Lecture 20: Spinal Cord Flashcards
Describe the organization and cross-sectional anatomy of the spinal cord w/ regard to distribution of gray and white matter, columns, and horns.
Gray: sympathetic
forms regions known as HORNS, = CNS nuclei. Posterior (dorsal) horns: receive incoming sensory fibers.
Anterior (ventral) horns: site of cell bodies alpha motor neurons to skeletal muscle fibers.
LAteral horns: thoracic/lumbar regions only. Site of cell bodies of ANS motor neurons.
White:
Forms longitudinal columns (funiculi). Consists of myelinated tracts. posterior (dorsal). Lateral columns..
Commisures: cross from one side CNS to the other
White=anterior/posterior
Gray=anterior/posterior
Relate the organization of the spinal cord gray and white matter to sensory and motor pathways.
Gray:
Dorsal (posterior) horns are entry for incoming sensory neurons.
Ventral (anterior) horns: mark the exit of motor neurons
White:
dorsal columns carry myelinated fibers up spinal cord to the brain [afferent/sensory tracts]
Lateral columns: Carry both sensory/motor tracts
Ventral (anterior) columns: mostly motor tracts
List in order the meninges and spaces that surround the spinal cord
Inside ->out
- denticulate ligaments
1. Pia mater-covers spinal cord - subarachnoid space
2. Arachnoid - subdural space
3. Dura
4. Epidural space*different from brain
Explain the development of the cauda equina
Spinal cord nerves begin to grow outward horizontally. Spinal cord doesnt grow inferior as far as vertebral column thus the nerves must grow inferior as well to reach below the end of the spinal cord.
Slide 10
Describe the vertebral column ligaments and r.t them the spinal cord
Anterior longitudinal ligament and Posterior longitudinal ligament Help to reinforce the annulus and help keep disc from bulging out anterior/posterior. But there’s isn’t one to the side. So it usually bulges to the side.
Supraspinous ligament, interspinous ligament, and Ligamentum flavum must be passed through for LP
Describe the basic structure of a spinal nerve and r/t motor and sensory pathways and ganglia
Slide 14
Discriminate btw the dorsal and ventral rami of the spinal nerves
Dorsal: carries sensory fibers into spinal cord /columns-brain-epaxial musculature.
Ventral rami: carry motor fibers from spinal cords. Hypaxial musculature.
W/in spinal cords=columns
W/in Brain: masses of gray matter-nuclei
Distinguish btw the origins of the sympathetic and parasympathetic systems
Autonomic NS:
-depends on sensory input from viscera. Visceral motor system. Subconsciously.
Sympathetic (thoracolumbar)and
Parasympathetic (craniosacral)
Differentiate btw preganglionic and postganglionic neurons
Preganglion: 1st neuron originates in CNS either the brain or spinal cord. Cell bodies are located either in gray matter of the spinal cord or specific nuclei in the brain.
Postganglionic: peripheral ganglia. NEVER myelinated. Terminate in smooth muscle of viscera.
Relate the gray and white rami to autonomic pathways and distinguish among the types of ganglia
.SLide 24?
Describe each of the twelve traditional cranial nerves and know their number, modalities, and functions.
Traditional pattern:
Additional nerves: 0
I Olfactory
II Optic
III Oculomotor
IV Trochlear
V Trigeminal
VI Abducens
VII Facial
VIII Vestibulocochlear
IX Glossopharyngeal
X Vagus
XI Spinal accessory
XII Hypoglossal
Realistically about 25 cranial nerves though.
Compare cranial nerves that have only motor function, only sensory function, and mixed function.
Special sensory-SSS: special senses derived from ectoderm; sight, sound, balance.
Special viasceral sensory-SVS: special senses endoderm; taste
Special visceral motor-SVM: muscles derived from pharyngeal arches
GHeneral Visceral sensory-GCS: general sensation from viscera
General visceral motor-GVM: to smooth muscle of gut tract. Autonomic motor
General somatic sensory-GSS: general senses from ectoderm
General somatic motor-GSM: skeletal muscles
Explain why cranial nerves I and II are not typical.
CN I: olfactory through cribiform plate to olfactory bulbs-SVS;
CNII: begins in ganglionic layer of retina. 50% decussation in optic chiasma in mammals but complete decussation in most other vertebrates.
SSS modality; ectoderm
Know which cranial nerves have parasympathetic function and trace the pathways of the preganglionic and postganglionic neurons and identify the nuclei and ganglia involved.
PArasympathetic:
3,7,9,10
Oculomotor, facial, glossopharyngeal, vagus
