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NERVOUS SYSTEM CENTRAL NERVOUS SYSTEM (CNS) Brain Spinal Cord PERIPHERAL NERVOUS SYSTEM Cranial & Spinal Nerves Somatic -- supplies the skeletal muscles.

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Presentation on theme: "NERVOUS SYSTEM CENTRAL NERVOUS SYSTEM (CNS) Brain Spinal Cord PERIPHERAL NERVOUS SYSTEM Cranial & Spinal Nerves Somatic -- supplies the skeletal muscles."— Presentation transcript:

1 NERVOUS SYSTEM CENTRAL NERVOUS SYSTEM (CNS) Brain Spinal Cord PERIPHERAL NERVOUS SYSTEM Cranial & Spinal Nerves Somatic -- supplies the skeletal muscles & skin Autonomic Nervous System (ANS) 1. Sympathetic Nervous System 2. Parasympathetic Nervous System -- supplies smooth muscles, cardiac, & glands

2 NEURON -- structural unit of the nervous system -- conducts impulse towards the cell body -- contains the nucleus -- conducts impulses away from the cell body Dendrites Cell Body Axon

3 Nervous tissue contain cells called Neuroglial (glial) -- supply nutrients -- cleans up debris -- assist in the production Cerebrospinal fluid Schwann Cell -- is that part of the Schwann cell that contains the nucleus & allows for regeneration of the nerve -- type of neuroglial cell found outside the CNS & forms the Myelin Sheath a connective tissue that binds nerve fibers together Neurilemma Sheath

4 Nodes of Ranvier Synapse or Synaptic Cleft -- junction between the Axon of one neuron & the Dendrite of another -- are bare spots where myelin is not present The Myelin sheath acts as an insulator & speeds up nerve transmission to the next & further increase speed of transmission -- allows impulse to jump from one node

5 TYPES OF NEURONS MOTOR (EFFERENT) SENSORY (AFFERENT) send impulses to the brain & spinal cord send impulses away from the brain & spinal cord found only in the CNS & can be sensory or motor INTERNEURON --the more complex the required action, the greater the number of interneurons involved

6 NEUROTRANSMITTERS Epinephrine Norepinephrine produced by the Adrenal Medulla Dopamine-- found only in the brain & helps regulate body movement & facial expression -- Serotonin-- Histamine -- GABA-- Endorphins -- Prostaglandin -- Glutamate Others: -- are certain chemicals releases from the axon of one neuron that changes the permeability of allow Sodium into the cell the cell membrane of the receiving neuron to Acetylcholine-- released at the neuromuscular junction

7 SPINAL CORD -- contains 31 pairs of spinal nerves 1. It is a pathway for conducting impulses to and from the brain & spinal cord 2. It is an area of reflex activity Spinal Tracts are nerve fibers in the cord -- Ascending Tracts -- carries sensory impulses -- Descending Tracts -- carries motor impulses -- consists of gray & white matter -- found in the columns of white matter

8 Spinal Roots -- Each spinal nerve is attached to the cord by 2 roots or horns located in the gray matter Ventral Root -- carries motor signals Dorsal Root -- carries sensory signals -- these roots are combined in the spinal nerve as it leaves the vertebral column making all spinal nerves Mixed Nerves -- Areas where roots combine: Cervical -- serves muscles & skin of neck & diaphragm (Phrenic Nerve) Brachial -- serves muscles & skin of the arms & hands (Radial Nerve) Lumbosacral -- serves muscles & skin of lower abdomen, genitalia, legs & feet (Sciatic Nerve)

9 CEREBRUM -- contains 2 hemispheres ( right & left) Frontal lobe Thalamus HypothalamusPituitary Corpus callosum Parietal lobe Temporal lobe Occipital lobe Cerebellum Pons Medulla oblongata Midbrain Third ventricle Lateral ventricle Fourth ventricle Thalamus & Hypothalamus together is called the Diencephalon

10 FUNCTIONS OF THE HYPOTHALAMUS 1. Body Temperature 2. Some emotions, such as fear & pleasure 4. Control of the Pituitary gland 5. Water balance 6. Appetite 7. Sleep 8. Center for mind over body phenomena 3. Control of the Autonomic Nervous System Link between nervous & endocrine systems

11 Cerebral Cortex Cerebral Cortex (Cerebrum) -- area of brain responsible for consciousness & functions in intelligence Major Functions 1. Sensory perception 2. Voluntary control of movement 3. Language 4. Personality Traits 5. Sophisticated mental events a. Thinking b. Memory c. Decision making d. Creativity e. Self-consciousness --tissues of the brain are convoluted Gyri Sulci

12 Lobes of the Brain -- thought association -- judgement -- discrimination -- control of skeletal muscles Frontal Lobe (damage to this area causes APHASIA ) -- understanding speech & using speech to express thoughts & feelings -- sensory area for pain, touch, & temperature Parietal Lobe -- Broca center located in the left hemisphere

13 -- sensory area for hearing & smelling Temporal Lobe -- interpreting what we see, hear, and smell Occipital Lobe -- responsible for vision -- combining visual images -- These areas when stimulated or depressed will result in certain expected symptoms

14 BRAIN STEM -- connects cerebellum, brain stem, spinal cord & cerebrum -- acts as a relay center for sight, hearing, & feeling -- helps to regulate breathing along with the Medulla -- reflex center concerned with head movement in response to visual & auditory stimuli Midbrain Pons -- also acts as connection for the cerebrum & spinal cord

15 -- is a relay center & contains many vital functions: Medulla Oblongata 1. Respiratory Center -- regulates rate, depth, & rhythm of respiration -- sensitive to decreased O 2, increased CO 2, & change in pH 2. Cardiac Center -- regulates rate & force of the heart beat 3. Vasomotor Center -- contracts or dilates blood vessels to regulate blood pressure

16 -- also contains cough, vomiting, & swallowing centers -- may affect hiccups -- area where nerve fibers shift so that right side of brain control left side of body & visa versa -- Reticular Activating System (RAS) area between the Pons & Medulla responsible for keeping us awake

17 -- aids in the co-ordination of voluntary muscles -- aids in muscle tone, so that all muscle fibers are slightly tensed CEREBELLUM -- helps maintain balance by receiving information from the inner ear -- it integrates impulses received from the cerebrum (Frontal Lobe)

18 CEREBROVASCULAR ACCIDENT (CVA) -- a disorder of the blood system to the cerebrum resulting in death of tissue -- also called a Stroke -- may be due to a blood clot or broken blood vessel -- area of dead tissue is called an Infarct ISCHEMIA -- a deficiency of blood to a body part Transient Ischemic Attack (TIA)

19 Central Nervous System is protected by: 1. Skull & vertebrae 2. Meninges -- thickest & toughest layer -- contains sinuses to collect venous blood -- middle web-like covering -- cerebrospinal fluid flows in the web-like spaces -- thin delicate layer that follows the contour of the brain & spinal cord B. Arachnoid membrane C. Pia Mater A. Dura Mater

20 Cerebrospinal Fluid -- occupies the spaces between the middle layer of the meninges -- it cushions & nourishes the brain & spinal cord -- it is obtained from the circulatory system Pathway:Lateral ventricleForamen of Munro Third ventricleAqueduct of Sylvius Fourth ventricleinto the subarachnoid space around the brain & spinal cord & returned to the circulatory system -- it is formed by the Choroid Plexuses (capillaries in the walls of the ventricles)

21 CRANIAL NERVES On Old Olympus, Towering Tops, A Fin Visiting Germany Viewed Some Hops II. OpticSight Sensory III. Oculomotor Controls eye muscles Motor IV. Trochlear Supplies one eye muscle Motor V. Trigeminal Deals with pain, touch, & temperature of the face Supplies muscles for chewing Both I. OlfactorySmellSensory

22 BothDeals with facial expression taste, salivary & lacrimal glands VII. Facial VI. AbducenMotor Supplies one eye muscle VIII. Vestibulocochlear SensoryHearing& balance IX. Glossopharyngeal muscles for swallowing Supplies tongue, parotid gland, & Both

23 X. Vagus Both Supplies thoracic & abdominal organs and digestive glands -- when stimulated can drop the heart rate XI. Spinal Accessory Supplies muscles of neck & back XII. Hypoglossal Motor Allows for tongue movement Motor

24 AUTONOMIC NERVOUS SYSTEM AUTONOMIC NERVOUS SYSTEM (ANS) -- part of the Peripheral Nervous System -- supplies smooth muscles, cardiac muscles, & glands -- functions to maintain homeostasis and is concerned with involuntary functions --begins in the thoracic region & SympatheticParasympathetic -- begins in the cranial area & in the lower sacral area extends to the 2nd lumbar spinal nerve

25 Function of the Sympathetic & Parasympathetic Nervous Systems -- Sympathetic nervous system stimulates while the Parasympathetic inhibits the activity of a given organ -- accelerationversusslowing down -- parasympathetic system is concerned with restorative process -- sympathetic system is involved with energy expenditure

26 FUNCTIONS OF THE AUTONOMIC NERVOUS SYSTEM SYMPATHETIC RESPONSE ORGAN PARASYMPATHETIC RESPONSE Increase rate HEART Decrease rate (to normal) Dilate BRONCHIOLES Constrict (to normal) (Smooth muscle) Pupils dilate IRIS Pupils constrict (to normal) Decrease secretion SALIVARY GLANDS Increase secretion (to normal) Decrease peristalsis STOMACH & INTESTINES Increase peristalsis for (Smooth muscle) normal digestion Decrease secretion STOMACH & INTESTINES Increase secretion for (Glands) normal digestion Contracts to prevent INTERNAL ANAL Relaxes to permit defecation defecation SPHINCTER Relaxes to prevent URINARY BLADDER Contracts for normal urination urination

27 Fight or Flight Syndrome -- what happens to our body when under stress ; whether frightened or angry -- increases heart rate, dilates pupils respiratory rate, & inhibits digestive & urinary tract

28 -- Most organs receive both Sympathetic & Parasympathetic stimulation -- Like the gas pedal and a brake on a car

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