Study sets, textbooks, questions
Upgrade to remove ads
NSCI 225 Lecture 4
Terms in this set (55)
Cluster of cells in the CNS
Clusters of cells in the PNS
Wrapped in connective tissue
Group of Axons in the CNS
Named fiber bundles
Group of Axons in the PNS
Wrapped in connective tissue
What is the PNS supported by?
What holds the CNS together?
The growth and differentiation of the neural plate leads to the formation of which two cell population?
Which embryological cell population develops into the CNS?
Which embryological cell population develops into the PNS? How?
The neural crest cells migrate away from the neural tube to populate structures in the periphery.
What are some major neuronal populations in the periphery?
Enteric nervous system of the gut
Cells of the adrenal medulla
Cell clusters called peripheral ganglia
What are the three major sections of the spinal cord (starting from the top to the bottom)?
Describe the embryonic development of the spinal cord. Which two neuron populations develop and which is the groove in the lateral wall of the neural tube dividing these two population?
The SULCUS LIMITANS= delineates the alar plate from the basal plate.
Cells within the neural tube divide in the ventricular zone, then migrate away from the ventricle within the wall.
In the spinal cord, two populations develop:
those in the dorsal ALAR PLATE
those in the ventral BASAL PLATE
Processes sensory information from neurons that have cell bodies in the dorsal root ganglia
Where are the right and left dorsal horns of the spinal cord derived from?
Where are the right and left ventral horns of the spinal cord derived from?
Describe any changes in the central canal during embryonic development of the spinal cord...
The central canal does not enlarge.
What are the dorsal and ventral horns made of?
gray matter (soma)
How do you tell which are the dorsal horns and which are the ventral horns?
The DORSAL HORNS appear to reach the pia.
How are axons in the white matter of the spinal cord arranged?
They are organized into groups (Fasciculi)
The axons in one fasciculus/tract carry information. Each tract is EITHER sensory or motor-- never mixed!
Describe the overall size (cross-sectional) of the spinal cord from cervical to sacral levels.
The overall size decreases.
Describe the volume of white matter of the spinal cord from cervical to sacral levels.
The volume of white matter decreases.
Describe the shape and volume of the gray matter at each level of the spinal cord.
The shape of the gray matter changes at each level
Greatest volumes of dorsal and ventral horn are in the areas of limb attachment.
Marginal Zone (1)
Substantia Gelatinosa (2-3)
Nucleus Proprius (4-5)
Column of Clarke (7)
Intermediolateral Cell Column (7)
Motor Neurons (9)
Do all sensory axons synapse on neurons in the dorsal horns?
No, some sensory axons coming in through the dorsal root ascend directly to the brainstem.
Other sensory axons synapse DO synapse on neurons in the dorsal horn, which relay the info up the spinal cord to the brain.
Note! Different lamina in the gray matter are related to different functional systems.
Three spinal somatosensory pathways:
2. Dorsal Column/ Medial Lemniscal
3. Anteriolateral (spinothalamic)
Spinocerebellar Pathway (axons)
Spinocerebellar Pathway (functions)
Dorsal Column / Medial Lemniscal System (axons)
Dorsal Column / Medial Lemniscal System (functons)
Fine touch ******
Vibration sense *******
Anterolateral System (spinothalamic)
How are neurons classified in the PNS?
1. Sensory neuron
2. Motor neuron
The cell body is located outside the CNS.
Soma has no dendrites because information is collected and integrated at the receptor, not at the soma.
How are sensory neurons classified?
1. Somatic (skin/ muscle)
2. Visceral (organ)
What type of neuron cell body has many dendrites?
Where is the cell body of a motor neuron located?
In an area of gray matter within the CNS.
How are motor neurons classified?
1. Somatic (muscle)
2. Autonomic ( smooth muscle, cardiac muscle, gland cell)
A chain of TWO NEURONS gets the info from the CNS to target cells within the organ.
What holds the bundles of axons in a peripheral nerve together?
Connective tissue (collagen).
Three types of peripheral nerves:
1. Motor nerve (muscle)
2. Cutaneous nerve (skin)
3. Splanchnic nerve (organ)
What's the difference between a motor axon + a sensory axon?
generated at different locations
info flows in opposite directions
Where are action potentials generated in motor neurons + sensory neurons?
Sensory= nerve ending in PNS
Motor= cell body in the CNS
What is myelin?
A lipid coating around axons in both CNS and PNS produced by the glial cell wrapping its membrane around the axon.
myelinates axons of the PNS
surrounds nodes of ranvier and synapses
lays down a basal lamina
How many axons does a PNS Schwann cell myelinate?
How many axons does CNS oligodendrocyte myelinate?
One neuron may have part of its axon myelinated by oligodendrocytes, part by Schwann cells.
What are the specific tissue coverings that organize axons in a peripheral nerve?
Name three structures/spaces at the bottom of the spinal cord.
Why is the tap usually performed at the L3/L4 or L4/L5 level?
The CSF can be accessed most safely in the lumbar cistern. Below L1/L2 the spinal cord terminates. The loose fibers of the cauda equina move out of the way of the needle without being damaged.
What is the strand of pia mater that attaches to the bottom of the dural sac called?
What is a plexus?
Rami combine to form a plexus.
Nerves branching from the plexus then distribute to muscles and skin.
Formed from ventral rami from L2-S3
Innervates muscles and skin of the LOWER LIMBS
Formed from ventral rami C5-T1
Innervates muscles and skin of the UPPER LIMBS
Recommended textbook explanations
Essentials of Human Anatomy and Physiology
Elaine N. Marieb, Suzanne M. Keller
Hole's Essentials of Human Anatomy & Physiology
David N. Shier, Jackie L. Butler, Ricki Lewis
Essentials of Human Anatomy & Physiology (NASTA EDITION)
Elaine Marieb, Suzanne Keller
Seeley's Anatomy & Physiology
Andrew Russo, Cinnamon VanPutte, Jennifer Regan
Sets with similar terms
Chapter 14 for final
IB 131 Midterm 2 - Chapter 12
Anatomy Ch 12
Ch 16 Spinal Cord and Spinal Nerves
Other sets by this creator
NSCI 225 Lecture 9
NSCI 225 Lecture 3
Biopsychology Exam 3
Other Quizlet sets
Global Pop Final
Excel 1.10-1.11 Study Guide