The HeartThe Heart

… … and blood flowand blood flow

Heart FactsHeart Facts

► Your heart is about the same Your heart is about the same size as your fistsize as your fist

► An average adult body An average adult body contains about five quarts of contains about five quarts of blood (1.25 gallons)blood (1.25 gallons)

► All the blood vessels in the All the blood vessels in the body joined end to end would body joined end to end would stretch 62,000 miles or two stretch 62,000 miles or two and a half times around the and a half times around the earth. earth.

Heart Facts continued….Heart Facts continued….

►The heart circulates the body’s blood The heart circulates the body’s blood supply ~1000 times each daysupply ~1000 times each day

►The heart pumps the equivalent of 1,250 The heart pumps the equivalent of 1,250 to 1,500 gallons of blood each dayto 1,500 gallons of blood each day

►The heart beats about 42,075,904 times The heart beats about 42,075,904 times per YEAR – imagine a lifetime?per YEAR – imagine a lifetime?

3 Layers of the Heart3 Layers of the Heart► PericardiumPericardium = protection, exterior, serous = protection, exterior, serous

membranemembrane►MyocardiumMyocardium = cardiac muscle tissue, = cardiac muscle tissue,

involuntary contractionsinvoluntary contractions► EndocardiumEndocardium = interior layer, lines heart = interior layer, lines heart

chamberschambers

Blood FlowBlood Flow

► Pulmonary CirculationPulmonary Circulation►No oxygen in bloodNo oxygen in blood

► carries deoxygenated blood away from the carries deoxygenated blood away from the heart, to the lung, and returns oxygenated heart, to the lung, and returns oxygenated blood back to the heartblood back to the heart

Overview of blood circulation

Blood Flow Blood Flow continued….continued….

►Systemic CirculationSystemic Circulation ►Oxygen in bloodOxygen in blood►carries oxygenated carries oxygenated

blood away from the blood away from the heart, to the body, heart, to the body, and returns and returns deoxygenated blood deoxygenated blood back to the heartback to the heart

Heart ValvesHeart Valves

►Allow blood to flow in only one directionAllow blood to flow in only one direction►Four valves:Four valves:

----Atrioventricular valvesAtrioventricular valves: between atria ventricles: between atria ventricles

• • Bicuspid valve or Mitral valve (left)Bicuspid valve or Mitral valve (left)

• • Tricuspid valve (right)Tricuspid valve (right)

----Semilunar valvesSemilunar valves: between ventricle and : between ventricle and artery/veinartery/vein

• • Pulmonary semilunar valvePulmonary semilunar valve

• • Aortic semilunar valveAortic semilunar valve

Chordae TendineaeChordae Tendineae

►The The chordae tendineaechordae tendineae, or , or heart heart stringsstrings, are cord-like tendons that , are cord-like tendons that connect the muscles to the tricuspid connect the muscles to the tricuspid valve and the mitral valve in the heart.valve and the mitral valve in the heart.

►When the right ventricle of the heart When the right ventricle of the heart contracts, the blood pressure pushes contracts, the blood pressure pushes the tricuspid valve closed and the tricuspid valve closed and prevents a backflow of blood into the prevents a backflow of blood into the right atrium.right atrium.

Chordae Tendineae Chordae Tendineae (a.k.a. “heart strings”)(a.k.a. “heart strings”)

heart strings

Blood Flow STEP by STEP