The Peripheral Nervous System and Reflex Activity

Flashcards covering key concepts from Chapter 13 on the Peripheral Nervous System and Reflex Activity.

Peripheral Nervous System (PNS)

All neural structures outside of the brain and spinal cord.

Sensory Receptors

Neurons specialized to respond to changes in the body’s environment.

Mechanoreceptors

Sensory receptors that respond to mechanical forces.

Thermoreceptors

Sensory receptors that respond to changes in temperature.

Photoreceptors

Sensory receptors that respond to light.

Chemoreceptors

Sensory receptors that respond to chemical stimuli.

Nociceptors

Sensory receptors that respond to pain.

Epineurium

Connective tissue that surrounds and protects the entire nerve.

Perineurium

Connective tissue that surrounds bundles of nerve fibers called fasicles.

Endoneurium

Connective tissue that surrounds individual nerve fibers.

Ganglia

Collections of neuron cell bodies associated with nerves in the PNS.

Cranial Nerves

Twelve pairs of nerves associated with the brain.

Olfactory Nerve (I)

Sensory nerve carrying impulses for smell to the brain.

Optic Nerve (II)

Sensory nerve carrying impulses for vision to the brain.

Oculomotor Nerve (III)

Motor nerve controlling extrinsic eye muscles and pupil size.

Trochlear Nerve (IV)

Motor nerve controlling the superior oblique muscle of the eye.

Trigeminal Nerve (V)

Mixed nerve carrying sensory impulses for touch and motor impulses for mastication.

Abducens Nerve (VI)

Primarily motor nerve controlling the lateral rectus muscle of the eye.

Facial Nerve (VII)

Mixed nerve controlling muscles of the face and carrying sensory input from the face.

Vestibulocochlear Nerve (VIII)

Sensory nerve carrying impulses for hearing and equilibrium.

Glossopharyngeal Nerve (IX)

Mixed nerve carrying sensory and motor inputs related to the pharynx and tongue.

Vagus Nerve (X)

Mixed nerve affecting internal organs and muscles of the larynx and pharynx.

Accessory Nerve (XI)

Primarily motor nerve carrying impulses to neck and larynx muscles.

Hypoglossal Nerve (XII)

Primarily motor nerve controlling tongue movement.

Spinal Nerves

Thirty-one pairs of mixed nerves arising from the spinal cord.

Reflex

A rapid, predictable motor response to a stimulus.

Somatic Reflexes

Reflexes involving skeletal muscle contractions.

Autonomic Reflexes

Reflexes involving smooth muscle, cardiac muscle, and gland activity.

Reflex Arc

The pathway traveled by reflexes in the body.

Receptor

The site of stimulus action in a reflex arc.

Sensory Neuron

Neuron that detects stimulation and sends impulses to the spinal cord and brain.

Integration Center

Part of the reflex arc where decisions about the reflex are made.

Motor Neuron

Neurons that conduct impulses from the integrating center to muscles and glands.

Effector

The muscle or gland that responds to impulses from the motor neuron.

Patellar Reflex

Reflex indicator of nerve damage in the mid-lumbar region involving knee extension.

Achilles Reflex

Reflex involving extension of the big toe, may be absent in diabetics.

Babinski Sign

Reflex involving extension of the great toe and fanning of the other toes.

Analgesia

Reduced ability to feel pain; associated with pain-relieving drugs called analgesics.

Neuralgia

Pain along the course of one or more nerves, often due to inflammation.

Neuritis

Inflammation of a nerve.

Sensation

Awareness of external or internal stimuli.

Stimulus

A change in the environment that can activate sensory neurons.

Transduction

The conversion of a stimulus into an impulse by sensory neurons.

Conduction

The movement of an impulse from the body to the central nervous system (CNS).

Integration

The conversion of an impulse into a sensation, occurring in the brain.

Exteroceptors

Sensory neurons that respond to external stimuli.

Interoceptors

Sensory neurons that respond to internal stimuli.

Somatic Senses

General senses associated with the skin and body.

Special Senses

Senses that include taste, smell, sight, hearing, and balance.