Worksheet on the Nervous System

Worksheet on the Nervous System Interneurons are constantly ________. What does this provide the context for? - active; for interpreting sensory input and directing an appropriate response What are the three main functions of the nervous system? - sensory input, integration, motor output What structures comprise the CNS? - brain and spinal nerve cord in vertebrates Motor output is the conduction signals from the _______ to the ___________. - CNS; effector cells such as muscles Signals are conducted by __________, which are bundles of ________ wrapped in connective tissue. - nerves; neurons What are the four main parts of a neuron? - cell body, dendrites, axon, synaptic terminals The structural and functional unit of the nervous system is the ___________. - neuron The site of contact between a synaptic terminal of a neuron and a target, such as another neuron, a muscle cell, or a gland, is called a _________. - synapse What are cells called that lie on each side of a synapse? - pre-synaptic cell and post-synaptic cell The simplest type of nerve circuit is termed a _________. - reflex arc What is the minimum number of neurons that can make up a "reflex arc", and what would these neurons be? - 2, there must be at least one sensory neuron and at least one motor neuron What are "interneurons"? - these are neurons within the CNS Ganglia and nuclei are collections of ____________. How do they differ from one another? - cell bodies of neurons; ganglia are found in the PNS while nuclei are within the brain Supporting cells, called __________, are _______________. - glia or glial cells; essential for the structural integrity of the nervous system and for the normal functioning of the neurons Which glial cells provide structural and metabolic support for neurons? - astrocytes What do these glial cells also form? - the blood-brain barrier What cells form the insulating sheaths around axons? Where are these cells found? - Schwann cells; outside the CNS, oligodendrocytes are within the CNS All cells have an electrical charge different across their plasma membrane called the ___________. - membrane potential The membrane potential exists because ___________________. - the different concentration of certain ions across the cell membrane The membrane potential of an unstimulated neuron is called the ____________. - resting membrane potential What makes invertebrates like squid and lobsters such good animals for the study of nerve impulses? - they are large in diameter