Topic 6 1 3
.
. Control of Heart Rate
Overview +
key terminology :
sinoatrial node (SAN)-
top of R A .
right
atrium
· left
atrium
ve
vena
&
2 pulmonary
vein
Cava
·
Avalve
&
atrioventricular
node (AUN)- Bundle of His-
between
R A and RV in sceptum
i
.
.
right left
ventricle Ventricl
a
--
n
purkyne
Fibres
Electrical Coordination of heartbeat-Model Answer
SAN pacemaker initiating the heartbeat
·
act as ,
.
>
sends wave of depolarisation both atria to contract
across
atria-causing at same time
AVN delays electrical allowing time for fill blood before they
·
activity
-
ventricles to with contract
Bundle His
through Purkyne
~
AUN sends wave of depolarisation down of and fibres
both ventricles to base
causing contract from up-
·
pushes blood up into arteries
,Responding to Stimul
- heart will contract without nervous stimulation-
any
however heart rate be altered to needs of the
, can in response body
·
heart
eg ,
during exercise rate will increase to supply more
oxygen
to
respiring muscle cells
Heart rate is under the control of the autonomic nervous
system
Parasympathetic
L
(s) Sympathetic (speeds up] (PS) (slows down
stimulates inhibits
·
effectors effectors
·
"HR HR
fight
W
controls
activity at rest
· ·
Neurotransmitter noradrenaline neurotransmitter :
acetylcholine
·
·
:
* the two branches of the autonomic nervous
system are
antagonistic Opposite effects
-
* HR down P S
can also be increased by fewer impulses nerve ,
.
down S
or decreased by fewer impulses nerve
HR the MEDULLA OBLONGATA brain :
is controlled
by in the
~ medulla has a centre has 2 parts different functions
cardioregulatory which
performing 2
-
,
① ACCELETORY -
increase heart rate (4HR) ,
linked to SAN
by Sympathetic nervous
system
SINHIBITORY -
decrease heart rate (dHR),
linked to SAN
by Parasympathetic nervous system
.
. Control of Heart Rate
Overview +
key terminology :
sinoatrial node (SAN)-
top of R A .
right
atrium
· left
atrium
ve
vena
&
2 pulmonary
vein
Cava
·
Avalve
&
atrioventricular
node (AUN)- Bundle of His-
between
R A and RV in sceptum
i
.
.
right left
ventricle Ventricl
a
--
n
purkyne
Fibres
Electrical Coordination of heartbeat-Model Answer
SAN pacemaker initiating the heartbeat
·
act as ,
.
>
sends wave of depolarisation both atria to contract
across
atria-causing at same time
AVN delays electrical allowing time for fill blood before they
·
activity
-
ventricles to with contract
Bundle His
through Purkyne
~
AUN sends wave of depolarisation down of and fibres
both ventricles to base
causing contract from up-
·
pushes blood up into arteries
,Responding to Stimul
- heart will contract without nervous stimulation-
any
however heart rate be altered to needs of the
, can in response body
·
heart
eg ,
during exercise rate will increase to supply more
oxygen
to
respiring muscle cells
Heart rate is under the control of the autonomic nervous
system
Parasympathetic
L
(s) Sympathetic (speeds up] (PS) (slows down
stimulates inhibits
·
effectors effectors
·
"HR HR
fight
W
controls
activity at rest
· ·
Neurotransmitter noradrenaline neurotransmitter :
acetylcholine
·
·
:
* the two branches of the autonomic nervous
system are
antagonistic Opposite effects
-
* HR down P S
can also be increased by fewer impulses nerve ,
.
down S
or decreased by fewer impulses nerve
HR the MEDULLA OBLONGATA brain :
is controlled
by in the
~ medulla has a centre has 2 parts different functions
cardioregulatory which
performing 2
-
,
① ACCELETORY -
increase heart rate (4HR) ,
linked to SAN
by Sympathetic nervous
system
SINHIBITORY -
decrease heart rate (dHR),
linked to SAN
by Parasympathetic nervous system
