Neuromuscular System Flashcards
Muscle fibers - Slow twitch
(Type I)
Features:
-Small Diameter fibre
-Large myoglobin content (carry oxygen)
-Many mitochondria (lots of energy)
-Many capillaries (good gas exchange)
Functional features:
-Increased oxygen delivery
-Produce less force
-Slow contractions
-Resistant to fatigue
Ex. Endurance activities.
Generally most muscles have more slow twitch to manta in posture. 45-55%
Muscle fibers - fast twitch
(Type IIa)
Structural features:
-Medium diameter fibre
-Smaller myoglobin content
-Midway mitochondria
-Midway capillaries
Functional features:
-Decreased oxygen delivery
-Produces force
-Slow contractions
-Midway resistant to fatigue
Ex, 800m run
Muscle fibers - fast twitch
(Type IIx)
Structural features:
-Large diameter fibre
-Smaller myoglobin content
-Fewer mitochondria
-Fewer capillaries
Functional features:
• Decreased oxygen delivery
• Produce more force
• Short term contractions
• Less resistant to fatigue
Ex, 100m sprints
Sliding filament theory
-Electrical impulse travels down the spinal cord along motor neurons to muscle fibers.
-To protect the signal,Myelin Sheath (insulator), surrounds the axon.
-Myelin Sheath breaks along the axon. This breaks are nodes of Ranvier. Impulse travels from one node to another.
-A impulse reaches end of Axon, it triggers the release of acetyl choline at the end of muscular junction.
-The neurotransmitter is secreted into the synapse to assist nerve impulse across the gap.
If there are enough noodle, transmitters, muscle action potential is created and a wave of contraction occurs.
Axon
Carrie’s the Action Potential (AP) from the cell body to the neuromuscular junction
Myelin sheath
An insulator that surrounds the axon, made up from fatty materials.
Acetyl choline
A neurotransmitter released at the neuromuscular junction and diffuses along the synapse
Synapse
The space between the neuromuscular junction and skeletal muscle
