Nervous System Notes Part 1

Nerve impulses to and from the brain travel as fast as 170 miles per hour. INTERESTING NERVOUS SYSTEM FACTS The brain operates on the same amount of power as 10- watt light bulb Your brain generates as much energy as a small light bulb even when you’re sleeping.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the Nervous System Figure 7.1

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of the Peripheral Nervous System  Sensory (afferent) division  Nerve fibers that carry information to the central nervous system  Motor (efferent) division  Nerve fibers that carry impulses away from the central nervous system

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organization of the Nervous System Figure 7.2

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of the Peripheral Nervous System  Motor (efferent) division (continued)  Two subdivisions  Somatic nervous system = voluntary  Autonomic nervous system = involuntary

NOTES – THE CENTRAL NERVOUS SYSTEM (CNS) Central Nervous System 2 parts1. brain 2. spinal cord

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain  Cerebral hemispheres (cerebrum)  Diencephalon  Brain stem  Cerebellum

The Cerebrum Cerebral Cortex gray matter on the surface of the cerebrum enables us to perceive, communicate, remember, understand, appreciate and move voluntarily (consciousness)

3 functional areas of the Cerebral Cortex 1. Motor Areas controls movements of skeletal muscles, speech and eyes 2. Sensory Areas conscious awareness of sensations (hot, cold, pressure, pain) 3. Association Areas connect different parts of the cortex involved in recognizing smells, tastes, etc.

Examples of Association Areas sensory association areas visual association areas auditory association areas general interpretation area: integrates all incoming signals into a single thought prefrontal cortex: most complicated part of brain – intellect and complex learning (abstract ideas, judgment, reasoning)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum Figure 7.12b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum  Cerebral Hemispheres (Cerebrum)  Paired (left and right) superior parts of the brain  Includes more than half of the brain mass  The surface is made of ridges (gyri) and grooves (sulci)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum  Lobes of the cerebrum  Fissures (deep grooves) divide the cerebrum into lobes  Surface lobes of the cerebrum  Frontal lobe  Parietal lobe  Occipital lobe  Temporal lobe

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum Figure 7.13b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum  Specialized areas of the cerebrum  Primary somatic sensory area  Receives impulses from the body’s sensory receptors  Located in parietal lobe  Primary motor area  Sends impulses to skeletal muscles  Located in frontal lobe  Broca’s area  Involved in our ability to speak

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum Figure 7.13c

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum Figure 7.14

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum  Cerebral areas involved in special senses  Gustatory area (taste)  Visual area  Auditory area  Olfactory area

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum  Interpretation areas of the cerebrum  Speech/language region  Language comprehension region  General interpretation area

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum Figure 7.13c

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum  Layers of the cerebrum  Gray matter—outer layer in the cerebral cortex composed mostly of neuron cell bodies  White matter—fiber tracts deep to the gray matter  Corpus callosum connects hemispheres  Basal nuclei—islands of gray matter buried within the white matter

Cerebral White Matter functions to provide communication between cerebral areas also provides communication between cerebrum and the rest of the brain

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebrum Figure 7.15

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon  Sits on top of the brain stem  Enclosed by the cerebral hemispheres  Made of three parts  Thalamus  Hypothalamus  Epithalamus

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon Figure 7.12b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon Figure 7.16a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon Figure 7.16b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon  Thalamus  Surrounds the third ventricle  The relay station for sensory impulses  Transfers impulses to the correct part of the cortex for localization and interpretation

What the hypothalamus controls Autonomic Control Center blood pressure, heart rate, digestive tract, eye pupil (involuntary responses) Emotional Responses pain perception, pleasure, fear, etc. (limbic system) body temperature, hunger, thirst, sleep endocrine system hormones Hypothalamus Disturbances body wasting, or obesity, sleep problems, dehydration, emotional imbalances, and more

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Diencephalon  Hypothalamus (continued)  An important part of the limbic system (emotions)  The pituitary gland is attached to the hypothalamus

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Brain Stem  Attaches to the spinal cord  Parts of the brain stem  Midbrain  Pons  Medulla oblongata

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Brain Stem Figure 7.16a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Brain Stem  Midbrain  Mostly composed of tracts of nerve fibers  Has two bulging fiber tracts— cerebral peduncles  Has four rounded protrusions— corpora quadrigemina  Reflex centers for vision and hearing

Parts of the Brain BRAINSTEM (4 parts) 1. Medulla Oblongata Function: regulation of heart rate, breathing, swallowing, vomit response, coughing, sneezing all involuntary actions

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Brain Stem  Medulla Oblongata  The lowest part of the brain stem  Merges into the spinal cord  Includes important fiber tracts  Contains important control centers  Heart rate control  Blood pressure regulation  Breathing  Swallowing  Vomiting

2. Pons functions as a bridge between the cerebrum and cerebellum

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Brain Stem  Pons  The bulging center part of the brain stem  Mostly composed of fiber tracts  Includes nuclei involved in the control of breathing

4. Reticular Activating System (RAS) located scattered in the brainstem functions in arousing & maintaining consciousness damage here results in a coma 3. Midbrain functions in hearing and visual reflexes

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Reticular Formation of the Brain Stem Figure 7.16b

Cerebellum processes inputs of cerebral cortex and sensory receptors results in smooth, coordinated movements of skeletal muscles injury results in loss of muscle tone and coordination

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebellum  Two hemispheres with convoluted surfaces  Provides involuntary coordination of body movements

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Regions of the Brain: Cerebellum Figure 7.16a

Brain Disorders (some examples) Parkinson’s Disease deficiency of the neurotransmitter dopamine Epilepsy sudden burst of irregular electrical activity in brain – can lead to seizures, convulsions Stroke blood clot in brain – paralysis appears on side of body opposite to side of brain affected Alzheimer’s Disease part of cortex shrinks, neurons lost results in dementia, memory loss, disorientation, loss of body function