Download LAB 10 NEURON and SPINAL CORD

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THIS IS A STUDY GUIDE, NOT AN ALL INCLUSIVE REVIEW.
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THERE MIGHT BE THINGS NOT COVERED BY THIS STUDY
GUIDE THAT MIGHT BE ASKED IN YOUR QUIZZES and
PRACTICAL TESTS.
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STUDENTS ARE RESPONSIBLE FOR STUDYING THEIR
MANUAL AND FOR ALL THE MATERIAL COVERED DURING THE
LABORATORY PERIOD, AS PER THE COURSE SYLLABUS

THIS STUDY GUIDE WILL GIVE YOU A GOOD ESTIMATE OF
YOUR OVERALL READINESS FOR THE TEST AFTER YOU HAVE
COMPLETED YOUR REVIEW OF EACH SUBJECT.
Lab # 10
Nervous System
- Neural Tissue
- Spinal Cord
NEURON STRUCTURE
Histology of the Nervous Tissue
1- Neurons
2- Neuroglia or glial cells
-In the CNS
-In the PNS
Glial cell
(astrocyte)
Neurons
The glial cells are supporting cells, which are associated to the
neurons and provide a supportive scaffolding for neurons
NEURON STRUCTURE
Nucleus
Perikaryon
The Structure of
Neurons
Cell body or Soma
Telodendria
Dendrite
R.E.R.
Nissl bodies
Protein
Free
ribosomes synthesis
Axon
Axon terminal ,
synaptic terminal,
or synaptic knob
It carries the nerve impulses
Axon away form the soma.
Axon hillock
It is the trigger zone for
the nerve impulse.
Telodendria
Neurofibrils
Dendrites
They receive the nerve impulse.
They provide internal support for the
extensions and are responsible for
intracellular transport.
Axon terminal or
synaptic terminal
Synapses with another neuron and
releases the neurotransmitters.
It is the plasma
Axoplasm
It is the cytosol
of the axon.
Axolemma
Neurilemma membrane of the
Schwann cells.
It is the plasma
membrane of
the axon.
Nucleus of
Schwann cell
Schwann cell
They produce the
myelin sheath.
Myelin sheath
Nodes of
Ranvier
It is where the depolarization of
the membrane occurs during
saltatory conduction.
It electrically insulates the axon
and enables saltatory conduction.
Synapse: It is a junction that mediates information transfer
from one neuron to the next or from a neuron to an
effector cell (ex: muscle cell, gland).
Synapse from neuron
to neuron.
Neuromuscular
junction
Synapse from neuron
to effector cell.
The Synapse
The operation of the nervous system depends on the
flow of information through chains of neurons
functionally connected by synapses.
It conducts impulses
towards the synapse.
It conducts impulses
away from the synapse.
Presynaptic neuron
Postsynaptic neuron
Structural Classification of the Neurons
Locations: Brain and
special sense organs.
Functions: Poorly
understood.
Locations: Special sense organs (retina,
olfactory epithelium).
Functions: They relay
information about sight,
smell or hearing from
receptors cells to other
neurons.
Locations: Dorsal root
ganglia of spinal cord.
Functions: Most sensory
neurons of the PNS.
Locations: Anterior gray
horn of spinal cord, primary
motor cortex of the cerebrum.
Functions: Motor neurons
that control skeletal muscles.
Functional Classification of the Neurons
1- Sensory or afferent neurons
They carry information towards the Central
Nervous System.
2- Motor or efferent neurons
They carry information away from the Central
Nervous System.
3- Association neurons or Interneurons
They carry impulses between sensory and motor
neurons located at CNS.
Spinal Cord
and
Spinal Nerves
White matter
Gray matter
Gray matter
Cell bodies of neurons
and glia (no myelin). It
forms nuclei in the CNS
White matter
Myelinated fibers. It
forms tracts and
nerves in the
Peripheral Nervous
System
The Anatomical Divisions of the Nervous System
Brain
Spinal cord
Central Nervous
System (CNS)
It consists of the brain and
spinal cord enclosed by
cranium and vertebral
column.
It is responsible for integrating,
processing and coordinating sensory
data and motor commands.
Tract: It is a bundle of nerve fibers
(axons) in the CNS (white matter).
Nucleus: It is a concentration of
neuron cell bodies in the CNS
(gray mater).
Ganglia
Nerves
Peripheral Nervous
System (CNS)
It is all the nervous system
except the brain and spinal cord.
It consists of nerves and ganglia.
It deliveries sensory information to the
CNS and carries motor commands to
peripheral tissues and system.
Nerve: It is a bundle of nerve
fibers (axons) wrapped in
fibrous connective tissue.
Ganglion:It is a knot-like swelling
in a nerve where neuron cell
bodies are concentrated.
Foramen
magnum
Gross Anatomy of Spinal Cord
Cervical
enlargement
Posterior median
sulcus
Lumbar
enlargement
L1 – L2
Conus
medullaris
Cauda
equina
(Fibrous tissue that avoids
Filum
up and down movements of
terminale
spinal cord)
Spinal meninges: Dura matter, arachnoid matter, pia
matter
Dura matter
Arachnoid
Pia matter
Arachnoid
Pia matter
Dura matter
Epidural
space
(Epidural
anesthesia)
Subarachnoid space
(It is filled with CSF)
Subdural
space
Denticulate ligament
(Prevent lateral movement)
Lumbar puncture (spinal tap) is the most common means of collecting a
specimen of cerebral spinal fluid. The spinal needle is inserted, usually
between the 3rd and 4th lumbar vertebrae. Once the needle is properly
positioned in the subarachnoid space, pressures can be measured and fluid
can be collected for testing.
GRAY MATTER
ORGANIZATION
Posterior
gray horn
POSTERIOR
Posterior median
sulcus
Posterior
gray
commissure
Dorsal or
posterior root
ganglion
Somatic sensory
Visceral sensory
Lateral
gray horn
Anterior
gray horn
Dorsal or
posterior root
Visceral motor
Somatic motor
Anterior
gray
commissure
Anterior median
fissure
ANTERIOR
Spinal
nerve
Ventral or
anterior root
Somato-sensory neurons
Visceral-sensory neurons
Visceral-motor neurons
Somato-motor neurons
Cerebral
cortex
Cerebral
cortex
Thalamus Hypothalamus
SS
VS
VM
SM
Somatic sensory fiber
Somatic motor fiber
Visceral sensory fiber
Visceral motor fiber
(Autonomic Nervous System)
WHITE MATTER
ORGANIZATION
POSTERIOR
Central canal
(Contains CSF)
Posterior
white
column
Lateral
white
column
Anterior
white
column
Anterior white
commissure
ANTERIOR