Download Cardiovascular System 1 - Conduction System and Cardiac Cycle

AS PE
CARDIOVASCULAR SYSTEM
CONDUCTION SYSTEM AND
CARDIAC CYCLE
LEARNING OBJECTIVES
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Can I describe the structures and
vessels of the Heart?
Can I explain the Cardiac Cycle and
the Conduction System?
BLP HABITS
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Listening and Collaborating
BLP STARTER
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See next slide
ANSWERS
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1 = Seven Seas
2 = Split Level
3 = Four give and four get
4 = Missing you
5 = Down Town
6 = Lucky break
7 = He’s beside himself
8 = See-through blouse
9 = First Aid
10 = West in D’s
ANSWERS
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11
12
13
14
15
16
17
18
19
20
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6 feet under ground
Glance backwards
Tricycle
Reading between the lines
Cross-roads
Zero Degrees
Neon Lights
Just between you and me
One in a Million
Broken promise
ANSWERS
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21 = You are out of touch
22 = Life after 40
23 = Jack in the box
24 = Growing Economy
25 = Up before 8
26 = Just in the corner
27 = Apple Pie
28 = Making up for lost time
29 = Standing ovation
30 = I understand you undertake to under mine
my under taking
STARTER
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Describe where the structures of
the Heart are and what is their
purpose/function
CONDUCTION SYSTEM
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The heart is said to be Myogenic as it
generates its own electrical impulse
The Cardiac Impulse is initiated by the sinoatrial (SA) Node (also known as the
Pacemaker) which is found in the posterior
wall of the right atrium
The impulse travels through the atria and cause
them to contract
The ventricles are not stimulated yet as they
are insulated from the atria
The impulse reaches the Atrioventricular
(AV) Node in the right atrium which passes
the impulse down the Bundle of His found in
the septum
This then splits down the left and right reaching
the ventricle walls via a network of Purkinje
Fibres which cause the ventricles to contract
THE CONDUCTION SYSTEM OF THE
HEART
Sinoatrial
(SA) Node
Atrioventricular
(AV) Node
Bundle of His
Atrioventricular
Bundle Branches
Purkinje Fibres
CODUCTION SYSTEM
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YouTube clips of the Conduction
System:
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http://www.youtube.com/watch?v=te_
SY3MeWys
http://www.youtube.com/watch?v=bxK
BQqe_Bo0
CARDIAC CYCLE
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This is the mechanical events of one
heart beat
It is made up of two phases:
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Diastole (the relaxation phase lasting
about 0.5 seconds)
Systole (the contraction phase lasting
about 0.3 seconds)
DIASTOLIC PHASE (0.5 seconds)
Both atria fill with blood. AV valves closed
Arterial blood pressure rises above ventricular
pressure
Rise in BP forces AV valves open and blood
passively passes into ventricles. Semilunar valves closed
SYSTOLIC PHASE (0.3 seconds)
Both atria contract actively forcing blood
into ventricles
Atrial
Systole
Semi-lunar valves remain closed
Both ventricles contract
Semi-lunar valves open. AV valves closed
Ventricular
Systole
Blood forced into Aorta (to body) and
Pulmonary Artery (to lungs)
Diastole of the next cardiac cycle begins.
Semi-lunar valves closed
CARDIAC CYCLE
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YouTube clips of the Cardiac Cycle:
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http://www.youtube.com/watch?v=5tU
WOF6wEnk
http://www.youtube.com/watch?v=rgu
ztY8aqpk
DOUBLE-CIRCULATION
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The Heart acts as a dual action
pump where two separate pumps
work simultaneously to send blood
to different areas of the body
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Systemic = to the body
Pulmonary = to the lungs
See diagram on the next slide for
clarification
DOUBLE-CIRCULATION
DEFINITIONS FOR THE
CARDIOVASCULAR SYSTEM
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HEART RATE (HR) =
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STROKE VOLUME (SV) =
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End-diastolic volume (EDV)
End-systolic volume (ESV)
CARDIAC OUTPUT (Q) =
EXAM QUESTIONS
d) Describe how the conduction system of the
heart controls the cardiac cycle.
(3 marks)
c) Endurance (aerobic) performance is
dependent upon the heart supplying blood
to the muscles.
Describe the flow of blood through the
heart during the cardiac cycle (Diastole
and Systole Phases).
(4 marks)