ANATOMY OF THECARDIOVASCULAR SYSTEM

• THE HEART IS THE MUSCULAR PUMPING DEVICE

• ARTERIES, VEINS AND CAPILLARIES ARE THE TRANSPORTATION VESSELS

The human heart is a four-chamberedmuscular organ, sized and shaped roughly like a person’s closed fist.

It lies in the mediastinum (middle ofthe thorax) just behind the body of thesternum between the points ofattachment of ribs 2 – 6

Approximately two-thirds of the heart’smass is to the left of the body’smidline, with the other third to theright side

Posteriorly, the heart rests against thebodies of the 5th – 8th thoracicvertebrae

The arrangement of cardiac muscletissue make the heart an efficient“pumping machine

LOCATION OF THE HEART WITHIN THE THORACIC CAVITY

Heart:Left VentricleRight Ventricle

HEART IN EARLY HUMAN EMBRYO

AS IN THE ADULT, SURVIVAL OF THE DEVELOPINGEMBRYO DEPENDS ON THE CIRCULATION OF BLOODTO MAINTAIN HOMEOSTASIS AND A FAVORABLE CELLULARENVIRONMENT. IN RESPONSE TO THIS EARLY NEED, THECARDIOVASCULAR SYSTEM MAKES AN APPEARANCE EARLYIN DEVELOPMENT AND REACHES A FUNCTIONAL STATELONG BEFORE ANY OTHER MAJOR ORGAN SYSTEM

THE HEART BEGINS TO BEATREGULARLY EARLY IN THE 4TH

WEEK AFTER FERTILIZATION

IN THE INFANT, THE HEART APPEARS LARGEIN COMPARISON TO THE OTHER ORGANS AND IS 1/130 OF THE TOTAL BODY WEIGHT, COMPARED TO 1/300 IN ADULTS

IMPORTANT BORDERS OF THE HEART

The lower border is theapex, forming a bluntpoint that lies on thediaphragm, pointingtoward the left

The upper border isthe base. It liesjust below the2nd rib

5

6

2

“Normal” boundaries may be affected by age, body build and state of contraction. . .In adults, the shape of the heart tends to resemble that of the chest: In tall individuals, the heart is frequently elongated, whereas in short,stocky individuals, the heart has a greater width (transverse shape)

COVERINGS OF THE HEART

The PERICARDIUM is a loose-fitting inextensible sacsurrounding the heart. It is made of tough white Fibrous tissue but is lined with smooth, moist serousMembrane.

The pericardium consists of two parts:

• fibrous pericardium- tough, loose-fitting, inelastic sac around the heart

• serous pericardium - parietal layer: lining inside the fibrous pericardium - visceral layer (epicardium): adhering to the outside of the heart; between visceral and parietal layers is a space (pericardial space) which contains a few drops of pericardial fluid which helps reduce the friction of the heart moving against the wall

ACTUAL CUT- AWAY VIEW OF THE HEART WITHIN THE PERICARDIAL SAC

STRUCTURE OF THE HEART – THE HEART WALL

ENDOCARDIUM

Fibrouspericardium

SerousPericardium(visceral layer)

EPICARDIUM

Serous Pericardium(parietal layer)

Space

MYOCARDIUM (muscle layer)

PERICARDIUM

Epicardium Corresponds to the visceral pericardium. Functions as an outer protective layer. Serous membrane that consists of connective tissue covered by epithelium. Includes blood capillaries, lymph capillaries, and nerve fibers.

Myocardium Relatively thick. Consists largely of cardiac muscle tissue responsible for forcing blood out of the heart chambers. Muscle fibers are arranged in planes, separated by connective tissues that are richly supplied with blood capillaries, and nerve fibers.

Endocardium Consists of epithelial and connective tissue that contains many elastic and collagenous fibers. Connective tissue also contains blood vessels and some specialized cardiac muscle fibers called Purkinje fibers. Lines all of the heart chambers and covers heart valves. Is continuous with the inner lining of blood vessels--endothelium.

CHAMBERS OF THE HEART AND ASSOCIATED STRUCTURESAND BLOOD VESSELS

The interior of the heart is divided into four cavities, or heart chambers

• the two superior chambers are called atria (atrium, sing.); atria are receiving chambers. Each atrium has a little flap protruding from it called an auricle

• the two lower chambers are called ventricles; ventricles are the larger chambers that pump the blood out of the heart

VALVES OF THE HEART PREVENT BACK FLOW

TRICUSPID VALVE

MITRAL VALVE (BICUSPID)

AORTIC VALVE

PULMONARY VALVE

ATRIOVENTRICULAR (AV)• CUSPIDS

SEMILUNAR (SL)• PULMONARY• AORTIC

HEART SOUNDS

Heart valves closing causes the lub-dub or thump-thump heart beat sound.

Heart rate = beats per minute

What influences the heart rate?...

Activity

size/age

Emotions

Chemicals(natural and artificial)

Posture

THE “SKELETON” OF THE HEART

The fibrous structure surrounding theheart is a set of connected rings thatserves as a semi-rigid support for theheart valves (on the inside of the rings)and for the attachment of themyocardium (on the outside of the rings).

This “skeleton” also serves as an electricalbarrier between the myocardium of theatria and the myocardium of the ventricles

This image shows an electron microscope view of the fibrocollagenous material which makes up the 'skeleton' of the heart. It is important not only from the point of enabling the heart to maintain it's shape but also because it prevents atrial contraction of heart muscle being automatically transferred to the ventricles unless it is triggered by the AV node.

BLOOD VESSELS DIRECTLY ASSOCIATED WITH THE HEART

Superiorvena cava

Inferiorvena cava

Pulmonaryveins

Aorta

Pulmonary artery

blood flow

Left subclavian artery

Left common carotid artery

Brachiocephalic trunk

FLOW OF BLOOD THROUGH THE HEART

LET’S START WITH THE RETURN OF OXYGEN-POOR BLOOD TOTHE HEART . . .

THE RIGHT ATRIUM

• receives deoygenated blood from the body by way of the: - superior vena cava (vein returning blood from the head and neck area - inferior vena cava (vein returning blood from the lower body)

•The Rt. Atrium contracts.•The Rt ventricle relaxes pulling the tricuspid valve flaps down and blood enters the right ventricle.

•The ventricle contracts closing the tricuspid valve and opening the pulmonary semilunar valve, BLOOD flows through the pulmonary arteries to the lungs where CO2 is exchanged for O2 in the capillaries of the lungs.

Oxygenated blood returns to the heart

• The pulmonary veins carry oxygenated blood back to the heart where it enters the left atrium.

• The left ventricle relaxes and pulls down on the mitral valve flaps.

• The blood flows into the left ventricle through the mitral valve.

10 Pulse/pressure points

• Heart Rate = beats/contractions per minute

• Influenced by activity,

posture changes, chemicals, and emotions

Facial

Blood Pressure• Systolic pressure is

the pressure in the arteries when the heart contracts or beats.

• Diastolic pressure is the pressure in the arteries when the heart relaxes or is refilling with blood.

Factors Affecting BPNeural – Sympathetic Nervous systemvasoconstriction and vasodialationRenal – controls blood volumeTemperature – vasoconstriction & vasodialationChemicals- Natural and ArtificialDiet- salts, fats, cholesterol

Taking someone’s BP

Blood Pressures

• NormalSystolic - less than 120 and Diastolic - less than 80

• Prehypertension S 120 – 139 or D 80 – 89• High Blood Pressure

(Hypertension) Stage 1 S 140 – 159 or D 90 – 99• High Blood Pressure

(Hypertension) Stage 2 S 160 or higher or D 100 or higher• Hypertensive Crisis

(Emergency care needed) S Higher than 180 or D Higher than 110

Right Bundle Branch

Left Bundle Branch

ELECTRICAL CONDUCTION WITHIN THE HEART

Bundle of His

What makes the Heart beat?

Heart function/valves/electrical function

AtrialDepolarization

Atrial Repolarization

Ventricular Depolarization

Ventricular Repolarization

ECG TRACING OF CARDIAC CYCLEElectrical conduction of the heart is tracked.

Cardiovascular Problems

• Arteriosclerosis – hardening of the arteries

Arterial walls thicken as calcium deposits form.

• Aneruysm – a section of the artery that has become abnormally widened because of weakening of the wall.

• Embolism – clot

• Hemorrhage- uncontrolled bleeding

Peripheral Artery DiseaseArteriosclerosis is

characterized by the hardening of the arteries that supply the legs and feet. It causes a decrease in blood flow that can damage nerves and tissues.

Heart Dysfunctions

• Fibrillation

uncoordinated muscle contractions

• Murmurs

irregular heart sounds

• Myocardial infarction

heart attack