Anatomy of the Nervous System
I. Cells
4. Transmit information to target cell (neuron, muscle, gland) Four functions of neurons 1. Receive and integrate inputs 2. Generate a nerve impulse (action potential) 3. Conduct the action potential dendrites, soma axon hillock axon nerve terminals
Dendrites and cell body Receive and integrate inputs Axon hillock and initial segment Generate action potentials Axon Conducts action potential Terminals Synaptic transmission
Conducts action potential Axon hillock Generates action potential Transmit to target cell receives and integrates inputs
Classifications of Neurons 1. Function 2. Structure 3. Shape 4. Effect 5. Axon length 6. Neurochemical identity
Classifications of Neurons 1. Function a. sensory neurons b. motoneurons c. interneurons
Classifications of Neurons 1. Function 2. Structure a. unipolar b. bipolar c. multipolar
100μm B A
Classifications of Neurons 1. Function 2. Structure 3. Shape e.g., pyramidal, stellate, basket, granule, etc.
Classifications of Neurons 1. Function 2. Structure 3. Shape 4. Effect a. excitatory neurons b. inhibitory neurons
Classifications of Neurons 1. Function 2. Structure 3. Shape 4. Effect 5. Axon length a. projection neurons (Golgi Type I) b. local neurons (Golgi Type II)
Classifications of Neurons 1. Function 2. Structure 3. Shape 4. Effect 5. Axon length 6. Neurochemical identity e.g., cholinergic, dopaminergic, GABAergic, etc.
Classifications of Neurons 1. Function 2. Structure 3. Shape 4. Effect 5. Axon length 6. Neurochemical identity
Types of glial cells 1.Astrocytes 2.Microglia 3.Oligodendroglia 4. Schwann cells
Types of glial cells 1.Astrocytes a. mechanical support b. metabolic support transport nutrients and wastes c. encapsulate synapses d. regulate chemical and ionic environment e. form scar tissue f. act as phagocytes
Types of glial cells 1.Astrocytes 2.Microglia a. act as phagocytes b. part of brain’s immune system
Types of glial cells 1.Astrocytes 2.Microglia 3.Oligodendroglia myelinate axons of central nervous system
Types of glial cells 1.Astrocytes 2.Microglia 3.Oligodendroglia 4. Schwann cells myelinate axons of peripheral nervous system
II. Gross Anatomy
Rostral toward the nose Caudal toward the tail Dorsal toward the back Ventral toward the belly Medial toward the midline Lateral away from the midline Proximal near a point of reference Distal distant from a point of reference Directional Terms
Afferent projecting toward Efferent projecting away from Ipsilateral on the same side Contralateral on the opposite side Directional Terms
Planes of Section Coronal or frontal perpendicular to the neuraxis perpendicular to ground apply only to brain Sagittal parallel to neuraxis perpendicular to ground midsagittal = axis of symmetry Horizontal parallel to ground parallel to neuraxis applies only to brain Transverse perpendicular to neuraxis applies to brain and spinal cord Oblique any section not in a standard plane
(intermediate gray)
A. Cervical spinal cord B. Thoracic spinal cord C. Lumbar spinal cord D. Lumbo-sacral spinal cord
Autonomic Nervous System (ANS) Sympathetic division (arousal) Parasympathetic division (maintenance)
Prosencephalon = diencephalon + telencephalon Mesencephalon = tegmentum + tectum Rhombencephalon = metencephalon (pons, + cerebellum) + myelencephalon (medulla)