Peripheral Nervous System

These flashcards cover critical vocabulary and concepts related to the peripheral nervous system, sensory receptors, reflexes, and associated structures.

Peripheral Nervous System (PNS)

The part of the nervous system outside the brain and spinal cord, consisting of sensory receptors, nerves, ganglia, and motor endings.

Sensory Receptors

Specialized cells that respond to environmental stimuli and trigger nerve impulses.

Sensory Neurons

Nerve cells that transmit sensory information to the central nervous system (CNS).

Reflex Arc

The neural pathway that mediates a reflex action, involving a receptor, sensory neuron, integration center, motor neuron, and effector.

Mechanoreceptors

Sensory receptors that respond to mechanical stimuli such as pressure, touch, and vibration.

Thermoreceptors

Sensory receptors that detect changes in temperature.

Photoreceptors

Sensory receptors that respond to light energy, primarily located in the retina of the eye.

Chemoreceptors

Sensory receptors that respond to chemicals, such as those involved in smell and taste.

Nociceptors

Sensory receptors that respond to pain-causing stimuli, including extreme temperatures or pressure.

Exteroceptors

Sensory receptors that respond to stimuli arising outside the body.

Interoceptors

Sensory receptors that respond to stimuli from internal organs.

Proprioceptors

Sensory receptors located in muscles, tendons, and joints that provide information about body position and movement.

Afferent Nerves

Nerves that carry sensory information from the body to the CNS.

Efferent Nerves

Nerves that carry motor commands from the CNS to the body.

Neuromuscular Junction

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

Endoneurium

The delicate connective tissue that surrounds individual nerve fibers (axons) in the PNS.

Perineurium

The connective tissue that surrounds a group of nerve fibers to form a fascicle.

Epineurium

The outermost layer of connective tissue surrounding a peripheral nerve.

Somatic Reflex

A reflex that activates skeletal muscles.

Autonomic Reflex

A reflex that activates visceral effectors (smooth muscle, cardiac muscle, or glands).

Adaptation

Decreased responsiveness of sensory receptors to a continuous or unchanging stimulus.

Hyperalgesia

Increased sensitivity to pain due to prolonged or intense pain.

Phantom Limb Pain

Pain that is felt in a limb that has been amputated; often due to reorganization in the nervous system.

Dermatome

An area of skin innervated by sensory fibers of a single spinal nerve.