Spinal Chord Flashcards
Why are there 8 Cervical nerves by only 7 cervical vertebrae?
Nerve comes out above,
so 7th cervical vertebrae has 2 nerves C7 & C8
To what vertebrae does the fetal chord extend to?
L3
What is a denticulate ligament?
Extension of pia
Where does the greater, lesser, and least splanchnic synapse?
- Celiac ganglion
- Superior mesenteric
- Renal Plexus
What is the film terminale extension of?
PIA
What fuses to form coccygeal ligament?
Dura & Pia
What is lumbar cistern?
Subarachnoid space caudal to conus medularis
In which vertebrae is the cord mostly caudal equine?
SACRAL cord
- very little white matter
How many anterior and posterior spinal chord arteries?
3
one anterior and 2 posterior
What arteries contribute to the Circle of Willis?
- Basilar
- Posterior SPinal
- Anterior Spinal
- AICA
- SCA
Which somites form the dermis, muscle, and skeleton?
- Dermatome
- Myotome
- Scleratome
Whats a major difference between dermatomes and Peripheral Nerves?
Dermatomes is an area of skin supplied by a single spinal nerve, (dorsal ganglion)
- peripheral nerve = multiple spinal nerve roots
- 2 or more dermatomes overlapped
What are the dermatomes for the following areas?
- Back of head
- Thumb & index finger
- Nipples
- Umbilicus
- Kneecap
- Lateral Foot
- C2
- C6
- T4
- T10
- L3/L4
- S1
Which rotates medially? laterally of the following:
- Thumbs
- Big toes
- Thumb = laterally
2. Toe = Medially
Which muscles, flexors or extensors, are pre-axial? Post-axial?
pre-axial = FLEXORS
post-axial = EXTENSORS
Where does the dorsal root enter?
Posterior Lateral Sulcus
What separates 2 white bundles?
Posterior Intermediate Sulcus
between Gracilus and Cuneatus
Where is the Anterior spinal artery found?
Anterior Median FISSURE
Where is the ventral horn located?
(motor)
- Anterior Lateral Sulcus
What is another name for the zone of Lissauer?
Dorsolateral Fasciculus
-
What is a commissure? What is the largest commissure?
Connection between left & right
CORPUS CALLOSUM
Where are sympathetics located? Motor innervation? Sensory?
Sympathetics = IML Intermediate Gray
Motor - Anterior Horn
Sensory = Posterior Horn
What are spinal chord nuclei?
Group of neurons with a common function
ex: 12 only has GSE so hypoglossal nucleus
Where are GSA & GVA found (dorsal/ventral horn)…what about GVE, GSE?
GSA, GVA = DOrsal Horn
GSE, GVE = VENTRAL horn
Which is motor and which is sensory:
Alar Vs. Basal
Alar = Sensory
Basal = Motor
What modifies sensory input by synapsing in the NUCLEUS PROPRIUS?
Substantia Gelatinosa
- axons ascend/descend in Lissauer’s Tract
- similar to spinal trigeminal nucleus
- receives dorsal root afferents
What is the proper sensory nucleus that contains “tract cells” that project as the SPINOTHALAMIC tract?
Nucleus Proprius
Which tract relays pain & temp from spinal chord to thalamus? Through which nucleus?
Spinothalamic tract
- through Nucleus Proprius
- white fibers in the DORSAL HORN
Where is the nucleus prepress & Substantia Gelitinosa located?
DORSAL HORN
What is the nucleus in the IML that is “Clark’s Nucleus” and receives muscle spindle information? Where does it project?
- Nucleus Dorsalis
- Projects to the Cerebellum as DORSAL SPINOCEREBELLAR TRACT
C8- L3
Where are pre-ganglionic cholinergic sympathetic efferents found? Which vertebral Levels?
IML
- T1-L3
GVE
What is in the IMM?
- Visceral afferents
What are medial and lateral motor nuclei made up of?
alpha motor neurons for skeletal muscle
What vertebral segments are the following nuclei
- Phrenic Nucleus
- Spinal Accessory N
- C3-C5
- C1-C6
- close to midline = more AXIAL things (shoulders)
- away = more lateral –> fingers
What are the motor neurons that innervate skeletal muscle called?
Motor Neurons
Where is the phrenic nucleus found?
CERVICAL VENTRAL HORN
- C3-C5
What are the 3 non-encapsulated sensory receptors? The 6 Encapsulated?
- Free Nerve Endings
- Merkel’s DIsc
- Hair Receptors
- Meissner’s COrpuscles
- Pacinian Corpuscles
- Ruffini Endings
- Joint Receptor
- Neuromuscular SPindle
- Golgi Tendon Organs
What are the free nerve ending sensors?
SKIN
- Pain & Temp
- Skin & Viscera
- SLOW ADAPTING
What are the three types of Meckel’s Nerve ending sensors?
- TOUCH
- Distal extremities, lips, genitalia, nipples
- SLOW ADAPTING
What is Meisner’s Corpuscle? Where are they found? IS it slow or fast adapting?
connective tissue sheath of flattened epithelial cells
- foundL FINGERS, toes feet, lips, tongue, genital,s joint capsules, LIGAMENTS
RAPIDLY ADAPTING
Is Pacinian Corpuscle a fast or slow adapting nerve ending? Where is it found primarily? Is it afferent or efferent? How does it look?
FAST ADAPTING
- found: fingers, toes, soles, palms, joint capsules, mesenteries, viscera
- GUT
Sense: Light pressure, stretch, and VIBRATION
- looks like a red onion
- AFFERENT
Which nerve ending is specialized for light pressure, stretch in viscera, and VIBRATION?
Pacinian Corpuscle
What are the 6 encapsulated receptors?
- Ruffini Ending
- dermis, slow adapting to stretch+pressure - Joint Receptor
- free nerve ending
- slow adapting - Neuromuscular spindle
- muscle length - Golgi Tendon
- muscle tendon jundion & slow adapting - MEISNER’s CORPUSCLE
- PACINIAN CORPUSCLE
What receptors in muscles and joints is an important prproreceptor?
Muscle SPindle
What receptor detects muscle length that helps it maintain proper tension?
MUSCLE SPINDLE
What is the difference between the firing pattern of muscle spindles & GTO?
Spindle = MUSCLE STRETCH
GTO = ISOMETRIC CONTRACTION
What helps increase in muscle tension during isometric contraction? (change area without changing joint angle)
GTO
Where do the neurons of the SPINDLE fibers synapse? What fires once the fibers synapse?
Anterior Horn - synapses fire ALPHA MOTOR NEURONS
What needs to occur in order for the SPINDLE to fire?
Stretching of the NUCLEAR BAG
What resets the SPINDLE for the next hamstring stretch after the SPINDLE fires?
GAMMA MOTOR NEURONS
What is the sequence of events when one stretches to touch ones toes?
- Spindle stretches
- Spindle FIres
- Shortens hamstrings to resist over-stretching
- Shortens spindle
- UNRESPONSIVE STATE until
- Gamma motor neurons “RESET” the spindle (nuclear bag)
When muscle is stretched, what fires the alpha motor neurons?
Afferent SPINDLE fibers from
Where are gamma fibers and alpha motor neurons found? How is this different from the Muscle Spindle
VENTRAL HORN (Anterior horn)
muscle spindle travels through the Dorsal Root Ganglion
What are the 3 fast adapting receptors?
- Hair Follicle
- Meisner’s Corpuscle
- Pacinian Corpuscle
What is the function of the following receptors?
- Free Nerve Endings
- Merkel’s Disk
- Hair Follicle
- Meisner’s COrpuscle
- Pacinian Corpuscle
- Ruffini Ending
- Joint Receptor
- Neuromuscular Spindle
- Golgi Tendon
- Pain/temp
- Touch
- Touch
- 2 Point Discrimination (MEISNER’s corpuscle)
- Vibration (PACINIAN**)
- Stretch pressure
- Joint Position
- Limb muscle, stretch
- Muscle Tension
What receptor is responsible for 2 point discrimination?
Meisner’s Corpusle
- fast adapting
- encapsulated
What receptor is responsible for vibration?
PACINIAN
- fast adapting
- encapsulated
What two receptors are responsible for touch? Are they Encapsulated? Slow or Rapid adapting?
Merkel’s DIs & Hair follicle
NOT ENCAPSULATED
- Merkel’s = slow
- Hair follicle = FAST
What are the 3 fast adapting receptors?
- Hair follicle
- Meisner’s corpuscle
- Pacinian Corpuscle