PHYS30005 Lecture Notes - Lecture 1: Motor Unit, Myocyte, Skeletal Muscle

• School: University of Melbourne
• Department: Physiology
• Course: PHYS30005
• Professor: Charles Sevigny

Document Summary

Lecture 1 functional properties of skeletal muscle. Muscle is made up of bundles (fascicles) of fibres. Each fibre is made up of many myofibrils. The myofibrils appear striated because of the alternating dark (a) and light (i) bands in register. The arrangement of fibres relative to the axis of force generation. Fibre length is never (or rarely) the same as muscle length. Most fibres insert obliquely into the tendon resembles a feather arrangement (cid:272)alled (cid:862)pi(cid:374)(cid:374)atio(cid:374)(cid:863) or (cid:862)pe(cid:374)(cid:374)atio(cid:374)(cid:863) More fibres can be packed in, increasing the effective cross- sectional area (csa) of the muscle. Architectural specialization (muscles are designed for a specific function: (cid:373)us(cid:272)les for fi(cid:374)e (cid:272)o(cid:374)trol, (cid:373)us(cid:272)les for for(cid:272)e a(cid:374)d power output. Isometric = fixed or same length in muscle, force = load. Miometric (concentric) = shortening of length in muscle, force > load. Pliometric (eccentric) = lengthening in muscle, force < load. Relationship between actin and myosin filament overlap and isometric force.