1. Cardiac and Smooth Muscle

2. 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

3. EXCITATION-CONTRACTION COUPLING IN A CARDIAC MYOCYTE
Excitation/contraction coupling is similar to skeletal muscle --no neurotransmitter required. --Contains T-tubes -- Ca2+ channels linked indirectly.

4. SMOOTH MUSCLE
--No striations, no sarcomeres --contains actin and myosin -- extremely long filaments, which attach to the plasma membrane and to proteins called dense bodies. --lines blood vessels, bronchioles, digestive tract (peristaltic waves), ureters, ductus deferens, uterine tubes

5. Single-unit & Multi-unit smooth muscle
--Neurotransmitter is released along the length of an autonomic neuron
from varicosities.
--Form synapses en passant (synapses in passing)
--Receptor proteins are on the entire surface of smooth muscle cells
--A number of smooth muscle cells are stimulated at once.

6. EXCITATION-CONTRACTION COUPLING: Smooth Muscle
Relaxation involves pumping Ca2+ out of cell