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100 Cards in this Set
- Front
- Back
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Central nervous system (CNS) |
- brain and spinal cord - integration of sensory input and associating stimuli with appropriate motor output |
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Effector cells |
- muscle cells/gland cells that carry out body's response to stimuli |
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Nerves |
- threadlike extensions of nerve cells wrapped in connective tissue |
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Peripheral nervous system (PNS) |
- network of nerves extending into different parts of body - carry sensory input to CNS and motor ouptut away from CNS |
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Neurons |
- cells specialized for transmitting chemical and electrical signals from one location in body to another |
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Cell body |
- large part of neuron - contains most cytoplasm, nucleus, and other organelles - most cell bodies located in CNS |
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Dendrites |
- convey signals to cell body - short, numerous, and extensively branched to increase SA to where cell is likely to be stimulated |
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Axons |
- conduct impulses away from cell body - long, single processes |
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Myelin sheath |
- insulating layer wrapped around axons |
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Schwann cells |
- form myelin sheath in PNS |
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oligodendrocytes |
- form myelin sheath in CNS |
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Synaptic terminals |
- release neurotransmitters - many branches connected to axon |
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Synapse |
- gap between synaptic terminal and target cell, either dendrites of another neuron or effector cell |
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Sensory neurons |
- convey information about external and internal environments from sensory rceptors to CNS - most cynapse with interneurons |
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Interneurons |
- integrate sensory and motor output - located within CNS - synapse only with other interneurons |
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Motor neurons |
- convey impulses from CNS to effector cells |
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Reflex |
- simplest circuits between sensory and motor neurons (e.g. knee jerk circuits) - complex circuits: (1) Convergent: information from several presynaptic neurons come together at a single postsynaptic neuron (2) Divergent: information from a single neuron spreads out to several postsynaptic nerons, single source -> several parts of brain (3) reverberating: signal returns to source, memory storage |
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Ganglion |
- cluster of nerve cell bodies in PNS |
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Nuclei |
- cluster of nerve cell bodies in brain |
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Supporting cells (glia) |
- Reinorce, protect, insulate, and assist neurons - Do not conductimpulses, buit outnumber neurons (1) Astrocytes: encircle capillaries in brain, contribute to BBB, communicate via chemical signals (2) oligodendrocytes and Schwann cells - myelination occurs when glia grow around axon -> plasma membrane forms concentric layers |
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Blood-brain barrier |
- Restricts passage of most substances into CNS |
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Membrane potential |
- voltage across plasma membrane - maintained by sodium-potassium puimp: 3 Na+ out, 2 K+ in |
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Excitable cells |
- neuron and muscle cells - can change membrane potentials in response to stimuli |
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Resting potential |
- -70 mV membrane potential - Principle cation in cell: K+, principle cation outside: Na+ - Principle anion in cell: proteins, amino acids, sulfate, phosphate, principle anion ouside: Cl- |
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Gated ion channels |
- transmembrane proteins that allow specific ions to pass through membrane - open in response to stimuli - sensory neurons: receptors triggered by environmental stimuli - interneurons: stimuli produced by activation of other neurons |
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Hyperpolarization |
- K+ efflux - Interior of cell becomes more negative |
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Depolarization |
- Na+ influx - Reduced membrane potential |
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Graded potentials |
- Voltage changes caused by stimulation - Magniude of change depends on strength of stimulus |
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Threshold potential |
- Cell triggers action potetial - -55 mV |
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Action potential |
- Rapid change in membrane potential of excitable cell, caused by voltage-gated ion channels (1) Resting (2) Depolarizing, Na+ influx (3) Repolarizing, Na+ gates close, K+ efflux (4) Undershoot, K+ still open |
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Voltage-gated ion channels |
- Activation gate opens rapidly, inactivation gate closes slowly |
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Refractory period |
- Occurs during undershoot - Neuron is insensitive to depolarizing stimuli - Limits the maximum rate at which action potentials can be stimulated |
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Saltatory conduction |
- Action potential jumps from nodes of Ranvier (skips myelinated regions) - Nodes of Ranvier: concentrated voltage-gated ion channels, place where extracellular fluid comes into contact for ion exchange - Larger axon diameter -> faster rate of transmission |
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Presynaptic cell |
- transmitting cell |
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Postsynaptic cell |
- receiving cell |
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Synaptic cleft |
- separates pre- and post-synaptic cells so the are not electrically coupled |
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Synaptic vesicles |
- contain thousands of neurotransmitter molecules |
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Neurotransmitter |
(1) action potential depolarizes presynaptic membrane (2) Ca2+ rushes through voltage-sensitive cannels (3) synaptic vesicles fuse with presynaptic membrane and release neurotransmitter into the synaptuiic cleft tthrough exocytosis (4) neurotransmitter diffuses to postsynaptic membrane, where it causes ion gates to open |
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White matter |
- channels of communication in brain and spinal cord - inner region in brain, outer region in spinal cord |
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Presynaptic membrane |
- where synaptic vesicles and neurotransmitters are located |
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Postysynaptic membrane |
- where neurotransmitter receptors are located |
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Excitatory postsynaptic potential (EPSP) |
- excitatory synapses allow Na+ to enter and K+ to leave |
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Inhibitory postsynaptic potential (IPSP) |
- inhibitory synapses allow K+ top leave or Cl- to enter, causing hypepolarization |
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Summation |
- additive effect of EPSPs - temporal: close in time - spatial: different presynaptic neurons, same postsynaptic cell - when EPSP exceeds IPSP: action potential |
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Biogenic amines |
- neurotransmitters derived from amino acids |
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Epinephrine |
- type of biogenic amine produced from tyrosine |
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Norepinephrine |
- type of biogenic amine produced from tyrosine - functions in PNS |
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Dopamine |
- type of biogenic amine produced from tyrosine - imbalances associated with mental illness - Parkinson's: lack of dopamine |
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Serotonin |
- type of biogenic amine synthesized from tryptophan |
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Gamma aminobutyric acid (GABA) |
- amino acid neurotransmitter - most abundant inhibitory neurotransmitter - increases membrane permeability to Cl-, reduces anxiety |
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Glycine |
- amino acid neurotransmitter - inhibitory in CNS |
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Glutamate |
- amino acid neurotransmitter - most common in CNS |
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Aspartate |
- excitatory amino acid transmitter - most abundant in CNS |
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Neuropeptides |
- short chains of amino acids that operate via G-coupled protein receptor |
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Substance P |
- excitatory neuropeptide that mediates pain perception |
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Endorphins |
- natural analgesic, decresing pain perception - released in physical or emotional strress |
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Cephalization |
- evolutionary trend for sensory and feeding organs on anterior end: brains! - found in bilaterally symmetrical animals, not in sessile animals - in flatworms: simple, copntains many large interneurons that coordinate nervous functions - annelids and arthropods: well-defined ventral nerve cord and prominent brain, ganglia coordinate actions of each body segment - cephalopods: most sophisticated among invertebrates, large brain and giant axons |
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Nerve cord |
- along with brain, composes CNS |
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Gray matter |
- outer region in bain, inner in spinal cord |
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Central canal |
- filled with cerbrospinal fluid in spinal cord |
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Ventricles |
- filled with cerebrospinal fluid in brain |
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Cerebrospinal fluid |
- functions in circulation of hormones, nutrients, and WBCs - functions in shock absorption, which cushions brain |
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Meninges |
- protective layers of connective tissue which cover brain and spinal cord |
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Cranial nerves |
- innervate organs oif head and upper body - 12 - most sensory and motor, but some sensory only (e.g. optic nerves) |
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Spinal nerves |
- innervate entire body - contain sensory and motor neurons |
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Sensory division |
- division of PNS which brings information from sensory receptors to CNS |
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Motor division |
- division of PNS which carries signals from CNS to effector cells |
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Somatic nervous system |
- carries signals to skeletal muscles in response to external stimulli - includes reflexes - voluntary |
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Autonomic nervous system |
- automatic, visceral functions of smooth and cardiac muscles - involuntary - parasympathetic, sympathetic, and enteric |
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Parasympathetic division |
- enhances activities that gain and conserve energy, i.e. rest-and digest (e.g. glycogen production) - complements sympathetic dvision in reproductive activity |
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Sympathetic and enteric division |
- enhances activities that increase energy expenditures (e.g. eye dilation, accelerates heart, etc.) or fight-or-flight - enteric: exerts direct and partially independent control over digestive tract, pancreas, gallbladder |
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Forebrain |
- differentiated neural tube - telencephalon and diencephalon regions |
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Midbrain |
- differentiated neural tube - mesencephalon region |
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Hindbrain |
- differentiated neural tube - metencephalon and myelencephalon regions |
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Brain stem |
- conducts data and automatic activities - formed by mesencephalon, metencephalon, and myelencephalon - three parts: medulla oblongata, pons, midbrain |
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Medulla oblongata |
- controls visceral functions including: (1) breathing (2) heart and BV activity (3) swallowing, vomiting, digestion (4) large-scale movements, e.g. waking |
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Pons |
- controls visceral functions including:(1) breathing(2) heart and BV activity(3) swallowing, vomiting, digestion(4) large-scale movements, e.g. waking |
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Inferior colliculi |
- receives auditory fibers - region of midbrain that functions in auditory system |
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Superior colliculi |
- receives input from retina and visual cortex - participates in visual reflexes - region of mibrain that functions in visual system |
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Cerebellum |
- derived from part of metencephalon - functions in balance and coordination of movement |
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Epithalamus |
- includes pineal gland (for melatonin synthesis) and choroid plexus - arises from embryonic diencephalon |
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Choroid plexus |
- cluster of capillaries that produces cerebrospinal fluid |
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Thalamus |
- prominent integrating center in diencephalon - relays sensory information to and rom cerebrum - nuclei dedicated to one type of sensory information - sorts sensory info -> sends to appropriate brain centers for further interpretation and integration - receives input from cerebrum and parts of the brain that regulate emotion and arousal |
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Hypothalamus |
- regulates homeostasis - source of posterior pituitary hormones (e.g. ADH) and releasing hormones of anterior pituitary - Contains thermostat and hunger and thirst regulator - Plays role in sexual response and mating, fight-or-flight response, and pleasure |
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Suprachiasmatic nuclei |
- pair of nuclei in mammal hypothalamus that function as a biological clock - use visual information to synchronize certain bodily functions with night and day - maintains bodyrhythms like: sleep, BP, sex drive -> like clock gene! |
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Cerebral hemispheres |
- divisions of cerebrum, which is derived from embryonic telencephalon - consists of cerebral cortex, white matter, and basal nuclei - if damaged, motor impulses can no longer be sent to muscles -> passivity and immobility -> if in basal ganglia, Parkinson's - four lobes: primary motor cortex (sends commands to skeletal muscles) and primary somatosensory cortex (for asociation o impulses to specific body parts, proportionally more for certain parts like hands) form boundary between frontal and parietal lobes |
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Basal nuclei |
- clusters of nuclei deep within white matter in cerebrum - centers for motor coordination, relaying impulses from other motor systems - send motor impulses to muscles |
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Cerebral cortex |
- outer covering of gray matter - highly folded convolutions -> SA of about 0.5 m^2 - bilaterally symmetrical - special cortical regions integrate special senses: vision, hearing, smell, and taste |
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Corpus callosum |
- thick band of fibers (white matter) that connects two hemispheres - transfers information between hemispheres - left: speech, language, calculation, and rapid serial processing of detailed information - right: context, creative abilities, andpatial perception - severing corpus callosum will dissociate sensory input from spoken response -> aphasia! |
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Electroencephalogram (EEG) |
- measures electrical potential between areas of cortex - Alpha waves: slow, synchronous; produced in relaxed close-eye wakefullness - Beta waves: faster, less synchronous; produced during mental alertness/problem solving - Theta waves: more irregular; early stages of sleep/REM - Delta waves: slow, high amplitude, highly synchonized; deep sleep |
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Reticular formation |
- has a reticular activating system (RAS), a center in cerebrum and brain stem that controls sleep and arousal - RAS filters which sensory information reaches cortex |
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Limbic system |
- group of giant nuclei and interconnecting axon tracts in forebrain - emotions depend on interactions of cerebral cortex and limbic system - parts of the thalamus, hypothalamus, and inner portions of cerebral cortex (amygdala and hippocampus) - linked to learning -> close relationship between emotion and thought |
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Amygdala |
- part of limbic system - for emotional memory - may filter memory by ting it to an event or emotion |
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Short-term memory |
- immediate sensory perceptions of an object or idea - occurs before an image is stored |
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Long-term memory |
- stored inormation that can be recalled at a later time |
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Hippocampus |
- part of limbic system - for learning and memory - certain synapses functionally change as a result of altered responsiveness by postsynaptic cells |
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Long-term depression |
- occus in hippocampus - postsynaptic cell displays decreased responsiveness to action potentials |
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Long-term potentiation |
- occurs in hippocampus - postsynaptic cell displays increased responsiveness to action potentials - mechanism involves presynaptic release of glutamate -> bindswith postsynaptic rceptors, opens gated channels highly permeable to Ca2+ -> Ca2+ influx triggers intracellular changes -> LTP - can be positive feeback loop, as postsynaptic cell signals presynaptic cell to release more glutamate, likely due to NO |
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Consciousness |
- Hypotehesis: simultaneous cooperation of extensive areas of cerebral cortex - cerebral neurons and functional groups of neurons generating conscious thoughts while engaged in less complex tasks |
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Nerve net |
- loosely organized system of nerves with no central control - conducts impulses in both directions throughout body - cnidarains, ctenophores, echinoderms |
