Spinal cord Flashcards
What receptors are non encapsulated?
Free nerve endings, merkel’s disk, and hair follicles
What receptors are encapsulated?
Meissner’s corpuscle, pcinian corpuscle, ruffini ending, joint receptor, neuromuscular spindle, golgi tendon organs
What is the function of free nerve endings?
pain/temperature, slow adapting
What is the function of merkel’s disk?
touch, slow adapting
What is the function of hair follicles?
touch, fast adapting
What is the function of meissner’s corpuscle?
2 point discrimination, fast adapting
What is the function of pacinian corpuscle?
vibration, fast adapting
What is the function of ruffini ending?
stretch, pressure, slow adapting
What is the function of joint receptor?
joint position, slow adapting
What is the function of neurmuscular spindle?
limb muscle, strength/length, slow adapting
What is the function of golgi tendon organs?
muscle tension, slow adapting
Describe the lateral division of the dorsal root afferents
thin, lightly myelinated fibers, pain and temp, light touch, visceral afferents
Describe the medial division of dorsal root afferents
thick, heavily mylenitaed fibers, 2 point touch, limb position, muscle stretch, sends collaterals to medulla
What are the spinal segments?
Cervical: 1-8 Thoracic: 1-12 Lumbar: 1-5 Sacral: 1-5 Coccygeal: 1
How far does the fetal cord extend?
to L3
What gives the denituclate ligament?
Pia matter; anchors the cord to the dura
What are the short/long pre/post ganglionic rules?
- Parasympathetics have long pre and short post
- Sympathetics have short pre and long post EXCEPT splanchnics: greater synapses in celiac, less in superior mesenteric and aortico renal, and least in renal plexus
Somites in the embryo become what?
Dermis, muscle, skeleton
What are the common dermatomal references?
C2: back of head C6: thumb and index finger T4: nipples T10: umbilicus L3: kneecap S1: lateral foot
Where does the dorsal root enter?
posterior lateral sulcus
What is the separation between gracilus and cuneatus?
posterior intermediate sulcus
Where is the anterior spinal artery?
anterior median fissure
Where does the ventral root leave?
anterior lateral sulcus
What makes up the posterior funiculus?
white matter ascending acons mostly from the dorsal column pathway
What happens in the dorsolateral fasciculus/zone of lissauer?
area where axons ascend or descend several segments
What happens at the anterior commissure?
fibers cross from one side to the other
What are the three grey matter regions in the spinal cord?
anterior horn, intermediate gray, and posterior horn
What is the substantia gelatinosa?
small compact cells that modify sensory input by synapsing on dendrites in nucleus proprius. Recieves small diamter dorsal root afferents. All cord levels
What is the nucleus proprius?
proper sensory nucleus, recieves many sensory inputs and contains main interneurons, contains tract cells that project contralaterally as the spinthalamic tract. all cord levels
What is the nucleus dorsalis?
Clark’s nucleus. C8-L3. Homologous to the lateral cuneate nucleus in the medulla. recieves muscle spindle information. projects ipsilaterally to the cerebellum as the dorsal spinocerebellar tract.
What is the intermediolateral nucleus?
Origin of preganglionic cholinergic sympathetic efferents. T1-L3. GVE
What is the intermediomedial nucleus?
recieves visceral afferents, projects to the IML, found at all spinal cord levels
What are the medial and lateral motor nuclei?
made up of large alpha motor nueorns that innervate skeletal muscle. Phrenic nucleus exists at c3-c5 in the medial n (cervical ventral horn). spinall accessory n exists at c1-6 laterally.
Where are motor nuclei largest?
in the cervical and lumbar enlargements
