Neuro Flashcards
What is the Autonomic Spinal reflex center?
- Intermediomedial nucleus (IMM)
- Intermediolateral nucleus (IML)
Found in the Lateral horn of the spinal cord (para, symp)
Lamina I
- Marginal Zone (Posteromarginal nucleus)
- Input from Lissauer’s Tract
- Pain / Temp (nociceptive)
Lamina II
- Substantia Gelatinosa (Rolando)
- Direct input from Dorsal sensory nerves
- Modulation of Pain reception
Lamina III, IV, V
- Nucleus Proprius
- Carries Sensory info
- Light touch / Pain / Temp
(V: Pain processing for Joints, Muscles, Skin)
What Laminas make up the Dorsal horn?
Laminas I to IV
Lamina V, VI
- Sensory afferent info
- Skin, Muscle, Joint (mechano-R)
Proprioception
Lamina VII
- Clark’s Column
- Proprioception (mucles)
What Laminas make up the intermediate zone?
Laminas V to VII
Lamina VIII
- Commissural Nucleus of Lenhossek
- Interneurons
- Axons cross in white commissure
Lamina IX
- Large Motor neurons (a/y)
- Somatic / Visceral Motor-N
Lamina X
Grey matter around the central canal
Protopathic Sensibility
- Crude touch
- Temperature
- Pressure
Proprioceptive Sensibility
Detection of movement & position of joints/muscles
Epicritic Sensibility
- Fine touch
- Vibration
- Two-point discrimination
Extrafusal muscle fiber
- Regular skeletal muscle fiber
- Innervated by a-Motor neuron
Intrafusal muscle fiber
- Fibers inside muscle spindles for stretch detection
- Innervated by y-Motor neuron
Proprioceptive reflex
Protects muscles from overstretch to help maintain balance
e.g: Patellar reflex
What is the receptor in Proprioception?
Muscle spindles’ intrafusal fibers have type Ia sensory neurons that wrap around the spindles
(annulospiral nerve endings)
Collateral inhibition
When a muscle in contracted that nerve also sends a signal to the inhibitory interneuron in the S.C to inhibit the antagonist muscle from opposing the action
(Antagonistic muscle pairs)
Gamma-Loop
Stimulation of y-Motor neurons causing intrafusal fibers to contract/shorten causing which activates Spinal Proprioceptive reflex causing a-Motor neuron activation and more contraction
Renshaw Cells
Prevent over-activation of a-Motor Neurons by activation of the Renshaw cell directly by the a-Motor neuron, or by Ia inhibitory interneurons.
Golgi-Tendon Organ
Sends sensory signals (from tendon overstretch) to S.C using Ib sensory neurons to Ib inhibitory interneurons to inhibit a-Motor neurons from overstretching
What is the receptor in Nociception?
Free Nerve Endings (nociceptors)
e.g Withdrawal Reflex
What are motor neurons split into in Medulla?
- Ventrolateral
- Dorsomedial
Ventrolateral motor axons path in Medulla
From Nucleus Ambiguous to join the Accessory (XI) and Vagus (X) Nerves
Dorsomedial motor axons path in Medulla
From Hypoglossal Nucleus to Hypoglossal Nerve
What is the only Viscerosensory nucleus for CNs?
Solitary nucleus in Medulla
Nuclei of the Cerebellum
- Dentate
- Emboliform
- Globose
- Fastigial
(Dont eat greasy food)
Parts of the Cerebellum
- Vesibulocerebellum (oldest)
- Spinocerebellum
- Cerebrocerebellum
Layers of the Cerebellum
1) Inner Granular Layer
2) Purkinje/Ganglionic Layer
3) Outer Molecular Layer
What types of cells are in Cerebellar Molecular layer?
- Stellate Cells
- Basket cells
(inh. interneurons)
What types of cells are in Cerebellar Granular layer?
- Granule cells (glutamate only)
- Golgi cells
What are the largest neurons in the CNS
Purkinje cells in Cerebellum
