Download AP150 HEART IMAGES--post

Systemic and pulmonary circuits
Figure 22.2
Position of the
heart in the body
Figure 22.2
Figure 22.3
The heart walls
and membranes
that surround the
heart
Figure 22.6
Figure 22.5
Figure 22.5 continued
Figure 22.7
Fibrous Skeleton:
--composed of dense collagenous CT
-- anchors and supports valves
--electrically isolates (insulates) the atria from ventricles
--anchor/attachment for cardiac muscle
Myocardial Cells (myocytes, cell that contract):
-Short
-Branched
-Uninucleate
-Many, many mitochondria
-Connect end-on-end to other myocytes
-contain SR that releases calcium
--has mild t-tubules
--alternating, and overlapping myosin and actin filaments for contraction
Figure 22.10
CARDIAC MUSCLE CELLS
• Branched
• joined by intercalated discs
– desmosomes: tightly bind cells & transfer of tension
– gap junction: electrical synapses that directly transfer electrical
activity/AP from one cell to the next
• Contractile/myocardial Cells (myocytes) => contract and conduct AP’s
• Conductile/autorhythmic cells => produce and conduct action potentials
Conceptual Overview: Electrical Stimulus originating at SA node is distributed to heart leading to
contraction.
--Blood is pumped out of the heart during contraction
--Blood fills the heart during relaxation
Fig. pf 20.13
Intrinsic/natural
pacemaker
Electrical
connection
between atria and
ventricles
Figure 22.11
Nervous System regulation of heart
•
Heart is regulated by medulla oblongata (cardiac control center)
•
Medulla receives sensory input through vagus nerve (CN X) and
glossopharyngeal nerve (CN IX).
– Baroreceptors in aorta (aortic sinus) and common carrotid artery (carotid
sinus)
• Some receptors in heart
•
Medulla sends motor output through the:
– Vagus nerve—parasympathetic division of ANS
– Sympathetic nerves (cardiac plexus)—sympathetic division of ANS
Sensory input and motor output of cardiac control centers in medulla
Glossopharyngeal nerve
Vagus nerve
Figure 22.12
Motor output to heart (from medulla)
PD
Figure 22.13
Figure 22.13 continued
Figure 22.14
Figure 22.14
Figure 22.8
Figure 22.9
Coronary vessels:
•Significant anastomoses
•Flow during diastole
•Directly to R. A.
Table 22.1
Table 22.2
Table 22.3