neuro (under pros--> neuro--> patho)

introduction

ways to classify the nervous system

parts of the nervous system

anatomy

function

internal vs external

CNS vs PNS

sensory vs motor

somatic vs visceral

nerve cells/neurons

parts of the CNS/PNS

CNS

PNS

brain

spinal cord

cranial nerves (12): nerves exiting from the brain

spinal nerves (31): nerves exiting from the spine

spinal cord

white matter

grey matter

ventral horm

lateral horn

dorsal horn

sensory (ascending)

motor (descending)

different parts according to the

  • lobes
  • forebrain, midbrain, hindbrain
    REFER BACK TO THE DOCS TO MMEMORISE THE PARTS

cerebrum

Ventricles/Cavities

thalamus

  • integrating centre for sensory, motor and cognitive
  • its in the centre so its good for connecting people together

Hypothalamus

Basal Ganglia

Limbic system

Amygdala

prefrontal cortex

Brainstem

Corpus Callosum

Cerebellum

insert the photo for the summary of the functions

neuro histology

insert photos for the different types of cells

neurons (name all the parts of a normal neuron)

non-neuronal cells: glial cells

cell body: soma

Axons

dendrites

Synapses

Astrocytes

Oligodendrocytes

Microglia

group of neurons in CNS: nucleus/nuclei

group of neurons in the PNS: ganglion/ganglia

synapse: part where two neurons meet

  • ganglia: encapsulated colleciton of neuronal cell bodies located outside of the CNS

spinal pathways 1: sensory pathways

sensory pathways

three types of neurons

  1. sensory
  2. motor
  3. autonomic

Spino-thalamic (antero-lateral system)

Dorsal column medial lemniscus

Spinocerebellar

insert the image of the homoculus

Trigemino-thalamic tract

anterior

lateral

modalities

  • crude touch
  • pressure

modalities

  • pain
  • temperature

neuronal pathway
1st order neuron (sensory dorsal root ganglion) —> 2nd order neuron (cross midline at dorsal horn neuron in spinal cord) —> 3rd order neuron (in the thalamus) —> sensory cortex

modalities

  • fine/discriminative touch
  • Vibration
  • Pressure
  • Proprioception —> knowing your body parts in relation to space

neuronal pathway
first order (dorsal root ganglion) —> 2nd order neuron (cross midline at the medulla obonglata) —> 3rd order neuron (thalamus) —> sensory cortex

dorsal spinal cerebellar tract

  • uncross (ipsilateral)
  • Goes to the inferior cerebellar peduncle

ventral spinocerebellar tract

  • Cross → contralateral
  • Goes to superior cerebellar peduncle

modalities
Proprioception (subconscious) → from muscles, joints etc


function

  • Control muscle tone
  • Regulate movements coordination

pathway

  • 1st order neuron (dorsal root ganglion) → 2nd order neuron (spinal cord) (most of the neurons do not cross the midline) → cerebellum (stops here, does not go to the sensory cortex because it is subconscious)

sensory homunculus

motor

sensory

More feeling: hands, face tongue
Less feeling: legs and lower body

More control: fingers and face (fine control)
Less control: lower body

modalities
Proprioception (subconscious) → from muscles, joints etc

function
Receive sensation of pain and temperature from the head

pathway
1st order: Trigeminal ganglion (in the PNS) →
2nd order: sensory nucleus of V →
3rd order: thalamus

problems with the sensory pathways

  • Brown-sequard syndrome
  • characterized by a lesion in the spinal cord which results in weakness or paralysis on the side of the lesion of the body and a loss of sensation on the opposite side

spinal pathways 2: motor pathways

types of neurons

Lower Motor neurons (LMN)

Upper Motor neurons (UMN)

Pyramidal system/Cortico-spinal tract

  • more direct and intentional control
  • pathway
    How do axons travel: Corona radiate (CR) → internal capsule (IC) → midbrain (cerebral peduncle) → medulla (pyramids) → from there there are two different paths to go Decussate → lateral corticospinal tract (CST) Ventral CST

Extrapyramidal system

Rubro-spinal tract

  • From red nucleus

Tecto-spinal tract

  • From superior colliculus/tectum (at level of midbrain)

Vestibulospinal tract

lateral vestibulo-spinal tract

  • From lateral vestibular nucleus
  • Controls extensor (anti gravity) muscles → for tone and equilibrium
  • For maintenance of posture and balance

Medial Vestibulo-spinal tract

  • From medial vestibular nucleus
  • For controlling correct position of head and neck

reticulo-spinal tract

problems with the
motor pathways

lesions

specific organs of the motor pathways

midbrain

  • midbrain
  • pons
  • medulla

Cerebral cortex

lateral cortico-spinal tract

  • cross at the brainstem

anterior cortico-spinal tract

  • cross at the ventral horn

premotor cortex

supplementary motor area

damage

signs

long tract signs (means lesions for the whole pathway)

segmental signs (means lesions
for a segment of the nerves)

damage to LMN and axons

  • hypotonia
  • muscle atropy
  • areflexia
  • muscular fasciculations

damage to UMN and axons

  • Hypertonia/spasticity rigid paralysis
  • Increased muscles stretch reflex
  • Pathologic reflexes
  • motor: weakness and atrophy in a myotomal pattern (means relating to a single portion of the spinal cord)
  • sensory: sensory loss in dermatomal distribution
  • reflexes: loss of tendon reflexes at the level of lesion
  • Motor: upper motor neuron dysfunction → characterised by weakness, spasticity, increased tendon reflexes and babinski responses
  • Sensory: sensory loss below the level of lesion
  • Autonomic: means subconscious functions, but the most clinically useful ones are bladder control

general neurophysiology

concept of equilibrum potential

concentration gradient
(basically a difference in concentration

electrical gradient
(basically a difference in electric charge)

  • Equilibrium potential is a balance between the concentration gradient and the electrical gradient
    • Both of them need to be balanced
  • Nernst equation and Goldmann equation
    • used to calculate the equilibrium potential for each ion

parts of the cell that helps to
maintian the eqilibrum potential

Pumps

Sodium and potassium
channels

sypnaptic transmission

Neurotransmitters

specific types and their functions
that you must know

postsynaptic potentials

inhibitory postsynaptic potential (IPSP)

  • membrane potential is more negative and closer to resting potential

excitatory postsynaptic potential (EPSP)

  • membrane potential is more positive and further from resting potential
  • sodium potassium pumps ( actively transports three sodium ions out of the cell and two potassium ions into the cell) vs
  • sodium channels (allows the passive movement of sodium ions (Na+) across the cell membrane.)
  • remember that the concentration of Na+ outside the cell is higher than insdie the cell (just imagine the big sea)
  • resting potential for neurons is -64mV

there is another type of transmission method called the gap junction transmission method


compare synaptic transmission method vs gap junction method

broad three categories

Amino acids

amines

peptides

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anatomy of the vertebrae column and spinal nerves

spinal cord

  • located in upper 2/3 of the vertebral canal
  • caudal end of the spinal cord is called conus medullaris
  • eahc spinal segment gives rise to one pair of cranial nerves

vertebrae column =! spinal cord

  • vertebrae column and spinal column are the same thing --> they refer to the bone
  • spinal cord and spinal nerves are the same thing --> they refer to the

vertebral column

Cervical (7)

Thoracic (12)

Lumbar (15)

Sacral

Coccyx

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layers of the spinal cord

pia mater

arachnoid mater

Dura mater


myotomes vs dermatomes
(insert dermatomes picture)

spinal reflex

somatic

  • Involuntary control of skeletal muscular system

visceral

  • Involuntary controls of glands, smooth and cardiac muscle

arteral supply

spinla arteries

  • longitudinal
  • run parallel to the vertebral column

radicular/segmental artieries

  • from arteries on the wall of the thorax
  • runs perpendicular to the vertebral column