Physiology Exam I

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Physiology Exam I
2011-05-01 11:56:05

Cellular intro & Neurophysiology
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  1. Describe the Visual Central Pathway
    Hyperpolarization ->action of rods-> alter synpatic activity with biopolar, amacrine, horizontal cell-> AP ganglion cells of optic N-> relay to thalamus nucleus LGN-> 1* visual cortex (occiptal lobe)
  2. Visual Transduction steps net result is a generation of ___________ in the ________ cells
    • hyperpolarization via closing Na channels
    • rod leading -> bipolar cells, amacrine cell, horizontal cells AP in the ganglion cells
  3. Tranduction of sound result in _________ of _________ cells which transmitt release _________ to fire AP to _________ nerve that synapse with____________
    • depolarization of hairs cells
    • spiral ganglion cells
    • Cochlear branch of CN VIII (Vestibularchochlear N)
    • Cochlear nuclei of medulla oblongota
  4. Prefrontal cortex
    • on of the main Association cortex
    • the homeostatic and sensorimotor systems are integrated into
    • conscious thoughts
    • Tertiary Motor Cortex- strating pt for output from the brain
    • site of Working Memory ( short-term memory)
  5. Feedforward pathway
    • 1>2>3>3>2>1
    • sensory cortex > PTO> Prefrontal Cortex< 2* motor<1*motor cortexs(cerebal cortex highest motor heiarchy)> alpha motor neuron> skeletal muscle
  6. PTO
    • posterior association cortex
    • where parietal, temporal, occipital all abut each other
    • association take the form of symbols & language
    • "library"
    • multimodal info process
  7. 1* sensory input vs 2*
    gets input from thalamus 2* doesn't
  8. Sensorimotor System
    • perceiving the external world & moving the body (skeletal muscles) through the external world
    • input - perception
    • output- moving skeletal muscle through
  9. Homeostatic system
    • perceiving the internal environment of the body & regulating the viscera via Endocrine & autonomic system
    • input-perception of internal environment
    • output- regulating via endocrine & autonomic
  10. Homeostatic adjustments effector organs
    • cardiac muscles
    • smooth muscles
    • exocrine glands
    • endocrine glands
  11. Gilia are ________. Ratio to neuron_________
    • Astrocytes
    • microglia
    • Oligodendrocytes
    • Schwann cells
    • 10:1
  12. Astrocyte
    • sustain neurons metabolically (nutrition) & trophically (growth)
    • support them physically: structural function
    • maintian extracellular fluid composition (uptake of K+)
    • maintain blood-brain barrier
  13. microglia
    scavenger immune cells in CNS
  14. Oligodendrocytes
    myelination of CNS axon
  15. Schwann cells
    myelination of PNS axons
  16. Blood Brain Barrier
    tight junctions in capillaries prevent diffusion of substances from blood to brain extracellular space, except Water & Lipid soluble substances
  17. Dendrites
    • input end
    • reception of information as Graded potential
  18. Cell body
    metabolisms, gene expression, protien synthesis, graded conduction
  19. Axon hiliock
    site of generation of AP (action potential)
  20. Axon
    transmission of AP
  21. Axon Terminal
    • secretion of NT
    • output end
  22. Cell that have the ability to conduct electricity along their plasma membrane
    • neurons
    • cardiac muscle cell
    • skeletal muscle cell
    • smooth muscle cell
  23. Neurons conduct electricity
    • = change in membrane potential =flow of ions across the neuron's membrane
    • because of ion channels
  24. Graded potential
    • caused by ligand-gated channels (NT- ligand)
    • take on any value
    • come about b/c ligand gated ion channel stays open for a variable amout of time
  25. Action Potential (AP)
    • fixed changes
    • caused by voltage gated ion channels
    • stay open for a fixed amount of time, allowing only the same amount of ions to pass each time the voltage gated channel is open
  26. What prevents the AP from propagating backward?
    fast Na+ channels go to an inactive state after they close
  27. What are the steps in protein function during an AP
    (Na+ and K+ channels)?
    • high (-) V force keeps Na channel closed by 1st gate
    • relatively (-) V force ( threshold) opens 1st gate Na+ enter
    • high (+) V force close Na+ channel via 2nd gate Na channel is inactive
    • relief of (-) V force open K gate hyperpolarization
    • increase in (-) V force Na 2nd gate is replace by 1st gate
    • High (-) V force membrane V keeps both Na & K closes
  28. Purpose of Myelin in comparison to nonmyelin
    • to enhance the conduction of AP along the axon
    • is an insulator
    • depend on electric field and not on diffusion of ions
    • fatty sheath
    • nonmyelin is depend on distance of thershold to adjacent channels
  29. What keeps ion concentration constant on both sides a neuronal membrane__________? And at what point would this cease___________ ,what is the name of this condition?
    • Na-K ATPase
    • 3Na -out
    • 2K -in
    • requires ATP
    • after 4 minute of brain deprived of blood flow Na and K are equilibrate
    • ischemia --> why stroke cause death to neural tissue
  30. The greater the frequency of AP arrival to the synapse
    • greater the influx of Ca2+
    • more NT is released into synaptic cleft
  31. What is the sequence of events at a synapse
    • Presynaptic ending - recieves AP ->increase perm. to Ca2+ ->exocytosis of NT from presynaptic vesiscles
    • into Synaptic cleft-> interaction with NT with Postsynaptic cell NT receptors ->AP
  32. What is the difference between temporal & spatial summation?
    • T- addition/subtraction of two synaptic inputs over a short time interval (happening sequentially)
    • S- addition/subtraction of two synapt inputs occurring simultaneously but different location
  33. Excitatory vs. Inhibitory
    • E- depolarization Na or Ca of postsynaptic cell
    • I- hyperpolarization Cl influx or K efflux
  34. NT
    • elicit EPSP or IPSP in postsyn. element via ligand gated ion channel
    • Ach
    • Glut- EPSP
    • Asp-EPSP
    • GABA -IPSP
    • Gly
  35. Spine synapse
    • post synaptic element forms a specialized extrusion
    • cortical & hippocampal pyramidal neurons
  36. "En passant" synapse
    • presyn element dose not terminate but exist along the course of the axon
    • cerebellar granule cell axons
  37. Neuromodulator
    • amplify or dampen the effectiveness of NT in either pre- or postsyn using 2nd messenger system
    • NO
    • biogenic amines - NEPI, DO, EPI, histamine,
  38. Receptor subtypes
    • Ultimately the body can use the same NT for different effects depending on where it binds in the NS or periphery
    • Ex. EPI alpha1, alpha2, beta1, beta2
  39. Muscarinic vs Nicotinic
    • both receptors Ach bind
    • M-Gprotein receptor->everywhere else
    • N- ion channel ->skeletal muscle
  40. Gray matter vs White matter
    • G-structures made of cell bodies & dendrites
    • clusters or sheets of neurons
    • W-structures made of axons, fibrous texture,
    • columns, nerves, commissures , fasciculus, lemniscus, peduncle
  41. Reticular Formation
    • loose grouping of nuclei in brainstem involved in controlling levels of awareness and alertness of the brain
    • make neuromodulators
  42. Brainstem
    • involved w/ UNconscious reflexes of both a motor & homeostatic nature
    • Pon
    • Medulla
    • Midbrain
    • all 3 involved in motor coordination & organization of skeletal mus. movement
  43. Cerebellum
    • exist @ level of brainstem
    • involed in motor coordination & organization of skeletal mus. movement
  44. Thalamus
    • Diencephalon
    • relay station for conscious sensory input, regulation of states of arousal
  45. Hypothalamus
    • Diencephalon
    • regulation of endocrine system, autonomic system, & emotional rxns
  46. Subcortical Nuclei and their functions
    • Basal ganglia- motor planning & conscious awareness
    • Limibic system (Hippocampus & Amygdala) - memory
    • emotions, drives (sex, hunger)
  47. What are visceral Inputs
    • GI tract: Mechanoreceptors, gustatory sensation, chemoreceptors, nociceptors
    • Cardio: bareoreceptors, stretch receptors, nociceptors, chemoreceptors
    • Pulmonary system, Urogential system: stretch receptors
  48. What are the two main typees of procession for visceral inputs
    • Reflex loop: mediate by spinal interneurons, relay to NTS, ->synapse w/ spinal cord, pontine, medulla-> efferents->ANS preganglia
    • Central integration w/ senosrimotor system: relay to NTS->hypothalamus or limbic (amygdala) -> hormonal output
  49. Homeostatic outputs
    • endocrine system via Hypothalamus
    • ANS via NTS, hypothalamus, amygdala, & brainstem
  50. Thoracolumbar ANS
    • Sympathetic NS
    • preganglionic neurons at T & L level of spinal cord
    • postganglionic neurons are in sympathetic trunck
    • unified response
  51. Caniosacral ANS
    • Parasympathetic NS
    • preganglionic neurons is in Brainstem or Sacral spinal cord
    • postganglionic neurons is close to effector organ
    • localized/ discrete reponse
  52. Sensory Receptors
    cells which transduce environmental energy into changes in membrane potential
  53. Stimulus
    the energy form that activates the sensory receptor
  54. adequate stimulus
    the type of energy to which a receptor best responds
  55. Doctrine of Specific Nerves Energies
    activation of a specific type of receptor gives rise only to a single type of sensation
  56. Labeled-line Coding
    sensory modalities are kept separate from one another in their assent to the brain
  57. Types of stimulus energy
    • chemical -chemoreceptors
    • light- photoreceptors
    • thermal-thermoreceptors
    • pressure, vibration, stretch, touch - mechanorecptors Ex. Somatosensation, auditory, vestibular
    • pain- nociceptors
  58. The aspects of sensory input coded by the nervous system
    • 1) Stimulus Type
    • 2) Stimulus Location
    • 3) Stimulus Duration
    • 4) Stimulus Instensity
  59. Convergence vs Divergence
    • C- many receptor axons synapse to a post-syn cell
    • increase signal over a nosiy background
    • D-single receptor axon synapses w/ many postsynaptic cells
    • amplify the effect of the single receptor
  60. Lateral Inhibition
    most active cells inhibit their neighbors, increases sensation contrast
  61. Somatosenstation
    • Stretch
    • Pain
    • Temp
    • Pressure
    • Vibration
    • Touch
  62. Dorsal Column Relay vs Anterolateral Tracts
    • Both Ascending somatosensory tracts- sensations from R side body are processed in L side of Forebrain & vice versa
    • D- cross-over in medulla
    • touch, pressure, & vibration
    • A-pain & temp cross-over in spinal cord
  63. Nucleus cuneatus
    from arm, shoulders, neck
  64. Nucleus gracilis
    legs & trunk
  65. Thalamus Nucleus of Auditory Relay vs Thalamus Nulecus of Visual Relay
    • Vis- Lateral geniculate nucleus
    • Aud- Medial geniculate nucleus
  66. Two component of Vestibular System
    • Semicircular Canals- detects Angular acceleration of head
    • Utricle & Saccule - detect Linear acceleration of head