The Nervous System. Functions of the Nervous System input gathering To monitor occurring inside and outside the body Changes =

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1 The Nervous System Functions of the Nervous System input gathering To monitor occurring inside and outside the body Changes = To process and sensory input and decide if is needed output A response to integrated The response activates or Structural Classification of the Nervous System system (CNS) cord nervous system (PNS) Nerves the brain and spinal cord nerves nerves Functional Classification of the Peripheral Nervous System Sensory ( ) division Nerve fibers that carry information the central nervous system Motor ( ) division Nerve fibers that carry impulses from the central nervous system Organization of the Nervous System Functional Classification of the Peripheral Nervous System (efferent) division subdivisions nervous system = nervous system = Nervous Tissue: Support Cells cells in the CNS are grouped together as Function: to,, and neurons

2 Abundant, -shaped cells Brace Form between and neurons Control the environment of the Spiderlike Dispose of cells Line of the brain and spinal cord cerebrospinal fluid around fibers in the central nervous system Produce cells neuron cell bodies cells Form sheath in the nervous system Nervous Tissue: Neurons = nerve cells Cells specialized to Major regions of neurons body and metabolic center of the cell fibers that from the cell body body substance rough endoplasmic reticulum Cell body cytoskeleton Maintains cell Large Processes the cell body

3 conduct impulses the cell body conduct impulses from the cell body Axons end in Axonal terminals contain with Axonal terminals are separated from the next neuron by a gap cleft gap between adjacent neurons junction between sheath, fatty material covering cells produce sheaths in jelly roll like fashion Nodes of in myelin sheath along the Neuron Cell Body Location Most cell bodies are found in the matter cell bodies and fibers clusters of cell bodies within the matter of the central nervous system collections of bodies outside the Functional Classification of Neurons Sensory ( ) neurons Carry impulses the sensory receptors the sense organs detect or Motor ( ) neurons Carry impulses the central nervous system viscera,, or (association neurons) Found in pathways in the Connect and neurons Neuron Classification Structural Classification of Neurons neurons extensions from the cell body neurons axon and dendrite neurons have a short leaving the cell body Functional Properties of Neurons Ability to respond to

4 Ability to transmit an Nerve Impulses neuron The plasma at rest is positive are the cell than outside the cell A depolarizes the neuron s A depolarized membrane allows (Na+) to flow the membrane The exchange of ions initiates an in the neuron potential If the action potential ( ) starts, it is propagated over the Impulses travel when fibers have a sheath ions rush out of the neuron after ions rush in, which the membrane The sodium-potassium, using, restores the original configuration Transmission of a Signal at Synapses Impulses are able to cross the to another is released from a nerve s axon The dendrite of the next neuron has that are stimulated by the An potential is started in the The Reflex Arc, predictable, and response to a stimulus Occurs over pathways called Reflex arc route from a neuron, to an, to an Types of Reflexes and Regulation reflexes Activation of muscles Example: When you move your hand away from a stove

5 reflexes muscle regulation and pressure regulation Regulation of system regulation Patellar, or -, reflex is an example of a -neuron reflex arc Central Nervous System (CNS) CNS develops from the tube The neural tube becomes the and cord The of the neural tube becomes the Four within the Filled with fluid Regions of the Brain hemispheres (cerebrum) Brain stem Regions of the Brain: Cerebral Hemispheres (Cerebrum) (left and right) parts of the brain Includes more than of the brain The surface is made of ridges ( ) and grooves ( ) of the cerebrum (deep grooves) divide the cerebrum into lobes Surface lobes of the cerebrum lobe lobe lobe lobe areas of the cerebrum sensory area impulses from the body s receptors Located in lobe Primary area

6 impulses to muscles Located in lobe area Involved in our ability to Cerebral areas involved in senses area (taste) area area area areas of the cerebrum /language region Language region interpretation area of the cerebrum matter layer in the cerebral cortex composed mostly of neuron matter tracts to the gray matter connects hemispheres nuclei of matter buried within the white matter Regions of the Brain: Diencephalon Sits on top of the Enclosed by the cerebral Made of three parts Surrounds the ventricle The relay station for impulses Transfers impulses to the correct part of the cortex for and the thalamus Important nervous system center

7 Helps regulate body Controls balance Regulates An important part of the system ( ) The gland is attached to the hypothalamus Forms the of the ventricle Houses the body (an gland) Includes the forms cerebrospinal fluid Regions of the Brain: Brain Stem Attaches to the Parts of the brain stem oblongata Mostly composed of tracts of Has two bulging fiber tracts Has rounded protrusions Reflex centers for and The center part of the brain stem Mostly composed of tracts Includes involved in the control of Medulla The part of the brain stem Merges into the cord Includes important fiber tracts Contains important control centers Heart control pressure regulation Breathing

8 Formation Diffuse mass of matter along the Involved in control of organs system ( ) plays a role in cycles and Regions of the Brain: Cerebellum hemispheres with surfaces Provides coordination of body Protection of the Central Nervous System and skin Skull and fluid (CSF) -brain barrier Meninges mater -layered covering attached to inner surface of the Meningeal layer covering of the Folds in several areas layer layer Web-like mater layer Clings to the of the brain Cerebrospinal Fluid ( ) Similar to blood Formed by the Forms a cushion to the brain

9 Circulated in space,, and central of the spinal cord Hydrocephalus in a Newborn CSF and exerts on the brain if not allowed to drain Blood-Brain Barrier Includes the capillaries of the body Excludes many potentially substances Useless as a barrier against some substances and fat soluble molecules gases Traumatic Brain Injuries brain injury No brain damage Nervous tissue occurs Nervous tissue does not Cerebral from the inflammatory response May and brain tissue Cerebrovascular Accident ( ) Commonly called a The result of a blood vessel supplying a region of the brain Brain supplied with from that blood source Loss of some or may result Alzheimer s Disease degenerative brain disease Mostly seen in the, but may begin in middle age changes in the brain include abnormal deposits and

10 fibers within Victims experience loss,, confusion, and ultimately, and Spinal Cord Extends from the of the skull to the or lumbar vertebra pairs of spinal arise from the spinal cord is a collection of spinal nerves at the end Spinal Cord Anatomy Internal matter is mostly (posterior) (ventral) Gray matter surrounds the Central canal is filled with fluid white mater conduction tracts,, columns cover the spinal cord Spinal leave at the level of vertebrae root Associated with the dorsal root collections of cell bodies the central nervous system root Contains Peripheral Nervous System ( ) and the central nervous system Nerve = bundle of neuron Neuron fibers are bundled by tissue PNS: Structure of a Nerve surrounds each Groups of fibers are bound into by Fascicles are bound together by PNS: Classification of Nerves

11 nerves Both and fibers (afferent) nerves Carry impulses the CNS (efferent) nerves Carry impulses from the CNS PNS: Cranial Nerves pairs of nerves that mostly serve the and Only the pair of nerves extend to and cavities Most are nerves, but are sensory only I nerve sensory for II nerve sensory for III nerve motor fibers to muscles IV motor fiber to eye muscles V nerve for the ; fibers to muscles VI nerve fibers to eye muscles VII nerve sensory for ; motor fibers to the VIII nerve sensory for and IX nerve sensory for ; motor fibers to the X nerves sensory and motor fibers for,, and XI nerve motor fibers to and upper XII nerve motor fibers to PNS: Spinal Nerves There is a of spinal nerves at the level of each for a total of pairs Formed by the combination of the and roots of the cord Named for the from which they arise

12 PNS: Anatomy of Spinal Nerves Spinal nerves soon after leaving the rami serve the skin and muscles of the trunk rami form a complex of networks (plexus) for the PNS: Autonomic Nervous System subdivision of the PNS Consists of motor nerves Also known as the nervous system activities of and muscles and glands subdivisions division division PNS: Differences Between Somatic and Autonomic Nervous Systems : motor neuron : and postganglionic nerves organs Somatic: muscle Autonomic: muscle, muscle, and Somatic: always use Autonomic: use,, or PNS: Anatomy of the Sympathetic Division Originates from through are at the trunk (near the spinal cord) pre-ganglionic neuron and post-ganglionic neuron transmit impulse from to the and epinephrine are to the organs PNS: Anatomy of the Parasympathetic Division Originates from the stem and through are at the organs Always uses as a neurotransmitter

13 PNS: Autonomic Functioning Response to stimulus Takes over to activities Remember as the division Exercise,,, and embarrassment activites energy Maintains daily body functions Remember as the division,, and Development Aspects of the Nervous System The nervous system is formed during the month of embryonic development Any infection can have extremely effects The is one of the areas of the brain to develop No more are formed after, but growth and continues for several years The brain reaches weight as a young adult