Zesty_Lemon
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General
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Nervous system: gathers, analyses, filters information from internal AND external, for appropriate (long/short term, observable/internal) response for survival and reproduction.

CNS-> brain + spinal cord
PNS-> somatic NS + autonomic/visceral NS + spinal nerves + cranial nerves
autonomic NS-> parasympathetic + sympathetic + enteric

Sizes: 70-100 micrometers is large neuronal cell body

Anatomical positioning: contralateral/ ipsilateral <3, rostral (front) /caudal (back), sagittal plane (see middle side)/ coronal plane (see back to front of head)/ horizontal plane, proximal/distal, medial/lateral, dorsal/ventral, anterior/ posterior









Nervous cells
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Terminology:
Neuropil - cell bodies, axons, dendrites, synapses, glia
Nucleus - cluster of neurons
Area - Sheet/layer/lamina of neurons
Tracts/fasciculus/faniculus/lemniscus - bundles of nerve fibres
Commissure/decussation - tracts that cross over brain midline (symmetrical like corpus callosum and asymmetrical respectively)
Chiasma/chiasm - crossing of optic nerve



Neurons
Glia
Cranial nerves
Biochemistry
Excitatory: glutamate, aspartate
Inhibitory: GABAergic












The brain
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Runs on glucose, can't store it.

Meninges
Large blood supply, innervated, feel pain
Dura mater: outer, tough, fibrous layer inside bone
Arachnoid: fine sheet connected to Pia mater by elastic strands
Subarachnoid space: contains cerebral fluid (CSF)
Pia mater: membrane on surface of brain

Cerebral Fluid:
  • Produced by choroid plexuses (small artery network lining inner surface of brain ventricles), shock absorption, reduces brain weight (1500g real -> 50g effective on bone), keeps extracellular milieu constant (buffer), movement reduces toxic substances, circumventricular organs sit in ventricles, sense levels of stuff in bloodstream, no BB-barrier
  • Moves from lateral ventricle>third>fourth>subarachnoid space>blood stream

Blood-brain barrier
  • Barrier between blood + extracellular fluid in brain/spinal cord
  • ECF composition important for neuronal excitability
  • Formed by specialised endothelial cells of brain capillaries and specific cellular transport mechanisms in/out and pumps out of the ECF


Forebrain
Includes diencephalon, hypothalamus, cerebral cortex and deep cerebral structures.

Midbrain
Includes part of brainstem, superior and inferior colliculi.

Hindbrain
Includes rest of brainstem and cerebellum.

Brainstem
Upper: thalamus, hypothalamus, Pituitary, Pineal gland.
Middle: midbrain
Lower: Pons, Medulla, Cerebellum,

Thalamus
Gateway to the cortex. First step in sensory perception (except smell). Integrated in association cortex. Integrates + coordinates motor and autonomic function
Largest nucleus, 3 distinct nuclei.
Specific: 1 sensory modality input, project to specific cortical region.
Associative: connects to associate cortex, sensory integration, memory of stimuli, emotional behaviour aspects.
Diffuse: projections widespread through cortex and thalamus, arousal, cortical excitability.

Cerebellum
Coordination and control of complex movement, posture, balance, hand-eye coordination.
Compares motor commands with actual movement and uses feedback to adjust motor commands.
Input from vestibular system (body position in space)
Outputs are deep cerebellar nuclei -> thalamus, brainstem and spinal cord
Each folium codes for 1 movement.
Crystalline structure with 3 layers: molecular, Purkinje cell and granular (out to in)
mossy fibres->granule cells->Purkinje cell (stimulate)
Climbing fibres(from inferior olive)->Purkinje cell (inactivate) (report error signal?)
Parallel fibres->Purkinje cell (synapse is plastic)
Stellate and basket cells perform surround inhibition
Golgi cells->granule cells (feedback inhibition)

Hippocampus
Forming and recalling long term memories; place memory.
Long-term potentiation
Closely connected to amygdala
4 major subdivisions: dentate gyrus, Ca region, subiculum, entorhinal cortex
Information flow from the perforate pathway: entorhinal cortex->dentate gyrus->CA3->CA1->Subiculum
Cells: granule, axons mossy fibres, pyramidal cells, Schaffer collaterals.

Cerebral Cortex
Analyses input from senses, combines with memory, for understanding and complex behaviour.
6 columnar layers:
molecular,
external granular,
external pyramidal, (large pyramidal cells that connect to other cortical areas)
internal granular, (main input for sensory from thalamus)
internal pyramidal, (large pyramidal cells, axons to striatum and spinal cord)
multiform (part of feedback loop regulating incoming thalamic activity, variety of cells, most excitatory mainly glutamate and aspartate)
Local circuits.
Topographic arrangement (homunculus, retinotopic, tonotopic)



The spinal cord
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8 cervical segments
12 thoracic segments
5 lumbar segments
5 sacral segments
1 coccygeal segment

Spinal cord starts outside skull below foramen magnum, extends to the sacrum
Connected to muscles, viscera, blood vessels
White matter on outside, grey on inside. The white matter has bundles of axons connecting brain with periphery.
Dorsal Horn, grey matter. Has a dorsal root ganglion: cell bodies of sensory neurons that send axons into spinal cord
Ventral horn, grey matter, motor cell bodies, each cluster represents input to specific muscle group. Ventral root has no ganglion, transmits info through alpha and gamma motor neuron, post ganglionic sympathetic neurons and preganglionic parasympathetic neurons to periphery.
Pairs of spinal nerves arise from spinal cord and leave spine through intervertebral foramina.

2 ascending, sensory pathways
Spinothalamic for pain and temperature
Dorsal column pathway for touch/proprioception, to somatosensory cortex.

1 descending motor pathway
From motor cortex









Spinal nerves
Sensory and Motor systems












Neuropharmacology
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Hill-Langmuir Equation











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