Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Med Neuro Lect9
Med Neuro Lect9 Spinal Cord Anatomy
| Question | Answer |
|---|---|
| Afferent spinal cord systems | 1.Spinal Nerve. 2.Dorsal Root. 3.Dorsal Root Entry Zone (DREZ) |
| 2 divisions of DREZ | 1.Medial Division (large myelinated fibers). 2.Lateral Division (small unmyelinated fibers). |
| Which Horn in the spinal cord is Sensory? Motor? | SENSORY: Dorsal. MOTOR: Ventral. |
| Is there a difference between the Dorsal/Ventral Roots and Rami? | YES, the rami contain both motor and sensory fibers. **Ventral rami is much larger than dorsal rami b/c it innervates more. |
| What is contained within the Dorsal Rootlets? | Axons from the DRG which either synapse in the dorsal horn at that segmental level, ascend upwards to the brainstem, or synapse on interneurons. |
| Medial DREZ: 3 different fibers making up the large fiber (heavey myelination) system | 1.Group Ia: Muscle spindles. 2.Group Ib: Golgi tendons 3.Group II: Cutaneous touch receptors. **1&2 are proprioceptive, 3 is light touch. **Test via vibration sense |
| Lateral DREZ: 2 different fibers making up the small fiber system | 1.Group III (minimal myelin): Introception. 2.Group IV (no myelin) |
| Which has the lower threshold of activation? (requires less energy) | LARGE fibers (rapid conductors). **small fibers are usually activated only when something is irritating tissue |
| What is another name for small fiber systems? | Nocioceptive systems (pain, irritation). |
| how do large and small fibers differ in terms of synapse within the spinal cord? | LARGE: enter spinal cord and travel up to medulla. SMALL: innervate dorsal horn intermediate neurons which then carry the signal up to the medulla. |
| Laminae located in the Dorsal horn (move laterally to medially) | Laminae 1-VI: I.Marginal Nucleus (projecting to thalamus): Sharpe cutaneous pain, cuts. II.Substantia Jelatinosa. III. IV. Nucleus Proprious (proper nucleus of the spinal cord). V. VI. **I-IV small nocio neurons. III & IV synapse on large or sma |
| Laminae located in the Intermediate zone | Laminae VII: coordinates large alpha motor neurons **found all throughout majority of the ventral horn. |
| Laminae located in the Ventral horn | VIII. Medial. IX. Innervates axial muscles along the spinal column (All throughout ventral horn, including more medial than VIII). X. found in the middle of the spinal cord. |
| Somatotropic organization: Where in the ventral horn will you find the neurons for the axial muscles? Appendicular muscles? | AXIAL: Medial. APPENDICULAR: Lateral. |
| Somatotropic organization of spinal cord from medial to lateral in the ventral horn? in terms of flexors and extensors? | 1.(most medial) Trunk. 2.Shoulder. 3.Arm. 4.Forearm. 5.(most lateral) Hand. **Flexors are Posterior Ventral horn in each section, Extensors are Anterior Ventral horn. |
| Pathway of somatic efferents from the spinal cord to the target? | 1.Ventral horn. 2.Ventral root. 3.Spinal Nerve. 4.Motor end plate. 5.Skeletal muscle. |
| Knowing ACh is released at the neuromuscular junction, does the muscle send anything back to the alpha motor neuron? | YES, protein communication. **Muscle will also recieve growth factors from neuron. |
| What should you see in patients with a LOWER motor neuron lesion? What are the 5 main characteristics of this? | FLACCID WEAKNES: 1.Weakness. 2.Hypotonia. 3.Hyporeflexia. 4.Fasciculations (dying motor neur releases ACh packets). 5.Atrophy & wasting (Muscle isnt getting growth factors from dying neuron). |
| What is a Fasciculation? Can they be healthy? | A muscle movement that doesn't move the endpoints of the muscle (ripples under the skin) due to dying neurons releasing ACh packets onto end plate. **Can be normal in very active person. |
| What is the best test for diagnosing Flacid weakness and thus a LOWER motor neuron lesion? | No muscle resistance with Passive ROM |
| What could cause Flacid muscle weakness and lower motor neuron weakness? | 1.Diabetes I & II. 2.Polio. 3.ALS (and other degenerative diseases). |
| What is Spasticity an indicator of? | UPPER motor neuron (corticospinal) loss. **Reflex arch will still be intact to hyperreflexia will be seen with alternating antagonist contractions (back and forth). |
| Origin, decussation point, and target of the lateral corticospinal tract | 1.Origin: Motor Cortex (Pre-central gyrus). 2.Dec: Caudal Medulla. 3.Target: Lateral ventral horn (large motor neurons and interneurons). **Provides us with dexterity and FINE motor control. |
| Where will paralysis occur if the Lateral corticospinal tract is transected BELOW the decussation? ABOVE? | **Decussation at Caudal Medulla. BELOW: IPSIlateral side. ABOVE: CONTRAlateral side. |
| 2 divisions of the Dorsal Column system (ascending systems in the dorsal horn) | 1.Fasciculus Gracilis (lower extremity: S2 most medial, T5 most lateral). 2.Fasciculus Cuneatus (Thorax & upper extremity, T6 most medial, C5 most lateral). **Transmitts info from cutaneous receptors to brain at high speeds |
| 2 divisions of the Anterolateral System | 1.Spinothalamic tract (spinal cord to thalamus). 2.Spinoreticular tract (spinal cord to reticular). **Warning/homeostatic signals to adjust ANS. |
| Origin, Primary & secondary cells bodies, Decussation, and target of Drosal Column System | 1.Origin (Input): Group II afferents (rapid). 2.Primary Cell body: Ipsilateral DRG. 3.Secondary Cell body: Ipsilateral Nucleus Gracilis & cuneatus. 4.Dec: Internal arcuate fibers of caudal medulla. 5.Target: Ventroposterior lateral nucleus oth thalam |
| Where will sensory info from the left hand end up in the brain? What will you lose if dorsal nuclei in the spinal cord is damaged from a stroke? | will reach the nuc cuneatus via lateral aspect of fasciculus cuneatus, decussate via internal arcuate fibers of the caudal medulla & reach the lateral aspect of the Post-central gyrus on the RIGHT side. **Loss of discrimitive touch in IPSIlat side |
| Origin, Primary & secondary cell body, decussation, and target of the Anterolateral System? | 1.Origin/Input: Group III & IV afferent fibers. 2.Primary cell body: IPSIlateral DRG. 3.Secondary Cell body: IPSIlateral Dorsal Horn. 4.Dec: Anterior White commissure. 5.Target: Ventroposterior & posterior thalamic nuclei. **Homeostatic info (pain, h |
| At what of the anterior white commisure does the Anterolateral system decussate? | AT that SAME spinal segmental level. |
| Ascending up the AL system, where will the lower extremity be located? Upper extremity? | LOWER: Lateral. UPPER: Medial. |
| Where will pain/heat (assesed via pin prick) be lost if the Dorsal horn is damaged? | The IPSIlateral side at that spinal segement. |
| Where will pain/heat (assesed via pin prick) be lost in the ALS column is damaged? | the CONTRAlateral side at that spinal segment AND BELOW!! |
| Which side do the do sensory tracts represent below the medulla (within spinal cord)? Above the medulla? | BELOW: 1.Dorsal column: ISPI. 2.ALS column: CONTRA. ABOVE: 1.Dorsal column: CONTRA. 2.ALS column: CONTRA. |
| Analgesia | Loss of pain sensation to noxious stimuli. **Tested with Pin Prick. Seen if the ALS column or dorsal horn is damaged (Anterolateral system). |
| What would vibrations be testing? | Sensory (not noxious). DORSAL COLUMN SYSTEM. |
| How would a patient present if the midline of the spinal column is damaged? How could this occur? | 1.Bilateral Analgesia over damaged segments. **could occur if cut, Sarynx/cyst post tramatically, or from an infarction of the ANterior Spinal Artery. |
| What all will an Infarct in the Anterior Spinal Artery affect? | 1.Motor (ventral horn). 2.ALS (noxious stimuli). **Dorsal Column (sensory) and dorsal horn will still be ok. |
| Sensory Dissociation | Sensory loss (dorsal column) on one side, Analgesia (ALS column) on the other side. |
| What is Spasticity (Spastic motor weakness) a sign of? what are the 4 main symptoms? | UPPER motor neuron lesion: 1.Weakness. 2.Hyperreflexia. 3.Hypertonia. 4.RESISTANCE TO PASSIVE ROM!! (Vel dependent in that there will be Inc resistance with Inc ROM speed). **Alpha motor neurons are still INTACT. |
| Spinal Shock will have what affect on the alpha motor neurons? | 1.Loss of descending control. 2.hyperpolarization of ventral horn cells. 3.Flaccid weakness(hypotonia & reflexia) break throuh clonus. 4. 2 weeks but then become hypertonic with a higher resting Em. |
Created by:
WeeG
Popular Neuroscience sets