Peripheral Nervous System and Sensory Receptors

These flashcards cover key concepts related to the organization of the peripheral nervous system and the function of sensory receptors.

Spinal Nerve Organization

Refers to the structure of spinal nerves, where motor axons originate from the spinal nerve, exiting via the ventral root, and sensory axons enter via the dorsal aspect.

Dorsal Root Ganglion

A collection of neuron cell bodies in the dorsal root of a spinal nerve, housing the cell bodies of sensory neurons.

Rami Communicans

Branches of spinal nerves associated with the autonomic nervous system, connecting the spinal nerve to sympathetic ganglia.

Dermatome

An area of skin supplied with sensory innervation by a pair of spinal nerves.

Myotome

A group of muscles that a specific spinal nerve innervates.

Nerve Plexus

Network formed by the intertwining of anterior rami of spinal nerves, combining several nerves to innervate the same body part.

Cervical Plexus

Formed by the anterior rami of spinal nerves C1-C4, innervating structures in the neck.

Brachial Plexus

Complex network of nerves formed from the anterior rami of C5-T1, responsible for innervating the upper limb.

Mono- vs. Polysynaptic Reflexes

Monosynaptic reflexes contain one synapse between receptor and effector, while polysynaptic reflexes involve one or more interneurons.

Autonomic Reflexes

Visceral reflexes involving reactions of the body to stimuli, regulated by the autonomic nervous system.

Receptive Field

The area through which a stimulus is detected by a sensory receptor, inversely correlating with receptor density.

Tonic Receptors

Sensory receptors that respond continuously to stimuli at a constant rate.

Phasic Receptors

Sensory receptors that detect changes in stimulus intensity and adapt rapidly to sustained stimuli.

General vs. Special Senses

General senses are usually simpler sensory receptors like touch, while special senses have complex structures like the eyes and ears.

Exteroceptors

Receptors that detect stimuli from external sources; found at or near body surfaces.

Interoceptors

Receptors that detect stimuli from internal organs, including changes within visceral organs.

Phototransduction

The process by which photoreceptors convert light energy into nerve signals.

Color Perception

Depends on the stimulation of different cone types in response to various wavelengths of light.

Convergence and Acuity

Acuity varies with the degree of convergence; lower convergence yields higher acuity.

Rods and Cones

Two types of photoreceptors in the retina; rods are sensitive to dim light, cones are responsible for color vision.