Motor Physiology Flashcards
Skeletal muscle type: In muscle spindle
Intrafusal
Skeletal muscle type: For muscle contraction
Extrafusal
Extrafusal Skeletal Muscle: Larger (2x), faster, Glycolytic, more active (2-3x) enzymes in phosphagen & glycogen-lactic acid energy sytem, less active enzymes in aerobic sustem, high myosin ATPase, less mitochondria, in EOMs, fast contration velocity, short duration
Fast-Twitch/Fast Glycolytic/White muscle/Type II
Extrafusal Skeletal Muscle: Smaller, slower, Oxidative, less active enzymes in phosphagen & glycogen-lactic acid energy sytem, more active enzymes in aerobic sustem, low myosin ATPase, more mitochondria, in Soleus, Anti-gravity muscles of the back, moderate contration velocity, prolonged duration
Slow-Twitch/Slow Oxidative/Red Muscle/Type I
Smooth Muscle Type: Act on their own, no Gap junctions, no true Action Potential, Junctional Potential only, no spontaneous contractions (eg: ciliary eye muscle, iris, piloerector muscle, vas deferens)
Multi-unit Smooth Muscle
Smooth Muscle Type: Act together as one, controlled by nerve signals, hormones, stretch, local factors, with Gap junctions, Slow waves, Spike Potentials & Plateau Potentials, exhibit spontaneous contractions (eg: intestines, bile ducts, ureters, uterus)
Unitary Smooth Muscle (aka Syncytial Smooth Muscle, Visceral Smooth Muscle)
Rhythmic, Intermittent Smooth Muscle (eg: walls of the GI and Urogenital Tracts)
Phasic Smooth Muscle
Continuously Active Smooth Muscle (eg: vascular smooth muscle, respiratory smooth muscle, sphincters)
Tonic Smooth Muscle
Surrounds muscle fiber
Endomysium
Surrounds muscle fascicle
Perimysium
Surrounds skeletal muscle
Epimysium
Plasma membrane that surrounds muscle fiber
Sarcolemma
Invaginations of the sarcolemma in close proximity to the terminal cisternae of the Sarcoplasmic Reticulum
Transverse Tubules
Endoplasmic reticulum surrounding myofibril that contains Calcium
Sarcoplasmic Reticulum
Functional unit of the muscle; Area between 2 Z lines; Exhibited by skeletal and cardiac muscles; Has thick and thin filaments
Sarcomere
Thick filaments
Myosin
Thin filaments
ActinTropomyosinTroponin
Attaches troponin complex to tropomyosin
Troponin T
Inhibits Actin-Myosin binding
Troponin I
Calcium binding protein
Troponin C
Tethers Myosin to Z lines (scaffolding); Binds Z lines to M lines
Titin
Stabilizes Sarcolemma & prevents contraction-induced rupture
Dystrophin
Binds Actin to Z lines
Actinin, Capz Protein
Binds Z lines to Sarcolemma
Desmin
Act as a molecular ruler that sets the length of actin during assembly
Nebulin
Involves motor neurons & extrafusal fibers; Demonstrated by the Sliding-Filament Model
Skeletal Muscle Contration
Actin & Myosin Interaction
Cross-Bridge Formation
Thin filaments “slides” against the thick filaments towards the center of the sarcomere
Sliding Filament Model
What is the distance achieved in each cross-bridge cycle?
10 nanometers
True or False: All muscle fibers innervated by a single motor nerve fiber
True
“Final common pathway” or “Lower motor neuron”
Alpha motor neuron
Small Motor Units are recruited first before Big Motor Units
Size Principle
Multiple Fiber Summation
Spatial Summation
Frequency Summation
Temporal Summation