Trigeminal Vsicles: What Is Trigeminal Nerve?

Table of Contents
INTRODUCTION 1
ANATOMY 4
PHYSIOLOGY 5 continous conduction 5 saltatory conduction 6
Discussion 7 pain pathway 7

INTRODUCTION
Trigeminal nerve is the most largest and most complex of the 12 nerves. It supplies sensations to the face, mucous membrane and other structures of the head. It provides a motor nerve to the muscles of mastication and contains proprioceptive receptors. It consists of a large sensory and small motor nerve that exits through the pons at it junction with the middle cerebral peduncle. Laterally it passes to join the semilunar ganglion in the Meckel Cave. The nerve passes anteriorly to end at the trigeminal ganglion, from where the three main branches of trigeminal nerve arises. The
Axon which propagates or takes the nerve impulses toward another neuron, a gland cell or muscle fibers. The dendrites which are the main input region. Integration occurs in the cell body, which includes cellular organelles. Synapses are places for functional contact between 2 excitable cells. Axon terminals contain synaptic vesicles filled with neurotransmitter molecules. Fast and slow axonal transport are systems for conveying materials to and from the cell body and axon terminals. Neurons are generally classified as motor, sensory, and interneurons. Sensory neurons carry information out into the CNS. Motor neuron carry information out of the CNS to effector organs. Interneurons are located within the CNS between the sensory and motor neurons. Neuroglia in the CNS support, protect and nurture neurons and maintain the interstitial fluid that bathes them, it includes astrocytes, oligodendrocytes, microglia and ependymal cells. Neuroglia in the PNS include Schwann cells and satellite cells. Unmyelinated fibers that are surrounded by Schwann cells. Myelin sheaths serves as an insulating property that enable it to conduct impulses at a much faster rate than any unmyelinated nerve of equal
Continuous conduction
2. Salutatory conduction
CONTINOUS CONDUCTION
• Resting state: all voltage gated K+ and Na+ channel are closed. Small buildup of negative charges inside surface of membrane and equal buildup of positive charges along the outside of membrane cause the axon plasma membrane to be at resting membrane potential.
• Depolarizing phase: membrane potential of axon reaches threshold, Na+ channels activates gate open. Positive charges buildup as Na+ ions move into the neuron thus membrane becomes depolarized.
• Repolarization phase: Na+ gates close and K+ channels gate open. As K+ ions leave the neuron membrane becomes repolarized since little negative charges buildup along inside the membrane. More negative charges buildup inside the membrane as more K+ ions leave the neuron. Due to outflow of K+ ions resting membrane potential is eventually restored.
• After-hyperpolarization phase: the voltage gated K+ channels remain open and the membrane potential becomes even negative -90m V. As the channels close, membrane potential returns to resting level of -70 m V. A refractory period is when another action potential cannot be