Lecture 2 - Peripheral Nervous System & Spinal Cord Flashcards
From medial to lateral, list the path of a spinal nerve.
Posterior/Anterior horn → root → nerve → ramus
Afferent (sensory) nerves are in the _____ portion of the spinal cord, while efferent (motor) nerves are in the _____ portion.
- posterior (dorsal)
- anterior (ventral)
List the 4 spinal nerve types.
- visceral efferent (VE) (vessels) ←ventral, lateral horns
- somatic efferent (SE) (skeletal muscles) ← ventral horn
- somatic afferent (SA) (skin) ← dorsal horn
- visceral afferent (VA) (smooth muscles) ← dorsal
3 functional components of spinal cord gray matter:
- posterior horn (SA, VA)
- lateral horn (VE)
- anterior horn (SE)
The outermost extension of the dura that covers peripheral nerves and lends them tensile strength is the _______.
epineurium
The _______ dural layer surrounding peripheral nerves is continuous with the arachnoid mater, and possesses a blood-nerve barrier.
perineurium
Individual nerve fibers are surrounded with an _______ covering.
endoneurium
Myelin forms the membrane of _____ cells, covers up to ____ cm of an axon, and increases ________ _____ of action potentials.
- glial
- 1
- conduction velocity
In the CNS, myelin is produced by _________ cells. In the PNS, it is produced by _____ cells.
- oligodenroglial
- Schwann
The region of a neuron where an axon begins is called the ______ ______. Action potential is summated here, then carried down the axon. On myelinated neurons, it jumps across sections of myelin to exposed axon regions called _______ ___ ______.
- axon hillock
- nodes of Ranvier
“Jumping” conduction of action potentials with depolarization occuring at nodes of Ranvier down an axon is called ______ ______. It can be bi-directional.
saltatory conduction
In the PNS, Schwann cells wrap _____ neuron in myelin. In the CNS, oligodendrocytes can wrap ______ neurons in myelin.
- 1
- many
Schwann cells possess a cytoplasmic-like wrapping in the myelin sheaths called a _______. Oligodendrocytes lack this.
neurilemma
The larger the diameter of a myelin sheath, the _____ the conduction velocity.
faster
- Fastest to slowest: Ia (muscle spindle), Ib (golgi tendon organ), α (lower motor neurons), Aβ (corpuscles), γ (intrafusal fibers), δ (sharp pain, cold), C fibers (heat, pain)
__________ sense taste, smell, pH, and metabolite concentrations.
chemoreceptors
_______ are retinal visual receptors for light.
photoreceptors
______ sense temperature changes.
thermoreceptors
__________ sense physical deformation, touch, muscle length/tension, and are part of auditory/vestibular receptors.
mechanoreceptors
______ sense pain.
nociceptors
Muscle spindles are types of __________, which sense position of the body in space.
proprioceptors
Visceral receptors:
Hollow organs, such as blood vessels, possess _________ to sense changes in pressure. Other visceral receptors, such as the carotid body, detect chemical changes (ex: partial pressure of O2), and are _______.
- mechanoreceptors
- chemoreceptors
Receptor Organization:
Stimuli are detected at the _______ area. Messages are then sent through the _______ area (often a cleft). Physical stimuli (such as neurotransmitters) are then converted into electrical signals, generating _____ _____ that is decipherable by the nervous system.
- receptive
- synaptic
- receptor potential
Receptor potentials (electrical signals) tell the nervous system the ______ and ______ of a stimulus.
- intensity
- duration
Information about the location of a stimulus is recorded in the ______ _______. This information is preserved via “______” patterns in the ascending sensory pathways.
Ex: can feel specific pinprick location on patch of skin
- receptive field
- wiring
