Nervous System

1. Nervous System Honors Anatomy & Physiology Spring 2005

2. The Function • To act as the master _____________________________ system for the body

3. Central Nervous System (CNS) Includes _________ and spinal cord Acts as integrating and ___________ ______________ Peripheral Nervous System (PNS) Includes nerves outside of CNS ________________ Cranial nerves Links all parts of body by _______________ impulses Structural Classifications

4. PNS Assignment • There are 12 cranial nerves (pgs. 220-221) You are responsible for knowing their number, name and function. For example: Cranial nerve I: olfactory, sense of smell Quiz to be announced!!

5. Subdivisions of PNS • 1.) ________________________: voluntary nervous system • Contains __________ and motor nerves • Makes you aware of the world around you & allows you conscious control

6. Subdivisions of PNS • 2.) Autonomic System: involuntary nervous system • Consists of motor nerves that carry impulses to _______________, blood vessels and glands • The unconscious or “_____________________________”

7. A. Sympathetic division Active during stress  heart rate, respiratory rate and rate of __________ breakdown B. Parasympa-thetic Division Active during conditions of ______________ ______________ ______________ Subdivisions of Autonomic System

8. Cells of the Nervous System • 1. _________________ • Acts to support neurons • Makes up ~ _____% of brain and spinal cord (s.c.) • There are 5 different types of neuroglial cells

9. Assignment • Using page 194 in your text, draw the different types of neuroglia and list their location and function within the nervous system below each drawing • DO NOT draw Schwann cells but do list its location and function

10. Cells of the Nervous System • 2. Neurons • The conducting nerve cell • Senses ___________________ environment, integrates information, carries out motor responses • Structure: each _______________ varies in shape and size, but all have 3 main parts (dendrite, axon and cell body)

11. Neuron Anatomy A. _________________: a process off of the cell body; receives impulses from adjacent neurons & conducts _______________ impulses TOWARD the cell body; ~1000/neuron

12. Neuron Anatomy B. Axon: aka ______________; acts to transmit impulses AWAY from the cell body; 1 axon/neuron C. Cell Body: contains the nucleus and _______________ center of the cell

13. Neuron Anatomy D. Myelin sheath: made by __________________ in PNS and oligodendrocytes in CNS; encloses the ____________ & speeds up the rate of nervous conduction i. Gray matter: non-myelinated nerve fiber ii. White matter: myelinated nerve fiber

14. Neuron Anatomy E. Nodes of ________________: gaps in ___________________ @ regular intervals; aids in increasing speed of nervous conduction

15. 3 Types of Neurons 1. Afferent (_____________) Neurons: transmit impulses from PNS to CNS i.e. pain receptors and proprioceptors 2. Efferent (motor) Neurons: transmit impulses _____________ to muscles or glands

16. 3 Types of Neurons 3. _______________________ (association neurons): located within CNS and conducts impulses between _______________ and _______________ neurons

17. Nervous System Ongoing Assignment • Based on notes and class discussion, you should be able to answer the following questions. This is an on-going assignment: 1. What are the organs of the CNS? 2. What body structures receive their nerve supply from the autonomic system?

18. Assignment Continued 3. Which neuroglial cells are found in the CNS? 4. What 3 structural features do all neurons have in common? 5. In what direction do impulses travel as they pass through the axon? 6. What are the 3 functional distinctions of neurons?

19. Left Brain Language Logic _______________ Scientific Skill Numbers R hand control Right Brain Visual/spatial info. _______________ Insight 3-D forms Musical Awareness _______________ Central Nervous System

20. Assignment • Go to http://www.mindmedia.com/ and take the right brain/left brain quiz Print out your results and bring to class

21. CNS: Spinal Cord • A _________________ of the brain running from base of brain to 1st or 2nd lumbar vertebrae • Is enclosed within spinal column • Is ~ size of ____________ except at enlarged cervical and lumbar plexuses (spinal nerve distribution to upper and lower limbs)

22. CNS: Spinal Cord • Provides a _______________ pathway to and from the brain • Serves as a reflex center • Has _______ linear segments giving way to 31 spinal nerves (relay info. from PNS to CNS and vice versa) • ________________: collection of spinal nerves at the inferior end of the vertebral column

23. Spinal Cord Cross-Section • Gray Matter: unmyelinated • Located in center of cord forming an “H” • _______________________: upper “arms” of H; contains terminal ends of sensory neurons • Anterior Horn: lower “legs” of H; contain cell bodies of motor neurons • Lateral Horn: between post. & ant. horns; contain cell bodies of _____________________ found within autonomic nervous system

24. Spinal Cord Cross-Section • ___________ Commissure: horizontal bar connecting right and left sides of the “H” • Central Canal: in center of gray commissure; carries __________________________ throughout canal

25. Spinal Cord Cross-Section • White Matter: myelinated fibers • Surrounds central gray matter • Divided into __________________, posterior and lateral columns • Each column holds longitudinal nerve tracts • _______________________: carry sensory info to brain • Descending tracts: carry motor info. away from brain

26. Reflex Center • _______________: an extremely rapid response to an emergency situation • Occurs in spinal cord or ________________; does not require thinking • The Reflex Arc: • Receptor: at end of sensory neuron; can generate an action potential to ____________ • Association neurons: receive info. from sensory neuron and routes response to motor neuron • Motor neurons: conduct impulses to effectors

27. ____________: skull and vertebral column _________________ (CSF): Made from the blood Forms a watery cushion that protects tissue from trauma Changes in composition indicates brain pathology Protections of CNS

28. Protections of CNS • ___________________: connective tissue membranes • A. Dura mater: tough outer covering of brain and s.c. • B. Arachnoid mater: middle layer • C. _________________: inner surface which clings tightly to surface of brain and s.c. • _________________________: separates the arachnoid and pia maters; filled with CSF

29. Protections of CNS • _________________________ • Composed of least permeable capillaries in body • Brain depends on a very constant internal environment • Allows: water, glucose, and essential amino acids • Disallows: ________________________________ _________________________________________ • Cannot block: fats, respiratory gases and fat soluble molecules (alcohol, nicotine and anesthetics)

30. Nervous System Ongoing Assignment 7. How is the high sodium ion concentration maintained on the outside of the plasma membrane? 8. The rapid movement of which ions into the cell leads to depolarization? 9. What two changes in the plasma membrane lead to repolarization? 10. What is the chemical that carries an impulse between the synaptic cleft between neurons?

31. Nervous System Ongoing Assignment 11. What is the outermost meningeal layer? 12. How does the posterior gray horn differ functionally from the anterior gray horn in the spinal column? 13. What are the conduction tracts in the spinal column? 14. What are the components of a reflex arc?