1 / 15

The Nervous System: Neurons & Neuroglial Cells, & Synapses

The Nervous System: Neurons & Neuroglial Cells, & Synapses. pp. 222-230. Central vs. Peripheral NS. General Pathway. Animation Sensory receptors – on dendrites of peripheral nerves (PNS), activated by stimuli Sensory/Afferent neurons – sensory input to CNS, cell bodies in PNS

dieter-spence
Télécharger la présentation

The Nervous System: Neurons & Neuroglial Cells, & Synapses

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Nervous System:Neurons & Neuroglial Cells, & Synapses pp. 222-230

  2. Central vs. Peripheral NS

  3. General Pathway • Animation • Sensory receptors – on dendrites of peripheral nerves (PNS), activated by stimuli • Sensory/Afferent neurons – sensory input to CNS, cell bodies in PNS • Interneurons – integration by CNS • Motor/Efferent neurons – motor output from CNS, cell bodies in CNS • Somatic – controls skeletal muscle (voluntary) • Autonomic – controls cardiac muscle, smooth muscle, & glands (involuntary) • Effectors – muscles & glands at the ends of peripheral nerves (PNS)

  4. General Pathway

  5. Neurons & Neuroglia • Neurons • Nerve cells • Respond to stimuli & transmit electrical impulses to communicate to other nerves, muscles, or glands • Cannot divide • Neuroglia • Support, insulate, & protect neurons • Can’t transmit electrical impulses • Can divide

  6. Myelin • A lipid that sometimes coats axons • White matter = myelinated axons in CNS • Gray matter = cell bodies & unmyelinated axons in CNS • Produced by some neuroglial cells • Insulates neurons & increases efficiency of nerve impulses • Multiple sclerosis

  7. PNS Neuroglial Cells Schwann cells – Wrap around axon, forming myelin sheath • Neurilemma – outer layer containing the cytoplasm & organelles • Nodes of Ranvier – gaps in the sheath Satellite cells –Protect & cushion neurons

  8. CNS Neuroglial Cells • Microglial cells • Phagocytosis • Oligodendrocytes • Form myelin sheath around axons • No neurilemma • Astrocytes • Connect to capillaries – living barrier • Control chemical environment of brain • Ependymal cells • Line cavities & circulate cerebrospinal fluid

  9. Neuron Parts: • Cell body • Dendrites • Axon • Axon terminals

  10. At the Synapse • Presynaptic neuron • Axon terminal • Vesicle • Neurotransmitters • Synaptic cleft • Receptors • Postsynaptic neuron

  11. Neurotransmitters • Action potential reaches axon terminal • Ca+2 ions rush into the presynaptic neuron • Vesicles fuse with cell membrane (exocytosis) • NT’s released into synaptic cleft

  12. Neurotransmitters, part 2 • NT’s bind to receptors on postsynaptic neuron • Na+ ions rush into postsynaptic neuron • A new nerve impulse begins • Animation

  13. Neuron Types

  14. Damage to Nerves • Neurons don’t divide, but neuroglial cells can divide! • Injury to cell body – kills the neuron • Injury to the axon • In PNS • Axons may regenerate – Schwann cells help • In CNS • Axons do not regenerate – no Schwann cells • Neural stem cells in the brain

More Related