Download 循環生理 黃基礎

循環生理
黃基礎
1998, 10, 23
Design of circulatory system
• Three essential components:
1. blood: circulatory fluid
2. vascular system :
through which the fluid can circulate
3. a heart: to pump the blood
• Two type of circulatory system
1. open circulatory system
2. closed circulatory system
Two types of circulatory system
• Open circulation
1.hemolymph
2.hemolymph was
circulated into hemocoel
3. Hemocoel is large,
constitued 20-40% of body
weight. Blood vol is about
30% of body volume
4. Low pressure
• Closed circulatio
1. Blood
2. Blood was circulated
through vessels: artery,
capillaries, vein
3. Blood vol is about 510% of body volume
4. High pressure
arterial pres and pul pres
Two types of circulatory system
• Open circulation
5. Pulsaltile vessel to
propel hemolymph
6. Velocity and distribution
of blood flow is limited.
• Closed circulatio
5. Heart contraction to
pumpb blood
6. Capillary walls are thin.
Oxygen delivery to tissure
rapidly.
7. Ultrafiltration occur in
the kidney to separate the
fitrate from plasma.
8. Lymph system to recover
the fluid lost
The Heart
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Cardiac muscle
Electrical activity of the heart
Pacemaker potential
Ionic mechanism of cardiac action potential
Electrocardiogram
Heart rate
Cardiac output and venous return
Cardiac cycle
Cardiac muscle
Cardiac muscle
• Intercalated disk
between cardiac cells
• Gap junction let ions
flowing from cell to
cell
• syncitiun
Conducting system
• Sinoatrial node
(SA node) or
Pacemaker
• Atrioventricular
node (AV node)
• His bundle
• Purkinje fibers
Electrical activity of the heart
Electrical activity of the heart
• There are two
types of
cardiac action
potential
• the slow
action
potentail and
• the fast action
potential
Ionic mechanism of the fast action
potential
• Occurs in the
following cells:
1.Purkinje fibers
2.Atrial cells
3.ventricular
cells
4.His bundle
Ionic mechanism of the slow action
potential
• Seen in the
following cells
• sinus node
(sinoatrial node;
SA node; or
pacemaker)
• atrioventricular
node (AV node)
Electrocardiogram
Electrocardiogram
Heart rate:
Sympathetic nerve
+
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Parasympathetic nerve
Heart rate