Chapter 1: Structure & Function of the Muscular, Nervous, & Skeletal Systems Flashcards
Muscular System Types: Types of muscles
Smooth(GI Tract), Cardiac (Heart), Skeletal (Attach to Bones)
Muscle Parts Name Break Down: Three Parts, each within another.
Whole Muscle: Epimysium
Fascicle: Perimysium
Muscle Fiber: Endomysium
(fig1)
Microscopic Anatomy of Skeletal Muscle: Five part
Sarcolemma, Multi-Nucleated, Sarcoplasm, Mitochondria, Sarcoplasmic Reticulum
Sarcolemma
Plasma membrane surrounding each muscle fiber.
Regulates movement of materials in/out of cell.
Action Potentials*
Multi-Nucleated
Contain DNA - Initiate physical adaptations
Sarcoplasm
Cytoplasm of muscle cells
Mitochondria
Site of aerobic ATP production
Sarcoplasmic Reticulum
Stores calcium and regulates the muscle action process
Myofibril
Is a bundle of myofilaments.
There are two kinds:
Myosin (Thick):
(red golf club shaped fiber)
-Head, Neck, Tail
Actin (Thin):
(Green ball looking fiber)
-Tropomyosin
-Troponin
-Troponin + Calcium = Tropomyosin moves away from myosic binding sites.
Sarcomere
Basic unit of muscle.
Z-line to Z-line
Five Parts:
-A Band: Width of myosin
-H Zone: Myosin; no Actin
-M Line: Aligns Myosin
-I Band: Between two sarcomeres; only action.
Neuromuscular Junction
NJ
Where muscle fibers receive stimulus from the nervous system.
Structures:
-Axon
-Motor Endplate
-Synaptic Cleft
Sliding Filament Theory
Types of Muscle Actions
Isometric, Concentric, Eccentric
Isometric
Muscle Force = Resistance, Muscle remains the same
Holding Weight
Concentric
Muscle Force > Resistance, Muscle Shortens.
Curling in
Eccentric
Muscle Force < Resistance, Muscle Lengthens
Curling out
“Negative Rep”
“Can be used to get clients to come back as it’ll create a very SORE feeling.”
Delayed-Onset Muscle Soreness (DOMS)
Is Soreness resulting from connective and muscle tissue damage.
Eccentric movements tend to lead to a greater amount of DOMS.
DOMS is not indicative of a good workout. Soreness isn’t a necessity but..
This is a good way to sell yourself as a good PT, people may think you gave them a good workout if they come out of it sore.
Muscle Fiber Types
Type I, Type IIa, Type IIx.
Type I: Long Distance, Slow Twitch, smallest muscle size
Type IIa: Fast Twitch Oxydative, 400m / 800m. Largest Muscle fiber size.
Type IIx or b: Fast Twitch Glycolytic, Short Sprints.
The Nervous System
Motor Cortex controls the muscular system. (middle horizontal path along brain.) Connects to Medulla Oblongate to CNS pathways which are located in spinal cord segment that connects to nerve which finally touches somatic motor pathway then muscle.
Parts of the Nervous System
Central Nervous System (CNS), Periphereal Nervous System (PNS).
CNS: Brain & Spinal Cord
PNS: relay impulses from CNS to rest of body and vice-versa.
Autonomic - Involuntary
Somatic - Voluntary
Neuron (Nerve Cell): Three types and function
Motor Neuron, Sensory Neuron, Synapse.
Motor Neuron:
-Conducts impulses from the CNS to muscles.
- Causes muscle to contract.
Sensory Neuron:
-Carry impulse from the periphery toward the CNS.
-Tension, stretch, movement, pain, etc.
Synapse:
-Site of communication between two neurons or a neuron and a gland or muscle cell.
-Neuromuscular Junction: Synapse between a motor neuron and a muscle fiber.
Sensory Neurons
Muscle Spindle, Golgi Tendon Organ.
Muscle Spindle: Stretch receptor dispersed through most skeletal muscle. Sense different changes to the muscle length, when stretched in a certain way, rapidly a stretch flex occurs and contracts the muscle to prevent injury.
Gogli Tendon Organ: Senses change in muscle tension, when force exceeds muscle potential relaxes working muscle and activates the antagonist muscle to protect body.
Motor Unit (MU)
A motor neuron and the muscle fibers it innervates. All fibers within a MU are the same fiber type. MU may very in the number of fibers innervated.
Gradation of Force
Motor Unit Recruitment, Rate Coding, & Size Principle.
MUR: NS varies the number of motor units (muscle fibers) that are activated.
RC: Increase the firing rate of motor units already activated.
SP: Order of activation: Type I -> Type IIa -> Type IIx