Circulation and Immunity - biology-with-cooper - homefunction$to: Transport$blood$and$its$contents Carry$out$gas$exchange Regulate$blood$pressure Direct$blood$Flow II) CIRCULATION

Circulation and ImmunityA) The Circulatory System

SCHOOL HOUSE ROCKS ~THE BODY MACHINE

A) The Circulatory System

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

• 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

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

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.

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.

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

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.

WALLS ARE ONE CELL THICK FOR EASY EXCHANGE.

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$

• 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

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

• 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

• Varicose"veins

• Abnormal"and"irregular"dilations"in"super<icial"veins

• Hemorrhoids"are"varicose"veins"in"the"rectum

• Develop"when"the"valves"of"the"veins

• Varicose"veins

• Abnormal"and"irregular"dilations"in"super<icial"veins

• Hemorrhoids"are"varicose"veins"in"the"rectum

• Develop"when"the"valves"of"the"veins

• Phlebitis

• InFlammation$of$a$vein

• Thromboembolism$can$occur

Thromboembolism

Thrombo$~blood$clotEmbolism$~blockage

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

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

• 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

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

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

~"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

$Right$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

• 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

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

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

• 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

• 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

• 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

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

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 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.

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.

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.

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

CONTRACTION

Impulses$that$travel$during$the$cardiac$cycle$can$be$recorded$as$an$electrocardiogram$(ECG$or$EKG)

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

• 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

• 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.

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.

• 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.

SCHOOL HOUSE ROCKS ~ DO THE CIRCULATION

Circulation and Immunity - biology-with-cooper - homefunction$to: Transport$blood$and$its$contents Carry$out$gas$exchange Regulate$blood$pressure Direct$blood$Flow II) CIRCULATION

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