Nervous System Anatomy PDF

nervous tissue - neural tissue nervous system - respond to changes in external and internal environment cns - brain and spinal cord - protected by skull and vertebral column - meninges (dense irregular) - csf protective coverings of brain - skull - meninges pns - peripheral nerves - ganglia - cr...

nervous tissue - neural tissue nervous system - respond to changes in external and internal environment cns - brain and spinal cord - protected by skull and vertebral column - meninges (dense irregular) - csf protective coverings of brain - skull - meninges pns - peripheral nerves - ganglia - cranial and spinal nerves - cranial because its outside the protection functional: somatic - regulation of voluntary control - one somatic neuron per skeletal muscle - acetylcholine autonomic - 2 shorter nuerons - preganglionic neuron and postganglionic neuron) - involuntary physiologic processes 1. sympathetic - pupil and bronchi dilation - glycogen to glucose - adrenaline - inhibit bladder contraction and peristalsis - fight or flight - shorter preganglionic acetylcholine - postganglionic norepinephrine 2. parasympathetic - rest and digest - longer preganglionic acetylcholine - shorter postganglionic acetylcholine 3. enteric - within walls of gastrointestinal tract - contracts segmentally - function independently of cns and autonomic - mucosa, submucosa, muscularis, serosa - nerves in muscularis is called myenteric or auberbach's plexus for contraction - submucosa nerves called meissner's plexus control secretion of glands - modulated by autonomic ns neurons - soma cell body has nucleus - axon covered by myelin sheath - cns neuron is more angular - many rer or nissl bodies or chromatophilic substance for making neurotransmitters group of cell bodies - nucleus in cns - ganglia in pns dendrites - darker than axons - carry impulse towards cell bodies axons - myelin sheath composed of lipids axon hillock - no organelles nerve transmission - afferent or sensory input from pns to cns - efferent or motor ourput from cns to pns grey mater - h shaped - dendrites and cell body white mater - axons sensory neuron from dorsal root to posterior horn then white matter white matter to anterior gray horn to ventral root types of neurons morphology 1. multipolar neurons - multiple dendrites, one axon - motor impusle, most common 2. bipolar neurons - one axon one dendrite - sensory retina 3. unipolar - axon and dendrite connected - spinal and dorsal root ganglia posterior gray horn have interneurojs for reflex cns neuroglia 1. astrocytes - maintains blood brain barrier - absorb excess neurotransmitters - defense against oxidative stress - forms scar tissue - glial fibrillary acid protein 2. oligodendrocytes - makes myelin sheath 3. microglial cells - phagocytic cell 4. ependymal cells - produces csf in the choroid plexus pns neuroglia 1. schwann cells - myelin sheath neurilemma 2. satellite cells - capsule around cell body central canal lined by ependymal cells brain - gray matter in periphery - protoplasmic astrocytes in gray matter - fibrous astrocytes in white matter meninges dura mater - type 1 collagen fibers - dense irregular arachnoid mater - spongy arachnoid trabeculae - perivascular space to give blood pia mater - in contact w brain and spinal cord csf - subarachnoid space - arachnoid villi drains into blood filled sinuses in the dura mater nerves are just axons an axon is covered by endoneurium perineum covers fascicle epineurium covers whole nerve organization of nerve nodes of ranvier - gaps - increase speed of travel of nerve impulse nerve in pns, tract in cns cerebellum - motor movement gray mater cerebellum 1. molecular layer 2. purkinje cell layer 3. granule cell layer cerebrum - 6 layered gray mater - molecular, granular, pyramindal, granular, pyramidal, multiform