Please enable JavaScript.

Coggle requires JavaScript to display documents.

Neurology - Physiology and Anatomy (Nerve conduction (*Action Potentials…

- - - - Myelin Physiology
        
        Myelin TIME constant
        
        Myelin LENGTH constant
        
        NOTES:
        
        think of myelin in terms of 2 properties for veolcity
        
        v = d/t
        
        increase in d = increase length constant per AP
        --> myelin increases the distance an AP travels by increased ratio of cytoplasm ion movement / trasnmembrane ion movement (insulation)
        
        DECREASE in time constant
        --> time constant refers to time for Na+ channels to open and the resistance in the membrane to ion leakage
        
        myelin increases Velociity 2 fold
        --> higher distance constant
        --> lower time constant for Na+ channels
      - Clinical Cases
        
        Clinical Case
        
        Notes:
        
        note that
        
        Clinical Case
        
        myelinated vs Unmyelinated Nerve Fibres
        
        Case presentation:
        
        Notes:
        
        note that postganglionic nerve fibres are actually unmyelinated
        
        Pacinian corpuscles are myelinarted, where I thought thy weren't
        
        unmyelinated nerve fibres are also called = C group fibres
      - A B C Nerve *Fibres:
        
        first 3 Fibres = MYELINATED:
        A - Alpha , Beta , Gamma = Large fibres which are largely Myelinated.
        
        Final 3 fibres = UNmyelinated:
        A - Delta , B , C = Small fibres which are not Myelinated as much.
        
        KEY point = more complex (evolution) sensations and movements of body --> myelinated
        
        think of nerve fibres in terms of evolution, the more basic sensations / actions of life
        --> dull pain = c fibres and
        --> temperature = a delta fibres (think of delta being the D fibre --> lower with B and C)
        --> bladder and autonomic = b fibres
        are unmyelinated and are the same in many animals
        
        the more advanced fibres are A - alpha, beta, gamma
        
        MYELINATED Fibres = A fibres (alpha, beta, gamma, NOT delta = D)
        
        UNmyelinated Fibres = B, C, A-delta
  - - - Clinical Cases
        
        Clinical Case
        
        Clinical Case
        
        Notes:
        
        note that
- - - - Notes:
        
        note that most Doapmine producing neurons are in the midbrain = meso, rest are in the hypothal = tubero
        
        midbrain = meso DA neurons
        --> VTA and substantia nigra
        
        hypothal DA neurons = tubero
        -->
- - - - TEL = Forebrain
        
        cerebral hemispheres
      - PRO = Prosencephalon
        
        TEL DI
        
        TEL = Forebrain
        
        cerebral hemispheres
        
        TEL = Forebrain
        
        cerebral hemispheres
      - MES = Midbrain
      - RHOMB = Rhombencephalon
        
        MET MY
        
        MET = metencephalon
        
        PONS and Cerebellum
        
        MY = Myencephalon
        
        Medulla
        
        *CTZ = Chemoreceptor Trigger Zone
        
        the CTZ is central brain PYLORIC SPHINCTER of the 4th ventricle STOMACH
        --> the 4th ventricle looks like a stomach with the CTZ as the pyloric sphinctre
        --> vomitting centre
        
        area postemia = right at the end of the 4th ventricle of the medulla
        
        fenestration area where there is NO Blood BB
        
        chemicals --> alcohol, chemo treatment, etc. can trigger emesis