The HeartThe Heart

How it worksHow it works

The HeartThe Heart

FactsFacts

The heart is the organ that supplies blood and The heart is the organ that supplies blood and oxygen to all parts of the body and gets rid of oxygen to all parts of the body and gets rid of waste as wellwaste as well

It is about the size of your clenched fistIt is about the size of your clenched fist It weighs 10.5 ozIt weighs 10.5 oz The heart is surrounded by a fluid filled sac that The heart is surrounded by a fluid filled sac that

helps to anchor the organ in place and provides helps to anchor the organ in place and provides lubrication and protection called the pericardium.lubrication and protection called the pericardium.

Superior Vena CavaSuperior Vena Cava

Large diameterLarge diameter Short veinShort vein Carries Carries

deoxygenated deoxygenated blood from the blood from the upper half of the upper half of the body to the right body to the right atriumatrium

Inferior vena CaveInferior vena Cave

Large veinLarge vein Carries de-Carries de-

oxygenated blood oxygenated blood from the lower half from the lower half of the body to the of the body to the right atriumright atrium

Right AtriumRight Atrium

One of four One of four chambers in the chambers in the human hearthuman heart

It receives de-It receives de-oxygenated blood oxygenated blood from the SVC and from the SVC and the IVCthe IVC

Pumps the blood Pumps the blood into the right into the right ventricleventricle

Atrioventricular Valve - Atrioventricular Valve - TricuspidTricuspid

On the right side On the right side between the right between the right atrium and the right atrium and the right ventricleventricle

Three leaflets that Three leaflets that open when the open when the atrium contracts to atrium contracts to push the blood into push the blood into the ventriclethe ventricle

Prevents the Prevents the backflow of bloodbackflow of blood

Right VentricleRight Ventricle

The second of four The second of four chambers for the chambers for the blood to enterblood to enter

Receives the Receives the deoxygenated deoxygenated blood and pumps it blood and pumps it into the pulmonary into the pulmonary artery through the artery through the pulmonary trunkpulmonary trunk

More muscular More muscular than the atriumthan the atrium

PumpingPumping

The right ventricle will contract when The right ventricle will contract when there is the proper amount of blood there is the proper amount of blood and pressure in the chamberand pressure in the chamber

The atrioventricular valve (tricuspid) The atrioventricular valve (tricuspid) will close so the blood DOES NOT go will close so the blood DOES NOT go back into the right atriumback into the right atrium

The pulmonary valve will open when The pulmonary valve will open when the pressure from the contraction is the pressure from the contraction is increased.increased.

Pulmonary ValvePulmonary Valve Also called the Also called the

semilunar valvesemilunar valve Lies between the Lies between the

ventricle and the ventricle and the pulmonary trunk pulmonary trunk then arteriesthen arteries

It disperses the It disperses the deoxygenated blood deoxygenated blood into the pulmonary into the pulmonary arteries and arteries and prevents backflowprevents backflow

Pulmonary ArteriesPulmonary Arteries

Arteries carry blood Arteries carry blood away from the heart!away from the heart!

Usually it is Usually it is oxygenatedoxygenated

BUTBUT These arteries These arteries have have deoxygenateddeoxygenated blood and it is blood and it is transferred to the transferred to the lungslungs

Pulmonary VeinsPulmonary Veins

Large blood vesselLarge blood vessel Always carry blood Always carry blood

to the heart, to the heart, usually usually deoxygenateddeoxygenated

BUTBUT these carry these carry oxygenatedoxygenated blood blood from the lungs from the lungs back to the heartback to the heart

There are four There are four pulmonary veinspulmonary veins

Left AtriumLeft Atrium

Gathers the Gathers the oxygenated blood oxygenated blood from the from the pulmonary veinspulmonary veins

When the right When the right atrium contracts, atrium contracts, so does the leftso does the left

Mitral ValveMitral ValveAKA: Atrioventricular valveAKA: Atrioventricular valve

On the left side of the On the left side of the heartheart

Separates the blood in Separates the blood in the atrium from the the atrium from the blood in the ventricleblood in the ventricle

Has two leafletsHas two leaflets The diagram shows a The diagram shows a

malfunction where it malfunction where it allows blood back into allows blood back into the atrium – Prolapsethe atrium – Prolapse

Prevents the backflow Prevents the backflow of bloodof blood

Left VentricleLeft Ventricle

Very muscular 4Very muscular 4thth chamber of the chamber of the heartheart

Must pump the Must pump the oxygenated blood oxygenated blood to all parts of the to all parts of the body through the body through the aortaaorta

PumpingPumping The oxygenated blood is pumped from the lungs The oxygenated blood is pumped from the lungs

where the oxygen is ‘picked up’ to the heart by the where the oxygen is ‘picked up’ to the heart by the pulmonary veins.pulmonary veins.

It then enters the left atrium and when there is It then enters the left atrium and when there is sufficient volume and pressure (greater than that in sufficient volume and pressure (greater than that in the left ventricle) the atrium contracts which opens the left ventricle) the atrium contracts which opens the mitral (atrioventricular) valve. The blood rushes the mitral (atrioventricular) valve. The blood rushes into the ventricle and when the pressure and volume into the ventricle and when the pressure and volume here are correct the muscular ventricle will contract here are correct the muscular ventricle will contract and the mitral valve closes and the aortic valve opens.and the mitral valve closes and the aortic valve opens.

There is NO backflow of the blood in the heartThere is NO backflow of the blood in the heart The musculature of the left ventricle is greater than The musculature of the left ventricle is greater than

that of the right. WHY?that of the right. WHY?

Aortic ValveAortic Valve Valve that is opened Valve that is opened

when the left when the left ventricle contracts ventricle contracts allowing the allowing the oxygenated blood to oxygenated blood to enter the aortaenter the aorta

Normally has three Normally has three leafletsleaflets

The blood in the The blood in the ventricle must have ventricle must have a greater pressure a greater pressure than that in the aortathan that in the aorta

AortaAorta The largest artery in the The largest artery in the

human bodyhuman body Originates from the left Originates from the left

ventricle and extends ventricle and extends down into the abdomendown into the abdomen

It distributes oxygenated It distributes oxygenated blood to all parts of the blood to all parts of the bodybody

The blood from the aorta The blood from the aorta first passes into the first passes into the coronary arteries to coronary arteries to supply blood to the supply blood to the cardiac (heart) muscle.cardiac (heart) muscle.

Cardiac CycleCardiac Cycle

The sequence of events that occurs The sequence of events that occurs when the heart beatswhen the heart beats

Two phases:Two phases:

Diastole – Ventricles are relaxed, lower Diastole – Ventricles are relaxed, lower pressurepressure

Systole – Ventricles contract, higher Systole – Ventricles contract, higher pressurepressure

DiastoleDiastole

During this portion of the cycle, the During this portion of the cycle, the ventricle is relaxed ventricle is relaxed

The atrioventricular valves are openThe atrioventricular valves are open The pulmonary valve and the aortic valve The pulmonary valve and the aortic valve

are closedare closed The ventricles fill with blood – right is The ventricles fill with blood – right is

deoxygenated and the left is oxygenateddeoxygenated and the left is oxygenated The atria contract filling the ventricles until The atria contract filling the ventricles until

the pressure is greater than in the blood the pressure is greater than in the blood vesselsvessels

SystoleSystole

Ventricles have contractedVentricles have contracted The atrioventricular valves have The atrioventricular valves have

closedclosed The aortic and pulmonaric valves are The aortic and pulmonaric valves are

openedopened Blood rushes from the ventricles to Blood rushes from the ventricles to

the aorta and pulmonary arteriesthe aorta and pulmonary arteries

Fun FactsFun Facts

The heart beat is strong enough to squirt The heart beat is strong enough to squirt blood 30 feetblood 30 feet

The longer a boy’s ring finger is, the less The longer a boy’s ring finger is, the less likely they are to suffer a heart attacklikely they are to suffer a heart attack

The human heart beats ~ 35 million times The human heart beats ~ 35 million times per yearper year

The heart pumps ~ 1 million barrels of The heart pumps ~ 1 million barrels of blood in a lifetimeblood in a lifetime

Most heart attacks occur between 8 – 9 Most heart attacks occur between 8 – 9 a.m.a.m.

Fun FactsFun Facts

The blue whale has the largest heart – it The blue whale has the largest heart – it weighs one ton (approximately)weighs one ton (approximately)

The hummingbird heart beat is 1000 times The hummingbird heart beat is 1000 times per minuteper minute

Your entire blood volume goes through your Your entire blood volume goes through your entire body once every minuteentire body once every minute

Humans have ~ 60, 000 miles of blood Humans have ~ 60, 000 miles of blood vessels in their bodiesvessels in their bodies

Pig and baboon hearts have been Pig and baboon hearts have been transplanted into humanstransplanted into humans

Blood directionBlood direction

DEOXYGENATEDDEOXYGENATED

Superior vena cava and inferior vena cava Superior vena cava and inferior vena cava Right Right Atrium Atrium through the tricuspid valve through the tricuspid valve Right Right Ventricle Ventricle through the aortic valve through the aortic valve the Pulmonary the Pulmonary arteries arteries TO THE LUNGS TO THE LUNGS

OXYGENATEDOXYGENATED

Pulmonary veins Pulmonary veins Left Atrium Left Atrium through the mitral through the mitral valve valve Left Ventricle Left Ventricle through the aortic valve through the aortic valve Aorta Aorta to every cell of the body to every cell of the body back to the vena back to the vena cava!!cava!!

Full Circle!Full Circle!