2024-12-08T22:02:47+03:00[Europe/Moscow] en true <p>What does the PNS afferent/sensory division consist of?</p>, <p>what do receptors of the afferent division of the PNS do? How are they categorized?</p>, <p>What are the 3 different locations PNS receptors can be? What do they do at each location?</p>, <p>What are the types of stimulus PNS receptors can detect (stimulus categories)?</p>, <p>What are the 2 different structures of PNS receptors (general sense only)?</p>, <p>What are first order neurons?</p>, <p>What do first order neurons have cell bodies in?</p>, <p>What do first order neurons have axon terminals in?</p>, <p>What is the general vague path of the afferent PNS division?</p>, <p>What is the general vague path of the PNS motor division?</p>, <p>What are the two subdivisions of the PNS motor division?</p>, <p>What is the effector of the somatic and autonomic subdivisions?</p>, <p>What cells does the somatic subdivision consist of? Where does it have cell bodies?</p>, <p>What cells does the antonomic subdivision consist of? Where does it have cell bodies?</p>, <p>What is the path of the 2 successive multipolar neurons from CNS to effector?</p>, <p>What are the 2 subdivisions of the PNS autonomic division?</p>, <p>Where is the cell body of preganglionic neuron in SNS and PSNS of the autonomic division of PNS?</p>, <p>Where is the autonomic ganglia in SNS and PSNS of the autonomic division of PNS? (sns on left of answer)</p>, <p>What are the postganglionic neurons in SNS and PSNS of the autonomic division of PNS?</p>, <p>What are the functions of the SNS and PSNS of the autonomic division of PNS?</p>, <p>Where do the SNS and PSNS of the autonomic division of PNS exit the CNS (what nerves)?</p>, <p>What are the 2 nervous system pathways </p>, <p>What does the ascending pathway do?</p>, <p>What are the 3 successive neurons from receptor to cortex of the ascending pathway? What do they do?</p>, <p>What are the 3 different pathways/tracts of the ascending spinal tracts</p>, <p>What does the Dorsal (Posterior) Column Pathway/Tract do?</p>, <p>What do the Spinothalamic Pathway/Tracts do?</p>, <p>What do the Spinocerebellar Pathway/Tracts do?</p>, <p>What does the descending pathway do?</p>, <p>What are the two neurons of the 2 neuron pathway of the descending pathway?</p>, <p>What tracts form the descending spinal tracts?</p>, <p>What are the corticospinal tracts?</p>, <p>What are the indirect tracts?</p> flashcards

Unit 19 - Nervous System pt. 4 (PNS sensory division, motor division, nervous system pathways)

PNS sensory/afferent division, PNS efferent/motor division, nervous sytem pathways

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  • What does the PNS afferent/sensory division consist of?

    receptors and first order neurons

  • what do receptors of the afferent division of the PNS do? How are they categorized?

    —  detect changes in environment

    —  classified by: Location, Type of stimulus received, Structure of Receptor (general senses only)

  • What are the 3 different locations PNS receptors can be? What do they do at each location?

    - exteroceptors: stimulus in external environment so receptors at body surface (e.g. touch, special senses)

    - interoceptors: stimulus in internal environment (in viscera, blood vessels, etc.)

    - proprioceptors: located in joints, skeletal muscles, etc. that monitor body position (stretch receptors, muscle spindles ) – balance and movement

  • What are the types of stimulus PNS receptors can detect (stimulus categories)?

    - mechanoreceptors: mechanical stimuli (e.g. pressure, touch, hearing)

    - thermoreceptors: temperature

    - chemoreceptors: chemical

    - photoreceptors: light

    - nociceptors: pain

  • What are the 2 different structures of PNS receptors (general sense only)?

    - free nerve endings: terminal dendrites of unipolar sensory neurons e.g. pain, root hair plexus

    - encapsulated nerve endings: terminal dendrites enclosed in CT e.g. Meissner’s and Pacinian corpuscles

  • What are first order neurons?

    —  unipolar neuron attached to or associated with receptor (may be encapsulated)

    —  axon travels in cranial/spinal nerves to CNS

  • What do first order neurons have cell bodies in?

    —  cell bodies in:

    - sensory ganglia of cranial nerves

    - dorsal root ganglia of spinal cord

  • What do first order neurons have axon terminals in?

    —  axon terminals in:

    - brain

    - dorsal horn of spinal cord

  • What is the general vague path of the afferent PNS division?

    stimulus  to   receptor   to   Central Nervous System (CNS)

  • What is the general vague path of the PNS motor division?

    Central Nervous System (CNS)  to   Effector  

  • What are the two subdivisions of the PNS motor division?

    somatic and autonomic

  • What is the effector of the somatic and autonomic subdivisions?

    somatic: skeletal muscle

    autonomic: smooth muscle, cardiac muscle, glands

  • What cells does the somatic subdivision consist of? Where does it have cell bodies?

    - consists of lower motor neurons: single multipolar neuron

    - cell bodies in ventral horn of spinal cord to effector

    - cell bodies in motor nuclei of brainstem to effector (e.g. facial motor nucleus for CN VII)  

  • What cells does the antonomic subdivision consist of? Where does it have cell bodies?

    —  2 successive multipolar neurons from CNS to effector:

    1. preganglionic neuron: myelinated, cell body in brain stem or lateral horn of spinal cord

    2. postganglionic neuron: unmyelinated, cell body in autonomic ganglion (outside CNS)

  • What is the path of the 2 successive multipolar neurons from CNS to effector?

  • What are the 2 subdivisions of the PNS autonomic division?

    - Sympathetic (SNS)

    - Parasympathetic (PSNS)

  • Where is the cell body of preganglionic neuron in SNS and PSNS of the autonomic division of PNS?

    SNS: lateral horn (of T1-L2)

    PSNS: brain stem and S2-S4

  • Where is the autonomic ganglia in SNS and PSNS of the autonomic division of PNS? (sns on left of answer)

  • What are the postganglionic neurons in SNS and PSNS of the autonomic division of PNS?

    SNS: long axons

    PSNS: short axons

  • What are the functions of the SNS and PSNS of the autonomic division of PNS?

    SNS: fight or flight

    PSNS: rest & digest

  • Where do the SNS and PSNS of the autonomic division of PNS exit the CNS (what nerves)?

    SNS: mainly as thoracic nerves

    PSNS: mainly (80%) as vagus nerve (cranial nerve X)

  • What are the 2 nervous system pathways

    Ascending pathway (sensory) and descending pathway (motor)

  • What does the ascending pathway do?

    - conducts impulses from general sense receptors into brain

    - has 3 successive neurons from receptor to cortex

    - axons of 1st and 2nd order neurons form ascending spinal tracts

  • What are the 3 successive neurons from receptor to cortex of the ascending pathway? What do they do?

    - First Order Neuron: receptor to spinal cord (PNS)

    - Second Order Neuron: interneuron, multipolar (CNS), cell body in dorsal horn of spinal cord or medulla (CNS), decussates (crosses over) in medulla

    - Third Order Neuron: interneuron, multipolar, cell body in thalamus – impulses to postcentral gyrus (sensory cortex) (CNS)

  • What are the 3 different pathways/tracts of the ascending spinal tracts

    - Dorsal (Posterior) Column Pathway/Tract

    - Spinothalamic Pathway/Tracts

    - Spinocerebellar Pathway/Tracts

  • What does the Dorsal (Posterior) Column Pathway/Tract do?

    —  sensations can be precisely located (touch)

    —  receptors = free nerve endings, Meissner’s etc.

  • What do the Spinothalamic Pathway/Tracts do?

    —  non-specific, difficult to localize

    —  receptors = temperature, pain                       

  • What do the Spinocerebellar Pathway/Tracts do?

    —  ascending tracts from spinal cord to cerebellum

    —  receptors = proprioceptors

    —  2nd order neuron directly to cerebellum (no 3rd order): no conscious perception, no decussation

  • What does the descending pathway do?

    - conduct impulses from brain to effector

    - 2 neuron pathway

    - axons of upper motor neurons form descending spinal tracts

  • What are the two neurons of the 2 neuron pathway of the descending pathway?

    - Upper Motor Neuron (CNS): multipolar interneurons, cell bodies in cortex or brainstem nuclei

    - Lower Motor Neuron (cell bodies in CNS and axons in PNS)

  • What tracts form the descending spinal tracts?

    corticospinal tracts and indirect tracts

  • What are the corticospinal tracts?

    —  cell bodies in cerebral cortex

    —  tracts mainly decussate in medulla

  • What are the indirect tracts?

    —  cell bodies in brainstem nuclei

    —  receive impulses from motor cortex, basal nuclei, cerebellum