Nervous System Health Science Technology I Dr. Wood

Objectives Identify the main parts of a neuron. Describe the function of each of the main parts of the brain. Understand the structure of and the messages sent along the spinal cord. Name the three meninges and their function. Contrast the actions of the sympathetic and parasympathetic nervous system. Understand the major diseases of the nervous system. Define and understand the vocabulary words.

Vocabulary Words Afferent Autonomic nervous system Brain Central nervous system Cerebrospinal fluid CerebellumCerebrumDiencephalonEfferentHypothalamus Medulla oblongata MeningesMidbrain Nervous system NeuronParasympathetic Peripheral nervous system Pons Spinal cord SympatheticThalamusVentricles

Nervous system Complex, highly organized system that coordinates all the activities of the body Allows the body to respond and adapt to changes that occur

Neuron Nerve cell Basic structural unit of the nervous system

Parts of a neuron Cell body: contains the nucleus Dendrites: carry impulses to the cell body Axon: single nerve fiber that carries impulses away from the cell body Myelin sheath: lipid covering around the axon which increases the rate of impulse transmission and insulates the axon Synapses: spaces between the axon of one neuron and the dendrites of other neurons

Central nervous system Consists of the brain and spinal cord

Brain Mass of nerve tissue protected by the skull

Cerebrum Largest section of the brain Divided in to lobes: frontal, parietal, occipital and temporal Responsible for reasoning, memory, speech, sight, smell, hearing, voluntary movement

Cerebellum Responsible for muscle coordination, balance and posture

Diencephalon Contains the thalamus and hypothalamus Thalamus: relay center and directs sensory impulses to the cerebrum Hypothalamus: regulates and controls the autonomic nervous system, temperature, appetite, sleep

Midbrain Conducts impulses between brain parts and for certain eye and auditory reflexes

Pons Below the midbrain Responsible for some reflex actions including chewing, tasting, saliva production

Medulla oblongata Lowest part of the brain stem Connects with the spinal cord and is responsible for regulating heartbeat, respiration, swallowing, coughing and blood pressure

Spinal Cord Continues down from the medulla oblongata and ends at L1 or L2 Protected and surrounded by the vertebrae Carries afferent (sensory) messages up to the brain Carries efferent (motor) messages from the brain to the nerves and then muscles

Meninges Membranes that cover and protect the brain and spinal cord Dura mater: thick outer layer Arachnoid membrane: web like middle layer Pia mater: inner layer attached to the brain and spinal cord and contains blood vessels that nourish the brain

Ventricles Hollow spaces in the brain that connect with each other and the subarachnoid space

Cerebrospinal fluid Fluid in the ventricles, circulates continually, produced by choroid plexus Shock absorber to protect the brain and spinal cord Carries nutrients and helps remove some metabolic waste

Peripheral Nervous System Consists of the cranial and spinal nerves

Somatic nervous system 12 pairs of cranial nerves 31 pair of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal Carry messages to and from the spinal cord, both sensory and motor

Autonomic nervous system Helps maintain a balance in the involuntary functions of the body and allows the body to react in times of emergency 2 divisions: sympathetic and parasympathetic

Sympathetic nervous system In times of emergency, fight or flight response Increases heart rate, respiration & blood pressure

Parasympathetic nervous system Works with the sympathetic nervous system to maintain balance or homeostasis After the emergency, slows heart rate and respiration, lowers blood pressure

Nervous system diseases

Cerebral palsy Caused by brain damage Disturbance in voluntary muscle action

Cerebrovascular accident Blood flow to the brain is impaired either by a hemorrhage or blockage Common symptoms: weakness or paralysis on one side, mental confusion, difficulty swallowing (dysphagia)

Encephalitis Inflammation of the brain Caused by virus, bacteria, or chemical agent Viral infection often carried by mosquito

Epilepsy Seizure disorder Abnormal electrical impulses

Hydrocephalus Excessive accumulation of CSF in the ventricles Abnormally large head, bulging eyes, retardation

Meningitis Inflammation of the meninges Caused by bacteria, virus, fungus or toxins

Multiple sclerosis (MS) Chronic, progressive disabling Results from a degeneration of the myelin sheath

Parkinson’s disease Chronic, progressive involving degeneration of brain cells Symptoms include tremors, stiffness, shuffling gait, loss of facial expression

Shingles Inflammation of nerve cells cause by a herpes virus, which also causes chicken pox Severe pain, vesicles along the nerve path

Paralysis Usually from injury, results in loss of function and sensation below the level of injury Hemiplegia: paralysis on one side Paraplegia: paralysis in legs Quadriplegia: paralysis of arms and legs

Image Citations Slide 5, 7, 8, 10, 23, 26: Delmar Learning’s Medical Terminology Image Library, Second Edition. Version 1.0, ISBN: Slide 9: 1/13/06, The brain and spinal cord, 3.jpg 3.jpg 3.jpg Slide 12: 1/13/06, Cerebellum, pecimens/cerebellum.gif pecimens/cerebellum.gif Slide 13: 1/13/06, Diencephalon, stuttgart.de/phonetik/joerg/sgtutorial/graphic/diencephalon.gif stuttgart.de/phonetik/joerg/sgtutorial/graphic/diencephalon.gifhttp:// stuttgart.de/phonetik/joerg/sgtutorial/graphic/diencephalon.gif Slide 14: 1/13/06, Midbrain and Cerebellum, Slide 15: 1/13/06, Pons, Slide 16: 1/13/06, Hindbrain, images/hindbrain.jpg images/hindbrain.jpghttp:// images/hindbrain.jpg Slide 20: 1/13/06,

Image Citations Slide 21: 1/13/06, Slide 24: 1/13/06, The Peripheral Nervous System, gif gif gif Slide 30: 1/13/06, Sympathetic vs. Parasympathetic, c2/Brain/03.GIF c2/Brain/03.GIF c2/Brain/03.GIF Slide 32: 1/13/06, Cerebral Palsy Images, Slide 36: 1/13/06, Hydrocephalus, Slide 36: 1/13/06, Slide 37: 1/13/06, Meningitis strikes campus,

Image Citations Slide 38: 1/13/06, Slide 39: 1/13/06, pg pg pg Slide 40: 1/13/06, treaments.jpg treaments.jpghttp:// treaments.jpg Slide 41: 1/13/06,