Muscular System and Nervous System II Vocabulary

Vocabulary practice flashcards covering key definitions and anatomical terms from the Muscular System and Nervous System II chapters.

Muscle Fiber

A single muscle cell, characterized as long, cylindrical, and multinucleated in skeletal muscle tissue.

Fascicle

A bundle of individual muscle fibers.

Epimysium

The connective tissue layer surrounding the entire muscle organ.

Perimysium

The connective tissue layer surrounding a muscle fascicle.

Endomysium

The connective tissue layer surrounding each individual muscle fiber.

Tendon

A band of connective tissue that attaches muscle to bone.

Aponeurosis

A broad, sheet-like connective tissue attachment for muscles.

Compartment Syndrome

A condition in which swelling or fluid builds pressure within a fascia-enclosed section, reducing oxygen and nutrients and causing severe pain.

Sarcolemma

The cell membrane of a skeletal muscle fiber.

Sarcoplasmic Reticulum (SR)

A specialized membrane network in muscle cells that stores calcium ions ($Ca^{2+}$).

Triad

A structural grouping in skeletal muscle fibers composed of 1 T tubule and 2 SR cisternae.

Sarcomere

The basic contractile unit of a muscle fiber, extending from one Z line to the next Z line.

I Band

The region of a sarcomere that contains actin only, which narrows during muscle contraction.

A Band

The region representing the entire length of myosin filaments in a sarcomere, which stays the same length during contraction.

H Zone

The central region of a sarcomere containing myosin filaments only, which narrows during contraction.

Tropomyosin

A regulatory protein on thin filaments that blocks actin binding sites at rest.

Neuromuscular Junction

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

Motor End Plate

The specialized area of the muscle fiber sarcolemma that contains acetylcholine (ACh) receptors.

AChE (Acetylcholinesterase)

An enzyme that breaks down acetylcholine (ACh) to allow muscle relaxation.

Myoglobin

A pigment in muscle tissue that stores oxygen ($O_2$).

Threshold Stimulus

The minimum stimulus strength required to elicit a muscle contraction.

Twitch

A single muscle contraction generated by one stimulus, consisting of latent, contraction, and relaxation phases.

Summation

The process where repeated stimuli arrive in rapid succession to add force to a muscle contraction.

Tetanus

A sustained, forceful muscle contraction caused by very rapid, continuous stimuli.

Motor Unit

A functional unit made up of 1 motor neuron and all the muscle fibers it controls.

Recruitment

The activation of additional motor units to produce greater muscle force.

Concentric Contraction

An isotonic muscle contraction where the muscle shortens because generated force exceeds resistance.

Eccentric Contraction

An isotonic muscle contraction where the muscle lengthens under tension because generated force is less than resistance.

Isometric Contraction

A contraction where muscle tension increases without a change in muscle length or joint movement.

Type I Fiber (SO)

A slow-twitch, red, oxidative muscle fiber that is fatigue-resistant and adapted for endurance.

Type IIb Fiber (FG)

A fast-twitch, white, glycolytic muscle fiber that is powerful and fatigues quickly, specialized for strength.

Hypertrophy

An increase in muscle size caused by exercise and use, resulting in more and larger fibers.

Atrophy

A reduction in muscle size and strength resulting from disuse.

Intercalated Discs

Specialized cell junctions in cardiac muscle that enable self-exciting, coordinated contractions.

Calmodulin

The key calcium-binding protein utilized in smooth muscle cells.

Meninges

The three connective tissue membranes protecting the central nervous system: dura mater, arachnoid mater, and pia mater.

Subarachnoid Space

The space situated between the arachnoid mater and pia mater that contains cerebrospinal fluid (CSF).

Choroid Plexus

A specialized vascular structure within brain ventricles that produces cerebrospinal fluid (CSF).

Arachnoid Granulations

Structures that reabsorb cerebrospinal fluid (CSF) back into the bloodstream.

Gyri

The elevated ridges located on the surface of the cerebrum.

Sulci

The shallow grooves on the surface of the cerebral cortex.

Fissures

Deep grooves in the brain that separate major regions or lobes.

Wernicke Area

A specialized region of the cerebral cortex responsible for language understanding.

Broca Area

A specialized region of the cerebral cortex responsible for speech production.

Long-Term Potentiation (LTP)

A process that persistent strengthens synaptic connections, enhancing synaptic signaling for memory storage.

Basal Nuclei

Deep brain structures that assist in smoothing and coordinating voluntary motor movements.

Parkinson Disease

A nervous system disorder associated with the loss of dopamine-producing neurons in the substantia nigra.

Thalamus

The main sensory relay station in the diencephalon for all incoming sensory signals except smell.

Hypothalamus

A diencephalon region critical for maintaining internal body homeostasis.

Limbic System

A brain functional group involved in emotional experience and survival instincts.

Medulla

The brainstem region containing vital autonomic centers for controlling heart rate, blood pressure, breathing, and swallowing.

Reticular Formation

A network of nerve fibers in the brainstem responsible for controlling wakefulness and filtering sensory signals.

Arbor Vitae

The tree-like pattern of white matter inside the cerebellum.

Posterior Root

The dorsal root of a spinal nerve that conducts incoming sensory impulses into the spinal cord.

Anterior Root

The ventral root of a spinal nerve that conducts outgoing motor impulses away from the spinal cord.

Reflex Arc

A direct neural pathway consisting of receptor $\rightarrow$ sensory neuron $\rightarrow$ interneuron $\rightarrow$ motor neuron $\rightarrow$ effector.

Ascending Tracts

Spinal cord tracts that carry sensory information upward toward the brain.

Descending Tracts

Spinal cord tracts that carry motor signals downward from the brain.

Spinothalamic Tract

An ascending spinal tract that transmits pain and temperature sensations to the brain.

Corticospinal Tract

A descending spinal tract responsible for carrying voluntary motor commands to skeletal muscles.

Dermatome

A specific skin area innervated by sensory fibers from a single spinal nerve.

Sympathetic Nervous System

The fight-or-flight division of the autonomic nervous system originating from spinal segments $T1$ through $L2$.

Parasympathetic Nervous System

The rest-and-digest division of the autonomic nervous system originating from cranial nerves ($III$, $VII$, $IX$, $X$) and sacral nerves ($S2$ through $S4$).