ANHB1101 Lecture Notes - Lecture 25: Glycogen, Myosatellite Cell, Epimysium
3 Jun 2018
School
Course
Professor
Lecture 25
Thursday, 5 May 2016
12:09 pm
Muscle
Characteristics of Muscle Tissue:
• Excitable - respond to a stimulus
• Extensible - stretch and recoil
• Elastic - bounce back when stretched
• Contractile - produced movement in the movement
• Highly cellular
• Well vascularised - need good blood supply
• Cells all contain myofilaments necessary for contraction - actin and myosin
Muscle Types:
• Skeletal/voluntary
• Smooth/non-striated
• Cardiac
Function:
• Produces movement
• Maintains posture
• Stabilised joints
• Generates heat - skeletal muscle used in particular
Skeletal Muscle:
• Striated - cross-striations (stripes)
• Cell shape - cylindrical
• Replication - adult skeletal muscle cells cannot replicate
• Control - voluntary (conscious control), can move under reflexes
• Rapid contraction and recovery - tire easily
• Refraction period - 1-2milliseconds (time between when a muscle is stimulated
to contract and how long it takes for it to be able to contract again)
Terminology for skeletal muscle:
• Prefixes = 'myo' and 'sarco'
• Muscle and fibres (myofibres)
• Sarcolemma (membrane)
• Sarcoplasm (cytoplasm)
• Sarcoplasmic reticulum (ER)
Gross Anatomy of Named Skeletal Muscle:
• Standardised anatomy
• Discrete organ made up of many muscle fibres
• Connective tissue prominent
• Blood vessels and nerves run in connective tissue
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Document Summary
Function: produces movement, maintains posture, stabilised joints, generates heat - skeletal muscle used in particular. Terminology for skeletal muscle: prefixes = "myo" and "sarco, muscle and fibres (myofibres, sarcolemma (membrane, sarcoplasm (cytoplasm, sarcoplasmic reticulum (er) Lots of collagen around - continuous all the way through and becomes the tendon: collagen prevents over-extension of muscles, recoil of collagen. If a little damage occurs, satellite cells can do a little repair: anything bigger = connective tissue repair (scar tissue, adult skeletal muscle cells cannot divide - repair comes from satellite cells (limited) Involves myosin and actin sliding across each other: sliding filament theory. Motor unit: connective tissue insulate skeletal muscle cells and prevent interaction between fibres, must be stimulated by a nerve in order to contract. If motor nerve is damaged, they cannot be contracted by the muscle fibre next door: depending on relationship between neuron and number of cells it controls gives either fine or gross control.
