endomysium: individual muscle fibers or cells

perimysium: fascicles (bundles of fibers)

epimysium: whole muscle

involuntary actions:

peristalsis (GI tract)

vascular system - blood flow and pressure (blood vessels)

parturition

vomiting

piloerector muscles

airway constriction and relaxation

pupil diameter

slow to contract

sustained contraction, resists fatigue

influenced by neuronal, mechanical, endocrine stimulation and ANS

fusiform cells

single central nuclei

eosinophilic cytoplasm, homogeneous

in GI tract

90 degree angles so a sample can have cross section and longitudinal section

function in peristalsis

anchor myofilaments in cytoplasm

pinocytic vesicles: neutrotransmitter uptake

great speed and strength of contractions

contract 70% of resting length

stretch 130% of resting length

(smooth muscle contracts 10% and stretches 190%)

very large cells

multiple peripheral nuclei

striations

eosinophilic, abundant cytoplasm

cross section: polygonal (not round like sm muscle)

no branching

in center of I bands

defines ends of sacromere

must have innervation to function

one axon may supply multiple muscle fibers

each muscle fiber only has one motor end plate

rhythmic contraction, blood circulation

involuntary

highly vascularized

elongate cells

central, single nuclei (sometimes 2)

eosinophilic cytoplasm

distinct cell margins

BRANCHING

intercalated discs

gap junctions (communication)

desmosomes (adhesion)

intercalated discs (lower electrical resistance)

purkinje cells (electric conduction)