201 Describe mechanism of action
of calcium channel blockers in Vascular smooth muscle cells and cardiac conduction cells
voltage gated calcium channels
manage electrical of cells by allowing the selective-diffusion of calcium ions in response to changes in cellular membrane potential
signalling
·
-
activated
by membrane depolarization >
-
less negative more positive -
depolarize and open channel
-
allows cast to enter cells down the concentration gradient- high concentration
extracellularly (outside the cell) so it moves In to the cell
2 hen the channel opens since its low inside gradient
L
type (long lasting) calcium channels .
-> What calcium channel blockers target
cardiovascular diseases we look at this have a
longer action
>
-
-
present in vascular smooth muscle and ventricular myocytes . Present in many cells .
cast is involved in the process of contraction of
·
responsible for excitation -
contraction
coupling in skeletal smooth and cardiac muscle
,
3 smooth muscle
· cardiac conduction tissue (sino-atrial and atrioventricular node
simplified cellular mechanism -
vascular smooth muscle
t - cells that surround the smooth muscles in arteries or the vein
so cart
ENTERS
Cell
>
-
if you stop calt going in it will stop the actin-myosin bridge and
activai
reduce or stop contraction
The control of membrane polarisation /depolarisation is complicated Can be influenced by neurotransmitters and hormones
notetracted
> the pulling
itcartDona
-
makes the muscle smaller
actin-myosin bridge
calcium)/ of the
↓ ↓ les
activateamyosin bridge
lots of contraction
relaxation
pulsitthenesses
contraction
and they
due to active
more
contract
aa
lots of
caux pullingmaleenter >
- since cells are smaller
, simplified cellular To pump
mechanism -
cardiac electrophysiology :
·
heart starts with an electrical
higher
- calt allows at pacemaker
signal a
current to go
Faster the heart
·
flows through past atria
Y lower cast allows
Y 7 slows
dowe current to
slower
go · slows down in AU node
allowing contraction
calcium channels to happen in the atria
overall slow HR
down
·
pushing blood into the ventricles
·
after a short time it allows the electricity
to come
rapidly so bundle branch
·
makes the ventricle muscle pump blood out
* conduction > how around the heart the aorta
electricity flows or pulmonary artery
-
· the current will stop in the top left corner here in the sinoatrial node
· causes a contraction of the atrium
· Then it pauses in AU node - allows blood to fill into the ventricles after a short delay
· The AU node current passes through allowing current to rapidly go across ventricle
· causes a fast contraction of blood out
Simplified cellular mechanism -
cardiac electrophysiology activities
is channel
ifthere n
calcium
↳
I heart beat calcium channel blockers the cardiac
especially
- - polarises
Selective ones
afrect
>
-
decease the phase O
up slope
can
therefore prolonging the overall cycle
Ms
>
-
Y channel
impact
> cast
-
goes in upstroke ↓ > therefore slowing down the HR
depending
-
how longer time between
on each
each Cycle
active is
channel
Y slower cycle
natural cycle in AU node and pacemaker cell due to range of different types of channels
S
a
being
opened or closed . Allows the membrane
potential slowly drift from being hyper polarized to depolarized hitting a
threshold allowing cast to come in
of calcium channel blockers in Vascular smooth muscle cells and cardiac conduction cells
voltage gated calcium channels
manage electrical of cells by allowing the selective-diffusion of calcium ions in response to changes in cellular membrane potential
signalling
·
-
activated
by membrane depolarization >
-
less negative more positive -
depolarize and open channel
-
allows cast to enter cells down the concentration gradient- high concentration
extracellularly (outside the cell) so it moves In to the cell
2 hen the channel opens since its low inside gradient
L
type (long lasting) calcium channels .
-> What calcium channel blockers target
cardiovascular diseases we look at this have a
longer action
>
-
-
present in vascular smooth muscle and ventricular myocytes . Present in many cells .
cast is involved in the process of contraction of
·
responsible for excitation -
contraction
coupling in skeletal smooth and cardiac muscle
,
3 smooth muscle
· cardiac conduction tissue (sino-atrial and atrioventricular node
simplified cellular mechanism -
vascular smooth muscle
t - cells that surround the smooth muscles in arteries or the vein
so cart
ENTERS
Cell
>
-
if you stop calt going in it will stop the actin-myosin bridge and
activai
reduce or stop contraction
The control of membrane polarisation /depolarisation is complicated Can be influenced by neurotransmitters and hormones
notetracted
> the pulling
itcartDona
-
makes the muscle smaller
actin-myosin bridge
calcium)/ of the
↓ ↓ les
activateamyosin bridge
lots of contraction
relaxation
pulsitthenesses
contraction
and they
due to active
more
contract
aa
lots of
caux pullingmaleenter >
- since cells are smaller
, simplified cellular To pump
mechanism -
cardiac electrophysiology :
·
heart starts with an electrical
higher
- calt allows at pacemaker
signal a
current to go
Faster the heart
·
flows through past atria
Y lower cast allows
Y 7 slows
dowe current to
slower
go · slows down in AU node
allowing contraction
calcium channels to happen in the atria
overall slow HR
down
·
pushing blood into the ventricles
·
after a short time it allows the electricity
to come
rapidly so bundle branch
·
makes the ventricle muscle pump blood out
* conduction > how around the heart the aorta
electricity flows or pulmonary artery
-
· the current will stop in the top left corner here in the sinoatrial node
· causes a contraction of the atrium
· Then it pauses in AU node - allows blood to fill into the ventricles after a short delay
· The AU node current passes through allowing current to rapidly go across ventricle
· causes a fast contraction of blood out
Simplified cellular mechanism -
cardiac electrophysiology activities
is channel
ifthere n
calcium
↳
I heart beat calcium channel blockers the cardiac
especially
- - polarises
Selective ones
afrect
>
-
decease the phase O
up slope
can
therefore prolonging the overall cycle
Ms
>
-
Y channel
impact
> cast
-
goes in upstroke ↓ > therefore slowing down the HR
depending
-
how longer time between
on each
each Cycle
active is
channel
Y slower cycle
natural cycle in AU node and pacemaker cell due to range of different types of channels
S
a
being
opened or closed . Allows the membrane
potential slowly drift from being hyper polarized to depolarized hitting a
threshold allowing cast to come in
