THEHEART

CARDIOVASCULAR SYSTEM

• muscular organ

• size of a closed fist

• weigh appr. 250 to 350 grams

• BASE is attached to the aorta, pulmonary arteries and veins, and the vena cava.

• APEX of the heart rests superior to the diaphragm.

THE HEART OVERVIEW

BASE

APEX

AORTA

SUPERIORVENA CAVA

PULMONARY ARTERY

INFERIORVENA CAVA

PULMONARY VEINS

• circulatory pump

– takes in deoxygenated blood through the veins and delivers it to the lungs for oxygenation

– blood is pumped into the various arteries (which provide oxygen and nutrients to body tissues by transporting the blood throughout the body).

THE HEART OVERVIEW

THE HEART LOCATION

LUNGS

HEART

LIVER

DIAPHRAGM

ESOPHAGUS

T8VERTEBRA

STERNUM

• Posterior to the sternum

• Anterior to the esophagus and vertebra

• Medial to the lungs

• 2/3 left, 1/3 right

THE HEART LOCATION

THE HEART PERICARDIUM

• Prevent friction between beating heart and organs

• Holds the heart in position and maintains a hollow space for expansion when full.

THE HEART HEART WALL

• EPICARDIUM – outermost layer, same as visceral layer of pericardium.

• MYOCARDIUM – muscular middle layer of the heart.

• ENDOCARDIUM – simple squamous epithelium lining the inside of the heart.

• short, fat, branched and interconnected.

• interlock at dark-staining junctions called intercalated discs.

• gap junctions allow ions to pass

• muscles behave like a single coordinated unit.

THE HEART CARDIAC MUSCLESCARDIAC MUSCLE CELL

INTERCALATED DISC

DESMOSOME

GAP JUNCTION

THE HEART CARDIAC MUSCLES

CARDIACMUSCLE

SKELETALMUSCLE

Structure Short, fat, branched,Interconnected

Long, cylindrical,multinucleate

Means of Stimulation

Nerve StimulusSelf-excitable

Nerve stimulus

Contraction Contract as a unit Individually activated

Refractory period

200 ms 1-2 ms

MITRAL VALVE

TRICUSPID VALVE

AORTICVALVE

PULMONARY VALVE

Chordaetendineae

THE HEART VALVES

• Prevents the blood from flowing backwards or regurgitating back into the heart.

• Two types:

– Atrioventricular (AV) valve

– Semilunar valve

THE HEART VALVES

Atrioventricular or AV Valve

Tricuspid – right side

Mitral – left side

prevent backflow into the atria when

the ventricles contract.

MITRAL VALVE

TRICUSPID VALVE

AORTICVALVE

PULMONARY VALVE

Chordaetendineae

THE HEART VALVES

Semilunar Valve

Aortic– left side

Pulmonary – right side

blood flows from ventricles to the arteries

MITRAL VALVE

TRICUSPID VALVE

AORTICVALVE

PULMONARY VALVE

Chordaetendineae

THE HEART CHAMBERS

ATRIA

VENTRICLES

• receiving chambers for blood

• smaller and less muscular than ventricles

• larger, stronger• pumps blood out of the

heart

THE HEART CHAMBERS

RIGHT ATRIUM

• deoxygenated blood(body)• FROM:

superior/inferior vena cavacoronary sinus

• PUMPTS TO:right ventricle

• THROUGH THE:tricuspid valve

SUPERIOR VENA CAVA

INFERIOR VENA CAVA

TRICUSPID VALVE

THE HEART CHAMBERS

RIGHT VENTRICLE

• deoxygenated blood• FROM:

right atrium• PUMPTS TO:

pulmonary artery• THROUGH THE:

tricuspid valve (in)pulmonary valve(out)

PULMONARY ARTERY

TRICUSPID VALVE

THE HEART CHAMBERS

LEFT ATRIUM

• oxygenated blood (lungs)• FROM:

left /right pulmonary veins• PUMPTS TO:

left ventricle• THROUGH THE:

mitral valve

MITRAL VALVE

PULMONARY VEINS

THE HEART CHAMBERS

LEFT VENTRICLE

• oxygenated blood• FROM:

left atrium• PUMPTS TO:

aorta (to the body)• THROUGH THE:

mitral valve (in)aortic valve(out)

AORTA

MITRAL VALVE