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A. location of heart (p.530)in thorax, in inferior
mediastinumposterior to sternummedial to lungssuperior to
diaphragmanterior to vertebraeorientation - obliqueapex points down
and to the left2/3 of mass on left side of body
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BIOL 2304 Fall 2008Chapter 18*
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C. pericardium serous membranes of heart (p. 531)1. parietal
pericardium - double membrane surrounding heart, attached only at
base of vessels on superior margin of heart, also called the
pericardial saca. outer layer (fibrous pericardium) = fibrous
c.t.b. inner layer (parietal layer of serous pericardium) = serous
membrane (simple squamous e. + areolar c.t.)2. visceral [layer of
serous] pericardium - attached to surface of heart= serous membrane
(simple squamous e. + areolar c.t.)
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D. heart wall (p. 531, 532) 1. epicardium = visceral
pericardium2. myocardium = cardiac m. ; bundles of cells arranged
in spiral pattern3. endocardium = simple squamous e. + areolar
c.t.
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E. chambers and vessels (p. 535)1. atria (right and
left)superior separated from each other by interatrial septum
atrioventricular groove / coronary sulcus separates atria from
ventricles
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a. right atrium forms right border of heartauricle = outer wall
of atriumfossa ovalis in interatrial septumsuperior and inferior
vena cavae return blood from body to heartcoronary sinus returns
blood from coronary circulation to heartb. left atrium forms most
of posterior surfaceauriclepulmonary veins return blood from lungs
to heart
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2. ventricles (right and left)inferiorinterventricular septum
separates ventricles from each otherinterventricular sulci = groves
on outside of heart over interventricular septum; anterior and
posteriortrabeculae carnae = ridges of muscle tissue seen on
internal surface of ventricles
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a. right ventricle (thinner wall)right border of heartpulmonary
trunk carries blood from heart to lungsb. left ventricle (thicker
wall)apex and inferior surface of heartaorta carries blood from
heart to bodyBIOL 2304 Fall 2008Chapter 18*
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F. valves - control direction of blood flow; prevent
backflowvalves are opened and closed by pressure gradients (p.
539)
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1. atrioventricular (AV) valveshave cusps attached to
ventricular wall by chordae tendineae at papillary musclesa. right
= tricuspidb. left = bicuspid or mitralBIOL 2304 Fall 2008Chapter
18*
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2. semilunar (SL) valves have 3 cusps attached to wall at
junction of ventricle and arterya. right = pulmonaryb. left =
aortic
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G. fibrous skeleton (p. 538)made of dense fibrous c.t.separates
atria and ventriclessurrounds and anchors valves; prevents
overdilationserves as insertion for cardiac muscle bundlesblocks
electrical impulses
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H. conducting system (p. 543)1. autorhythmic cells vs
contractile cellsa. contractile cells (99%) are specialized for
contractionb. autorhythmic cells (1%) are specialized for
generating and conducting electrical signalssmaller diameter, less
actin and myosin than contractile cellsautomatically generate
action potentials and conduct cardiac impulse through heart
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2. conducting system (components red, conduction pathway blue,
effect on heart green)sinoatrial (SA) node = normal pacemaker of
heart located in superior, lateral right atriuminternodal pathways
= cells in right and left atriaatrial myocardium contraction of
atria (systole)atrioventricular (AV) node - located in medial,
inferior right atriumatrioventricular bundle (bundle of His) pass
from AV node into superior interventricular septumleft and right
bundle branches run down interventricular septum then upwards into
outer ventricule wallsconduction myofibers (Purkinje fibers) -
large cells, few myofilamentsventricular myocardium contraction of
ventricles (systole)
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I. innervation(p. 544)
1. sensory visceral afferent neurons
2. motora. sympathetic (cardiac nerves)originate in cervical and
thoracic ganglia and pass throughthe cardiac plexusinnervate
myocardium, nodes, coronary vesselsb. parasympathetic (branches of
vagus nerve)branches of vagus nerve pass through the cardiac
plexusinnervate SA node and AV node, some cells in atrial
myocardium*notice that the parasympathetic division does not
innervate the ventricle
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J. coronary circulation (p. 545)left and right coronary arteries
leave aorta just above aortic semilunar valve1. left coronary
artery runs posterior to pulmonary trunk and branches just lateral
of the pulmonary trunk into:a. anterior interventricular a. located
in anterior interventricular sulcus supplies interventricular
septum and anterior walls of both ventriclesb. circumflex a.
located in atrioventricular sulcus supplies left atrium and
posterior left ventricleBIOL 2304 Fall 2008Chapter 18*
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2. right coronary artery in AV sulcus (p. 545)a. marginal a.runs
along right margin of heartsupplies right ventricleb. posterior
interventricular a.located in posterior interventricular
sulcussupplies interventricular septum and posterior walls of both
ventricles3. capillaries4. cardiac veins5. coronary sinusBIOL 2304
Fall 2008Chapter 18*
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