Understanding the Nervous System: Structure, Functions, and Neural Communication

1. Maria Buan, Melissa Jonhson, Jane Long p.5 The Nervous System – Ch. 9

2. The Nervous System • Feeling, thinking, remembering, moving • Sends & receives information that stimulates muscles and glands • Brain, spinal cord, neurons, & nerves

3. The Nervous System SENSORY FUNCTIONS • Involuntary actions • Detects changes in the body • Creates sensations • Produces thoughts and memories MOTOR FUNCTIONS • Voluntary actions • Responds to impulse • Muscles & glands • Controls skeletal muscle system

4. The Nervous System • Central Nervous System • Brain & spinal cord • Integrates information • “Control Center” Retrieved from http://www.umm.edu/ graphics/images/en/19588.jpg

5. The Nervous System • Peripheral Nervous System • Sensory & motor neurons throughout body • Receptors and effectors Retrieved from http://www.clipart.dk.co.uk/ 413/ subject/Biology/Nervous_system

6. Neurons • A specialized cell that transmits signals throughout the body • Cell body • Contains dendrites • Contains a nucleus Retrieved from http://scientopia.org/ blogs/scicurious/2011/05/04/science-101-the-neuron/

7. Neurons • Dendrites • Receives information • Axon • directs impulse away • Schwann Cells • Cells that wrap around axon • Produces myelin

8. Neurons Dendrites AxonTerminal Cell Body Axon Nucleus of Schwann Cell Schwann Cell Nucleus Retrieved from http://en.wikipedia.org/wiki/Neuron

9. Neurons Anaxonic Bipolar Unipolar Multipolar Retrived from http://iupucbio2.iupui.edu/ anatomy/images/Chapt13/FG13_10.jpg Retrieved from http://iupucbio2.iupui.edu/ anatomy/images/Chapt13/FG13_10.jpg

10. Synapse • Synapse: A junction between two neurons where an impulse from one neuron is sent to another • Synaptic cleft: space between two neurons

11. Synapse • Synaptic Transmission: Neurotransmitters cross synaptic cleft & bind to receptors of other neuron Retrived from http://scoehealthcoop.wikispaces.com/Neuron+and+Synapse

12. Synapse • Neurons in resting state have negative charge • As impulse move down axon, negative charges become positive, causing action potential Retrived from http://apbrwww5.apsu.edu/t hompsonj/Anatomy

13. Synapse • Action Potential: a rise in the number of positive ions in a neuron’s membrane that allows impulse to move down axon • Causes impulse to move across synaptic cleft to another neuron

14. Major Structures of the Brain • Cerebrum • Diencephalon • Brainstem • Cerebellum Retrieved from http://www.sharpbrains.com/ blog/2011/11/20/research-on-applied- neuroplasciticy-rewiring-the-brain-to-ease-pain/

15. Major Structures of the Brain • Cerebrum • Made up of two hemispheres • Contains 75% of all neurons • Divided into 4 lobes Retrieved from http://www.mayoclinic.com/ health/medical/IM00317

16. Lobes of the Brain Parietal Lobe Frontal Lobe Occipital Lobe Temporal Lobe Cerebellum Brain Stem Retrieved from http://en.wikipedia.org/wiki/File:Lobes_of_the_brain_NL.svg

17. Major Structures of the Brain • Four lobes of the brain: • Frontal: reasoning, planning, emotions • Parietal: orientation, recognition • Temporal: perception, memory, speech • Occipital: visual processing

18. Major Structures of the Brain • Functions of the Cerebrum • Provides higher brain functions • Sensory, motor, & association areas • Dominant hemispherefunctions better in verbal actions, whilenondominant specializes in nonverbal functions

19. Major Structures of the Brain • Diencephalon • Between the hemispheres • Thalamus and hypothalamus • Makes up the limbic system Retrieved from http://en.wikipedia.org/ wiki/File:Illu_diencephalon_.jpg

20. Major Structures of the Brain • Functions of the diencephalon • Receives all sensory impulses • Sensations • Maintains homestasis • Limbic system controls emotions

21. Major Structures of the Brain • Brainstem • Bundle of nervous tissue • Includes midbrain, pons, and medulla oblongata Retrieved from http://sccpsy101.com/home/ chapter-3/section-4/brain_stem/

22. Major Structures of the Brain • Functions of the Brainstem: • Midbrain: eye and head movements • Pons: sends impulses, helps regulate breathing • Medulla Oblongata: contains reflex centers

23. Major Structures of the Brain • Cerebellum • Located at the base of skull • Made of white matter and a thin, outer layer of gray matter Retrieved from http://neuroscience.uth .tmc.edu/s3/chapter05.html

24. Major Structures of the Brain • Functions of the Cerebellum • Communicates with nervous system • Specializes in positions of body parts and coordination of movements • Maintains posture

25. Two Nervous Systems Central • Brain & spinal cord • Processes & interprets info • Sends information to nerves Peripheral • Cranial & spinal nerves • Sends info to muscles and organs • Voluntary & involuntary

26. Autonomic Nervous System • Involuntary movements • Controlled by PNS • Divided into two categories • Sympathetic • Parasympathetic

27. Autonomic Nervous System Sympathetic • Emergency conditions • Leaves spinal cord • Secretes norepinephrine Parasympathetic • Ordinary conditions • Begins in brain and spinal cord • Secretes acetylcholine

28. Somatic Senses • Receptors in the skin, muscles & joints • Senses touch, temperature, pain, pressure Retrieved from http://www.medicalook.com/ human_anatomy/organs/Somatic_senses.html

29. Somatic Senses • Touch and pressure receptors -Senses mechanical forces that disform tissues • Free Nerve-endings • Common in epithelial tissues • Free ends extend between epithelial cells

30. Somatic Senses • Touch and pressure receptors cont. 2) Meissner’s corpuscles • Small, flattened connective tissue cells • Common in hairless parts of the skin • Responds to light touch

31. Somatic senses • Touch and pressure receptors cont. 3) Pacinian Corpuscles • Large connective tissue fiber & cells • Common in subcutaneous layer, muscle, tendons & joint ligaments • Responds to heavy pressure

32. Somatic Senses • Temperature senses • Warm receptors -sensitive to 77˚F(25˚C) or higher -unresponsive at & above 113˚F(stimulate pain receptors) (burning sensation)

33. Somatic Senses • Temperature senses cont. • Cold receptors -sensitive to 50˚F(10˚C)~68˚F(20˚C) -unresponsive below 10˚C (stimulate pain receptors) (freezing sensation)

34. Somatic Senses • Pain receptors • Distributed throughout the skin & internal tissues (NOT so much in the brain) • Once activated, it may send impulses to the CNS. • Thus, pain may persist.

35. Olfactory & Taste receptors • Chemoreceptors : chemicals dissolved in liquids stimulate them • We usually smell & taste food AT THE SAME TIME

36. Olfactory Nerve • Olfactory receptor cells (bipolar neurons) are stimulated by odorant molecules & send nerve impulses. • The fibers synapse with neurons in the olfactory bulbs. • Additional impulses travel along the olfactory tracts to the limbic system.

37. Taste buds • 10,000 taste buds associated with papillae • Taste cells (gustatory cells)=receptors • Every taste bud has 50 ~ 150 receptors

38. Taste Buds • 4 primary taste sensations -sweet: like sugar -sour: like lemon -salty: like salt -bitter: like caffeine

39. Taste Buds • Taste cell CAN respond to more than one taste sensation • Myth= one region of the tongue responds to particular sensation

40. Taste Buds • Sensory impulses travel to the medulla oblongata • Ascend to the thalamus and to the gustatory cortex (parietal lobe)

41. Taste & Smell • Odor and taste information help create the sensation of flavor • Tastants (chemicals in food) and odor molecules are similarly picked up by the cells

42. Taste & Smell • Taste & smell together detect flavor • Example: sick person with a stuffed nose cannot taste anything; loses appetite.

43. Diseases & Disorders • Huntington Disease • Disorder of the brain, involuntary movements and personality changes • Epilepsy • Disorder in CNS, causes seizures and loss of consciousness

44. Diseases & Disorders • Cerebral Palsy • Damaged cerebrum, causes partial paralysis/lack of muscle coordination • Aphasia • Loss of ability to use/understand words due to damage in cerebral association areas

45. Works Cited • "Brain Structures and Their Functions."Serendip Studio. N.p., n.d. Web. 27 Feb. 2013. <http://serendip.brynmawr.edu/bb/kinser • Cherry, Kendra. “What is a Neuron.” About.com Physcology. •  "Anatomy of the Brain - Cerebellum." Biology. N.p., n.d. Web. 27 Feb. 2013. <http://biology.about.com/od/anatomy/p/c

46. Works Cited • "Central Nervous System."Biology. N.p., n.d. Web. 27 Feb. 2013. <http://biology.about.com/od/organsystems/ss/central-nervous-system.htm>. • "Organization of the Nervous System." The Peripheral Nervous System. N.p., n.d. Web. 27 Feb. 2013.