cardiovascular system

posterior to sternum, medial to lungs, anterior to vertebral column, base lies beneath 2nd rib, apex @ 5th intercostal space, just above the diaphragm.

7,000

2.5 billion

sends oxygen-depleted (deoxygenated) blood to the lungs to pick up oxygen and unload carbon dioxide

sends oxygen-rich (oxygenated) blood and nutrients to all body cells and removes wasts.

by listening to the chest wall beween the fifth and sixth ribs about 7.5 cm to left of the midline

covering that encloses the heart and the proximal ends of the lg blood vessels to which it attaches.

outer fibrous bag of pericardium, surrounds double-layered serous membrane. Tough protective sac largely complosed of dense connective tissue. Attached to the central portion of the diaphragm, the posterior of the sternum, the vertebral column and the lag blood vessels emerging from the heart.

innermost layer of serous membrane, covers the heart

where the visceral pericardium turns back upon itself and forms the inner lining of the fibrous pericardium.

between the parietal and visceral layers of the pericardium, contains a small volume of serous fluid that pericardial membranes secrete.

reduces friction between the pericardial membranes as the heart moves within them.

epicardium, myocardium and endocardium

• -outer layer of wall of heart
• -protects heart by reducing friction.
• -secretes ferous fluid
• -serous membrane of connective tissue covered with epithelium and including blood capillaries, lymph capillaries and nerve fibers.

• -middle layer of heart wall
• -contracts to pump blood from the heart chambers
• -cardiac muscle tissue separated by connective tissues and including blood capillaries, lymph capillaries and nerve fibers.

• -inner layer of heart wall
• -forms a protective inner lining of the chambers and valves
• -membrane of epithelium and underlying connective tissue, including blood vessels and specialized muscle fibers (Purkinje fibers)

• -right atrium
• -right ventricle
• -left atrium
• -left ventricle

• -receives blood from the inferiorvena cava, superior vena cava, and coronary sinus
• -right upper chamber of heart

• -receives blood from the right atrium
• -pumps blood to lungs
• -right lower chamber of heart

• -left upper chamber of heart
• -receives blood from the pulmonary veins

• -receives blood from left atrium
• -pumps blood to the body
• -lower left chamber of heart
• -largest chamber of heart

earlike projections extending anteriorly from the atria, slightly increasing atrial volume.

separates right from left atrium

separates two ventricles

• -opening where the atrium on each side communicates with its corresponding ventricle
• -guarded by atrioventricular (AV) valve

atrioventricular orifice

• atrioventricular
• -tricuspid and mitral
• semilunar
• -pulmonary (pulmonic) and aortc

superior and inferior vena cava and coronary sinus

through pulmonary valve to pulmonary trunk to left and right pulmonary arteries

four pulmonary veins - 2 from right lung and 2 from left lung

• -the blood backing up in the pulmonary trunk closing the pulmonary valve, preventing a return flow into right ventricle
• -the aortic valve closes and prevents blood from backing up into the left ventricle when the left ventricle realxes.

-strong fibrous strings attaching to av valves

• -small mounds of cardiac muscle tissue
• -contract when the ventricles contract, pulling on the chordae tendineae and prevent the cusps from opening back into the atriums

• -located right av orifice
• -functions to prevent blood from backflowing from right ventricle into righ arium during venricular contraction

• -location - entrance to pulmonary trunk from right ventricle
• - functions to prevent blood from moving from pulmonary trunk into righ ventricle during ventricular relaxation

• location - left av orifice
• functions to prevent blood from moving from left ventricle into left atrium during ventricular contraction

• location-entrance to aorta from left ventricle
• functions to prevent blood from moving from aorta into left ventricle during ventricular relaxation

• -carry blood away from heart
• -usually oxygenated except when carrying blood from right ventricle to lungs (pulmonary arteries)

• -carry blood toward heart
• -usually deoxygenated, except when bring blood from lungs to left atrium (pulmonary veins)

systemic circuit - superior and inferior vena cava - right atrium - tricuspid valve - right ventricle - pulmonary valve - pulmonary trunk - pulmonary arteries (right and left) - lungs - alveolar capillaries (gas exchange) - pulmonary veins - left atrium - mitral (bicuspid) valve - left ventricle - aortic valve - aorta - systemic circuit.

The fibrous rings surrounding the pulmonary trunk and the aorta, together with other masses of dense connective tissue in the portion of the septum between the ventricles.

• -right ventricle has blood low in oxygen and high in carbon dioxide
• -left ventricle has blood high in oxygen and low in carbon dioxide

right and left coronary arteries.

Through the coronary veins that empty into the coronary sinus

state of contraction of the cardiac cycle

state of relaxation of the cardiac cycle

atrial contraction

atria relax

when ventricles relax

when ventricles contrace

the events required to complete a single heartbeat (contractions of both atria and both ventricles.)

• -blood flows passively into the ventricles
• -remaining 30% of blood is pushed into the ventricle
• -AV valves open and semilunar valves close
• -ventricles relax
• -causes increase in ventricular pressure

• -av valves close
• -chordae tendinae prevent the cusps of the valves from bulging too far into the atria
• -atria relax
• -blood flows into atria
• -ventricular pressure increases and opens semilunar valves
• -blood flows into pulmonary trunk and aorta

• -occurs during ventricular systole
• -closing of av valves

• -occurs during ventricular diastole
• -pulmonary and aortic semilunar valves are closing

abnormal heart sound from the cusps not completely closing

a mass of merging cells that act as a unit

in the arial walls (atrial syncytium) and the ventricle walls (ventricular syncytium)

system of specialized cardiac muscle fibers that conduct cardiac impluses from the SAnode into the myocardium.

• -small elongated mass of specialized cardiac muscle tissue just beneath the epicardium
• -in the wall of the right atrium near the opening of the superior vena cava
• -fibers are continuous with those of the atrial syncytium
• -pacemaker of the heart because it generates the heart's rhythmic contractions.
• -initiates each cardiac cycle by generating an electical impulse that spreads over the atria causing it to contract

a compact mass of pace setting cells

• -mass of specialized cardiac muscle tissue in the inferior portion of the interatrial septum and just beneath the endocardium.
• -relay signals to the ventricles.

• -conducting fibers that extend down the interventricular septum sending branches right and left
• -divides into the right and left bundle branches that lie just beneath the endocardium

• -spread from the interventricular septum into the papillary muscles an then continue downward to the apex of the heart
• -carry impulse to distant regions of the ventricular mycardium
• -faster than cell-to-cell conduction
• -transmit the impulse to the apex of the heart first so contraction begins at the apex and pushes the blood superiorly toward the aortic and pulmonary semilunar valves.

SA node - atrial synctium - junctional fibers - av node - av bundle (bundle of his) - bundle branches - purkinje fibers - ventricular syncytium

• -clumps of specialized cardiac muscle tissue which initiate and distribute impulses throughout the myocardium
• -coordinates the events of the cardiac cycle

• -a recording of the electrical changes in the myocardium during a cardiac cycle.
• - because body fluids can conduct electrical currents, such changes can be detected on the suface of the body.

• -represent the wave of depolarizaion that spreads from the SA node throughout the atria
• -Atrial contraction

• -ventricular depolarization
• -contraction

• -repolarization of ventricle muscle to resting state.
• - relaxation

-arise from neurons in the medulla oblongata and secrete acetycholine when they reach the effector ends of the SA and AV nodes

secrete norepinephrine and increase and strengthen the contraction of the heart

• -physical exercise
• -body temperature
• -concentration of various ions including potassium and calcium
• -parasympathetic impulses - decrease heart action
• -sympathetic impulses - increase heart action
• -cardiac center regulates autonomic impulses to the heart

• -organs of the cardiovascular system
• -form closed circuit to and from the heart
• -include: arteries, arterioles, capillaries, venules, and veins

• -Thick strong wall (three layers or tunics)
• -Endothelial lining
• -middle layer of smooth muscle and elastic tissue
• -outer layer of connective tissue
• -carries blood under relatively high pressure

• -thinner wall than an artery (three layers or tunics
• -endothelial lining
• -middle and outer layers are thinned
• -some smooth muscle tissue
• -small amount of connective tissue
• -helps control blood flow into a capillary

• -smallest diameter blood vessels
• -very thin walls - extension of the inner lining of arterioles
• -connnect the smallest arteriole and the smallest venule
• -ealls are endothelium only
• -semipermeable

• -microscopic vessels that continue from the capillaries and merge to form veins
• -thinner walls than arterioles
• -less smooth muscle and elastic tissue than arteriole

• -thinner walls than arteries (three layers of tunics)
• -middle wall poorly developed
• -many have flap-like valves
• -carry blood under relatively low pressure
• -function as blood reservoirs

the force the blood exerts against the inner walls of the blood vessels

• -rises when the ventricles contract
• -falls when the ventricles relax

the maximum pressure during ventricular contraction

minimum pressure when the ventricles relax