Neuroscience and Muscle Physiology Review

These flashcards cover key vocabulary and concepts related to neuromuscular physiology and neuroscience as reviewed in lecture notes.

Myosin

A motor protein that generates force during muscle contraction.

Regulatory Proteins

Proteins such as tropomyosin and troponin that regulate muscle contraction.

Nissl Bodies

Aggregates of rough endoplasmic reticulum in the neuronal cell body involved in protein synthesis.

Dendrites

Parts of a neuron that receive impulses.

Axon

Part of a neuron that discharges impulses away from the cell body.

Gated Channels

Membrane channels that open or close in response to stimuli, including ligand-gated, voltage-gated, and mechanically-gated channels.

Ligand-Gated Channels

Channels that open in response to the binding of a chemical messenger.

Voltage-Gated Channels

Channels that open or close in response to membrane potential changes.

Resting Membrane Potential

The electrical potential across the plasma membrane of a resting neuron.

Extracellular Fluid (ECF) Ion

Sodium (Na+) is found in a higher concentration in the ECF.

Tendon

A cord-like projection of connective tissue that attaches muscle to bone.

Aponeurosis

A fibrous sheet of connective tissue that connects muscles to adjacent muscles.

Endomysium

Connective tissue covering individual muscle fibers.

Perimysium

Connective tissue surrounding a fascicle of muscle fibers.

Epimysium

Connective tissue that surrounds the entire muscle.

Sarcolemma

The membrane enclosing a muscle fiber.

Sarcoplasm

The cytoplasm of a muscle cell.

Myofibrils

Cylindrical structures in a muscle fiber that contain sarcomeres.

Transverse Tubules (T-tubules)

Invaginations of the sarcolemma that aid in the transmission of action potentials.

Triad

Structure formed by the T-tubule and two adjacent terminal cisternae of the sarcoplasmic reticulum.

Myofilaments

Filaments of myofibrils, composed primarily of actin and myosin.

Sarcomere

The basic functional unit of a muscle, defined by two Z lines.

Contractile Proteins

Proteins responsible for muscle contraction, namely actin and myosin.

Actin

A globular protein that forms filaments and works with myosin for muscle contraction.

Acetylcholine (ACh)

A neurotransmitter released at neuromuscular junctions.

Intracellular Fluid (ICF) Ion

Potassium (K+) is found in a higher concentration in the ICF.

Leaky Channels

Channels that allow ions to move across the membrane freely, particularly K+ channels.

Anions

Negatively charged ions, such as proteins, that cannot cross the cell membrane.

Presynaptic Cell

The neuron that releases neurotransmitter into the synaptic cleft.

Postsynaptic Cell

The target cell that receives the neurotransmitter.

Synaptic Junction

The site where communication occurs between two neurons.

Neuromuscular Junction

The synapse formed between a motor neuron and a muscle fiber.

Synaptic Vesicles

Membrane-bound sacs in presynaptic terminals that contain neurotransmitters.

Calcium Role in Axon Terminal

Calcium ions trigger the fusion of synaptic vesicles with the presynaptic membrane, releasing neurotransmitters.

Graded Potential

A change in membrane potential that varies in size, affecting action potential generation.

EPSP (Excitatory Postsynaptic Potential)

A graded potential that makes the postsynaptic neuron more likely to fire.

IPSP (Inhibitory Postsynaptic Potential)

A graded potential that makes the postsynaptic neuron less likely to fire.

Threshold Stimulus

The minimal strength of stimulation required to trigger an action potential.

All-or-None Response

The principle that an action potential either occurs fully or not at all.

Action Potential Stages

Depolarization, repolarization, and hyperpolarization.

Depolarization Ion

The entry of sodium ions (Na+) into the neuron.

Repolarization Ion

The exit of potassium ions (K+) from the neuron.

Hyperpolarization Ion

The exit of potassium ions (K+) or entry of chloride ions (Cl-).

Absolute Refractory Period

A period during which a neuron cannot generate another action potential.

Relative Refractory Period

A period during which a neuron can generate another action potential but requires a stronger stimulus.

Motor End Plate

The depression on the muscle fiber's membrane where neurotransmitter receptors are located.

Calcium Binding Protein

Calmodulin, which binds calcium ions in smooth muscle.

Rigor Mortis

The stiffness of muscles post-mortem due to calcium release and lack of ATP.

Curare Effect

Paralysis due to competitive inhibition of acetylcholine at the neuromuscular junction.

Myogram

A graphical record of muscle contraction.

Isotonic Contraction

A contraction where muscle changes length while lifting a constant load.

Isometric Contraction

A contraction where muscle length remains unchanged while exerting force.

Concentric Contraction

A shortening contraction where the muscle overcomes resistance.

Eccentric Contraction

A lengthening contraction when muscle resists loads while lengthening.

Tetanic Contraction

A sustained muscle contraction without relaxation.

Muscle Tone

A state of mild contraction of muscles, maintaining posture and readiness.

Staircase Effect

Gradual increase in muscle contraction strength following a series of stimuli.

Recruitment

The activation of additional motor units to increase muscle force.

Lactic Acid Accumulation

Occurs when anaerobic metabolism exceeds aerobic metabolism during intense activity.

Duchenne Muscular Dystrophy

An X-linked genetic disorder causing muscle degeneration.

Smooth Muscle Characteristics

Non-striated muscle fibers with unique characteristics such as one nucleus, and no T-tubules.

Peristalsis

The coordinated contraction and relaxation of smooth muscle to move contents through tubes.

CNS (Central Nervous System)

The brain and spinal cord which control the body.

PNS (Peripheral Nervous System)

Nerves outside the CNS connecting to limbs and organs.

Neuroglia

Supporting cells in the nervous system that maintain homeostasis, form myelin.

Myelin Sheath

Protective insulating layer around nerve fibers produced by oligodendrocytes in CNS and Schwann cells in PNS.

Unipolar Neurons

Neurons with one process, primarily sensory neurons.

Bipolar Neurons

Neurons with two processes, found in sensory organs like the retina.

Multipolar Neurons

Neurons with multiple processes, primarily motor neurons.

Node of Ranvier

Gaps in the myelin sheath that facilitate rapid conduction via saltatory conduction.

Excitatory NT at NMJ

Acetylcholine (ACh) is the primary excitatory neurotransmitter at the neuromuscular junction.

Glutamate

An excitatory neurotransmitter that is also linked to neuronal injury or stroke.

Endorphins

Neurotransmitters that alleviate pain and induce feelings of pleasure.