Anatomy: Unit 2 Nervous System--Cells and Organization
- 1. ANATOMY Unit 2 Notes: Cells & Organization
- 2. (1) Neurons • Neuron = Nerve Cell • Types: Multipolar + Unipolar • Basic Structural Components: – Dendrites (Incoming) – Cell Body (Integrate + Process) – Axon (Outgoing) – Myelin Sheath (Insulation + Speed) – Axon Terminal (Final Destination)
- 5. (2) Unipolar Neurons • Use: Afferent Input (Sensory Input) • Main Job: – Get message to CNS – Let CNS process and decide (NO need to have cell body right by dendrites) • Process: – Dendrites connected to sensory organ – Message sent to cell body Out Axon – Message sent out of axon terminal
- 7. (3) Multipolar Neurons • Use: Efferent Output (Motor Output) • Main Job: – Organize messages by importance – Make organs do things (Important to have cell body right next to dendrites) • Process: – Cell body directly connected to dendrites – Dendrites coming from CNS / Efferent path effected organ
- 9. (4) Neuroglia • Function: Support, insulate and protect neurons. – Cannot transmit nerve impulses – Can continuously divide through mitosis • Types: – Astrocytes – Microglia – Ependymal – Oligodendrocytes – Schwann Cells & Satellite Cells
- 10. (5) Astrocytes • Connect neurons to capillaries • Transfer blood-nutrients to neurons (and neuron waste to blood)
- 13. (6) Microglia • Phagocytize neuron debris and infectious agents.
- 15. (7) Ependymal Cells • Pillow-Shaped cells • Line brain and spinal cord cavities • Beat cilia + Circulate cerebrospinal fluid • Provide Shock Absorption
- 17. (8) Oligodendrocytes • Flat, Straw-Shaped cells • Wrap around a neuron’s axon • Fatty insulation for axon (myelin sheath)
- 19. (9) Schwann & Satellite Cells • Schwann Cell: –Form Myelin Sheath around axons –Cover Oligodendrocytes • Satellite Cell: –Protective Cushioning –Surround Cell body of neurons
- 20. (10) Junctions • Junction = Meeting of Neuron + Neuron or Neuron + Organ – A.K.A. Synapse, Synaptic Cleft • Nerve Impulse Axon Axon Terminal Release Neurotransmitter – Neurotransmitter = Chemical Message – Causes an effect – Binds with cell membrane on other side
- 22. (11) Nervous System Organization CENTRAL NERVOUS SYSTEM PERIPHERAL NERVOUS SYSTEM (SENSORY / AFFERENT INPUT) PERIPHERAL NERVOUS SYSTEM (MOTOR / EFFERENT OUTPUT) BODY (INITIAL STIMULUS / IMBALANCE) AUTONOMIC (INVOLUNTARY) SOMATIC (VOLUNTARY) PARASYMPATHETIC (REST & DIGEST) SYMPATHETIC (FIGHT / FLIGHT)
- 23. (12) Defining the Levels • Sensory = Afferent = Going to the CNS • Motor = Efferent = Going away from the CNS • Somatic = Voluntary • Autonomic = Involuntary • Sympathetic = Emotional • Parasympathetic = Non-Emotional
- 24. (13) Voluntary Responses • Voluntary = You consciously choose to move a body part / respond. • Pathway: Stimulus Sensory / Afferent Division Central Nervous System Motor / Efferent Division Effector Organ Somatic Division
- 25. (14) Involuntary Emotional Responses • Involuntary = Without control. • Emotional = Scared, Anxious, Angry, Happy, Excited • Pathway: Stimulus Sensory / Afferent Division Central Nervous System Motor / Efferent Division Effector Organ Autonomic Division Sympathetic Division
- 26. (15) Involuntary Non-Emotional Responses • Involuntary = Without control. • Non-Emotional = Every day homeostatic mechanisms. • Pathway: Stimulus Sensory / Afferent Division Central Nervous System Motor / Efferent Division Effector Organ Autonomic Division Parasympathetic Division