click below
click below
Normal Size Small Size show me how
Chapter 10 Questions
Question | Answer |
---|---|
Distinguish between neurons and neuroglia (361) | Neurons are the structural and functional cells reacting to the physical and chemical changes in their environment. Neuroglia is the supporting cells necessary for nourishing and maintaining the neurons, among other functions. |
dendrites | highly branched, multiple processes that may have spines |
chromatophilic substance | rough ER |
axon | conducts impulses |
cell body | part of a neuron from which axons and dendrites extend |
neurofibrils | fine threads in an axon |
Distinguish between myelinated and unmyelinated axons (366) | A myelinated nerve fiber is one, which is bound by Schwann cells. The Schwann cells wrap tightly around the nerve fiber and form a myelin sheath. Unmyelinated nerve fibers lack these sheaths. Myelinated fibers are white. Unmyelinated are grey. |
List six functions of neuroglia (368) | 1. Structural support 2. Transport of substances 3. Communication between neurons 4. Induce synapse formation 5. Speed neurotransmission 6. Phagocytosis |
Explain how an injured neuron may reginerate (371) | If the axon of a peripheral nerve is separated from the cell body, the distal portion deteriorates and the fragments are removed by macrophages. |
Explain how information is passed from a presynaptic neuron to a postsynaptic cell (372) | Nerve impulses pass from neuron to neuron at synapses. A presynaptic neuron brings the impulse to the synapse and stimulates a postsynaptic neuron. A narrow space, or synaptic cleft, separates the two cells. |
Diffusion of which of the following ions into the synaptic knob triggers the release of neurotransmitter? (372) | calcium ions |
Explain how enzymes within synaptic clefts and reuptake of neurotransmitter prevents continuous simulation of the postsynaptic cell (380) | Enzymes in synaptic clefts and on postsynaptic membranes rapidly decompose some neurotransmitters. |