Exercise 17: Histology of Nervous Tissue
THE BASIC FUNCTIONAL UNIT OF THE NERVOUS SYSTEM IS THE NEURON. WHAT IS THE MAJOR FUNCTION OF THIS CELL TYPE?
TO TRANSMIT AND GENERATE MESSAGES (NERVE IMPULSES) FROM ONE PART OF THE BODY TO ANOTHER.
NAME FOUR TYPES OF NEUROGLIA IN THE CNS, AND LIST A FUNCTION FOR EACH OF THESE CELLS.
1. ASTROCYTES, HELPS REGULATE THE EXTRACELLULAR COMPOSITION OF BRAIN FLUID.
2. EPENDYMAL CELLS, SECRETES CEREBROSPINAL FLUID & HELPS MOVE CEREBROSPINAL FLUID IN BRAIN AND SPINAL CORD.
3. MICROGLIA, ARE PHAGOCYTIC CELLS IN THE CENTRAL NERVOUS SYSTEM (CNS)
4. OLIGODENDROCYTES, FORM PART OF THE MYELIN SHEATHS OF AXONS WITHIN THE CNS.
NAME THE PNS GLIAL CELL THAT FORMS MYELIN.
SCHWANN CELLS
NAME THE PNS GLIAL CELL THAT SURROUNDS DORSAL ROOT GANGLION NEURONS.
SATELLITE CELLS
THE BRAIN AND SPINAL CORD COLLECTIVELY
CENTRAL NERVOUS SYSTEM
SPECIALIZED SUPPORTING CELLS IN THE CNS
NEUROGLIA
JUNCTION OR POINT OF CLOSE CONTACT BETWEEN NEURONS
SYNAPSE
A BUNDLE OF NERVE PROCESSES INSIDE THE CNS
NERVE
NEURON SERVING AS PART OF THE CONDUCTION PATHWAY BETWEEN SENSORY AND MOTOR NEURONS
INTERNEURON
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GANGLIA AND SPINAL AND CRANIAL NERVES
TRACT
COLLECTION OF NERVE CELL BODIES FOUND OUTSIDE THE CNS
GANGLION
NEURON THAT CONDUCTS IMPULSES AWAY FROM THE CNS TO MUSCLES AND GLANDS
EFFERENT NEURON
NEURON THAT CONDUCTS IMPULSES TOWARD THE CNS FROM THE BODY PERIPHERY
AFFERENT NEURON
CHEMICALS RELEASED BY NEURONS THAT STIMULATE OR INHIBIT OTHER NEURONS OR EFFECTORS
NEUROTRANSMITTERS
REGION OF THE CELL BODY FROM WHICH THE AXON ORIGINATES
AXON HILLOCK
SECRETES NEUROTRANSMITTERS
AXON TERMINAL
RECEPTIVE REGION OF A NEURON
DENDRITE
INSULATES THE NERVE FIBERS
MYELIN SHEATH
SITE OF THE NUCLEUS AND MOST IMPORTANT METABOLIC AREA
NEURONAL CELL BODY
MAY BE INVOLVED IN THE TRANSPORT OF SUBSTANCES WITHIN THE NEURON
NEUROFIBRIL
ESSENTIALLY ROUGH ENDOPLASMIC RETICULUM, IMPORTANT METABOLICALLY
NISSL BODIES
IMPULSE GENERATOR AND TRANSMITTER
AXON
DRAW A "TYPICAL" MULTIPOLAR NEURON. INCLUDE ANDD LABEL THE FOLLOWING STRUCTURES ON YOUR DIAGRAM: CELL BODY, NUCLEUS, NUCLEOLUS, nISSL bODIES, DENDRITES, AXON, AXON COLLATERAL BRANCH, MYELIN SHEATH, NODES OF RANVIER, AXON TERMINALS, AND NEUROFIBRILS.
WHAT SUBSTANCE IS FOUND IN SYNAPTIC VESICLES OF THE AXON TERMINAL?
NEUROTRANSMITTER
WHAT ROLE DOES THIS SUBSTANCE PLAY IN NEUROTRANSMISSION? (NEUROTRANSMITTER)
IT DIFFUSES ACROSS THE SYNAPTIC CLEFT TO BIND TO MEMBRANE RECEPTORS ON THE NEXT NEURON; INITIATING AN ELECTRICAL CURRENT (SYNAPTIC POTENTIAL).
WHAT ANATOMICAL CHARACTERISTIC DETERMINES WHETHER A PARTICULAR NEURON IS CLASSIFIED AS UNIPOLAR, BIPOLAR, AND MULTIPOLAR?
THEIR DIFFERENTIATED ACCORDING TO THE NUMBER OF PROCESSES ATTACHED TO THE CELL BODY.
MAKE A SIMPLE LINE DRAWING OF EACH TYPE:
UNIPOLAR, BIPOLAR, OR MULTIPOLAR
CORRECTLY IDENTIFY THE SENSORY (AFFERENT) NEURON, INTERNEURON (ASSOCIATION NEURON), AND MOTOR (EFFERENT) NEURON IN THE FIGURE.
WHICH OF THESE NEURON TYPES IS/ARE UNIPOLAR?
SENSORY (AFFERENT) NEURON
WHICH IS/ARE MOST LIKELY MULTIPOLAR?
INTERNEURON (ASSOCIATION NEURON)
DESCRIBE HOW THE SCHWANN CELLS FROM THE MYELIN SHEATH AND THE NEURILEMMA ENCASING THE NERVE PROCESSES.
SCHWANN CELLS WRAP THEMSELVES TIGHTLY AROUND THE AXON IN A JELLYROLL FASHION; AND THE NEURILEMMA IS A EXPOSED PLASMA MEMBRANE, HAS MANY SCHWANN CELLS AND IS A DISCONTINOUS SHEATH.
WHAT IS A NERVE?
A NERVE IS A BUNDLE OF NEURON FIBERS (AXONS) WRAPPED IN CONNECTIVE TISSUE COVERING THAT EXTENDS TO AND FROM THE CNS AND VISCERAL ORGANS OR STRUCTURES OF THE BODY PERIPHERY.
STATE THE LOCATION OF EACH OF THE FOLLOWING CONNECTIVE TISSUE COVERINGS.
ENDONEURIUM, PERINEURIUM, EPINEURIUM
ENDONEURIUM - INNER MOST LAYER, AN ADDITIONAL SHEATH THAT SURROUNDS THE MYELIN SHEATH.
PERINEURIUM - MIDDLE LAYER, BOUNDS GROUPS OF FIBERS, FORMS BUNDLES OF FIBERS.
EPINEURIUM - OUTER MOST LAYER, BOUNDS FASCICLES TOGETHER, FORMS THE CORDLIKE NERVE.
WHAT IS THE FUNCTION OF THE CONNECTIVE TISSUE WRAPPINGS FOUND IN A NERVE?
TO INSULATE FROM OTHER PROCESSES AND TO BIND AND FORM BUNDLES, AND TO PROTECT.
DEFINE MIXED NERVE
A NERVE CARRYING BOTH SENSORY (AFFERENT) AND MOTOR (EFFERENT) FIBERS. MOST NERVES OF THE BODY, INCLUDING ALL SPINAL NERVES ARE MIXED NERVES.
IDENTIFY ALL INDICATED PARTS OF THE NERVE SECTION.