Nervous System Basics
What are the two main parts of the nervous system?
Central (CNS) and Peripheral (PNS)
What is the basic functional unit of the nervous system?
The neuron
What are the three types of muscle tissue?
Skeletal, cardiac, and smooth
What neurotransmitter is released at the neuromuscular junction?
Acetylcholine (ACh)
What is muscle fatigue?
A reduction in muscle power output due to tiredness or metabolite buildup
What is the main function of the CNS?
To process, interpret, and send out information
What covers axons to speed nerve impulses?
The myelin sheath (from Schwann cells)
What connective tissue surrounds an entire muscle?
Epimysium
What ion binds to troponin to start contraction?
Calcium (Ca²⁺)
What type of contraction lengthens the muscle?
Eccentric
What type of neurons carry information to the CNS?
Sensory (afferent) neurons
What happens during depolarization of a neuron?
Sodium (Na⁺) rushes into the cell
What is the smallest functional unit of a muscle fiber?
The sarcomere
What is the “power stroke”?
Myosin heads pull actin filaments toward the center of the sarcomere
Which muscle fiber type is most fatigue-resistant?
Type I (slow oxidative)
What type of neurons carry commands from the CNS to muscles?
Motor (efferent) neurons
What restores resting membrane potential?
The sodium-potassium pump moves 3 Na⁺ out and 2 K⁺ in
What two proteins form cross-bridges during contraction?
Actin and myosin
What supplies energy for contraction?
ATP
What is post-activation potentiation?
Greater force production after a warm-up contraction
Which part of the brain coordinates movement and balance?
The cerebellum
What is the “all-or-none law”?
Once a threshold is reached, the action potential fires completely
What structure stores calcium for muscle contraction?
The sarcoplasmic reticulum
What theory explains how muscles shorten?
The sliding filament theory
What is sarcopenia?
Age-related loss of muscle mass and strength