Marieb Human Anatomy & Physiology - Peripheral Nervous System and Reflex Activity

These flashcards cover key terms and concepts related to the Peripheral Nervous System and Reflex Activity from Marieb's Anatomy & Physiology course.

Peripheral Nervous System (PNS)

The part of the nervous system that consists of all neural structures outside the brain and spinal cord, linking the body to the external environment.

Sensory Receptors

Specialized structures that respond to changes in the environment and trigger nerve impulses.

Mechanoreceptors

Receptors that respond to touch, pressure, vibration, and stretch.

Thermoreceptors

Receptors that are sensitive to changes in temperature.

Photoreceptors

Receptors that respond to light energy, primarily located in the retina.

Chemoreceptors

Receptors that respond to chemical stimuli, such as smell, taste, and changes in blood chemistry.

Nociceptors

Pain receptors that respond to pain-causing stimuli such as extreme heat, cold, and pressure.

Exteroceptors

Sensory receptors that respond to stimuli arising outside the body, such as skin receptors for touch and temperature.

Interceptors (Visceroceptors)

Receptors that respond to stimuli arising from within the body, typically in internal organs.

Proprioceptors

Receptors that provide information about body position and movement through sensing stretch in muscles and joints.

Simple Receptors

General sensory receptors that are modified dendritic endings of sensory neurons, found throughout the body.

Nonencapsulated Nerve Endings

Free nerve endings abundant in epithelia and connective tissues that respond mainly to temperature, pain, and light touch.

Encapsulated Dendritic Endings

Receptors generally involved in mechanoreception that are encased in connective tissue.

Stretch Reflex

A monosynaptic reflex that maintains muscle tone and prevents excessive stretching.

Flexor Reflex

A polysynaptic reflex that causes automatic withdrawal of a threatened body part.

Crossed-Extensor Reflex

A reflex that helps maintain balance by causing contraction of muscles on the opposite side of the body when one side is withdrawn.

Cranial Nerves

Twelve pairs of nerves that arise from the brain, mainly serving head and neck functions.

Spinal Nerves

Thirty-one pairs of mixed nerves that emerge from the spinal cord, supplying the body below the head.

Reflex Arc

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

Tendon Reflex

A reflex that helps prevent damage due to excessive tension in a muscle.

Babinski’s Sign

An abnormal response characterized by the dorsiflexion of the big toe and fanning of the other toes, indicative of corticospinal tract damage.