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Nervous Tissue I: Functional Organization, Spinal Cord and Spinal Nerves. Lecture 12. Nervous Tissue. Found in brain, spinal cord and nerves Property Ability to produce action potentials (electric signals) Cells Nerve cells or neurons Neuroglia or support cells - PowerPoint PPT Presentation
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Nervous Tissue I:Functional Organization, Spinal
Cord and Spinal Nerves
Lecture 12
11-2
Nervous Tissue
• Found in brain, spinal cord and nerves• Property
– Ability to produce action potentials (electric signals)
• Cells– Nerve cells or neurons– Neuroglia or support cells
– Oligodendrocytes and Schwann cells
11-3
The Nervous System
• Subdivisions– Central nervous system (CNS)– Peripheral nervous system (PNS)
• Sensory receptor– Receptor of sensory information
• Nerve– Made up of a bundle of axons
• Ganglion– Collection of cell bodies of neurons
• Plexus– Network of spinal nerves
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Central Nervous System• Consists of
– Brain• Located in cranial
vault of skull– Spinal cord
• Located in vertebral canal
• Brain and spinal cord– Continuous with each
other at foramen magnum
• TractFig. 14.1
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Peripheral Nervous System• Two subcategories
– Sensory or afferent– Motor or efferent
• Divisions– Somatic nervous
system– Autonomic nervous
system (ANS)» Sympathetic (fight or flight)» Parasympathetic (rest and digest)
Fig. 14.2
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Spinal Cord• Extends from foramen
magnum to second lumbar vertebra
• Segmented– Cervical – Thoracic– Lumbar– Sacral
• Gives rise to 31 pairs of spinal nerves
• Not uniform in diameter throughout length
Fig. 16.1
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Meninges• Connective tissue
membranes surrounding spinal cord and brain– Dura mater– Arachnoid mater– Pia mater
• Spaces– Epidural: Anesthesia
injected– Subdural: Serous fluid– Subarachnoid:
cerebrospinal fluid (CSF)
Fig. 16.2
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Cross Section of Spinal Cord• White matter
– Myelinated axons forming tracts
– Three funiculi (columns)
• Gray matter– Neuron cell bodies,
dendrites, axons– Three horns
Fig. 16.3
Fig. 16.4
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Spinal NervesCervical Plexus
• C1-C4• Phrenic nerve
– from C3-C5 (cervical and brachial plexus)
– innervates diaphragm
Fig. 16.8
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Brachial Plexus• C5-T1• Major nerves
– Radial– Ulnar– Median
Fig. 16.9
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Lumbar Plexus
Fig. 16.10
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Sacral Plexus
Fig. 16.11
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Review Question
Compression of the ________ nerve against the medial epicondyle of the humerus will produce strong tingling sensations along the forearm and hand.
(a) Radial(b)Median(c) Phrenic(d)Femoral(e) Ulnar
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Points to Remember• Nervous system consists of central nervous system
(brain and spinal cord) and peripheral nervous system (all nervous tissue outside of central nervous system)
• Sensory (afferent) neurons carry sensory information to brain and spinal cord
• Motor (efferent) neurons carry motor away from brain and spinal cord to spinal nerves and cranial nerves
• Spinal nerves have a dorsal root (sensory neurons) and a ventral root (motor neurons)
• Names of nerves in plexuses generally describe the body region they travel
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Questions?