I. Functions: a.) Maintains a steady state 1. with fast response = ELECTRICAL signals 2. with slow response = CHEMICAL (HORMONES) signals to the ENDOCRINE system b.) Interprets SENSORY information Lab : Two-point Threshold Test • Purpose : To see if the distribution of Touch Receptors is an indication of size of the area of brain responsible for this reception. • Areas tested = Index finger, forearm, back of neck, back of calf, palm of hand, and lower lip Background • The more touch receptors the better able you are to distinguish 2 touch points. • We want to verify the fact that if you have more touch receptors in an area of the body You must have the larger the area of the brain to receive information from that area. Getting to a hypothesis: • Pick one area you think has the most touch receptors. Then pick one area you think has the least touch receptors – Index finger, forearm, back of neck, back of calf, palm of hand, and lower lip Hypothesis • I think that the most sensitive area of my body is the _____ and the least sensitive are is the ________ • I think the largest sensory area of my brain controls the _________ and the smallest sensory area controls the _______ Procedure • Conduct a two point threshold test on the – Index finger, forearm, back of neck, back of calf, palm of hand, and lower lip – Subject closes eyes while experimenter touched areas using two points at decreasing distance apart. – Subject reports a single or double sensation – Stop when subject can no longer distinguish 2 points. Observations Area 100 50 40 30 20 10 7 5 2 mm mm mm mm mm mm mm mm mm finger arm neck calf palm lip Conclusion • Which area was most and least sensitive? How do you know? • Which somatic area is the largest and smallest? How do you know? • Evaluate hypothesis • Explain what you learned What is the homunculus? • http://faculty.washington.edu/chudler/flash/hom.html • Homunculus animation • Body on the left side is the motor homunculus. The bigger the body parts more brainpower controls it. • The body half on the right is sensory homunculus. • Since the left side of brain controls the right side of the body and vise versa, clicking on an area on the left side of the body will trigger an area on the right side of the brain. To compare different areas, you may click on different parts of the picture. Online link for Homunculus • http://www.cs.uta.fi/~jh/homunculus.html • Be sure to include this information in the what I learned section of you lab report c.) provides higher MENTAL functioning d.) produces EMOTIONAL response e.) activates the MUSCLES for movement 2 3 1 4 13 5 6 12 7 11 10 8 9 II. Divisions: A.By structure: (TWO DIVISIONS) 1. CENTRAL nervous system CNS a.) BRAIN (about 3 pounds) b.) SPINAL NERVE cord (43-45cm) 2.PERIPHERAL nervous system PNS a.) NERVES (neurons) b.) supporting NERVOUS tissue (glia) B. By Functions: (TWO DIVISIONS of PNS) 1.) SOMATIC division a.) Regulation of CONSCIOUS or VOLUNTARY actions b.) pathway : ONE nerve from CNS to MUSCLE b.) pathway : ONE nerve from CNS to MUSCLE 2.)AUTONOMIC division a.) Regulates AUTOMATIC or INVOLUNTARY actions b.) pathway :TWO nerves from CNS to MUSCLE or GLAND c.) further divisions:(TWO) 1.) Parasympathetic division: a.)PEACEFUL, housekeeping division b.) in CONTROL most of the time c.) neutotransmitter = ACETYLCHOLINE. 2.) Sympathetic division: a.) STRESSFUL, action division b.) Usually speeds up actions like HEART RATE, BLOOD PRESSURE, BREATHING RATE c.) Neurotransmitter = NOREPINEPHRINE callosum hypothalamus Lateral ventricle 1 & 2 third ventricle Pituitary gland Protection of the CNS I. Nervous tissue is very SOFT and MUSHY. (consistency of WELL cooked OATMEAL) II. The brain and SPINAL cord are protected THREE ways. a.) BONE surrounds the BRAIN and SPINAL cord. b.)THREE membranes are found under the bone c.) A watery cushion is found within the 3rd MEMBRANES - ventricle CEREBRAL 4th ventricle SPINAL fluid (CSF) III. The Meninges: a.) The Dura MATER 1.) the outermost membrane 2.) DOUBLE layer 3.) Leathery and VERY TOUGH b.) The ARACHNOID mater 1.) the MIDDLE membrane 2.) SPIDERY and weblike 3. ) CSF circulates inside this layer in a space called the SUB-ARACHNOID space. c.) The PIA mater 1.) The INNERMOST membrane 2.) very THIN and delicate 3. ) clings TIGHTLY to each fold of the brain Without With Pia mater Pia mater d.) MENINGITIS - inflammation of the meninges 1.) diagnosed by a SPINAL tap 2.) bacteria treated with ANTIBIOTICS 3.) can be fatal 4.) symptoms = STIFF NECK and SORE THROAT Sagittal Lateral ventricle IV. Cerebrospinal fluid: (125-150 ML) A. Very similar to PLASMA (thick, viscous, sticky, salty to the taste) B. Produced inside the BRAIN 1.) the brain has four cavities called VENTRICLES a.) two LATERAL ventricles (one in each cerebral HEMISPHERE) b.) a third and FOURTH ventricle deep inside the brain 2.) in each cavity is a cluster of blood vessels called CHOROID PLEXUS that makes fluid. (produces 500 ml / day) C.) circulates around BRAIN and SPINAL CORD (protect brain and decreases pressure on the brain stem also circulates hormones) D.) drains into the BLOOD STREAM 1. At the top of the brain projections from arachnoid space called arachnoid villi control rate of drainage 2. Entrance to blood stream called SUPERIOR SAGITTAL SINUS E. ) Obstructions like TUMORS sometimes occur 1.)PRESSURE builds up 2.) CIRCULATION hampered 3.) HYDROCEPHALY occurs (water on the brain) 4.) Can occur in utero 5.) Blockage must be SURGICALLY removed and drainage must be reestablished. Sagittal Lateral ventricle Of lateral ventricle F. Circulation pattern Circulation patters • The ________________________ __________________ Choroid Plexus (1) of the _______________ Lateral Ventricle • __________________________(2) forms the cerebral spinal fluid. This fluid leaves the lateral ventricles through the ________________________ Interventricular Foramen ____________________(3) • It enters the ______________ Third Ventricle _______________________(4) where more cerebral spinal fluid is added by the ______________ Choroid plexus _________________(5) of the third ventricle. Circulation pattern continue • Next the fluid travels down the _____________________ Cerebral Aqueduct __________________(6) • into the ____________________ ______________ (7). Fourth ventricle Here the _______________ • _____________________ (8) of the fourth ventricle adds Choroid Plexus still more cerebral spinal fluid. The fluid can leave the fourth ventricle through one of three holes. There are two _____________________ ___________________(9) and Lateral Foramen one _______________ Median Aperture • ______________________ (10). Circulation pattern continued • Now the fluid enters the ________-_____________ Sub-Arachnoid Space _________________ (11). While it is in this space it circulates around the brain and the spinal cord. Eventually most of the cerebral spinal fluid is absorbed into the venous blood at the _______________________ Arachnoid Villi • ____________ (12). These villi are collection points that direct the cerebral spinal fluid into the _____________________ ________________ Superior Sagittal Sinus ______________ (13). • Approximately ________ml of cerebrospinal fluid is 500 produced and absorbed each day.
Pages to are hidden for
"nervous_"Please download to view full document