Psyc 552 Ergonomics & Biomechanics Lecture 4

Ligaments, Tendons, & Facia  Ligament: Dense connective tissue that connects bone to bone. Image from:

Flexor Retinaculum 1 scaphoid 2 trapezium 3 pisiform 4 hamate Image from:

Tendons  Tendons Attach muscles to bones Are surrounded by a sheath called a synovium Synovial fluid facilitates gliding  Fascia Dense connective tissue that covers organs or parts of organs and separates them from each other.

Collagen fibers  Collagen fibers form both ligaments and tendons.  In tendons, the fibers run parallel to one another  In ligaments, the fibers are not parallel

Muscles  3 types of muscles in the body Striated Cardiac Smooth  Muscles consist of Muscle cells 3 types of connective tissue… Nerve fibers

Muscle Connective Tissue Image from:

Muscle Fibers  Long multinuclear cylindrical cells composed of parallel myofibrils  Myofibrils Composed of 2 sub units called myofilaments  Myosin  Actin

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Muscle Contractile Unit  Sacromere The part of a cross-striated muscle fiber between the z-lines

Nervous Tissue Image from: vv.carleton.ca/~neil/neural/neuron-a.html

Nervous Tissue (cont)  Two branches Sensory Motor  Nerves connect to muscles via the neuromuscular junction  Nerve + muscle fiber = motor unit

Muscular Contraction Image from:

Muscle Contraction (cont)

Energy for Muscles  Adenosine triphosphate ATP  Anaerobic metabolism  Aerobic metabolism