CHAPTER 10 1. Cell Types of Neural Tissue: a) ________________ are specialized cells that react to physical and chemical changes in their surroundings. b) _________________ cells support neurons and aid in transmitting information. 2. Divisions of the Nervous System: a) The __________ consists of the brain and spinal cord. b) The __________ consists of the cranial and spinal nerves. 3. Divisions of the Peripheral Nervous System: a) _______________ picks up sensory info and delivers it to the CNS. b) _______________ carries info to the muscles and glands. _______________ carries info to the skeletal muscle. _______________ carries info to smooth and cardiac muscle and glands. 4. Functions of the Nervous System: a) Sensory—receptors gather info which is carried to the ___________. b) _________________—sensory info is used to create sensations, memory, thoughts, and decisions. c) Motor—decisions are acted upon and impulses are carried to the _____________________. 5. Neuron Structure: a) __________________--cellular processes that receive the input b) __________________--contains Nissl bodies which contain RER so these are the site of protein synthesis—also contains a nucleus and nucleolus, granular cytoplasm with mitochondria, lysosomes, Golgi, and microtubules c) __________________--longer process that carries info away from the cell Neuroglial cells called ___________________ cells encase the larger axons of peripheral neurons in lipid-rich sheaths formed by tightly wound layers of cell membrane. The layers are composed of_______________which has more lipid than other membranes. The myelin sheath is surrounded by a sheath called the _________________________. The nucleus is also outside the myelin sheath. Narrow gaps in the myelin sheath between the Schwann cells are called ______________________________________. 6. Myelination of Axons: a) _______________ matter contains myelinated axons. b) _______________ matter contains unmyelinated axons, cell bodies, and dendrites. Axons smaller in diameter may not contain myelin sheaths. 7. Classification of Neurons/Structural Differences: Draw the following Neurons below: (See p. 362). Multipolar Bipolar Most common ears, eyes, nose Motor and interneurons Unipolar sensory ganglia 8. Classification of Neurons—Functional Differences a) ____________________--afferent; carry impulses to the CNS; unipolar or bipolar b) ____________________--link neurons; in the CNS; multipolar c) ____________________--efferent; carry impulses away from CNS to the effectors; multipolar 9. Types of Neuroglial Cells in the PNS: a) _______________--produce myelin; found on the larger peripheral myelinated neurons b) _______________--support clusters of neuron cell bodies (ganglia) 10. Types of Neuroglial Cells in the CNS: a) ________________--phagocytic cells b) ________________--form special type of scar tissue, mop up excess ions, induce synapse formation, connect neurons to blood vessels, aid in metabolism of glucose c) _________________--form myelin in the CNS d) _________________--ciliated, line central canal of spinal cord and ventricles of the brain, allow substances to flow between interstitial fluid and CSF 11. Regenerating Nerve Axon: p. 367 _____________ portion of axon degenerates. _____________ portion of axon may regenerate into tube of sheath cells. 12. The Synapse/Synaptic Transmission: The functional connection between the neuron and the skeletal muscle fiber is known as the ______________. Chemicals called ______________________are released when the impulse reaches the synaptic knob (the end of the axon). 13. The Resting Membrane Potential: The inside is ______________--relative to the outside when the neuron is at rest. The membrane is __________________ due to the distribution of the Na and K pump. This value is ______________. Various stimuli may affect the membrane potential. These stimuli may include __________________________________________________________________ _________________________________________________________________. If the neuron becomes more negative, (K ions diffuse out) the neuron becomes __________________________________. If the neuron becomes less negative, (Na ions diffuse in) the neuron becomes __________________________________. Graded means that the degree of change in the resting potential is directly proportional to the intensity of the stimulation. For example, if the membrane is being depolarized, the greater the stimulus, the greater the depolarization. If neurons are depolarized sufficiently, the membrane potential reaches a level called the ________________________ potential (-55mv). Summation (many neurons synapsing with the same cell join) can occur and lead to a threshold potential which can produce an action potential. At rest, the neuron is polarized—Na+ on outside (-70 mv). If threshold stimulus is reached, Na+ come in and neuron is depolarized. (may reach +30 mv). When K+ leave, the neuron is repolarized. 14. All Or None Response: If the stimulus is strong enough to cause a response in the neuron, it responds _______________________. A greater intensity of stimulation produces more impulses per second; not a _______________________ impulse. For a very short time following passage of a nerve impulse, a threshold stimulus will not trigger another impulse on an axon. This brief period is known as the _______________________________ period. See table 10.3 for the steps involved in impulse conduction (page 373). _____________________conduction along myelinated axons is very fast. The action potentials appear to jump from node to node. Thick, myelinated axons such as motor neurons associated with skeletal muscle, might travel 120 m/sec. Thin , unmyelinated axons are much slower such as sensory neurons associated with the skin which might travel at 0.5 m/sec. 15. Synaptic Potentials EPSP—excitatory postsynaptic potential Neurotransmitter binds to a postsynaptic receptor and opens Na ion channels Depolarization occurs; action potential likely IPSP—inhibitory postsynaptic potential Neurotransmitter binds to a postsynaptic receptor and opens K ion channels Hyperpolarization occurs; action potential unlikely Their integrated sums determine whether or not action potential occurs. 16. Neurotransmitters: Table 10.4 (page 376). 17. Events Leading to Neurotransmitter Release: Table 10.7 (page 377).