Structure and Function of the Nervous System

1. what are the two components of the central nervous system? what is the role of the CNS? brain and spinal cord process sensory input and generate motor output 2. what are the components for the peripheral nervous system? what is the role? peripheral nerves, cranial nerves(12 pairs) and spinal nerves(31 pairs) afferent sensory communication with CNS efferent motor output from CNS 3. afferent vs efferent nerves afferent- takes signals from peripheral tissue to CNS efferent- takes signals from CNS to peripheral tissue 4. neurones carry signals as nerve impulses or action potential high metabolic rate= constantly need o2 and glucose have extreme longetivity once formed and functioning, lose ability to divide 5. components of a neuron- dendrites receive signal inputs and gets converted into membrane voltage 6. components of a neuron-soma cell body mitochondria and golgi microtubules and neurofilaments gathers all inputs from dendrites transferred to axon hillock 7. components of neuron- if enough stimulation reached throughout the body, axon hillock it produces an action potential expresses ion channels needed for action potential 8. components of neuron-axon allows action potential to go towards target allow for transport of molecules to nerve terminals size can vary in diameter, reflects conduction speed 1/4 9. myelin axons are covered by myelin sheath myelinating cells- Schwann cells and oligodendrocytes initially, they're loose, over time cytoplasm squeezed out making them tight cytoplasmic free membrane= good electric insulator saltatory conduction- nodes of Ranvier(gaps) cause action potential to jump from one node to another 10. switching off a synapse neurotransmitter can be removed by the synaptic cleft by neurotransmitter break down or neurotransmitter uptake 11. types of neurons- func- sensory(afferent) neurons tional clasification motor(efferent) neurons interneurons(neurons that connect sensory and motor) 12. types of neurons- mor- pseudo-unipolar neurons: only axons and no denphological classifica- drites(sensory) tion bipolar neurons- 1 axon and 1 dendrite(olfactory, retina) multipolar neurons-many dendrite(motor neurons) 13. transport through the plasma membrane hydrophilic substances cannot pass the plasma membrane due to phospholipid bilayer need transporter proteins 14. types of transport through plasma membrane in terms of number of molecules transported: uniport-one molecule cotransport- one solute symport- one direction antiport- opposite direction in terms of energy requirements: passive transport- molecules moving according to conc gradients active transport- molecules moving against conc gradient 2/4 primary- sodium potassium pump secondary- sodium-glucose pump 15. at rest membrane po- membranes electrically charged- polarized tential in excitable cells positive charge on outside and negative charge on outside 16. voltage operated sodi- local anaesthetics(lidocaine) block Na+ ion chanum ion channels role nels nerve conduction so many Na+ in channels are inactive that an action potential cannot be sustained or generated 17. cells of the nervous system- Glia meaning 'glue' maintain environment around neurons have an important role in myelinating cells schwann cells and satellite glial cells 18. three layers of produra mater(thick and tough) tective cover surround- arachnoid mater(web like) ing brain and spinal pia mater(thin membrane held tightly to cortex) cord(meninges) 19. Anatomy of the brainforebrain cerebral cortex- cerebrum consciousness, thinking and motor skills 2 hemispheres by corpus callosm 20. Anatomy of the brainbrainstem midbrain-hearing and movement pons- tear production, chewing, blinking medulla oblongata- heart rate, breathing, blood flow 21. Anatomy of the brain-limbic system thalamus- relays sensory info to CNS hypothalamus-regulates pituitary gland amygdala- regulates emotions hippocampus- memory forming, connects memories with senses 22. anatomy of the brain- pi- posterior to bridge of nose tuitary gland link between nervous and endocrine system 3/4 releases many hormones that control growth metabolism and reproductive system 23. anatomy of the braincerebellum 'little brain' coordinates motor movements, maintains balance 24. anatomy of the CNSgrey and white matter grey matter- formed by cell body(soma) white matter- axons wrapped in myelin sheath 4/4