Presentation is loading. Please wait.

Presentation is loading. Please wait.


Similar presentations

Presentation on theme: "NERVOUS SYSTEM Brain Spinal Cord PERIPHERAL NERVOUS SYSTEM"— Presentation transcript:

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

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

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

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

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

6 NEUROTRANSMITTERS -- 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 Epinephrine Norepinephrine produced by the Adrenal Medulla Acetylcholine -- released at the neuromuscular junction Dopamine -- found only in the brain & helps regulate body movement & facial expression Others: -- Serotonin -- Histamine -- GABA -- Endorphins -- Prostaglandin -- Glutamate

7 SPINAL CORD -- contains 31 pairs of spinal nerves
-- consists of gray & white matter 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 -- found in the columns of white matter -- Ascending Tracts -- carries sensory impulses -- Descending Tracts -- carries motor impulses

8 -- Each spinal nerve is attached to the cord by
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) Corpus callosum
Parietal lobe Frontal lobe Temporal lobe Third ventricle Lateral Fourth Occipital lobe Pons Medulla oblongata Midbrain Thalamus Hypothalamus Cerebellum Pituitary Thalamus & Hypothalamus together is called the Diencephalon

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

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

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

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

15 Medulla Oblongata -- is a relay center & contains many vital functions: 1. Respiratory Center -- regulates rate, depth, & rhythm of respiration -- sensitive to decreased O2, increased CO2, & 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 CEREBELLUM -- aids in the co-ordination of voluntary muscles -- it integrates impulses received from the cerebrum (Frontal Lobe) -- helps maintain balance by receiving information from the inner ear -- aids in muscle tone, so that all muscle fibers are slightly tensed

-- 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 A. Dura Mater -- thickest & toughest layer -- contains sinuses to collect venous blood B. Arachnoid membrane -- middle web-like covering C. Pia Mater -- cerebrospinal fluid flows in the web-like spaces -- thin delicate layer that follows the contour of the brain & spinal cord

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 -- it is formed by the Choroid Plexuses (capillaries in the walls of the ventricles) Pathway: Lateral ventricle Foramen of Munro Third ventricle Aqueduct of Sylvius Fourth ventricle into the subarachnoid space around the brain & spinal cord & returned to the circulatory system

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

22 VI. Abducen Supplies one eye muscle Motor VII. Facial Deals with facial expression taste, salivary & lacrimal glands Both VIII. Vestibulocochlear Hearing & balance Sensory Supplies tongue, parotid gland, & IX. Glossopharyngeal Both muscles for swallowing

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

-- part of the Peripheral Nervous System -- supplies smooth muscles, cardiac muscles, & glands -- functions to maintain homeostasis and is concerned with involuntary functions Sympathetic Parasympathetic --begins in the thoracic region & -- 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 -- acceleration versus slowing down -- sympathetic system is involved with energy expenditure -- parasympathetic system is concerned with restorative process

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, respiratory rate, & inhibits digestive & urinary tract dilates pupils

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


Similar presentations

Ads by Google