Cardiovascular system

JEEVAN KISHORETBILISI STATE MEDICAL UNIVERSITY, GEORGIA

PHYSICS OF CARDIOVASC

ULAR SYSTEM

Cardiovascular

systemBLOOD

VESSELS

HEART

BLOOD

• SUPPLY ENERGY…

[FUEL FROM FOOD]

•SUPPY OF OXYGEN FROM THE AIR WE BREATHE…

• DISPOSE BY PRODUCT OF

COMBUSTIONS… [CO2, H2O, Heat, etc…]

HEART

DOUBLE PUMP

PROVIDES FORCE FOR CIRCULATION OF BLOOD

2 MAJOR SYSTEM OF CIRCULATION…

ù Pulmonary circulation ù Systemic circulation

4 CHAMBERED ù Right atrium ù Left atrium ù Right ventricle ù Left ventricle

BLOOD VESSELS

FLOW REGULATI

ON

and

ARTERIES

ARTERIOLES

VEINS AND VENULES

CAPILLARIES

ARTERIES…

Thick compliant walls…ù Must

withstand high BP

ù Puncture can be fatal

ù High BP damages

arterial walls, leading to

vessel disease

Large diameter…ù Low flow resistance

ù Transmits entire heart pressure to arterioles

ARTERIAL BLOOD PRESSURE

2 typesSystolic

ventricles contract, arteries expand, hold 2/3

of stroke volume

Diastolicventricles relax, arteries

recoil, squeezing blood to arterioles

VEINS AND VENULES…

ù very large radius and thin wallùLargest cross-sectional areaù Negligible flow resistanceù Large volume: holds 75% of blood and acts as blood reservoir

Maximize exchange… ù Huge surface area (~ football field) ù Thin walls (no smooth muscle) to facilitate diffusion ù Low blood velocity (~ 1 mm/s) gives more time for exchange

Flow is regulated by precapillary sphincter…

Only 1 of 30 capillaries is open in resting muscle…

CAPILLARIES…

Congestive heart failure

CHF is characterized by a heart that is weak and

enlarged due tov greatly increased ventricular filling.

But for a very high ventricular filling, cardiac output falls.Heart attackdeath of heart muscle

due to blockage of coronary arteries

Vessel disease

Cardiovascular

Disease

Symptoms of heart attack

ùThe most common symptom (> 80%) is a heavy, persistent pressure in the center of the chest, lasting 10 min or more.

ù The pain often radiates upward to the neck, jaw, or left arm and shoulder. Weakness and profuse sweating are also common.

ù Sometimes the pain is a burning sensation, similar to heartburn.

ù Rarely associated symptoms: brief and sharp pain, pain on breathing

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