Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Nervrous System
Nervous System Chpt 12
| Question | Answer |
|---|---|
| List the 3 overlapping functions of the nervous system. | 1) sensory input 2) integration 3) motor output |
| define sensory input | gathered information captured by sensory receptors |
| define integration | process in which the nervous system processes and interprests the sensory input and makes decisions about what should be done at each moment |
| define motor output | process in which the nervous system dictates a response by activating the efforctor organs or muscles or glands |
| List the 2 anatomical parts of the nervous system. | 1) central nercous system - CNS 2) peripheral nervous system - PNS |
| What does the central nervous system (CNS) consist of and what is its function? | brain and spinal cord - integrating and command center of the nervous system, receives incoming sensory signals, interprets the signals, and dicates motor responses |
| What does the peripheral nervous system (PNS) consist of and what is its function? | consists mainly of the nerves that extend from the brain to the spinal cord and ganglia |
| define ganglia | areas where the cell bodies of nerons are clustered |
| define afferent | carrying to or toward; especially a nerve fiber that carries impulses toward the central nervous system; afferent nuerons are sensory neurons |
| define efferent | carrying away or away from, especially a nerve fiber that carries impulses away from the central nervous system; efferent neurons are motor neurons |
| define somatic body region | pertaining to the region of the body that lies external to the ventral body cavity, including the skin, skeletal muscles, and the skeleton; opposite or visceral (skin, skeletal musculature, bones) |
| define visceral body region | contains the viscera within the ventral body cavity - the structures of the body's innter tube digestive tube, lungs, heart, bladder, and so on) |
| List the 4 major subdivisions of the PNS | 1) somatic sensory 2) visceral sensory 3) somatic motor 4) visceral motor or autonomic nervous system (ANS) |
| What is another name for visceral motor and describe its function | autonomic nervous system - involuntary motor innervation of the inner tube, specifically smooth muscle, cardiac muscle, and glands, arrctor pili muscles, and sweat glands) |
| describe somatic sensory | senses whose receptors are spread widely throughout the outer tube of the body - touch, pain, pressure, vibration, temperature, proprioception, special somatic senses |
| define proprioception | sensing one's own body, sense that detects the amount of stretch in muscles, tendons, and joint capsules |
| define special somatic senses | receptors are confined to relatively small areas rather than spread widely thorughout the body - these senses are usually confined to head hearing & equilibrium & vision |
| define visceral sensory | includes special visceral senses, senses that can be felt widely in the digestive, urinary tracts, reproductive organs - hunger, nausea |
| explain special visceral senses | referred to as the chemical senses - their sensory receptors localized to the tongue and nasal cavity |
| describe somatic motor | stimulates contraction of the skeletal muscles in the body, voluntary control, known as the voluntary nervous system |
| describe visceral motor | regulates the contraction of smooth and cardiac muscle and secretion by the body's glands, makes up the ANS |
| In which direction are the afferent signals carried? What type of information do these signals contain? | Afferent signals carry sensory information toward the CNS. |
| What subdivision of the nervous system regulates contaction of the muscle tissue in the heart? | The visceral motor (autonomic) division of hte peripheral nervous system regulates contaction of cardiac muscles. |
| What type of sensation is (a) pain from a pulled muscle, (b) nausea, (c) taste? | Somatic motor neurons to the muscles of the upper lib are located in the ventral horn of the lower vervical segments. Paralysis of these muscles would result from damage to this region of the spinal cord. |
| Nervous tissue is made up of what 2 type of cells? | 1) neurons- excitable nerve cells that transmit electrical signals 2)neuroglia nonexcitable supporting cells that surround and wrap the neurons |
| What cell types to neurons and neuroglia develop from? | neural tube and neural crest |
| What is the basic structural units of the nervous system? | neurons or nerve cells |
| define neurons | highly specialized cells that conduct electrical signals from one part of the body to another |
| explain action potential | a large, transient depolarization event, including polarity reversal, that is conducted along the plasma membrane of hte nerve axon or muscle cell without diminishing in intensity; also called nerve impulse |
| List some special characteristics of neurons | 1) extreme longivity (lifetime) 2) do not divide 3) high metabolic rate -- requires lots of oxygen & glucose, however they can survive minutes without it |
| What is the structure of a neuron? | large, complex cell; they contain a cell body and one or more processes |
| define a soma | cell body of a neuron, includes single nucleus surrounded by cytoplasm |
| explain chromatophilic (Nissl) bodies | found in the cytoplasm of neurons, large clusters of rough endoplasmic reticulum and free ribosomes that stain darkly with basic dyes - their function is to continually renew the membranes of the cell and the protein part of the cytosol |
| explain Neurofibrils | bundles of intermediate filaments that run in a network between the chromatophilic bodies - keeps the cell from being pulled appart when it is subjected to tensile forces |
| Where are ganglia found? | lie along the nerves in the PNS |
| What are neuron processes? | dendrites and axons |
| explain dendrites | processes that branch from the cell body - function as receptive sites - conduct electrical signals toward the cell body |
| explain axons | thins processes of uniform diameter throughout their length, impulse genortrs and conductors that transmit nerve impulses away from cell body - MIA organelles needed for protein synthesis - includes neurofilaments, actin microfilaments and microtubules |
| What is a nerve fiber? | a very long axon |
| What happens to the electrical current when the diameter of the axon increases? | increases |
| define axon collaterals | extend from the axon at more or less right angles |
| define axon terminals | knob like end found in a neuron |
| explain synapse | site at which neurons communicate |
| define presynaptic neuron | neuron that conducs signals toward a synapse |
| describe postsynaptic neuron | neuron that transmits signals away from the synapse |
| What are the 2 main types of synapses? | axodendritic synapses and axosomatic synapses |
| define axodendritic synapses | synapses occur between the axon terminals of one neuron and the dendrites of another neuron |
| define axosomatic synapses | synapses occur between axons and neuron cell bodies |
| define synaptic vesicles | membrane-bound sacs filled with neurotransmitters |
| define synaptic cleft | fluid-filled space at a synapse between neurons; also called synaptic gap |
| How does a synapse function? | 1)impulse stimulates the synaptic vesicles to fuse with presynaptic membrane 2)fused area ruptures releasing neurotransmitter molecules, synaptic then binds with membrane, this changes the membrance charge generating a nerve impulse |
| How are neurons classified? | multipolar, bipolar or unipolar |
| define multipolar neurons | has more than 2 processes, numerous dendrites and single axon |
| define bipolar neurons | have 2 processes that extend from opposite sides of the cell body, very rare found in inner ear, olfactory epithelium of the nose, retina of the eye |
| define unipolar neurons | have a short, single process that emerges from the cell body and divides line an iverted T into two long branches , found in sensory ganglia in the PNS, body divides into the central process and peripheral process |
| explain the central process | an axon, found in unipolar neurons, branch that runs centrally into the CNS |
| explain the peripheral process | found in unipolar neurons, branch that extends peripherally to the receptors |
| What are the functional classifications of Neurons? | sensory neurons, motor neurons, and interneurons |
| explain sensory neurons | also known as afferent neurons, make up the sensory division of the PNS - transmit impulses toward the CNS from sensory receptors in the PNS, pseudounipolar, cell bodies in glanglia outside CNS, central process terminates at CNS, 2 processes act as 1 |
| explain motor neurons | efferent neurons, make up motor division of the PNS, carry impulses away from the CNS, multipolar, cell bodies located in CNS, form junctions with effector cells, stimulating muscles to contract or glands to secrete |
| explain interneurons | also known as association neurons, lie between motor and sensory neurons, multipolar neurons are confined entirely to the CNS, multipolar neurons |
| Which type of neuron process receives stimuli? | The neuronal cell processes that receive stimuli are the dendrites. |
| What is the structural classification of most senstory neurons? | Most sensory neurons are unipolar (pseudounipolar) neurons. |
| What structural type is most abundant? What neurons in the PNS are of this type? | Multipolar neurons are the most abundant type of neuron. Motor neurons of hte PNS are multiplar neurons. |
| define neuroglia | nonexcitable cells of neural tissue that support, protect, and insulate neurons; glial cells |
| What is the physical differnece between a neuroglia and neurons | they both have a cell body and branching processes, however the neuroglia is smaller in size and stains darker |
| define astrocytes | star shaped, most abundant type of glial cell of the CNS, they have radiating processes that bulbs out and clings to neurons |
| What are the functions of astrocytes? | 1)regulating neurotransmitter levels by increasing the rate of neurotransmitter 2)signaling increased blood flow through capillaries in active regions 3.controlling the ionic envrnmnt around neurons |
| define microglia | smallest and least abundant neuroglia of the CNS, have elongated cell bodies and cell processes with many pointed projections; migrate, engulf, invading microorganisms and injured or dead neurons |
| define Ependymal cells | form a simple epithelium that lines the central cavity of the spinal coard and brain, provides permeable layer between cerebrospinal fluid, bear cilia |
| define Oligodendrocytes | have fewer branches than astrocytes, wrap their cell processes around thicker axdons in CNS, produce myelin sheaths |
| What are the 2 types of neuroglia found in the PNS? | Satellite cells and Schwann cells |
| explain satellite cells | satellite cells surround neuron cell bodies within ganglia |
| explain Schwann cells | surrond all axons in the PNS and form myelin sheaths around many of these axons |
| What are myelin sheaths | produced by oligodendrocytes in CNS and Schwann cells in the PNS, segmented structures composed of lipoprotein myelin and surround the thicker axons of the body |
| How are myelin sheaths formed? | 1) Schwann cells indent to receive axon by surrounding it 2) gradually squeezed 3)results in tightly packed coils 4) nucleus and most cytoplasm end up outside the layers called neurilemma |
| define neurilemma | exertal material ouside the myelin laters after myelin sheath is produced |
| define nodes of Ranvier | gaps in the myelin sheath, occur at regular intervals |
| explain unmyelinated axons | thin, slowly conducting axons that lack a myelin sheath |
| Which neuroglia make myelin in the CNS? In the PNS? | Oligodendocrocytes produce myelin in the CNS, and Schwann cells produce myelin in the PNS. |
| Which neuroglia are common in egions hwere synapses occur? | Astrocytes are common in regions where synapse occurs because they regulate ionic and neurotransmitter leels in neural tissue. |
| Do Schwann cells cover unmyelinated axons in the PNS? | Schwann cells do cover unmyelinated axons in the PNS; however, these axons are not wrapped by concentric layers of the Schwann cell. Numerous unmyelinated axons are embedded in a single Schwann cell. |
| describe a nerve | cablelike organ in the PNS consisting of many axons arranged in parallel bundles and enclosed by successive wrapping of connective tissue |
| explain endoneurium | delicate layer of loose connective tissue that covers the Schwann cell |
| nerve fascicles | bundle of nerves surrounded by perineurium |
| explain perineurium | covers the nerve fascicles |
| explain epineurium | tough fibrous sheath that covers the whole nerve |
| define neuron | nerve cell |
| define nerve fiber | a long axon |
| define nerve | collection of nerve fibers in the PNS |
| define gray matter | found in the brain and spinal cord; gray-colored zone that surrounds the hollow CNS cavity, in the spinal cord it is butterfly shaped, it is the site where neuron cell bodies are clustered |
| define white matter | contains no neuron cell bodies but millions of axons, white in color from the myelin sheath; consists of axons running between the different parts of the CNS |
| explain tracts | a collection of nerve fibers int he central nervous system having the same origin, destination, and function |
| define Cortex | additional layer of gray matter located superficially i the cerebrum and cerebellum |
| Name the connective tissue wrapping that encloses a bundle of verve fibers into a fascicle. | The perineurium wraps a bundle of nerve fibers (axons) into a fascicle. |
| Where do synaspes occur in the CNS, in white matter or in gray matter? | Synapses in the CNS always occur in the gray matter. |
| Why is white matter white? | The white matter of hte CNS appears white because the majority of the nerve fibers in these regions are myelinated. |
| The CNS is composed of interneurons that | 1)process received sensory information 2)direct this information to specific regions of the CNS 3)initiate the appropriate motor response 4) transport info (sensory & motor) from one region of the CNS to another |
| What are the components of a reflex arc? | 1) receptor 2) sensory neuron 3)integration center 4) motor neuron 5) effector |
| Structural link between the PNS and CNS occurs where? | In the gray matter of the CNS |
| define reflex arc | simple chains of neurons that cause our simplest, refexive behaviors and reflect the basic structural plan of the nervous system |
| how can reflexes be described? | they are either somatic reflexes resulting in the contraction of skeletal muscles or visceral reflexes activating smooth muscle, cardiac muscle, or glands |
| define neuronal circuits | interneurons of the CNS that are interconnected in different ways |
| define diverging circuit | one presynaptic neuron synpases with several other neurons |
| define converging circuit | many neurons synapse on a single postsynaptic neuron..example: single moter neuron receives both excitatory and inhibitory impulses from many other neurons |
| define reverberating circuit | one neuron in the circuit receives feedback fron another neuron in the same circuit..example: a branch off the axon of one neuron circles black and synapses with a previous neuron in the circuit example..breathing, swinging arms while walking |
| List the 2 ways in which information is processed in the nervous system. | 1) serial processing- neurons that synapse one-to-one in a sequence emple: reflex arc 2) parallel processing- information from a single neuron is sent along 2 or more parallel pathways exple: recognition & memory |
| If there is no interneuron in a reflex arc, as in the stretch reflex, what functions as the integration center? | axonal fibers from the thalamic nuclei extend to the cerebral cortex |
| If you touch a hot stove, you reflexively withdraw your hand. The sensation of pain comes after your hand has moved. Why does it take longer to feel pain than it does to move your hand? | The sensory impulse must be carried to the brain for processing the conscious sensation of pain. Their processing takes moe time than is required for processing the simple withdrawal reflex. |
| What typeof neural circuit contains multiple neurons synapsing on a single neuron, altering its potential to produce a nerve impulse? | A coverging circuit contains multiple presynaptic neurons synapsing on a single postsynaptic neuron. |
| explain Multiple Sclerosis | progressive disease that destroys patches of myelin in the brain and spinal coard, disrupting neuronal signals in the CNS and leading to sensory disorders and weakened musculature |
| How do neurons regenerate in sp | 1)identify & block chemicals that inhibit axonal growth in injured CNS 2)add neurotrophins to induce axonal sprouting & remyelination 3)make damaged region of spinal coard more like PNS by implanting Schwann clls 4)isolate neuronal stem clls & add to SC |
| Both peripheral nerves and the white matter of the spinal coard are composed of axonal processes. Why is it possible to regain function after an injury to a peripheral nerve but not after an injury to the spinal coard? | After a peripheral injury, axons in the PNS can regrow within regenration tubes formed by surviving Schwann cells. In the CNS, neuroglia do not guide regrowing axons and, in fact, secrete inhibitory chemicals that block neuronal regrowth. |
| From your understanding of the functions of myelin and functions of the white matter tracts of the CNS, explain how the loss of myelination in the CNS, as ocurs in multiple sclerosis, can cause the signs and symptoms typical of this disease. | Myelin insulates nerve signals & increases the speed of impulse conduction. Loss of myelin in the CNS, as occurs with MS, interferes with the conduction of nerve signals. All of the symptoms described for MS indicate disruption of neural processing. |
| Which structure is not part of the central nervous system? | nerve |
| Which cell forms myelin in the CNS? | oligodendrocytes |
| Which cell lines the central cavity of the brain? | ependymal cells |
| Which cells form myelin in the PNS | Schwann cells |
| Which cells are CNS phagocytes? | microglia |
| Which cells regulate ionic composition of the fluid around neurons in the CNS? | astrocytes |
| Which cells remove neurotransmitters in the CNS? | astrocytes |
| Which of the following structures is in the somatic part of hte human body? a)bladder b)biceps muscle c)lung d)stomach | biceps muscle |
| Classify as SS, VS, SM, or VM: pain from skin | SS |
| Classify as SS, VS, SM or VM: taste | VS |
| Classify as SS, VS, SM or VM: efferent innervation of a gland | VM |
| Classify as SS, VS, SM or VM: efferent innervatin of the gluteus maximum | SM |
| Classify as SS, VS, SM or VM: stomachache | VS |
| Classify as SS, VS SM or VM: sound one hears | SS |
| Classify as SS, VS, SM or VM: efferent innervation of the masseter | SM |
| As example of an effector is a) eye, B) gland C) sensory neuron D)motor neuron | B Gland |
| Which of the following parts of a neuron occupies the gray matter in the spinal coard? a) tracts of long axons b)motor neuron cell bodies c)sensory neuron cell bodies d)nerves | B motor neuron cell bodies |
| A gonglion is a collection of a)neuron cell bodies b)axons of motor neurons c)interneuron cell bodies d)axons of sensory neurons | A neuron cell bodies |
| A synapse between an axon terminal and a neuron cell body is classified as a)axodendritic b)axoaxonic c)axosomatic d)axoneuronic | C axosomatic |
| Afferent neurons of the PNS synapse in the CNS with a)axons in the white matter b)neuron cell bodies in the gray matter c)neuron cell bodies in the white matter d)axons in the gray matter | B neuron cell bodies in the gray matter |
| A monosynaptic reflex is an example of a)a convergent circuit b) parallel processing c)serial processing d)a reverberating circuit | C serial processing |
| Most nerves are composed of a)afferent neurons only b)efferent neurons only c)dendrites d)axons of afferent and efferent neurongs e)neuron cell b odies nad neuroglia | D axons of afferent and efferent neurons |
| Place the connective tissue coverings surrounding a nerve in order from superficial to deep : perineurium, epineurium, endoneurium | epineurium, perineurium, endoneurium |
Created by:
heatherpogo