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Anatomy Vocab Ch 7
Anatomy Vocab Ch 7 Marieb
| Question | Answer |
|---|---|
| nervous system | master controlling and communicating system of the body; considered by structure and functional classifications |
| sensory receptors | monitor changes occuring inside and outside the body |
| stimuli | actions that cause sensory receptors in the body to respond |
| sensory input | information gathered by the sensory receptors; processes and interprets to decide what should be the correct response |
| integration | the process of intrepreting sensory input and deciding what the response should be |
| motor output | the response by way of muscle or gland reaction, to integration or sensory input |
| central nervous system (CNS) | consists of brain and spinal cord, occupying the dorsal body cavity, integrating and command centers of the nervous system |
| peripheral nervous system (PNS) | the nervous system outside the central nervous system, nerves that extend from the brain and spinal cord |
| spinal nerves | carry impulses to and from the spinal cord |
| cranial nerves | carry impulses to and from the brain |
| afferent (sensory) | nerves that convey impulses to the central nervous system from sensory receptors |
| somatic sensory fibers | deliver impulses from the skin, skelatal muscles and joints; afferent division |
| visceral sensory fibers | sensory fibers transmitting impulses from visceral organs; afferent division |
| efferent (motor) | carry impulses away from the central nervous system to effect organs, muscles and glands |
| central nervous system (CNS) | consists of brain and spinal cord, occupying the dorsal body cavity, integrating and command centers of the nervous system |
| peripheral nervous system (PNS) | the nervous system outside the central nervous system, nerves that extend from the brain and spinal cord |
| spinal nerves | carry impulses to and from the spinal cord |
| cranial nerves | carry impulses to and from the brain |
| afferent (sensory) | nerves that convey impulses to the central nervous system from sensory receptors |
| somatic sensory fibers | deliver impulses from the skin, skelatal muscles and joints; afferent division |
| visceral sensory fibers | sensory fibers transmitting impulses from visceral organs; afferent division |
| efferent (motor) | carry impulses away from the central nervous system to effect organs, muscles and glands |
| somatic nervous system | allows conscious or voluntary control of skeletal muscles; AKA voluntary nervous system |
| autonomic nervous system (ANS) | regulates events that are automatic, ie. smooth, cardiac and glands; AKA involuntary nervous system; parasympathetic and sympathetic having opposite effects |
| parasympathetic and sympathetic | have opposite effects; actions of the autonomic nervous system |
| nervous tissue | two types of cells, supporting and neurons |
| neuroglia | nerve glue, support, insulate and protect neurons |
| glial cells (glia) | neuroglia all having special functions; astrocytes, microglia, ependymal and oligodendrocytes; not able to transmit nerve impulses; never lose ability to divide |
| astrocytes | star-shaped cells, account for almost half of neural tissue; swollen ends that cling to neurons; form the living barrier between capillaries and neurons |
| microglia | spiderlike phagocytes that dispose of debris, dead brain cells, bacteria |
| ependymal | line the central cavities of the brain and spinal cord; help circulate cerebrospinal fluid |
| oligodendrocytes | wrap flat extensions around nerve fibers, produce fatty insulating coverings called myelin sheath |
| supporting cells of the PNS | Schwann and Satellite cells |
| Schwann cells | form the myelin sheath around nerve fibers |
| Satellite cells | protective cushioning cells |
| neurons (nerve cells) | transmit message (impulses) from one part of the body to another; all have cell body and extensions from outer membrane of the cell; are excited by neurotransmitters released by other neurons |
| cell body | metabolic center of the neuron; contain abundant neurofibrils |
| Nissl substance | rough ER of the cell body of the neuron |
| neurofibrils | intermediate filaments that maintain cell body shape |
| neuron (parts of) | cell body, processes, myelin sheaths |
| processes of the neuron | armlike fibers microscopic to 3 feet long; convey messages; dendrites and axons |
| dendrite | process that conveys incoming messages toward the cell body |
| axon | process that conveys outgoing messages away from the cell body |
| axon hillock | the process that arises from the axon for relaying messages |
| axon terminal | terminals contain hundreds of vesicles containing neurotransmitters |
| neurotransmitter | when stimulated released into extracellular space; chemicals that transmit messages |
| synaptic cleft | what separates neurons from each other |
| synapse | the junction of neurons |
| myelin sheath | whitish, fatty material, protects and insulates fibers and increase transmission rate of nerve impulses |
| neurilemma | external to the myelin sheath, part of the Schwann cell, "neuron husk" |
| nodes of Ranvier | indentations of the myelin sheath between the joints of the Schwann cells |
| nuclei | clusters of cell bodies in the central nervous system |
| ganglia | small collections of cell bodies, in a few sites outside the CNS in the PNS |
| tracts | bundles of nerve fibers or neuron processes of the CNS |
| white matter | consists of dense collections of myelinated fibers of the CNS |
| gray matter | contains mostly unmyelinated fibers and cell bodies in the CNS |
| receptors | activated by specific changes occurring nearby |
| cutaneous sense organs | receptors of the skin; ie. pain receptors |
| proprioceptors | sensory receptors of the muscles and tendons; detect the amount of stretch or tension in skeletal muscles, tendons, joints; advise our brains of our own movements |
| interneuron (association neurons) | connect the motor and sensory neurons in neural pathways, always found in CNS |
| multipolar neuron | neuron having several processes extending from the cell body; most common structural type of neuron |
| bipolar neuron | neuron with two processes, an axon and dendrite; rare in adults |
| unipolar neuron | have a single process emerging from cell body; conducts nerve impulses both toward and away from the cell body; found in PNS |
| nerve impulses | irritability and conductivity |
| polarized | a resting or inactive neuron; fewer positive ions on the inner face of the neuron's plasma membrane than on the outer face |
| cell ions | positive ions inside cell are potassium (K+), ions on outside of cell sodium (Na+) |
| sodium ions (sodium entry) | when neuron is stimulated the sodium channels in cell membrane open allowing diffusion into the neuron changing polarization |
| depolarization | the changing of polarity of the neuron's membrane |
| graded potential | the rate of potential change when positive and less positive balance |
| repolarization | the outflow of positive ions restoring the electrical condition at the membrane to a resting state; neurons cannot conduct another response until repolarization |
| electrochemical event | transmission of an impulse |
| reflexes | raid, predictable and involuntary responses to stimuli; always go in the same direction |
| reflex arcs | neural pathway involving both CNS and PNS structures |
| somatic reflex | all reflexes that stimulate the skeletal muscles |
| autonomic relfex | regulate the activity of digestion, elimination, blood pressure and sweating |
| integration center | the synapse between the sensory and motor neurons, found in the CNS |
| knee-jerk response | two-neuron reflex arc, simplest found in humans |
| flexor or withdrawal freflex | three-neuron reflex arc; five elements: receptor, sensory neuron, interneuron, motor neuron and effector |
| nervous system disorder | reflexes become exaggerated, distorted, or absent; often occur before pathological condition is found |
| neural tube | central nervous system embryonic form of spinal cord and brain |
| ventricles | chambers of the brain |
| brain | largest and most complex mass of nervous tissue in the body, weighs just over three pounds |
| regions of the brain | cerebral hemispheres, diencephalon, brain stem, cerebellum |
| cerebrum | the paired cerebral hemispheres, superior part of the brain, the largest of the brain regions |
| gyri | elevated ridges of tissue covering the cerebral hemispheres |
| sulci | shallow grooves found in the gyri |
| fissures | deep grooves separating regions of the brain |
| longitudinal fissure | separates the cerebral hemispheres |
| regions of cerebral hemisphere | cortex, white matter, basal nuclei |
| cerebral cortex | control speech, memory, logical and emotional response, consciousness, interpretation of sensation, voluntary movement |
| primary somatic sensory area | in the cerebral cortex, in the parietal lobe; impulses from body's sensory receptors localized and interpreted here; recognize pain, cold, light touch |
| sensory homunculus | spatial map, upside down or reverse in the sensory area |
| occipital lobe | visual area of the cerebral cortex |
| temporal lobe | auditory area of the cerebral cortex |
| primary motor area | allows us to consciously move skeletal muscles |
| corticospinal (pyramidal) tract | motor tract descending to the spinal cord |
| motor homunculus | the body map of the motor cortex |
| Broca's area | specialized cortical area involved in ability to speak |
| speech area | located at the junction of temporal, parietal and occipital lobes |
| frontal lobe | part of the cerebral cortex involved with language comprehension |
| cerebral gray matter | contains cell bodies found only in cerebrum, of cerebral cortex |
| cerebral white matter | composed of fiber tracts carrying impulses to or from within the cortex |
| corpus callosum | large fiber tract connects cerebral hemispheres; AKA commisures; allows cerebral hemispheres to communicate with each other |
| association fiber tracts | connect areas within a hemisphere |
| projection fiber tracts | connect cerebrum with lower central nervous system centers |
| basal nuclei (basal ganglia) | islands of gray matter deep within the white matter of cerebral hemisphere; help regulate voluntary motor activity |
| diencephalon (interbrain) | sits atop the brain stem, enclosed by cerebral hemispheres; major structures are thalamus, hypothalamus, epithalamus |
| thalamus | encloses shallow third ventricle of brain, relay station for sensory impulses passing to the sensory cortex |
| hypothalamus (see limbic system) | under the thalamus, makes up floor of the diencephalon; plays a role in regulation of body temperature, water balance and metabolism; center of drives and emotions |
| limbic system | hypothalamus, the emotional-visceral brain, controls thirst, appetite, sex drive, pain, pleasure centers |
| pituitary gland | hangs from the anterior floor of the hypothalamus; produces hormones |
| mammillary bodies | reflex centers involved in olfaction, sense of smell |
| epithalamus | forms the roof of third ventricle; contain pineal body and choroid plexus; forms cerebrospinal fluid |
| brain stem | 3 inches long; structures are midbrian, pons, medulla oblongata; provides a pathway for ascending and descending tracts, contains small gray matter areas; control activities breathing, blood pressure. |
| midbrain | relatively small part of the brain stem, extends from mammillary bodies to pons; |
| cerebral aqueduct | tiny canal that travels through midbrain and connects third ventricle of diencephalon the fourth venticle |
| cerebral peduncles | little feet of the cerebrum, convey ascending and descending impulses |
| corpora quadrigemina | four rounded protrusions, bulging neuclei; reflex centers involved with vision and hearing |
| pons | rounded structure protruding just below midbrain; means bridge; mostly fiber tracts; involved in the control of breathing |
| medulla oblongata | most inferior part of brain stem, merges into spinal cord; contains nuclei that regulate vital visceral activities; control center for heart rate, blood pressure, breathing, swallowing, vomiting |
| retucular formation | entire length of the brain stem, diffuse mass of gray matter, involved in motor control of visceral organs |
| reticular activating system (RAS) | plays a role in consciouness and awake/sleep cycles |
| cerebellum | cauliflower-like, has two hemispheres, provides precise timing for skeletal muscle activity and controls balance and equilibrium; continuously compares brains intentions with body performance |
| meninges | connective tissue membrane covering and protecting the brain; the dura mater, arachnoid mater and pia mater |
| dura mater | outermost layer of the meninges, leathery, has different layers |
| periosteal layer | of the dura mater, is attached to the inner surface of the skull |
| meningeal layer | of the dura mater, forms the outermost covering of the brain and continues as the dura mater of the spinal cord |
| dural venous sinuses | collect venous blood, separation areas of the periosteal and meningeal layers of the dura mater |
| falx cerebri | one of the folds that attach the brain to the cranial cavity |
| tentorium cerebelli | separates the cerebellum from the cerebrum |
| arachnoid mater | middle weblike meningeal layer |
| subarachnoid space | the space between the arachnoid and pia mater; is filled with cerebrospinal fluid |
| pia mater | delicate, clings tightly to surface of the brain and spinal cord, follows every fold |
| arachnoid villi | protrude through the dura mater, absorbs venous blood in the dural sinuses |
| meningitis | inflammation of the meninges, serious threat to the brain |
| encephalitis | brain inflammation, spreading into the nervous tissue of the central nervous system |
| cerebrospinal fluid | similar to blood plasma, contains less protein and more vitamin C, formed from blood by the choroid pexuses; forms a cushion that protects the fragile nervous tissue |
| hydrocephalus | water on the brain; causes the head to enlarge as the brain increases in size |
| blood-brain barrier | the least permeable capillaries in the body; almost seamlessly bound together by tight junctions of water-soluble substances so that only water based stubstances can pass thru; super tight protection of the brain |
| concussion | when brain injury is slight, no permanent brain damage |
| contusion | the result of tissue destruction |
| intracranial hemorrhage | bleeding from ruptured vessels |
| cerebral edema | swelling of the brain due to inflammatory response to injury |
| cerebrovascular accidents (CVA) | stroke |
| Alzheimer's disease | progressive degenerative disease of the brain resulting in dementia |
| Parkinson's disease | results from a degeneration of the dopamine-releasing neurons of the substantia nigra; neuclei become overactive |
| hemiplegia | one-sided paralysis |
| aphasia | loss of ability to speak |
| temporary ischemic attack | restriction of blood flow, temporary, symptoms as numbness, temproary paralysis, impaired speech; "red flag" of impending stroke (CVA) |
| spinal cord | approx 17 inches long, the continuation of the brain stem; two-way conduction pathway to and from the brain, major reflex center |
| cauda equina | spinal nerves at the inferior end of the vertebral canal; looks like a horse's tail |
| gray matter of the spinal cord | looks like a butterfly or the letter H in cross section; dorsal (posterior) horns, ventral (anterior) horns; gray matter surrounds the central canal of the cord |
| dorsal root | where the sensory neuron is under the spinal cord |
| dorsal root ganglion | the enlarged area of the dorsal root |
| ventral root | contains the cell bodies of motor neurons of the somatic nervous system |
| spinal nerves | where the dorsal and ventral roots fuse |
| flaccid paralysis | nerve impulses do not reach the muscles affected, no vountary movement is possible |
| spastic paralysis | affected muscles stay healthy because they are stimulated by spinal reflex arcs, movement is involuntary and not controllable |
| white matter of the spinal cord | 3 columns: dorsal, lateral and ventral |
| endoneurium | a delicate connective tissue sheath surrounding a neuron fiber |
| perineurium | course connective tissue wrapping, surrounding the neuron fiber |
| fascicles | nerve fiber bundles |
| mixed nerves | nerves carrying both sensory and motor nerve fibers |
| cranial nerves | serve primarily the head and neck, numbered in their order |
| dorsal and ventral rami | the division of the spinal nerve containing both motor and sensory fibers |
| plexuses | complex network of nerves |
| preganglionic axon | the axon before the ganglion |
| postganglionic axon | the extention of the pre. axon to the organ it serves |
| sympathetic division | mobilizes the body during extreme situations such as fear, exercise or rage |
| parasympathetic division | allows us to unwind and conserve energy |
| pelvic splanchnic nerves | pelvic nerves, leaving the spinal cord and traveling to the pelvic cavity |
| sympathetic division | fight-or-flight system; activity is evident when we are excited or find ourselves in threatening situations |
| parasympathetic division | most active when the body is at rest and not threatened; resting-and-digesting state; housekeeping period for the body |
| cerebral palsy | neuromuscular disability in which the voluntary muscles are poorly controlled and spastic due to brain damage |
| anencephaly | failure of the cerebrum to develop, resulting in child who cannot hear, see or process sensory input |
| spina bifida | vertebrae form incompletely; several varieties, the worst leaves the spinal cord functionless |
| orthostatic hypotension | the body's inability to react quickly to counteract the pull of gravity, low blood pressure resulting from changes in postion (lightheadedness) |
| arteriosclerosis | cause a decrease in supply of oxygen to the brain neurons |
| senility | forgetfulness, irritability, difficulty in concentration or thinking clearly |