Cardiovascular System

Functions

To supply oxygen and nutrients to cells and To supply oxygen and nutrients to cells and tissues and remove waste productstissues and remove waste products

Buffers in blood regulate pH of body fluidsBuffers in blood regulate pH of body fluids Warm blood carries heat from one location to Warm blood carries heat from one location to

another; another; thermoregulationthermoregulation Defense Defense – white blood cells are carried throughout – white blood cells are carried throughout

body, fibrin formation slows blood loss and slows body, fibrin formation slows blood loss and slows spread of microorganismsspread of microorganisms

Heart

size varies with body sizesize varies with body size covered by pericardiumcovered by pericardium divided into 4 chambersdivided into 4 chambers

right atrium right atrium – receives blood from body– receives blood from body right ventricleright ventricle – pumps blood to lungs – pumps blood to lungs left atriumleft atrium – receives blood from lung – receives blood from lungss left ventricleleft ventricle – pumps blood to body – pumps blood to body

Heart cont.

AtriaAtria are thin walled; pump blood through valves are thin walled; pump blood through valves to the ventriclesto the ventricles

VentriclesVentricles are thicker walled, very muscular, are thicker walled, very muscular, pump blood long distances. Left pumps farther, pump blood long distances. Left pumps farther, has thicker walls than right.has thicker walls than right.

ValvesValves prevent blood from going backwards. prevent blood from going backwards. Found in the heart where there is a lot of pressure Found in the heart where there is a lot of pressure and in veins where flow is sluggishand in veins where flow is sluggish

Heart cont.

Chordae tendinae – anchored by papillary Chordae tendinae – anchored by papillary muscles, keep valves between atria and ventricles muscles, keep valves between atria and ventricles from going backwards when under pressurefrom going backwards when under pressure

The two sides are divided by the interventricular The two sides are divided by the interventricular septumseptum

Covered by pericardial membranesCovered by pericardial membranes Coronary arteries on the outside surface supply Coronary arteries on the outside surface supply

nutrients to the heart musclenutrients to the heart muscle

Blood Vessels

Arteries and arterioles Arteries and arterioles – carry blood away from – carry blood away from the heart. Made of endothelium, smooth muscle the heart. Made of endothelium, smooth muscle and c.t. Can contract to restrict blood flowand c.t. Can contract to restrict blood flow

Veins and venulesVeins and venules – carry blood back to the heart. – carry blood back to the heart. Similar in construction to arteries, but less muscleSimilar in construction to arteries, but less muscle

CapillariesCapillaries – where nutrient exchange takes place. – where nutrient exchange takes place. Single layer of epitheliumSingle layer of epithelium

Path of blood through the heart

Vena cavae bring blood Vena cavae bring blood low in oxygenlow in oxygen from the bodyfrom the body

Enters Enters right atriumright atrium Passes through the Passes through the tricuspid valvetricuspid valve to the to the

right ventricle right ventricle Pumped through a Pumped through a semilunar valvesemilunar valve to the to the

pulmonary arteriespulmonary arteries Travels to the Travels to the lungslungs where it is where it is oxygenatedoxygenated

Path of blood through the heart cont.

Returns to the heart through the Returns to the heart through the pulmonary veinspulmonary veins Enters the Enters the left atriumleft atrium Passes through the Passes through the mitral (bicuspid) valvemitral (bicuspid) valve into the into the

left ventricleleft ventricle Pumped through a Pumped through a semilunar valvesemilunar valve to the to the aortaaorta Oxygenated bloodOxygenated blood travels to all body parts and is travels to all body parts and is

recollected in the recollected in the vena cavaevena cavae

Cardiac CycleCardiac Cycle – the atria contract while the – the atria contract while the ventricles relax and vice versa. ventricles relax and vice versa. Heart soundsHeart sounds are are mostly valves slamming shutmostly valves slamming shut

Blood PressureBlood Pressure – the force exerted by the blood – the force exerted by the blood against the inside of the blood vessels. Expressed against the inside of the blood vessels. Expressed as systolic over diastolicas systolic over diastolic SystoleSystole – contraction of the ventricles – contraction of the ventricles Diastole Diastole – relaxation of the ventricles– relaxation of the ventricles Arterial B.PArterial B.P. – due to heart pumping. – due to heart pumping

Veins do not have much pressure, most blood is Veins do not have much pressure, most blood is pushed back to heart from breathing movements pushed back to heart from breathing movements and muscular contraction, especially blood from and muscular contraction, especially blood from the lower parts of the bodythe lower parts of the body..