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

Histology of the Nervous Tissue 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

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

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

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: Synapse from neuron to neuron. Synapse from neuron to effector cell. Neuromuscular junction

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

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

Spinal Cord and Spinal Nerves

White matter Gray 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 Ganglia Nerves Spinal cord Central Nervous System (CNS) Peripheral Nervous System (CNS) It consists of the brain and spinal cord enclosed by cranium and vertebral column. It is all the nervous system except the brain and spinal cord. It consists of nerves and ganglia. It is responsible for integrating, processing and coordinating sensory data and motor commands. 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. Tract: It is a bundle of nerve fibers (axons) in the CNS (white matter). It is a concentration of neuron cell bodies in the CNS (gray mater). Nucleus: It is a knot-like swelling in a nerve where neuron cell bodies are concentrated. Ganglion:

Posterior median sulcus Gross Anatomy of Spinal Cord L1 – L2 Foramen magnum Cervical enlargement Posterior median sulcus Lumbar enlargement Conus medullaris Cauda equina (Fibrous tissue that avoids up and down movements of spinal cord) Filum terminale

Spinal meninges: Dura matter, arachnoid matter, pia matter Denticulate ligament Dura matter Subarachnoid space Epidural space Subdural space (It is filled with CSF) (Epidural anesthesia) (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 3rd and 4th 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 Posterior median sulcus Dorsal or posterior root Dorsal or posterior root ganglion Posterior gray commissure Posterior gray horn Somatic sensory Visceral sensory Lateral gray horn Visceral motor Anterior gray commissure Anterior gray horn Somatic motor Spinal nerve Anterior median fissure Ventral or anterior root ANTERIOR

SS VS VM SM Cerebral cortex Cerebral cortex Thalamus Somato-sensory neurons Visceral-sensory neurons Visceral-motor neurons Somato-motor neurons 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 white column Central canal (Contains CSF) Posterior white column Lateral white column Anterior white commissure Anterior white column ANTERIOR