Reflexes and Reaction Times

Synapse

Junction between two nerve cells

Pre-synaptic neuron

Neuron sending a signal

Post-synaptic neuron

Neuron receiving a signal

Action potential

Electrical impulse that travels down the axon of a neuron

Neurotransmitter

Chemical used to communicate between neurons

Local potential

Small electrical impulse that fades over distance

Excitatory local potential

Causes a neuron to initiate an axon potential in its axon

Inhibitory local potential

Causes a neuron to be less likely to initiate an action potential

Afferent (sensory) neurons

convey impulses towards the central nervous system from sensory receptors found throughout the body

Efferent (motor) neurons

convey impulses away form the central nervous system to a target, which can be a muscle or a gland

Interneurons

found within the central nervous system - connect afferent and efferent neurons and integrate sensory input and motor output

Reflex

very fast, involuntary response to a stimulus

Latency

refers to the amount of time that passes between the initial stimulus and the response

Muscle stretch reflex

knee-jerk response included in this; triggered when a muscle is rapidly stretched

Muscle spindles

muscle fibers with sensory neurons axon terminals wrapped around them

SAME

Sensory = Afferent ; Motor = Efferent

White matter

contains axons of neurons that are wrapped in an insulating sheath known as myelin. (myelin contains proteins and fats, so it appears white)

Grey matter

contains primarily cell bodies of the neurons of the spinal cord. They are not covered in myelin and appear darker.

Posterior/dorsal Horn

location of axon terminals of sensory neurons

Lateral horn

the location of cell bodies of neurons of the autonomic nervous system

Anterior/ventral horn

the location of cell bodies of somatic motor neurons

Posterior/dorsal Root

bundle of tons (a nerve) that travel to the posterior horn

Dorsal root ganglion

the location of the cell bodies of sensory neurons

Anterior/ventral root

bundle of axons (a nerve) that travel from the lateral and ventral horns