What are the two principal divisions of the nervous system? The central nervous system and the peripheral nervous system
What are the two types of cells found in the nervous system? Neurons, or nerve cells, and glia, specialized connective tissue cellsWhat is the direction of neural transmission from sensory neurons and motor neurons? Sensory neurons transmit impulses TO the spinal cord and brain; motor neurons transmit impulses AWAY from the brain and spinal cord.What are interneurons? Interneurons conduct impulses from sensory neurons to motor neurons. Also called central or connecting neurons.
What is the function of glia cells? Glia cells (Greek for glue) hold the functioning neurons together, protect them, and regulate neuron function.How are the three types of glia different? (1)Astrocytes are relatively large, star-shaped cells that attach to neurons and small blood vessels to hold these structures close to each other. (2) Microglia usually remain stationary but in inflammation or degeneration of the brain, they enlarge, move about, and act as microbe-eating scavengers. (3) Oligodendrocytes help hold nerve fibers together and also produce the fatty myelin sheath.What is myelin? Myelin is a white, fatty substance.
Where is myelin produced in the central nervous system? In oligodendrocytes.Where is myelin produced in the peripheral nervous system? In Schwann cells.How might symptoms differ according to where myelin production is being impaired? Symptoms will depend on the nerve affected as well as the area of the nerve affected.
What is white matter composed of ? Nerve fibers usually have a myelin sheath and myelin is white.What is gray matter composed of ? Tissue composed of cell bodies and unmyelinated axons and dendrites is called gray matter because of its characteristic gray appearance.
Ask students to describe the coverings that surround an axon.
What is the difference between a neuron pathway and a reflex arc? A reflex arc is the simplest type of neuron pathway.What is a two-neuron arc? The simplest type of reflex arc consisting of only two types of neurons: sensory neurons and motor neurons.What is a three-neuron arc? It consists of three different types of neurons: sensory neurons, motor neurons, and interneurons.What is an effector, and how does it relate to the reflex arc?
Where does impulse conduction originate? It normally starts in receptors, the beginnings of dendrites of sensory neurons.The end of the sensory neuron’s axon synapses first with an interneuron before chemical signals are sent across a second synapse, resulting in conduction through the motor neuron. For example, application of an irritating stimulus to the skin of the thigh initiates a three-neuron reflex response that causes contraction of muscles to pull the leg away from the irritant.What are some types of stimuli that initiate nerve impulses? Pressure, temperature, chemical changes
What are the three structures that make up a synapse? A synaptic knob, a neurotransmitter, and a synaptic cleftHow does a nerve impulse travel from one neuron to another? Through a synapse via a neurotransmitterAsk students to draw a schematic diagram correctly charting the following structures and chemicals: axon terminal, synaptic knob, presynaptic neuron, postsynaptic neuron, neurotransmitter, synaptic cleft, plasma membrane, receptor molecules.
What is a neurotransmitter and how many are there? Neurotransmitters are chemicals by which neurons communicate. At least 30 different compounds have been identified as neurotransmitters.Name some of the neurotransmitters. Acetylcholine, norepinephrine, dopamine, serotonin, catecholaminesAcetylcholine is released at some of the synapses in the spinal cord and at neuromuscular junctions.Norepinephrine, dopamine, and serotonin belong to a group of compounds called catecholamines, which may play a role in sleep, motor function, mood, and pleasure recognition.Two morphine-like neurotransmitters called endorphins and enkephalins are natural painkillers.
What are the three main parts of the brainstem? The medulla oblongata, pons, and midbrainStructure—white matter with bits of gray matter scattered through it.What is the function of the brainstem? It functions as a two-way conduction pathway. Many important reflex centers (cardiac, respiratory, and vasomotor centers – “vital centers”) are located in the brainstem.
What is the structure of the hypothalamus? One of the most important brain structures. Lies below thalamus.What is the function of the hypothalamus? Manufactures hormones, part of the mechanism for maintaining body temperature, involved in regulation of water balance, involved in sleep cycle, involved in control of appetite and many emotions of pleasure, fear, anger, sexual arousal, and pain.
What is the structure of the thalamus? Dumbbell-shaped section of gray matter above the hypothalamus. What is the function of the thalamus? (1) Helps produce sensations – relays impulses to the cerebral cortex from sense organs; (2) associates sensations with emotions; (3) plays a part in the arousal or alerting mechanism
What is the lay term for CVA? StrokeHow would you describe hemiplegia, paraplegia, triplegia, quadriplegia, and spastic paralysis? Hemiplegia – spastic paralysis of one side of the body; paraplegia – paralysis of both legs; triplegia – paralysis of both legs and one arm; quadriplegia – paralysis of all four extremities; paralysis – inability to initiate voluntary contractions, may be accompanied by involuntary contractions of affected muscles.What is an EEG? An electroencephalogram is a graphic representation of brain activity.
Typically, how long is the spinal cord? About 17 to 18 inches long.Distinguish between the spinal cord and the spinal column. The spinal cord lies inside the spinal column in the spinal cavity.Tracts are functional organizations: all axons composing one tract serve a general function.Other ascending tracts transmit sensations of touch and pressure to the brain.
Nerve tissue needs to be protected, so the brain and spinal cord are surrounded by a tough, fluid-containing membrane called the meninges.The meninges are surrounded by bone. The spinal meninges form a tubelike covering around the spinal cord and line the bony vertebral foramen of the vertebrae that surround the cord.What are the three layers of the spinal meninges? Dura mater – tough outer layer that lines the vertebral canal; arachnoid mater – membrane between the dura and pia mater; pia mater – innermost membrane covering the spinal cord.
What are some of the structures included in the peripheral nervous system? Includes cranial and spinal nerves that connect the brain and spinal cord, respectively, to peripheral structures such as the skin surface and the skeletal muscles.Other structures in the autonomic nervous system are considered part of the peripheral nervous system; they connect the brain and spinal cord to various glands in the body and to the cardiac and smooth muscles in the thorax and abdomen.
What is the causative agent for herpes zoster? Varicella zosterWhat childhood disease has a patient contracted to be susceptible to herpes zoster? ChickenpoxWhat is a dermatome? Skin surface areas supplied by a single spinal nerve.
Motor nerves that control the voluntary actions of skeletal muscles are sometimes called the somatic nervous system.What are the two divisions of the autonomic nervous system (ANS)? Sympathetic nervous system, parasympathetic nervous systemSpinal nerves conduct impulses between the spinal cord and parts of the body not supplied by cranial nerves.Spinal nerves function to make possible sensations and movements.
What are autonomic effectors? Tissues to which autonomic neurons conduct impulses—cardiac and smooth muscle and glandular epithelial tissue.Autonomic paths to visceral effectors consist of two-neuron relays. Impulses travel over preganglionic neurons from the spinal cord or brainstem to autonomic ganglia. There they are relayed across synapses to postganglionic neurons, which then conduct the impulses from the ganglia to visceral effectors.In contrast, somatic motor neurons conduct all the way from the spinal cord or brainstem to somatic effectors with no intervening synapses.
What are the two divisions of the autonomic nervous system (ANS)? Sympathetic and parasympathetic; see Figure 9-26.What is the structure of the sympathetic nervous system? Also referred to as the “thoracolumbar system,” it leaves the spinal cord in the anterior (ventral) root of a spinal nerve, enters the spinal nerve, but soon leaves it to extend to and through a sympathetic ganglion and terminate in a collateral ganglion where it synapses with several postganglionic neurons whose axons extend to terminate in visceral effectors.
What are the functions of the sympathetic nervous system? It functions as an emergency system. It takes control of many internal organs when we exercise strenuously and when strong emotions are elicited. It other words, it functions during stress. See Table 9-3.What physiological changes are associated with the fight-or-flight response? Heart beats faster, blood vessels constrict causing blood pressure to increase, blood vessels in muscle dilate delivering more blood to the muscles, sweat glands and adrenal glands secrete more abundantly, salivary and other digestive glands secrete more sparingly, peristalsis becomes sluggish, and we are ready for “flight or flight.”The sympathetic nervous system controls visceral effectors during strenuous exercise and strong emotions (such as anger, fear, hate, or anxiety).
Where are the dendrite and cell bodies of the sympathetic preganglionic neurons located? In the parasympathetic nervous system in the spinal cord and brainstem.
What are the functions of the parasympathetic nervous system, and how do they differ from the functions of the sympathetic nervous system? It dominates control of many visceral effectors during normal, everyday conditions. Impulses tend to slow heartbeat, increase peristalsis, and increase secretion of digestive juices and insulin. See Table 9-3.
What are neurotransmitters? Chemicals that continue a nervous impulse through a synapse.Ask students to offer examples of neurotransmitters associated with the ANS, including the division of the ANS associated with each neurotransmitter.Three axons—the sympathetic preganglionic axon, the parasympathetic preganglionic axon, and the parasympathetic postganglionic axon—release acetylcholine. These axons are classified as cholinergic fibers.Only one type of autonomic axon releases the neurotransmitter norepinephrine; this is the axon of a sympathetic postganglionic neuron, and such neurons are classified as adrenergic fibers.What determines the nature of an organ’s response to stimulation by the autonomic nervous system? Cholinergic and adrenergic fibers
What are examples of stress-induced diseases? Heart disease, ulcers, colitis, autoimmune disorders, and a depressed immune system resulting in infections, colds, etc.Stress can oversecrete gastric hydrochloric acid.