Spinal Cord, Spinal Nerves, & Reflex Arc

These flashcards cover key concepts related to the spinal cord, spinal nerves, meninges, and reflex arcs as discussed in the lecture notes.

Meninges

Membrane layers that cover and protect the brain and spinal cord.

Epidural space

The most superficial layer of the meninges.

Cervical enlargement

The part of the spinal cord that contains nerves to/from the shoulder and upper limb.

Lumbar enlargement

The part of the spinal cord that contains nerves to/from the pelvis and lower limbs.

White matter

Part of the spinal cord composed of myelinated axons, located on the exterior.

Grey matter

Part of the spinal cord composed of non-myelinated neurons, arranged into functional groups called nuclei.

Dorsal horn

Part of the grey matter that serves sensory functions for somatic and visceral inputs.

Ventral horn

Part of the grey matter that serves motor functions for somatic outputs.

Commissure

Links the two sides of the spinal cord.

Dorsal Root

Carries sensory information to the brain.

Ventral Root

Carries motor information from the brain.

Nerve Plexus

A branching network of intersecting spinal nerves.

Epineurium

Connective tissue surrounding the entire nerve.

Perineurium

Connective tissue surrounding one fascicle within a nerve.

Endoneurium

Connective tissue surrounding each individual nerve cell.

Reflex

A rapid, automatic response to a specific stimulus.

Monosynaptic reflex

A reflex involving a single synapse between a sensory neuron and a motor neuron.

Polysynaptic reflex

A reflex involving 3 or multiple synapses and interneurons.

Stretch reflex

A monosynaptic reflex that causes muscle contraction in response to stretching.

Withdrawal reflex

A polysynaptic reflex that results in muscle contraction in response to a painful stimulus.

Crossed Extensor reflex

A reflex where the interneuron causes an opposite side reaction in the body.

Tendon reflex 

polysynaptic reflex that inhibits muscle contraction when excessive tension is detected in a tendon.

Development reflex

A reflex related to the neurological changes that occur as a child grows, often involved in motor skill development.

Response reflex

visceral reflex involving internal organs, often regulating functions like digestion and heart rate.

reflex function

to maintain homeostasis 

reflex general arc

stimulus reception→ transmission→ processing→ transmission→ effector

general arc process

Receptor: gets stimuli, Transmission: sends action potential down to dorsal root, Processing: occurs by an interneuron, Transmission: action potential down axon of a motor neuron, Response of effector

Dorsal and Ventral ramus

mixed nerves that branch into gray (postganglionic) and white (preganglionic) ramus

Ganglion

a group of neuron cell bodies

Spinal nerve Gross anatomy

cylinder of neurons; emerge from the spinal column thru in the intervertebral foramen

cervical spinal nerves

are named after the bone BELOW the nerve

thoracic, lumbar, & sacral spinal nerves

are named for the bone ABOVE the nerve

membrane layers in order

Epidural space, Dura mater, Subdural space, Arachnoid, Subarachnoid space, Pia mater

Pia Mater

is stuck to surface of brain/ spinal cord

Sensory

info from receptors to spinal cord & brain

Motor

sends commands to peripheral effectors from spinal cord & brain

Lateral horn

Part of the grey matter that serves motor functions for visceral inputs