Nervous System
Tissues of the Nervous System Neurons (Neurons, Myelin Sheath) Meninges Spinal Fluid
Parts of the Nervous System Brain Spinal Cord Peripheral Nerves
Vocabulary to Know Homeostasis –The regulation of steady, life-maintaining conditions inside an organism, despite changes in its environment
Nerve Cells Neurons –Basic functioning units of the nervous system
Neurons Made up of a cell body and branches called dendrites and axons –Dendrites receive messages from other neurons and send them to the cell body –Axons carry messages away from the cell body
Any message carried by a neuron is called an impulse
Neurons A message carried by a neuron is called an impulse
Types of Neurons Sensory Motor Interneuron
Sensory Neurons Receive information Send impulses to the brain or spinal cord
Interneurons Send impulses from sensory neurons to motor neurons
Motor Neurons Conduct impulses from the brain or spinal cord to muscles or glands throughout your body
Synapse Small space across which an impulse moves from an axon to the dendrites or cell body of another neuron
Synapse An impulse reaches the end of an axon Axon releases a chemical Flows across the synapse Stimulates the impulse in the dendrite of the next neuron Impulse moves from neuron to neuron
An impulse moves in only one direction across a synapse - from an axon to the dendrites or cell body of another neuron.
Two Parts Central (CNS) Peripheral (PNS)
Central Nervous System Brain Spinal cord
The Brain Coordinates body activities Made up of approximately 100 billion neurons Divided into three major parts- –the cerebrum –the cerebellum –the brain stem.
Cerebrum Largest part of the brain Thinking Memory is stored Movements are controlled Impulses from the senses are interpreted.
Cerebellum Interprets stimuli from eyes, ears, muscles Controls voluntary muscle movements Maintains muscle tone Helps maintain balance
Brain Stem Connects brain to spinal cord Made up of the midbrain, the pons, –Act as pathways connecting various parts of the brain with each other Medulla –controls involuntary actions
The Spinal Cord Extension of the brain stem Bundles of neurons that carry impulses from all parts of the body to the brain and from the brain to all parts of your body
Research Visit the Glencoe Science Web site at tx.science. glencoe.co m for more information about the nervous system. Make a brochure outlining recent medical advances. tx.science. glencoe.co m The Peripheral Nervous System Your brain and spinal cord are connected to the rest of your body by the peripheral nervous system. The PNS is made up of 12 pairs of nerves from your brain called cranial nerves, and 31 pairs from your spinal cord called spinal nerves. Spinal nerves are made up of bundles of sensory and motor neurons bound together by connective tissue. For this reason, a single spinal nerve can have impulses going to and from the brain at the same time. Some nerves contain only sensory neurons, and some contain only motor neurons, but most nerves contain both types of neurons. Somatic and Autonomic Systems The peripheral nervous system has two major divisions. The somatic system controls voluntary actions. It is made up of the cranial and spinal nerves that go from the central nervous system to your skeletal muscles. The autonomic system controls involuntary actions- those not under conscious control- such as your heart rate, breathing, digestion, and glandular functions. These two divisions, along with the central nervous system, make up your body's nervous system.
Peripheral Nervous System Connects body to brain & spinal cord 12 pairs of nerves from your brain (cranial nerves) 31 pairs from your spinal cord (spinal nerves) –Bundles of sensory and motor neurons held together by connective tissue
Cranial Nerves Mnemonics –Names On Old Olympic Tower Tops, A Fin And German Viewed Some Hops –Functions (Sensory, Motor, Both) Some Say Marry Money, But My Brother Says Big Brains Matter More
Cranial Nerves Olfactory – CN I - Sensory Optic – CN II – Sensory Oculomotor – CN III – Motor Trochlear – CN IV – Motor Trigeminal – CN V - Both Abducens – CN VI – Motor
Cranial Nerves (cont.) Facial – CN VII – Both Auditory (Vistibulocochlear) – CN VIII – Sensory Glossopharyngeal – CN IX – Both Vagus – CN X – Both Spinal Accessory – CN XI – Motor Hypoglossal – CN XII - Motor
Upper Extremity Dermatomes
Peripheral Nervous System Two divisions –Somatic –Autonomic
Somatic Nervous System Controls voluntary actions Made up of the cranial and spinal nerves that go from the central nervous system to your skeletal muscles
Autonomic Nervous System Controls involuntary actions-those not under conscious control-such as your heart rate, breathing, digestion, and glandular functions Two Divisions –Sympathetic – “Fight or Flight” –Parasympathetic – “Rest and Digest”
Review Divisions –Central Nervous System (CNS) Brain –Cerebrum –Cerebellum –Brain Stem Spinal Cord –Peripheral Nervous System (PNS) Somatic Nervous System Autonomic Nervous System –Sympathetic –Parasympathetic
Reflexes Involuntary, automatic response to a stimulus Involves a simple nerve pathway called a reflex arc
EXAMPLES OF DISEASES AND CONDITIONS OF THE NERVOUS SYSTEM
Cerebral Palsy Three forms- spastic, athetoid and atactic (spastic most common) Exaggerated reflexes, tense muscles, contracture development, seizures, speech impairment, sometimes mental retardation No cure – Physical, speech, occupational therapy helpful Some benefit with Chiropractic care
Cerebrovascular Accident (CVA) (Stroke) Two types – Occlusive or Hemorrhage Part of brain loses oxygen If not fatal, can lead to partial paralysis, visual disturbances, speech impairments, mental confusion. Occupational, physical, speech therapy Chiropractic Neurology can help with recovery
Epilepsy Seizure Disorder Can be caused by brain damage, but most idiopathic Anticonvulsant medications can be helpful Chiropractic care can be beneficial
Meningitis Inflammation of Meninges Symptoms – fever, HA, neck pain & stiffness, nausea, vomiting Antibiotics, anticonvulsants, pain meds
Parkinson’s Disease Symptoms – Tremors, stiffness, muscular rigidity, shuffling gait, Progressive disease/degeneration of brain cells No cure
Vertebral Subluxation Spinal Misalignment that interferes with nerve impulses Can be asymptomatic Effects muscles, organs and glands innervated by affected nerve Chiropractic adjustment only treatment