Spinal Cord Flashcards
What is the conus medullaris?
The end of the spinal cord with a cone shape
What is the cauda equina?
Bundle of roots at the end of the spinal column
what are the denticulate ligaments?
They are formed by pia mater and separate the anterior and dorsal rootlets
What are the layers passed during a lumbar tap?
Skin
Superficial fascia
Supraspinous ligaments that can be calcified and tough to pass
Interspinous ligaments
Space between the laminaes that contain the yellow ligaments which can be calcified
Epidural space which contains fat and epidural veins
Dura mater
Arachnoid space
Subarachnoid space which contains the nerve roots and the CSF needed
Difference between CNS and PNS?
The gray matter which is a collection of nerve cell bodies is in the cortex and nucleus in the CNS while in ganglions for the PNS
White matter which is axons with glial share (myelin) are called tract or fascicle in the CNS and they are nerves in the PNS
Types of somatic sensory pathways?
Dorsal column pathway-touch vibrations, proprioreception
Spinothalamic pathway-Pain and temperature
What are the characteristics of the dorsal column pathway?
Ascending pathway made of 3 orders neurons carrying sensory information to the brain.
First order neurons gives rise to fasciculus gracilis in lower extremity and fasciculus cuneatus in upper extremity, ascend ipsilaterally to medulla and synapse with second order neuron
Second order neuron ascend contralaterally to the brainstem and synapse with third order neuron
Third order send signals to somatosensory cortex
What are the characteristics of the Spinothalamic tract?
3 neurons system
First order neuron enter the spinal cord and synapse and the tip of the dorsal horn
Second order carry the information to the thalamus contralaterally
Third order carry information to the ipsilateral primary sensory cortex
What are the characteristics of the lateral corticospinal tract?
Descending motor pathway with 2 neurons system
Carries motor information from the cortex cross over in the brainstem and Exeter the ventral horn contralaterally
Controls fine movement of ipsilateral limbs
Different types of reflex mechanisms?
Myotatic reflex
Inverse myotatic reflex
The gamma loop
What are the characteristics of myotatic reflex?
Muscle contracts when it is stretched
Monosynaptic
Example knee jerk after tendon is tapped with reflex hammer
What are the characteristics of inverse myotatic reflex?
Skeletal muscle contraction is a response to increase in tension
Protection against injury from excessive tension
What is the characteristics of the gamma loop?
Contraction of the bundles at the poles of the muscle sends a signal which causes a contraction of the entire muscle for fine adjustments in muscle activity
