Name________Amanda Fox BIO 23500-60________
Chapter 10 –Nervous System I
1) Define the following word parts.
Ax-, axle: axon – cylindrical nerve process that carries impulses away from a neuron cell body. Dendr-, tree: dendrite – branched nerve process that serves as the receptor surface of a neuron. Funi-, cord, rope: funilicus – funiculi of spinal cord or bundle of nerve fibers. Gangli-, knot: ganglia – deliver information to the body
-lemm, rind or peel: neurilemma – sheath that surrounds the myelin of a nerve cell process. Mening-, meninges - The three fibrous membranes that surround the brain and spinal cord to protect the central nervous system. Moto-, moving: motor neuron – neuron that stimulates a muscle to contract or a gland to release a secretion. Peri-, all around: peripheral nervous system – portion of the nervous system that consists of the nerves branching from the brain and spinal cord. Plex-, plexus; network of nerves.
sens-, feeling: sensory neuron – neuron that can be stimulated by a sensory receptor and conducts impulses into the brain or spinal cord. Syn-, together: synapse – junction between two neurons.
Ventr-, belly side of the body
2) What are the two types of cells that make up nervous tissue? nerve cells, or neurons, and neuroglial cells, or neuroglia.
3) What are the two major groups of nervous system organs? Central Nervous System – brain and spinal cord
Peripheral Nervous System – cranial and spinal nerves that connect the CNS to other body parts
4) Define the following:
Dendrites – Small cellular processes that receive input
Axon – A long process that carries information away from the cell by nerve impulses; also called a nerve fiber
Nerve impulse – bioelectric signals
Nerves – bundles of axons
Synapse – the small space between a neuron and the cell with which it communicates
Neurotransmitters – biological messenger molecules that carry information
Central nervous system – brain and spinal cord
Peripheral nervous system – cranial and spinal nerves that connect the CNS to other body parts
Sensory receptors – Structures at the ends of peripheral neurons; they provide the sensory function of the nervous system.
Somatic nervous system – oversees conscious activities, such as skeletal muscle contraction
Autonomic nervous system – controls viscera, such as the heart and various glands, and thus controls subconscious actions.
5) Explain how an axon in the peripheral nervous system becomes myelinated. Oliogodendrocytes produce myelin that wrap around axons in the PNS.
6) Name and describe (including their function) the 4 types of neruoglia. Astrocytes. As their name implies, astrocytes are star-shaped cells. They are commonly found between neurons and blood vessels, where they provide support and hold structures together with abundant cellular processes. Astrocytes aid metabolism of certain substances, such as glucose, and they may help regulate the concentrations of important ions, such as potassium ions, within the interstitial space of nervous tissue. Astrocytes also respond to injury of brain tissue and form a special type of scar tissue, which fills spaces and closes gaps in the CNS. These multifunctional cells may also have a nutritive function, regulating movement of substances from blood vessels to neurons and bathing nearby neurons in growth factors. Astrocytes also play an important role in the blood-brain barrier, which restricts movement of substances between the blood and the CNS. Gap junctions link astrocytes to one another, forming protein-lined channels through which calcium ions travel, possibly stimulating neurons. Oligodendrocytes. Oligodendrocytes resemble astrocytes but are smaller and have fewer processes. They commonly occur in rows along myelinated axons, and they form myelin in the brain and spinal cord. Unlike the Schwann cells of the PNS, oligodendrocytes can send out a number of...
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