Download Cardiac and Smooth Muscles

Cardiac and Smooth Muscles
Cardiac Muscle
Remember that
intercalated disks contain
gap junctions. When one
cell is stimulated, all cells
are stimulated.
Cardiac myocytes each
have one nucleus
- they undergo
spontaneous depolarization
EXCITATION-CONTRACTION COUPLING IN A CARDIAC MYOCYTE
-Excitation/contraction
coupling is identical
with skeletal muscle,
but you don’t need a
neurotransmitter.
--Contains T-tubes
SMOOTH MUSCLE
--No striations; contains actin and
myosin but arrangement is not in
sarcomeres.
-- has extremely long thin filaments,
which attach to the plasma
membrane and to cytoplasmic
proteins called dense bodies.
--lines blood vessels, bronchioles,
digestive tract (peristaltic waves),
ureters, ductus deferentia (which
transport sperm cells, uterine tubes
(which transport ova)
Single-unit & Multi-unit smooth muscle
a. Neurotransmitter is released
along the length of an
autonomic neuron from
varicosities.
b. Receptor proteins are on the
entire surface of smooth
muscle cells
c. A number of smooth muscle
cells are stimulated at once.
d. Form synapses en passant
(synapses in passing)
EXCITATION-CONTRACTION COUPLING: Smooth Muscle