Cardivascular System

CARDIOVASCULAR SYSTEM

 is

composed of the heart and blood vessels

Functions:  PUMPING ACTION  Pumps blood to the body and the lungs  Receives blood from the body and the

lungs  Influences Blood Pressure

 TRANSPORTATION  Provide channels through which blood

and lymph travel  Provide areas (capillaries) where transfer of gases, nutrients, fluids, electrolytes, and wastes can occur

HEART  is

a strong, muscular pump about the size of a doubled-up fist.  It weighs less than one pound (approximately 250 to 310 g).  is shaped like an irregular and slightly flattened

LAYERS  Epicardium  Myocardium  Endocardium  Pericardium Visceral layer Parietal layer Fibrous pericardium

CHAMBERS  Atria  Ventricles

VALVES  Atrioventricular

valves  Tricuspid Valve  Bicuspid Valve

(mitral Valve)

 Semilunar  Pulmonary

Valve

Semilunar  Aortic Semilunar

ROUTE of Blood Flow

Blood Vessels of the Heart Right Coronary Artery Left Coronary Artery  receive their

blood supply during ventricular relaxation, when the valves are

Left Coronary Artery  Left

Main Coronary artery (LMCA)  Anterior

interventricular branch/Left anterior descending artery (LAD)  Left Circumflex Artery (LCX)

Right Coronary Artery  Margin

branch

 Main branch of

RCA

Posterior descending artery Left coronary dominance the PDA comes off the LCX to supply blood to these areas

Coronary Veins  Great

cardiac

vein  Middle cardiac

BLOOD VESSELS  Arteries  Capillaries  Veins

Arteries and Arterioles  ARTERIES  are elastic and smooth (involuntary)

muscular tubes that carry oxygenated blood to body cells.  They are known as “resistance vessels” that can support high pressures and hold large volumes of blood.

 ARTERIOLES  Is the smallest of the arteries  contain less elastic tissue and more

smooth muscle than arteries.  Constriction and dilation of the arterioles regulates blood pressure and flow.

MAJOR ARTERIES  Branches

of the Ascending Aorta

 Left and right coronary arteries

 Branches

of the Aortic Arch

 Brachiocephalic Artery (innominate) Right Subclavian Artery Right Common Carotid Artery  Left Common Carotid Artery  Left Subclavian artery

 Branches

of the Thoracic Aorta

 Bronchial Artery  Esophageal Artery  Intercostal Artery  Superior Phrenic Artery

Branches of the Abdominal Aorta          

Left gastric artery Splenic artery Hepatic artery Superior mesenteric artery Inferior mesenteric artery Phrenic artery Suprarenal artery Renal artery Ovarian/testicular artery Lumbar artery

 Common iliac branches into internal iliac For Pelvic muscles, bladder, rectum, prostate, reproductive organs  External iliac branches Femoral Popliteal Tibial Dorsalis pedis

Capillaries  smallest vessels  Blood flow through

the capillaries is known as microcirculation

Veins and Venules From the capillaries, the blood starts back toward the heart through venules, the smallest veins. The branches of the veins grow larger and fewer as they near the heart, until finally the blood reaches the superior vena cava (SVC) and inferior vena cava (IVC) (plural: cavae). These two large veins return blood to the right atrium. The SVC returns blood from the head, neck, and arms, and the IVC returns blood from the lower body. Venous blood is dark red because the oxygen has been replaced with carbon dioxide and other wastes.

MAJOR VEINS Superficial Veins     

Cephalic vein Basilic vein Median cubital Saphenous Temporal

 Deep

veins

 Axillary  Brachial  Subclavian  Radial  Ulnar

 Femoral  Popliteal  Tibial  iliac

 Jugular vein  Brachiocephal

ic vein

 Superior

Vena

Cava  Azygos Vein

 Inferior

Vena

cava  Receives blood

from:

Iliac veins Lumbar veins Testicular/ovarian veins Renal veins Supra renal veins Hepatic veins

Cardiac Conduction

Cardiac Cycle  SYSTOLE  In less than one second, both atria

contract as both ventricles relax.  Immediately after this, both ventricles contract as both atria relax.  DIASTOLE  Atrial relaxation, followed by ventricular

relaxation

Heart Sounds  S1

heart sound

 “lub” sound

 S2

heart sound

 “dub” sound

Abnormal Heart Sounds  S3

and s4 heart sound

 Known as “gallop” sounds

 Rub sound  Murmurs

Pulse  Is

due to atrial contractions as the heart pumps.  Pulse points

Cardiac Output  is

the amount of blood that the ventricles pump out in 1 minute.  Stroke Volume is the volume of blood ejected with each heartbeat. CO= SV x HR

Factors Affecting Ventricular Resistance  PRELOAD  is the amount of pressure or “stretching

force” against the ventricular wall at the end-diastole.

 AFTERLOAD  is the amount of pressure or resistance

the ventricles must overcome to empty their contents

Blood Pressure  is

the force that blood exerts against the walls of blood vessels.  Systolic pressure is the pressure exerted against the vessel walls during ventricular systole  Diastolic pressure is the pressure exerted during ventricular diastole  Pulse pressure Is the difference between systolic and diastolic pressure