Ch. 9 Muscle Tissue Flashcards
Smooth Muscle
Structure: Not striated
Location: Intestine, respiratory, blood vessels
Characteristics: Involuntary, autonomic, nervous, hormones
Cardiac Muscle
Structure: Striated
Location: Heart
Characteristics: Involuntary, autonomic nervous, hormones
Skeletal Muscle
Structure: Striated
Location: All over the body
Characteristics: Voluntary, learned patterns of movement
Functions of Muscle Tissue
- Body movement (In association with the skeleton)
- Stabilizing the body
- Standing upright
- Regulating movement (Sphincter muscles)
- Moving substances within the body (Peristalsis)
- Generating heat (Shivering)
Properties of Muscle Tissue
- Contractility: Contract and maintain tension
- Extensibility: Stretch without damage
- Elasticity: Return to original length
- Electrical excitability: Electric signals like a nerve cells
Anatomy of a Muscle (Big to Small structures)
Tendon (connects muscle to skeleton), epimysium (outer layer of connective tissue muscle), fascicle (bundles of muscle cells/fibers), perimysium (connective tissue around a fascicle), muscle fiber (cell), myofibril
Anatomy of a Muscle (Fascicle)
Perimysium (membrane around a fascicle), endomysium (connective tissue around a muscle fiber, inside a fascicle)
Tendon
Connects a muscle to the skeleton
Epimysium
Outer layer of connective tissue surrounding a muscle
Fascicle
Bundles of muscle cells/fibers
Perimysium
Connective tissue around a fascicle
Muscle Fiber
Basic functional unit of muscle tissue
Endomysium
Connective tissue around a muscle fiber, inside a fascicle
Sarcomere
The basic unit of a muscle
Consists of z discs, m line, I bands, A band, and H zone
Anatomy of a Muscle (Muscle Fiber)
Sarcolemma (cell membrane), myofibril (bundles of sarcomere’s), filaments
Sarcomere (Structure)
Thick Filament: Myosin
Thin Filament: Actin, troponin, and tropomyosin
Structural Proteins: Titin, myomesin
Muscle proteins
Myosin Actin Troponin Tropomyosin Titin Myomesin
Myosin
Contractile protein in thick filament. Has myosin heads and tails to attach to actin
Actin
Contractile protein in thin filament
Troponin
Regulatory protein in thin filament
Regulates when the muscle contracts and relaxes
Tropomyosin
Regulatory protein in thin filament
Titin
Structural protein; stretching (“springs”)
Myomesin
M line; structural protein
Thin filaments
Consists of actin, troponin, and tropomyosin
- Actin has the binding site for the myosin head
- Troponin and tropomyosin regulate the binding of the myosin heads
Fused Tetanus
Muscles completely contracted
Motor Unit
Lets you control how strong contractions are
Activates muscle fibers, each motor neuron activates a different group of motor units
Muscle Fibers
Three very different fibers: slow oxidative, fast oxidative, and fast glycolytic
Slow Oxidative Fibers
Thin, aerobic, slow twitch, many capillaries
Myoglobin: protein in the muscle that stores oxygen
Resistant to fatigue, do not build up waste piles
i.e. endurance muscles, repeated motion
Fast Oxidative Fibers
Medium thickness, aerobic, fast twitch
Many capillaries, myoglobin, high glycogen
Moderate resistance to fatigue
Middle ground type, between endurance and sprinting
Fast Glycolytic Fibers
Very thick, anaerobic, fast, powerful twitch
High glycogen, few capillaries, and myoglobin
Fatigues easily
i.e. Sprinters, powerful
Smooth Muscle (Structure)
Intermediate filaments, sarcomeres connected to dense bodies, not always in the same direction
Sarcomeres are organized differently
Smooth Muscle Physiology
Sliding filament contraction
- Slow, long lasting contractions
- Contracts further and stretches further
- Ca++ diffusion is slow
- No T tubules, and very little SR
