BIOB34H3 Lecture Notes - Neuromuscular Junction, Endoplasmic Reticulum, Fascia
Document Summary
Functions: movement, of whole body or body parts (skeletal, of substances within body (cardiac - pumps blood, smooth - substances move through hollow organs, heat production (mostly skeletal, maintain posture and stabilize joints (skeletal) Blood supply: lots of blood needed to supply oxygen and carry away wastes from these very active cells, vessels penetrate ct layers, lot of capillaries in endomysium. Muscle tone: small groups of motor units are periodically activated involuntarily, this keeps the muscle ready to contract. Basically the same set-up of myofilaments, etc. Cells connected by intercalated discs: desmosomes and gap junctions, cells contract as a unit, cardiac muscle, smooth muscle. Main electrical stimulation from specialized cells that spontaneously activate (autorhythmicity) 30 - 200 m long, 2 - 10 m diameter at middle. Has thick and thin filaments, but not in the same pattern as other muscle types.
