Muscle Review & Nervous System Intro (Week 6 – Ch. 14)

Vocabulary flashcards cover major lower-limb muscles, nervous-system organization, neuron anatomy, glial cells, conduction concepts, and connective-tissue coverings to support Week 6 lecture review.

Tensor Fascia Latae

Small lateral hip muscle that tenses the IT band and assists in hip abduction.

Sartorius

Long, thin muscle that crosses the thigh; laterally rotates and flexes the hip and flexes the knee—“tailor’s/cross-leg muscle.”

Gracilis

Medial, thin thigh muscle that adducts the hip; commonly strained in groin injuries.

Adductor Group (brevis/longus)

Deep medial thigh muscles that adduct the hip; synergists of gracilis.

Quadriceps Femoris

Four-part anterior thigh group (rectus femoris + three vasti) producing powerful knee extension.

Rectus Femoris

Superficial quad head that extends the knee and weakly flexes the hip.

Vastus Lateralis

Lateral quad head; extends the knee.

Vastus Medialis

Medial quad head; extends the knee.

Vastus Intermedius

Deep, central quad head; extends the knee.

Tibialis Anterior

Anterior leg muscle causing dorsiflexion and foot inversion; lies just lateral to the shin.

Extensor Digitorum Longus

Anterior leg muscle that extends toes 2-5 and aids dorsiflexion.

Extensor Hallucis Longus

Anterior leg muscle that extends the big toe (hallux).

Fibularis (Peroneus) Longus

Superficial lateral leg muscle; everts foot and assists plantar flexion.

Fibularis Brevis

Deep lateral leg muscle; everts foot.

Triceps Surae

Combined gastrocnemius (medial & lateral heads) plus soleus; chief plantar-flexors via Achilles tendon.

Gastrocnemius

Two-headed calf muscle that plantar-flexes the foot and flexes the knee; rich in fast fibers.

Soleus

Deep calf muscle with slow fibers; sustains plantar flexion during walking.

Tibialis Posterior

Deep posterior leg muscle; inverts and plantar-flexes foot.

Flexor Digitorum Longus

Deep posterior leg muscle that flexes toes 2-5.

Flexor Hallucis Longus

Deep posterior muscle that flexes the big toe.

Central Nervous System (CNS)

Brain and spinal cord; site of integration and decision-making.

Peripheral Nervous System (PNS)

All neural tissue outside CNS; nerves carrying information to/from CNS.

Sensory (Afferent) Division

PNS fibers conveying signals toward the CNS.

Motor (Efferent) Division

PNS fibers conveying signals away from the CNS.

Somatic Nervous System

Motor subdivision directing voluntary signals to skeletal muscles.

Autonomic Nervous System (ANS)

Motor subdivision controlling involuntary effectors—smooth & cardiac muscle and glands.

Sympathetic Division

ANS branch that mobilizes body for activity (“fight or flight”).

Parasympathetic Division

ANS branch that conserves energy and promotes rest (“rest and digest”).

Neuron

Excitable cell that conducts and transmits electrochemical signals; long-lived & amitotic.

Neuroglia (Glial cells)

Supportive nervous-system cells that protect, nourish, and insulate neurons.

Astrocyte

Star-shaped CNS glial cell that forms the blood-brain barrier and regulates extracellular fluid.

Ependymal Cell

CNS glial cell lining ventricles; cilia circulate cerebrospinal fluid.

Microglial Cell

Small CNS phagocyte providing immune defense within nervous tissue.

Oligodendrocyte

CNS glial cell whose processes wrap axons to form myelin sheaths.

Satellite Cell

PNS glial cell surrounding neuron cell bodies in ganglia; regulates chemical environment.

Neurolemmocyte (Schwann Cell)

PNS glial cell that myelinates a single axon segment.

Soma

Neuron cell body containing nucleus, Nissl bodies, and organelles.

Dendrite

Branched receptive process carrying signals toward the soma.

Axon

Long nerve fiber transmitting impulses away from the soma; may be myelinated.

Axon Hillock

Cone-shaped region where action potentials are initiated.

Myelin Sheath

Multilayered lipid wrapping insulating axons and speeding conduction.

Node of Ranvier (Neurofibril Node)

Gap between myelin segments where ion exchange occurs; enables saltatory conduction.

Unipolar Neuron

Neuron with one process; common in sensory (afferent) pathways.

Bipolar Neuron

Neuron with two processes; found in special senses (e.g., retina, olfactory epithelium).

Multipolar Neuron

Neuron with three or more processes; predominant type of interneurons and motor neurons.

Action Potential

Rapid, self-propagating electrical signal along the axon.

Saltatory Conduction

Fast impulse propagation jumping from node to node along myelinated axons.

Continuous Conduction

Slower impulse propagation along unmyelinated axons.

Synapse

Functional junction where a neuron communicates with another cell.

Chemical Synapse

Most common synapse; neurotransmitter crosses synaptic cleft causing excitation or inhibition.

Electrical Synapse

Gap-junction connection allowing direct ion flow between cells for rapid, synchronous activity.

Gray Matter

CNS regions containing neuron cell bodies (cortex & nuclei); in PNS called ganglia.

White Matter

CNS regions of myelinated axons; in PNS bundled as nerves.

Nerve

Bundle of PNS axons wrapped by connective tissue layers (epi-, peri-, endoneurium).

Tract

Bundle of myelinated axons within the CNS.

Epineurium

Dense irregular CT covering an entire nerve.

Perineurium

CT sheath surrounding a fascicle of axons.

Endoneurium

Delicate areolar CT surrounding individual myelinated axons.