CENTRAL NERVOUS SYSTEM Chapter 8

©2004 Delmar Learning, a division of Thomson Learning, Inc. INTRODUCTION TO THE CENTRAL NERVOUS SYSTEM Functions of the central nervous system: –Communication and coordination system in the body Receives messages from stimuli Brain interprets message Brain responds and carries out activity –Reasoning and intelligence

©2004 Delmar Learning, a division of Thomson Learning, Inc. INTRODUCTION TO THE CENTRAL NERVOUS SYSTEM Nervous tissue consists of two types of nerve cells: –Neuroglia - cells that insulate, support and protect neurons –Neurons - pass nerve impulses Sensory neurons (afferent) Motor neurons (efferent) Associative neurons (interneurons)

©2004 Delmar Learning, a division of Thomson Learning, Inc. INTRODUCTION TO THE CENTRAL NERVOUS SYSTEM

©2004 Delmar Learning, a division of Thomson Learning, Inc. INTRODUCTION TO THE CENTRAL NERVOUS SYSTEM Membrane excitability is the electric charge created by impulses in the nerve Synapse - messages go from one cell to the next –Synaptic cleft - space between axon or one cell and dendrite of another

©2004 Delmar Learning, a division of Thomson Learning, Inc. DIVISIONS OF THE NERVOUS SYSTEM There are 3 divisions of the nervous system: –Central nervous system - brain and spinal cord –Peripheral nervous system - nerves of the body –Autonomic nervous system - peripheral nerves and ganglia

©2004 Delmar Learning, a division of Thomson Learning, Inc. THE BRAIN Memory –Short term –Long term Coverings of the brain –Dura mater –Arachnoid mater –Pia mater

©2004 Delmar Learning, a division of Thomson Learning, Inc. THE BRAIN The brain contains four lined cavities called cerebral ventricles –Right lateral ventricle –Left lateral ventricle –Third ventricle –Fourth ventricle Cerebral fluid serves as liquid shock absorber

©2004 Delmar Learning, a division of Thomson Learning, Inc. THE BRAIN

©2004 Delmar Learning, a division of Thomson Learning, Inc. CEREBRUM The cerebrum is divided into 2 hemispheres; each hemisphere is divided into: –frontal lobe –parietal lobe –occipital lobe –temporal lobe

©2004 Delmar Learning, a division of Thomson Learning, Inc. CEREBRUM The cerebral surface is covered with furrows and ridges –Sulci - Shallow grooves –Fissures - deeper grooves Longitudinal fissure Transverse fissure Central fissure Lateral fissure Parieto-occipital fissure

©2004 Delmar Learning, a division of Thomson Learning, Inc. CEREBRUM Each lobe of the cerebral hemispheres control different functions –Frontal lobe - motor functions –Parietal lobe - sensory –Occipital lobe - eyesight –Temporal lobe - auditory and olfactory senses

©2004 Delmar Learning, a division of Thomson Learning, Inc. CEREBRUM

DIENCEPHALON Thalamus –Located between the cerebrum and midbrain –Acts as a relay station for incoming and outgoing nerve impulses

©2004 Delmar Learning, a division of Thomson Learning, Inc. DIENCEPHALON Hypothalamus –Autonomic nervous control –Cardiovascular control –Temperature control –Appetite control –Water balance –Manufacture of oxytocin –Gastrointestinal control –Emotional state –Sleep control

©2004 Delmar Learning, a division of Thomson Learning, Inc. CEREBELLUM Consists of two hemispheres –Right cerebellar hemisphere –Left cerebellar hemisphere Controls all skeletal muscle body functions: –Maintenance of balance –Maintenance of muscle tone –Coordination of muscle movement

©2004 Delmar Learning, a division of Thomson Learning, Inc. BRAIN STEM Brain stem is made of 3 parts: –Midbrain –Pons –Medulla

©2004 Delmar Learning, a division of Thomson Learning, Inc. SPINAL CORD The spinal cord functions as both a reflex center and a conduction pathway to and from the brain

©2004 Delmar Learning, a division of Thomson Learning, Inc. DISORDERS OF THE CENTRAL NERVOUS SYSTEM Meningitis Encephalitis Epilepsy Cerebral palsy Poliomyelitis Parkinson’s disease Hydrocephalus Multiple sclerosis Dementia Alzheimer’s disease Brain tumors Hematoma