THIS IS A STUDY GUIDE NOT AN ALL

� THIS IS A STUDY GUIDE, NOT AN ALL INCLUSIVE REVIEW. � THERE MIGHT BE THINGS NOT COVERED BY THIS STUDY GUIDE THAT MIGHT BE ASKED IN YOUR QUIZZES and PRACTICAL TESTS. � STUDENTS ARE RESPONSIBLE FOR STUDYING THEIR MANUAL AND FOR ALL THE MATERIAL COVERED DURING THE LABORATORY PERIOD, AS PER THE COURSE SYLLABUS � THIS STUDY GUIDE WILL GIVE YOU A GOOD ESTIMATE OF YOUR OVERALL READINESS FOR THE TEST AFTER YOU HAVE COMPLETED YOUR REVIEW OF EACH SUBJECT.

Lab # 10 Nervous System - Neural Tissue - Spinal Cord

NEURON STRUCTURE Histology of the Nervous Tissue 1 - Neurons 2 - Neuroglia or glial cells -In the CNS -In the PNS Glial cell (astrocyte) Neurons The glial cells are supporting cells, which are associated to the neurons and provide a supportive scaffolding for neurons

NEURON STRUCTURE Nucleus Perikaryon The Structure of Neurons Dendrite R. E. R. Nissl bodies Protein Free ribosomes synthesis Cell body or Soma Telodendria Axon terminal , synaptic terminal, or synaptic knob It carries the nerve impulses Axon away form the soma. Axon hillock It is the trigger zone for the nerve impulse. Telodendria Neurofibrils Dendrites They receive the nerve impulse. They provide internal support for the extensions and are responsible for intracellular transport. Axon terminal or synaptic terminal Synapses with another neuron and releases the neurotransmitters.

Axoplasm It is the cytosol of the axon. It is the plasma Axolemma It is the plasma membrane of the axon. Neurilemma membrane of the Schwann cells. Nucleus of Schwann cell They produce the myelin sheath. Myelin sheath Nodes of Ranvier It is where the depolarization of the membrane occurs during saltatory conduction. It electrically insulates the axon and enables saltatory conduction.

Synapse: It is a junction that mediates information transfer from one neuron to the next or from a neuron to an effector cell (ex: muscle cell, gland). Synapse from neuron to neuron. Neuromuscular junction Synapse from neuron to effector cell.

The Synapse The operation of the nervous system depends on the flow of information through chains of neurons functionally connected by synapses. It conducts impulses towards the synapse. It conducts impulses away from the synapse. Presynaptic neuron Postsynaptic neuron

Structural Classification of the Neurons Locations: Brain and special sense organs. Functions: Poorly understood. Locations: Special sense organs (retina, olfactory epithelium). Functions: They relay information about sight, smell or hearing from receptors cells to other neurons. Locations: Dorsal root ganglia of spinal cord. Functions: Most sensory neurons of the PNS. Locations: Anterior gray horn of spinal cord, primary motor cortex of the cerebrum. Functions: Motor neurons that control skeletal muscles.

Functional Classification of the Neurons 1 - Sensory or afferent neurons They carry information towards the Central Nervous System. 2 - Motor or efferent neurons They carry information away from the Central Nervous System. 3 - Association neurons or Interneurons They carry impulses between sensory and motor neurons located at CNS.

Spinal Cord and Spinal Nerves

White matter Gray matter Cell bodies of neurons and glia (no myelin). It forms nuclei in the CNS White matter Myelinated fibers. It forms tracts and nerves in the Peripheral Nervous System

The Anatomical Divisions of the Nervous System Brain Spinal cord Central Nervous System (CNS) It consists of the brain and spinal cord enclosed by cranium and vertebral column. It is responsible for integrating, processing and coordinating sensory data and motor commands. Tract: It is a bundle of nerve fibers (axons) in the CNS (white matter). Nucleus: It is a concentration of neuron cell bodies in the CNS (gray mater). Ganglia Nerves Peripheral Nervous System (CNS) It is all the nervous system except the brain and spinal cord. It consists of nerves and ganglia. It deliveries sensory information to the CNS and carries motor commands to peripheral tissues and system. Nerve: It is a bundle of nerve fibers (axons) wrapped in fibrous connective tissue. Ganglion: It is a knot-like swelling in a nerve where neuron cell bodies are concentrated.

Foramen magnum Gross Anatomy of Spinal Cord Cervical enlargement Posterior median sulcus Lumbar enlargement L 1 – L 2 Conus medullaris Cauda equina (Fibrous tissue that avoids Filum up and down movements of terminale spinal cord)

Spinal meninges: meninges Dura matter, arachnoid matter, pia matter Dura matter Arachnoid Pia matter Dura matter Epidural space (Epidural anesthesia) Subarachnoid space (It is filled with CSF) Subdural space Denticulate ligament (Prevent lateral movement)

Lumbar puncture (spinal tap) is the most common means of collecting a specimen of cerebral spinal fluid. The spinal needle is inserted, usually between the 3 rd and 4 th lumbar vertebrae. Once the needle is properly positioned in the subarachnoid space, pressures can be measured and fluid can be collected for testing.

GRAY MATTER ORGANIZATION Posterior gray horn POSTERIOR Posterior median sulcus Posterior gray commissure Dorsal or posterior root ganglion Somatic sensory Visceral sensory Lateral gray horn Anterior gray horn Dorsal or posterior root Visceral motor Somatic motor Anterior gray commissure Anterior median fissure ANTERIOR Ventral or anterior root Spinal nerve

Somato-sensory neurons Visceral-motor neurons Somato-motor neurons Cerebral cortex Thalamus Hypothalamus SS VS VM SM Somatic sensory fiber Somatic motor fiber Visceral sensory fiber Visceral motor fiber (Autonomic Nervous System)

WHITE MATTER ORGANIZATION POSTERIOR Central canal (Contains CSF) Posterior white column Lateral white column Anterior white commissure ANTERIOR