force$caused$by$a$difference$in$solute$concentration$on$either$side$of$a$membrane
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
Veins and Venules
• Return blood to the heart
• Venules
• Drain$blood$from$the$capillaries
• Join$together$to$form$veins
• Vein$walls$are$thinner$than$arterial$walls
• Valves$in$veins$prevent$backward$Flow$of$blood
• Varicose veins and phlebitis
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
• Join(together(to(form(veins
• Vein(walls(are(thinner(than(arterial(walls
• Valves(in(veins(prevent(backward(Flow(of(blood
• Varicose$veins$and$phlebitis
• Varicose$veins
• Abnormal$and$irregular$dilations$in$superFicial$veins
• Hemorrhoids$are$varicose$veins$in$the$rectum
• Develop$when$the$valves$of$the$veins$collapse
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
• Varicose"veins
• Abnormal"and"irregular"dilations"in"super<icial"veins
• Hemorrhoids"are"varicose"veins"in"the"rectum
• Develop"when"the"valves"of"the"veins
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
• Varicose"veins
• Abnormal"and"irregular"dilations"in"super<icial"veins
• Hemorrhoids"are"varicose"veins"in"the"rectum
• Develop"when"the"valves"of"the"veins
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
• Phlebitis
• InFlammation$of$a$vein
• Thromboembolism$can$occur
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
Thromboembolism
Thrombo$~blood$clotEmbolism$~blockage
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
Physiology"of"Circulation
• Velocity$of$Blood$Flow
• Slowest$in$capillaries
• CrossVsectional$area$is$at$its$maximum
• Allows$time$for$gas$and$nutrient$exchange
• Blood$Flow$increases$as$venules$combine$to$form$veins
• Velocity$of$blood$returning$to$the$heart$is$low$compared$to$that$of$blood$leaving$the$heart
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
Physiology$of$Circulation
• Venous$return$depends$on:
• A$blood$pressure$difference
• The$skeletal$muscle$pump$and$the$respiratory$pump
• contraction$of$skeletal$muscles$compress$the$walls$of$veins$causing$blood$to$move$past$a$valve
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
• The"skeletal"muscle"pump"and"the"respiratory"pump
• contraction"of"skeletal"muscles"compress"the"walls"of"veins"causing"blood"to"move"past"a"valve
• during$inhalation,$thoracic$pressure$falls$and$abdominal$pressure$rises$and$blood$will$Flow$from$an$area$of$higher$pressure$to$an$area$of$lower$pressure
• Total$blood$volume:
• if$blood$volume$decreases,$blood$pressure$falls
• if$blood$volume$increases,$blood$pressure$rises
II) CIRCULATION OVERVIEWB) BLOOD VESSELS
Heart$functions:
• keeps$O2Vpoor$blood$separate$from$O2Vrich$blood
• keeps$the$blood$Flowing$in$one$direction
• creates$blood$pressure
• regulates$the$blood$supply
• serves$as$an$endocrine$gland
III) THE HEARTA) ANATOMY AND PHYSIOLOGY
Pulmonary artery
Right atrium
Semilunar valve
Atrioventricular valve
Right ventricle
Left ventricle
Atrioventricular valve
Left atrium
Semilunar valve
Pulmonary artery
Aorta
Chambers$of$the$Heart
•$Right$atrium~$Receives$O2Vpoor$blood
~$Vessels$that$empty$into$right$atrium:
• Superior$vena$cava• Inferior$vena$cava• Coronary$sinus
~$Venous$blood$leaves$right$atrium$through$the$an$atrioventricular$(AV)$valve$(tricuspid)
• Directs$the$Flow$of$blood• Prevents$backFlow• Has$three$cusps
III) THE HEARTA) ANATOMY AND PHYSIOLOGY
~"Venous"blood"leaves"right"atrium"through"the"an"atrioventricular"(AV)"valve"(tricuspid)
• Directs"the"<low"of"blood• Prevents"back<low• Has"three"cusps
•$Right$ventricle~$Chordae$tendineae
• Fibrous$cords$connected$to$the$tricuspid$valve
• Connected$to$the$papillary$muscle$in$ventricle• shut$the$valve$after$blood$rushes$in$(the$lub$
sound$of$the$heart$beat)
~$Blood$passes$through$the$pulmonary$semilunar$valve$into$the$pulmonary$trunk
III) THE HEARTA) ANATOMY AND PHYSIOLOGY
$Right$ventricle
~$Chordae$tendineae
• Fibrous$cords$connected$to$the$tricuspid$valve
• Connected$to$the$papillary$muscle$in$ventricle~$Blood$passes$through$the$pulmonary$semilunar$
valve$into$the$pulmonary$trunk
III) THE HEARTA) ANATOMY AND PHYSIOLOGY
• Left$atrium
~$Receives$O2Vrich$blood
~$Blood$enters$atrium$through$4$pulmonary$veins
~$Blood$leaves$left$atrium$through$an$AV$valve$(bicuspid$or$mitral)$
• Left$ventricle
~$Forms$the$apex$of$the$heart
~$Blood$leaves$the$left$ventricle$through$the$aortic$semilunar$valve$and$enters$the$aorta
III) THE HEARTA) ANATOMY AND PHYSIOLOGY
Operation"of"the"Heart"Valves"
• AV"valves
• Normally"open
• When"ventricle"contracts
• AV"valves"shut
• Papillary"muscles"contract,"preventing"valve"from"reverting"into"an"atrium
• Semilunar"valves
• Normally"closed
• Contraction"of"ventricles"forces"valves"open
III) THE HEARTA) ANATOMY AND PHYSIOLOGY
Heart$Sounds
• First$sound,$“lub”
• Heard$when$ventricles$begin$to$contract
• AV$valves$close
• Lasts$longer$and$has$a$lower$pitch
• Second$sound,$“dub”
• When$ventricles$relax
• Semilunar$valves$close
III) THE HEARTA) ANATOMY AND PHYSIOLOGY
• Lasts"longer"and"has"a"lower"pitch
• Second"sound,"“dup”
• When"ventricles"relax
• Semilunar"valves"close
• Heart$murmurs
• Due$to$ineffective,$leaky$valves
• Valves$do$not$close$properly
• Allows$blood$to$backFlow$into$atria$or$ventricles$after$valves$have$closed
III) THE HEARTA) ANATOMY AND PHYSIOLOGY
• Heart"murmurs
• Due"to"ineffective,"leaky"valves
• Valves"do"not"close"properly
• Allows"blood"to"back"<low"into"atria"or"ventricles"after"valves"have"closed
• Coronary$Circulation
• Heart$cells$are$not$nourished$by$the$blood$in$the$chambers
• The$left$and$right$coronary$arteries$branch$from$the$aorta
• Coronary$arteries$branch$numerous$times
III) THE HEARTA) ANATOMY AND PHYSIOLOGY
• Coronary"Circulation
• Heart"cells"are"not"nourished"by"the"blood"in"the"chambers
• The"left"and"right"coronary"arteries"branch"from"the"aorta
• Coronary"arteries"branch"numerous"times
• Heart$is$encircled$by$small$blood$vessels
• After$blood$passes$through$cardiac$capillaries$it$enters$the$cardiac$veins
• Cardiac$veins$enter$the$coronary$sinus
• Coronary$sinus$enters$the$right$atrium
III) THE HEARTA) ANATOMY AND PHYSIOLOGY
Pulmonary$circuit
• Blood$from$the$body$collects$in$the$right$atrium
• Blood$moves$into$the$right$ventricle
• Right$ventricle$pumps$blood$into$the$pulmonary$trunk
• Blood$Flows$into$the$pulmonary$capillaries$in$the$lungs
• Blood$Flows$from$the$lungs$through$the$pulmonary$veins$and$into$the$left$atrium
IV) BLOOD FLOWA) CIRCULATION
Systemic$circuit
•$Includes$all$other$arteries$and$veins$of$the$body•$Aorta$and$venae$cavae$are$the$major$pathways$for$
blood$in$the$systemic$circuit
•$Aorta$is$the$largest$artery
•$Superior$and$inferior$venae$cavae$are$the$largest$veins
IV) BLOOD FLOWA) CIRCULATION
Systemic"circuit
•"Includes"all"other"arteries"and"veins"of"the"body•"Aorta"and"venae"cavae"are"the"major"pathways"for"blood"in"the"systemic"
circuit
•"Aorta"is"the"largest"artery
•"Superior"and"inferior"venae"cavae"are"the"largest"veins
•Begins$in$the$left$ventricle•$The$left$ventricle$pumps$blood$into$the$aorta•$Branches$from$the$aorta$go$to$the$major$body$
regions$and$organs
•$Blood$returns$from$the$capillaries$to$the$veins$then$to$the$venae$cavae
IV) BLOOD FLOWA) CIRCULATION
IV) BLOOD FLOWB) CARDIAC CYCLE
Cardiac$Cycle• All$events$that$occur$during$one$heartbeat• Systole$–$contraction$of$heart$muscle• Diastole$–$relaxation$of$heart$muscle
• Three$phases$of$the$cardiac$cycle:•$Phase$1:$Atrial$Systole
Both$atria$are$in$systoleVentricles$are$in$diastoleBoth$AV$valves$are$openThe$semilunar$valves$are$closed
IV) BLOOD FLOWB) CARDIAC CYCLE
• Three"phases"of"the"cardiac"cycle:•"Phase"1:"Atrial"Systole
Both"atria"are"in"systoleVentricles"are"in"diastoleBoth"AV"valves"are"openThe"semilunar"valves"are"closed
$•$Phase$2:$Ventricular$Systole
Both$ventricles$are$in$systoleThe$atria$are$in$diastoleSemilunar$valves$are$forced$openBoth$AV$valves$are$closed
•$Phase$3:$Atrial$and$Ventricular$DiastoleBoth$atria$and$both$ventricles$are$in$diastoleBoth$AV$valves$are$openThe$semilunar$valves$are$closed
http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_pumping.html
http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw_electrical.html
myogenic""""""""[mī′ōjen′ik]Etymology:"Gk,"mys"+"genesis,"origin
generated(by(muscles.(The(term(usually(refers(to(rhythmic(activity(in(cardiac(and(smooth(muscles,(which(do(not(require(neural(input(to(initiate(and(maintain(contractions.
V) HEART PHYSIOLOGYA) THE HEART BEAT
The heart muscle is self-stimulating because of the action of the sinoatrial node (SA node), a collection of nerves in the right atrium.
V) HEART PHYSIOLOGYA) THE HEART BEAT
Start(Nerve Impulse Generated)
The SA node acts as a pacemaker and sends signals to the atria and atrioventricular node in the septum of the heart.
V) HEART PHYSIOLOGYA) THE HEART BEAT
Step 3Impulse sent to AV node
Step 2(Atria contraction)
The AV node distributes the nerve impulse via nerves of the Bundle of His and then Purkinje fibres to the ventricles.
V) HEART PHYSIOLOGYA) THE HEART BEAT
Step 5Purkinje fibers receive impulse and ventricles contract
Step 4Impulse sent to ventricular region.
The$heart$contracts$from$top$to$bottom;$atria,$followed$by$ventricles
V) HEART PHYSIOLOGYA) THE HEART BEAT
CONTRACTION
CONTRACTION
CONTRACTION
CONTRACTION
CONTRACTION
CONTRACTION
CONTRACTION
CONTRACTION
CONTRACTION
CONTRACTION
Impulses$that$travel$during$the$cardiac$cycle$can$be$recorded$as$an$electrocardiogram$(ECG$or$EKG)
V) HEART PHYSIOLOGYA) THE HEART BEAT
Impulses$that$travel$during$the$cardiac$cycle$can$be$recorded$as$an$electrocardiogram$(ECG$or$EKG)
V) HEART PHYSIOLOGYA) THE HEART BEAT
P WAVE ATRIAL
DEPOLARIZATION(CONTRACTION)
QRS COMPLEX VENTRICULAR
DEPOLARIZATION(CONTRACTION)
T WAVE VENTRICULAR
REPOLARIZATION(RELAXATION)
The$pacemaker$is$inFluenced$by$nerves,$hormones,$body$temperature,$exercise,$chemicals
• Heart$rate$can$be$altered$by$two$nerves$coming$from$the$brain$to$the$SA$node.
• Vagus$nerve
~$more$impulses$slow$heart$rate.$Part$of$the$parasympathetic$nervous$system.
• Sympathetic$Nerve
~$more$impulses$increase$heart$rate.$$Part$of$the$$sympathetic$nervous$system
V) HEART PHYSIOLOGYA) THE HEART BEAT
• Vagus"nerve
~"more"impulses"slow"heart"rate."Part"of"the"parasympathetic"nervous"system.
• Sympathetic"Nerve
~"more"impulses"increase"heart"rate.""Part"of"the"sympathetic"nervous"system
V) HEART PHYSIOLOGYA) THE HEART BEAT
• Vagus"nerve
~"more"impulses"slow"heart"rate."Part"of"the"parasympathetic"nervous"system.
• Sympathetic"Nerve
~"more"impulses"increase"heart"rate.""Part"of"the"" sympathetic"nervous"system
•$$$Heart$rate$can$also$be$increased$by$the$release$of$epinephrine$(adrenaline)$by$the$adrenal$gland$into$the$blood.
V) HEART PHYSIOLOGYA) THE HEART BEAT
•$$$Heart$rate$can$also$be$increased$by$the$release$of$epinephrine$(adrenaline)$by$the$adrenal$gland$into$the$blood.
V) HEART PHYSIOLOGYA) THE HEART BEAT
Measuring$Blood$Pressure
•$blood$pressure$is$the$force$your$blood$exerts$on$blood$vessels.
•$blood$pressure$is$made$up$of$two$measurements•$Systole~$pressure$during$ventricular$contraction.(contractile$phase$of$heart)•$Diastole
$ ~$pressure$as$the$heart$reFills.$ (relaxation$phase$of$heart)
V) HEART PHYSIOLOGYB) MEASURING BLOOD PRESSURE
• Where$is$the$area$of$systemic$system$greatest?– at$the$capillaries
• Where$is$the$velocity$of$blood$the$lowest?
– at$the$capillaries
• Describe$blood$pressure$at$is$passes$through$the$systemic$system.
– highest$the$aorta$getting$lower$as$it$approaches$to$vena$cava.
V) HEART PHYSIOLOGYB) MEASURING BLOOD PRESSURE
• blood$pressure$(BP)$is$measured$in$mm$of$mercury$(Hg)$• an$average$brachial$artery$pressure$is$120$systolic$over$80$diastolic.• BP$is$regulated$by$pressure$receptors$located$in$2$places:
• high$blood$pressure$detected$in$the$aorta• low$blood$pressure$is$detected$in$the$carotid$arteries$(main$arteries$in$your$neck)
•BP is measured using a stethoscope and sphygmomanometer.
V) HEART PHYSIOLOGYB) MEASURING BLOOD PRESSURE
SCHOOL HOUSE ROCKS ~ DO THE CIRCULATION