Muscular System & Nervous System Lecture Notes

These flashcards cover key concepts from the muscular and nervous systems, including muscle types, neuroglial cells, action potentials, and sensory receptors.

Skeletal Muscle

Striated, voluntary muscle responsible for overall body motility.

Cardiac Muscle

Striated, involuntary muscle that occurs only in the heart, controlled by pacemakers and neural controls.

Smooth Muscle

Non-striated, involuntary muscle found in the walls of hollow visceral organs.

Epimysium

Dense regular connective tissue surrounding the entire muscle.

Perimysium

Connective tissue that surrounds groups of muscle fibers called fascicles.

Endomysium

Fine sheath surrounding each individual muscle fiber.

Sarcomere

The smallest contractile unit of a muscle, located between two Z discs.

Myofilaments

Structures within the sarcomere, including thick filaments (myosin) and thin filaments (actin).

Prime Movers

Muscles that provide the major force for a specific movement.

Antagonists

Muscles that oppose or reverse a particular movement.

Synergists

Muscles that add force to a movement or reduce unnecessary movement.

Fixators

Synergists that immobilize a bone or muscle's origin.

First Class Lever

Lever system where the fulcrum is between the load and effort.

Second Class Lever

Lever system where the load is between the fulcrum and effort.

Third Class Lever

Lever system where effort is applied between the fulcrum and load.

Astrocytes

Neuroglial cells that support and brace neurons and control the chemical environment.

Schwann Cells

Neuroglial cells that form myelin sheaths around PNS nerve fibers.

Oligodendrocytes

Neuroglial cells that form myelin sheaths in the CNS.

Dendrites

Short processes of a neuron that act as receptive or input regions.

Axons

Processes of a neuron that generate and transmit action potentials.

Graded Potentials

Short-lived, local changes in membrane potential that decrease in intensity with distance.

Action Potentials

Brief reversals of membrane potential that maintain strength over distance, used for neural communication.

Chemical Synapses

Synapses where a fluid-filled cleft prevents impulses from passing directly between neurons, ensuring unidirectional communication.

Acetylcholine (ACh)

A neurotransmitter released at the neuromuscular junction, degraded by acetylcholinesterase.

Excitatory Postsynaptic Potentials (EPSPs)

Graded potentials that can initiate an action potential.

Absolute Refractory Period

The period during which a neuron cannot generate an action potential.

Relative Refractory Period

The period during which only strong stimuli can increase the frequency of action potentials.

Rods

Photoreceptors in the eye that are sensitive to dim light, suited for night vision.

Cones

Photoreceptors requiring bright light, providing color vision and high resolution.

Lens

Structure in the eye that separates the internal eye into anterior and posterior segments.

Optic Disc

The blind spot of the eye where the optic nerve exits, lacking photoreceptors.

Organ of Corti

Hearing receptor located in the cochlea of the inner ear.

Crista Ampullaris

Receptor for dynamic equilibrium located in the inner ear.

Olfactory Epithelium

The sensory structure involved in smell, covering the superior nasal concha.

Taste Buds

Sensory structures found in the fungiform and circumvallate papillae that detect taste.