The Cardiovascular System
{The Heart}Chapter 13
Cardiovascular System a/k/a Circulatory System Heart
Pumps blood Blood
Fluid of system Blood vessels
Pathway of tubules for blood Veins (venules): capillaries heart
Vena cava = largest veins Arteries (arterioles): heart capillaries
Aorta = largest artery
Terminology Cardiology: study of the structure, function, &
diseases of the heart Electrocardiogram (ECG): recording of electrical
changes that accompany heart beat Cardiac cycle: one heart beat Systole: contraction of heart muscle Diastole: relaxation of heart muscle Stroke volume: the amount of blood pumped out
per beat Septum: divider
About the heart… Located in the mediastinum between lungs 2/3 to the left of midline Approx. the size of a fist Apex (tip) points downward Heart muscle = myocardium
Tissues of the heart Membranes (serous fluid in between layers)
Parietal pericardium: makes up a tough, fibrous cavity that the heart sits in
Visceral pericardium: covers surface of the heart
**Inflammation of the pericardial membranes = pericarditis
Muscle Epicardium: covers the exterior surface of the heart Myocardium: bulk of heart muscle Endocardium: lines the interior cavities of the heart
Cardiopulmonary Resuscitation (CPR) Rhythmic compression of the heart Coupled with artificial respiration it can be
life saving Works because the heart is sandwiched
between 2 firm surfaces Anteriorly, the sternum Posteriorly, the body of the vertebrae
Conditions/Disorders/Diseases Angina pectoris: chest pain (usually precursor to heart
attack) Myocardial infarction: heart attack; caused by
insufficient blood flow to myocardium; therefore tissue dies
Heart murmur: valve disorder; causes backflow of blood Palpitation: irregular heart beat Phlebitis: Inflammation of a vein Hypertension: high blood pressure Cardiovascular Disease
5 types of circulation Systemic: blood pumping to body (system) Pulmonary: blood pumping to the lungs Coronary: blood pumping to the heart itself Fetal: circulation of blood to and from the
placenta Hepatic: blood going through liver to be
filtered and detoxified
Electricity of the Heart Sinoatrial (SA) node: the heart’s natural
pacemaker; initiates action potentials; located in atrial wall
Atrioventricular (AV) node: the heart’s “back up” pacemaker
Bundle of His & Purkinje fibers carry impulse throughout heart
When SA node initiates… 1st: atria contract simultaneously while
ventricles are relaxing 2nd: atria relax while ventricles
simultaneously contract
**This simultaneous contraction and relaxation results in a lubb-dupp sound
The lubb-dupp of your heart… Results from closing of heart valves Lubb = quiet; systole of atria; diastole of ventricles
(AV valves closing) Dupp= loud; systole of ventricles; diastole of atria
(semilunar valves closing) 1 heart beat (cardiac cycle) takes about 0.8
seconds Average resting heart rate = 75 bpm (beats per
minute) Average stroke volume = 70mL
Components of heart Chambers
Upper Right atrium Left atrium
Lower Right ventricle Left ventricle
Vessels Pulmonary
Pulmonary artery Right & left branches
Pulmonary veins 2 right & 2 left
branches Systemic
Superior vena cava Inferior vena cava aorta
Valves of the heart Function: to prevent backflow of blood Held in place by papillary muscle (in base of chamber) &
chordae tendineae Lessens chance of oxygenated & deoxygenated blood
mixing Right AV valve (tricuspid): b/w right atrium & ventricle Left AV valve (bicuspid/mitral): b/w left atrium & ventricle Pulmonary semilunar valve: b/w right ventricle &
pulmonary artery Aortic semilunar valve: b/w left ventricle & aorta
Blood Flow Through Heart{Pulmonary Circulation} Superior vena cava (from upper body) & inferior vena cava
(from lower body) carry deoxygenated blood right atrium When right atrium fills, it contracts and forces blood through
the right AV valve (tricuspid) right ventricle When right ventricle fills, it contracts and forces blood
through the pulmonary semilunar valve pulmonary artery (trunk)
The trunk of the pulmonary artery divides into right and left pulmonary branches right and left lungs
In lungs: oxygen and carbon dioxide are exchanged
Blood Flow Through Heart{Systemic Circulation} Pulmonary veins carry oxygenated blood left
atrium When the left atrium fills, it contracts and forces
blood through the left AV valve (bicuspid, mitral) left ventricle
When the left ventricle fills, it contracts and forces blood through the aortic semilunar valve aorta (ascending, arch, & descending)
Aorta entire body
Blood Flow Through Heart{Coronary Circulation} Aorta
Ascending (1st inch) Coronary vessels branch off here Go back to myocardium
Arch (curve) 3 branches: services left arm, head & neck, and right arm
Descending (remainder) Thoracic aorta Abdominal aorta iliac arteries in legs
OverviewSuperior & inferior vena cava right atrium
right AV valve (tricuspid) right ventricle pulmonary semilunar valve pulmonary artery (& branches) lungs (drop off CO2, pick up O2) pulmonary veins left atrium left AV valve (bicuspid, mitral) left ventricle aortic semilunar valve aorta body (drop off O2, pick up CO2)
The Double Pump Although we describe the flow of blood as
linear, it is truly a double pump Both atria contract together Both ventricles contract together Myocardium in the right side of the heart is
thinner as it is pumping to the nearby lungs Myocardium in the left side of the heart is
thicker as it is pumping all over the body
Exceptions to the rule… Most of the time
Veins carry deoxygenated blood (dark reddish purple blood)
Arteries carry oxygenated blood (bright red blood)
However, Pulmonary arteries & umbilical arteries carry
deO2 blood Pulmonary veins & umbilical veins carry O2 blood
You must know… The flow of blood through the heart
4 chambers 5 vessels 4 valves (all names)