Transcript The Hearts conduction system

The Hearts conduction system
The electrical impulse responsible for
stimulating the heart to contract is
called the cardiac impulse.
To understand the processes involved with the
hearts conduction system.
To recap the phases of the cardiac cycle.
Video…
http://www.youtube.com/watch?v=fz
nchh3x54c
Conduction system
The heart is myogenic, hence it generates its
own electrical impulse.
The cardiac impulse is initiated from the sinoatrial (SA) node – located in the posterior wall
of the right atrium. This is referred to as the
pacemaker.
The impulse travels through both atria and
causes them to contract. What is this called?
 The impulse activates the AV node in the right
atrium, which passes the impulse down the
bundle of His, located in the septum of the heart.
 The bundle of His splits into two branches and
spreads the impulse down to the bottom of the
heart and then up around the walls of the two
ventricles using a network of purkinji fibres
causing both ventricles to contract, what is this
called?
 The cycle is then repeated with the next impulse.
Cardiac Cycle.
The conduction system initiates the cardiac
cycle, which ejects blood from the heart
through which arteries?
Can you remember how the cardiac cycle
works?
The stages?
How long each stage lasts for?
Task
Task : Prepare a 30 second talk on the
conduction system of the heart and the
cardiac cycle and how it initiates the cardiac
cycle.
Homework.
Exam Style Question….
Describe how the conduction system of the
heart controls the cardiac cycle. [6 marks].
We will be using this as our starter for Fridays
lesson!