The Nervous System: Central Nervous System I. Anatomy of the nervous system A. The CNS & the body by: 1. monitoring of the body 2. & information between parts of the body 3. acting as a to gather, store, integrate, and recall information 4. working closely with the system in maintaining B. The Central Nervous System is divided into two parts 1. 2. C. The Three layers of tissue that & the brain & spinal cord 1. outermost; very tough, white, fibrous connective tissue. ( space space outside of dura mater with lots of blood vessels.) 2. middle; network of fibers that forms a web-like structure. a. space under the arachnoid that is filled with ; protects against mechanical injury by acting as a shock absorber. b. fluid in & around the surfaces of the CNS; the tissue, and acts as a shock absorber; aids in of various diseases of the CNS. 3. inner; very delicate & contains many blood vessels to nourish the cells of the brain & spinal cord. II. The Spinal Cord A. Location 1. The spinal cord is with the and emerges from the 2. It extends downward through the and ends at or of the vertebral column. 3. At its termination it branches into many smaller nerves called (horse s tail). 4. The spinal cord is protected from injury by the B. Structure 1. A cross-section of the spinal cord reveals matter surrounding an central portion. 2. The 4 projections of matter are called the Horns and Horns. 3. The horns give rise to nerve roots at various intervals, which in turn give rise to the spinal nerves ( pairs) which connect to the various parts of the. 4. The posterior roots bring (afferent) nerves; the anterior roots carry (efferent) nerves. 1
5. The of the gray matter is the, which connects the left & right sides. 6. In the center of the gray commisure is a, which runs the length of the spinal cord. It is called the It contains cerebrospinal fluid, which circulates inside & outside the spinal cord to provide & 7. The white matter is organized into 3 columns. These contain mylenated nerves to speed up the conduction of impulses up & down the spinal cord. a. white column, white column, & white columns b. Ascending tracts carry impulses toward the brain; descending tracts carry impulses from the brain to various effectors. C. Functions of the spinal cord 1. of nerve impulses up & down its length. 2. Acts as a center for D. The Reflex Arc 1. A reflex is an, response to a change in the It helps to maintain 2. 3. Five parts of a reflex: a. Starts at the, which is stimulated by a change in the b. This sends an down a sensory neuron toward the c. The impulse comes into the spinal cord along a root and connects to an neuron where information processing occurs. d. After selection of the appropriate response, specific neurons are activated and carry the signal out of the root. e. The response impulse will eventually activate effectors (such as a gland or muscle) thus countering the original stimulus. 4. The reflex is a form of so that, instead of a sensory impulse traveling all the way to the and back down to cause an, it is done thus make the response time much 5. reflexes are the simplest reflexes which people are usually born with ( ); reflexes are learned responses ( ). III. The Brain A. The brain is divided into three major regions. 1. largest portion of the brain; contains centers for & functions; responsible for mental functions such as & 2. coordinates 2
3. (,,, & ) interconnects various parts of the nervous system & regulates various activities. B. The Cerebrum 1. Divided into cerebral hemispheres by the A bridge called the connects the hemispheres. 2. On the surface there are ridges ( ) and grooves ( ). The gyri & sulci increase the thus accommodating a greater number of 3. Lobes of the Cerebrum: the cerebral cortex is divided into four lobes named for the cranial bones, which overlay them. a. lobe 1) area control movements of the voluntary muscles. 2) area concentration, judgement, planning, complex problem solving, & consequences of behavior. b. lobe 1) area centers for touch, temperature, pressure, & pain of skin. 2) area speech, using words to express thoughts and feelings. c. lobe 1) area hearing 2) area interpretation of sensory experiences, memory of visual senses, music, complex sensory patterns. d. lobe 1) area vision 2) area combining visual images with other sensory experiences. 4. is a thin layer of gray matter that covers the bulk of the cerebrum. Most of the cerebrum is composed of matter. 5. Functions of the cerebrum a. of sensory impulses b. muscle contractions c. stores information for & this data for d. determines a person s and C. The Cerebellum 1. The separates the cerebrum & cerebellum. 2. The divides the cerebellum into two hemispheres. 3. It is composed mostly of white matter, but like the cerebrum, it has a thin layer of gray matter covering the outer surface called the 4. The arrangement if gray & white matter resembles a tree and thus is called the (Tree of Life). 3
5. Function of the cerebellum center for of voluntary & involuntary D. The connects the brain to the spinal cord; coordinates & integrates information between the brain and spinal cord. 1. The large bulge at the top of the brainstem a. contains nerve tracts which connect the & b. contains part of the center. 2. The has the same make-up as the spinal cord: white matter surrounding an H-shaped gray matter center. a. portion of the brain b. connects the to the cord c. - the phenomenon where the left side of the brain controls the rt. side of the body & vice versa. d. Functions 1) controls 2) controls (vasomotor center) 3) controls rate (with the pons) 3. The (Mesencephalon) - shortest portion of the brain located between the pons and diencephalon a. contains mostly white matter in the form of great fiber tracts b. connects the & with the, & 4. The (Interbrain) located near the center of the brain it contains the,,, & a. central relay for all (except smell). b. gland endocrine structure which secretes ; thought to control melanin production and (periods of wakefulness & sleep). c. system involved with states and drives; works with our to determine our state of d. regulates by serving as a link between the & systems. Functions include: 1) regulate 2) regulate 3) regulate 4) controls (hunger, thirst, rage, pleasure, etc.) 5) controls the 6) coordinates activities of the 4
E. Cranial Nerves Name Type Effect I. Olfactory sensory smell II. Optic sensory vision III. Oculomotor motor focus, pupil, eyelids IV. Trochlear motor move eyes V. Trigeminal mixed tears, move eyes, senses forehead VI. Abducens motor move eyes VII. Facial mixed taste, facial expressions VIII. Auditory sensory hearing, equilibrium IX. Glossopharyngeal mixed swallowing, salivary glands X. Vagus mixed various thoracic organs XI. Spinal accessory motor muscles of the neck & back XII. Hypoglossal motor move tongue F. The Ventricles 1. The ventricles are a series of, chambers inside the brain that are filled with fluid. 2. The largest cavities are called the (a.k.a. the I & II ventricles) and are located within each cerebral hemisphere. 3. The Ventricle is located in the center of the (interbrain) and is connected to the lateral ventricles. 4. The Ventricle is located posterior to the & It is connected to the 3 rd ventricle via the (cerebral) Aqueduct. 5. The 4 th ventricle narrows at the bottom & becomes continuous with the central canal of the spinal cord. It also communicates with the space. IV. The (ANS) part of the nervous system that functions without conscious effort. Two parts: A. Division active in times of ; produces the response. B. Division active under conditions. V. The machine used to measure & record electrical activities of the brain. A. Used to many types of brain B. (EEG) printed record of electrical activity. C. Brain waves are different patterns of electrical activity. 1. resting, awake adults 2. two types a. beta 1 sleep b. beta 2 or tension 3. in normal & in or stressed adults 4. in, in deep sleep, or in, brains 5
VI. Disorders of the CNS A. nonprogressive, incurable disorder that affects 1. Caused by brain during latter development, at or early B. or uncontrollable muscle contractions with or without the loss of 1. Due to sudden activity (or storms) in the brain 2. Two types a. (5-20 sec.) sever twitch-like contractions b. (20 sec. 5 min.) person falls down, the entire body stiffens, and than the body jerks uncontrollably. After the seizure, the person may be dazed & confused, and the person will be very tired and sore. 3. First Aid: do restrain the person or try to move them unless they are in 4. Treatment with or drugs or surgery in extreme cases. C. progressive, incurable disorder of the basal ganglia of the cerebral cortex due to a lack of the neurotransmitter dopamine. 1. Causes increased, stiffness & weakness which result in, slow movements, and a shuffling, 2. Treatment with the drug can help lessen the effects of the disease. D. (Stroke) tissue death of part of the brain due to a clot or hemorrhage within the brain. Stroke test: S.T.R. =,, both arms E. progressive, incurable of the nerve cells. 6