Nerve Physiology

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Nerve Physiology

Cells in the Nervous System
* Two types
* Nerve cell or neurons
* Glial cells or neuroglia
Neurons
* Functional unit of nervous system
* Have anatomically and physiologically specialized for communication and signaling * Neurocrene
* 10 billion neurons in nervous system
* Once they degenerate they don’t usually go REGENERATION

Neuroglia
* Nerve glue
* Supportive cells
* 10x greater of your neurons
* Not involve in impulse transmission (they can influence synaptic transmission) * Sustain neuron both physically and metabolically
* Includes
* Microglia – scavengers; cell that removes debris and cellular product from damage cells * Oligodendrocytes – cells in the CNS that produce MYELIN SHEAT * Schwann cells – cell in PNS that produce MYELIN SHEAT * Ependymal cells – cells responsible for CSF

* Astrocytes – cell with finger like projections, they surrounds blood vessels; BLOOD BRAIN BARRIER * Satellite cells – like astrocyte; responsible for maintenance of the environment of nervous system

Highly dividing cells are NEUROGLIA
Most common brain tumors are caused by problem in GLIAL CELLS Neurons are called post mitotic cells
Glial cells – mitotic cells

Brain Tumors
* Glial precursor cells are present in adult brain which give rise to most intrinsic brain tumors * Examples
* Astrocytoma and Glioblastoma multiforme
* Oligodendroglioma
* Ependymomas
* Meningiomas
* Acoustic neuromas
* In infants where neuron are still dividing
* Neuroblastoma
* Retinoblastoma

Nerve cells (neurons)
* Excitable cells (they can generate action and local potential) * Transmit impulses (action potential) along their membrane

* Physiologic properties
* Excitability (Irritability)
* Conductivity

Functional Anatomy

1. Dendrites – projections from cell bodies; receive...
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