© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Chapter 8 Central Nervous System

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. CNS Functions Communication and coordination system in the body Seat of intellect and reasoning Communicates with the endocrine system

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Divisions Central nervous system includes the brain and spinal cord The peripheral nervous system consist of 12 pairs of cranial nerves and 31 pairs of spinal nerves Autonomic nervous system includes the sympathetic and parasympathetic systems

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. The Nerve Cell Called the neuron –Transmits messages from one cell to another Nucleus, cytoplasm, and cell membrane Dendrites Axons (only one per cell) –Neurilemma or myelin sheath

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 8-1 Two types of neurons showing cell body, axon, and dendrite: (A) efferent (motor) neuron, (B) afferent (sensory) neuron

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Nervous Tissue/Cells Neuroglia –Astrocytes, microglia, oligodendrocytes and Schwann cells Neurons –Sensory or afferent –Motor or efferent –Associative or interneurons Membrane excitability

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Synapse When messages go from one cell to the next cell Synaptic cleft –The space between the axon of one nerve cell and the dendrites of another Neurotransmitters –Chemical substances that make it possible for messages to cross the synapse to a target receptor

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Effects of Aging Slowing nerve conduction Loss of brain size Slowing of reaction time Changes in sleep patterns Important to continue physical and mental activity to stimulate nerve cells, blood flow and neurotrophin production

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. The Brain (1 of 2) Weighs about 1,400 grams or 3 pounds 100 billion neurons Meninges and cerebrospinal fluid Without oxygen, brain damage occurs within 4–8 minutes

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. The Brain (2 of 2) Cerebrum Diencephalon Cerebellum Brain stem

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 8-5 A cross section showing the major parts of the brain: cerebrum, cerebellum, diencephalon, and brain stem

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Memory Storage of old and new information Role of the hippocampus of the limbic system Short- or long-term memory

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Coverings of the Brain Dura mater –Outer that lines the inside of the skull Arachnoid mater –Middle layer, resembles a fine cobweb Pia mater –Inner layer, covers the brain, consists of blood vessels (called the choroid plexus) and connective tissue Cerebrospinal fluid –Acts as a shock absorber and a source of nutrients

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Ventricles of the Brain Four lined cavities filled with cerebrospinal fluid Choroid plexus helps with the production of cerebral spinal fluid 1st and 2nd –Right and left lateral ventricles 3rd and 4th –Third is connected to the two lateral ventricles vis the interventricular foramen –The 3 rd and 4 th are connected via a narrow canal called the cerebral aqueduct

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Cerebrospinal Fluid (CSF) Formed inside the four ventricles Transports nutrients to and removes metabolic waste products from the brain cells Blood-brain barrier –Selectively permeable –Consist of choroid plexus capillaries Lumbar puncture

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Cerebrum Largest part of the brain Weighs about 2 pounds Cerebral cortex (gray matter) Two hemispheres and longitudinal fissure Fissures (deeper) and sulci (shallow) Gyri or convolutions (elevated ridges between the sulci)

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Five Major Fissures Longitudinal fissure Transverse fissure Central fissure Lateral fissure Parieto-occipital fissure

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 8-8 Lateral view of the brain

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Cerebral Functions Frontal lobe Parietal lobe Occipital lobe Temporal lobe Limbic lobe or system

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 8-9 (A) The parts of the brain

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Figure 8-9 (B) Areas of brain function

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Diencephalon Located between the cerebrum and the midbrain Thalamus –Relay station for incoming and outgoing nerve impulses Hypothalamus –Considered to be the “brain” of the brain

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Hypothalamus (1 of 2) Autonomic nervous control Cardiovascular control Temperature control Appetite control Water balance

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Hypothalamus (2 of 2) Manufacture of oxytocin Gastrointestinal control Emotional state Sleep control Mind-over-body experiences

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Cerebellum Located behind the pons and below the cerebrum Right and left cerebellar hemispheres connected by vermis Gray matter on the outside and white matter on the inside Communicates with the rest of the CNS by three pairs of tracts called peduncles

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Cerebellar Function Maintenance of balance Maintenance of muscle tone Coordination of muscle movements

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Brain Stem Midbrain Pons Medulla oblongata Pathway for ascending and descending tracts

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Spinal Cord Begins at foramen magnum of the occipital bone Ends at the second lumbar vertebrae 31 pairs of spinal nerves Protected by meninges and other tissues White and gray matter Functions –Carry messages from the sensory neurons to the brain for interpretation, then carry the response back through the motor neurons to muscles and glands

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Disorders (1 of 3) Meningitis Encephalitis Epilepsy Cerebral palsy

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Disorders (2 of 3) Poliomyelitis Hydrocephalus Parkinson’s disease Essential tremor

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Disorders (3 of 3) Multiple sclerosis West Nile virus (WNV) Dementia Alzheimer’s disease Tumors

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Brain Injuries Hematoma Concussion Coup and contrecoup injury Spinal cord injuries –Quadriplegia –Paraplegia

© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Headaches Tension Migraine Cluster