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38 Cards in this Set
- Front
- Back
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Nervous system subdivision
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- CNS
- PNS |
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CNS
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- brain and spinal cord
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PNS
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Includes:
- nerves formed of axons that transmit efferent information to muscles and internal organs - afferent axons that transmit sensory information toward CNS |
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PNS divisions
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- somatic NS
- autonomic NS |
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Somatic NS
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axons that transmit efferent information to muscles
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Autonomic Nervous System
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transmits efferent information towards internal organs
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Autonomic NS divisions
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- sympathetic
- parasympathetic |
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The neuron is the basic unit for _______.
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operation of nervous system
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Role of neuron
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transmits electrical signals
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resting potential
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measurement of voltages between extracellular and intracellular spaces
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resting potential due to ________.
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electrochemical gradient between intracellular and extracellular spaces
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How are ion concentration maintaining inside cell?
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by ATPase pump that removes 3 Na+ ions and adds 2 K+ ions
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What type of pump is the ATPase pump? Why?
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- electrogenic pump
- because it removes more positive charges than it adds |
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role of facilitated diffusion pumps
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removes Cl- and adds HCO3- in equal proportions to maintain low concentration of Cl-
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Why do ion channels exist?
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because ions can't flow through hydrophobic membrane
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ion channel location
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- cell synthesizes proteins that become ion channels in membrane
- located where they are useful |
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components of ion channels
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- receptive region
- trigger zone for action potential - axon - terminal region for secretion of neurotransmitter |
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How is action potential signal triggered?
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at initial axon segment when membrane potential is depolarized above action potential threshold
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Action potential mechanism
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- change in potential detected by voltage-gated channel in axon
- activation gate of sodium channel opens allow entry of sodium which depolarization membrane towards equilibrium - before equilibrium reached, voltage-gated potassium channel opens and activation gate of sodium channel closes |
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What is marked by the closing of the activation gate of the sodium channel?
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absolutely refractory period
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action potential propagation
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through length of axon towards terminal
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when does the role of the ionotropic receptor begin?
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one action potential is in terminal and it triggers opening of Ca+++ voltage-gated channel
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How are metabotropic receptors linked?
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indirectly via metabolic cascades to opening of channels
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Sensory receptor purpose
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used to detect state of internal and external milieu
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sensory receptor classification
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- anatomical location of stimuli
- type of stimuli - complexity of structure |
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locations of sensory stimuli
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- exteroceptors
- visceroceptors - proprioceptos |
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types of sensory stimuli
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- mechoreceptors
- thermoreceptor - photoreceptor - chemoreceptor - nociceptor |
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complexity levels of sensory receptors
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- complex
- simple |
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transduction
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energy of stimulus transformed into electric activity
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types of potentials
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- opening of ionic channel leading to receptor potentials
- depolarization beyond threshold of excitation leading to action potential |
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intensity of stimulus
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frequency of action potential discharge corresponds to intensity of stimulus
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adaptation
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initial response of receptor decreases over time
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adapts quickly
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phasic receptor
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adapts slowly
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tonic receptor
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first stage of perception of environment
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transmit sensory information to cerebral cortex
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papillae
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- structures on surface of tongue that give it a rough texture and contains taste buds
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types of papillae
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- fungiform
- circumvallate |
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types of epithelial cells
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- supporting
- gustatory - basal |
