PNS and reflex (chapter 13)

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  1. A receptor which responds to light
  2. a receptor which responds to smell, taste, changes in blood chemistry
  3. a receptor which is sensitive to pain-causing stimuli:
    extreme heat or cold
    excessive pressure 
    inflammatory chemicals
  4. a receptor which responds to vibration and stretch
  5. define "exteroceptor"
    • responds to stimuli outside the body 
    • receptors are located in skin and in most sense organs
  6. define "interoceptor"
    • respond to stimuli arising in the viscera and blood vessels
    • sensitive to chemical changes, tissue stretch and temperature changes
  7. define "proprioceptor"
    • respond to stretch in skeletal muscles, tendons joints, ligaments and CT coverings of bones and muscles
    • continuously inform the brain of the bodies position and movements 
  8. _______ receptors detect the general senses. _______ receptors detect the special senses.
    • simple
    • complex
  9. Simple receptors are either noncapsulated or encapsulated nerve endings. 
    Describe nonencapsulated nerve endings.
    • abundant in the epithelia and CT
    • responds to mostly to temperature and pain
    • some respond to pressure-induced tissue movement
  10. Name 3 non encapsulated dendritic endings of simple receptors
    • thermoreceptors
    • nociceptors
    • touch receptors
  11. all mechanoreceptors are enclosed in a __________ _________ _________
    connective tissue capsule
  12. contrast "sensation" and "perception"
    • sensation: awareness of stimuli 
    • perception: conscious interpretation of stimuli
  13. list several stimuli that activate nociceceptors
    • chemicals from damaged tissue
    • extreme temperatures
    • inflammatory chemicals
    • excessive pressure
  14. list and describe 3 levels of sensory integration
    • Receptor level: sensory reception and transmission to the CNS
    • Circuit Level: processing in ascending pathways
    • Perceptual Level: processing in cortical sensory centers
  15. describe the role of endogenous opioids in pain suppression
    to suppress pain signals within the brain
  16. Structure of a nerve. Order the smallest unit to the largest.
    myelin sheath
    • axon
    • myelin sheath
    • Endoneurium
    • Peroneurium
    • Epineurium
  17. Describe the role of Schwann cells in nerve fiber regeneration
    • Schwann cells align to form a regeneration tube
    • The axon regenerates and a new myelin sheath forms
  18. Describe spinal nerves. Distinguish between spinal roots and rami.
    • Spinal nerves are quite short. 
    • Spinal roots (ventral and dorsal) branch off from the spinal cord.
    • The root than branches off into the spinal nerve which branches into the dorsal ramus, ventral ramus. 
    • Ventral rami for the nerve plexuses.
  19. Name the Major plexuses
    • Cervical Plexus
    • Brachial Plexus
    • Lumbar Plexus
    • Sacral Plexus
  20. State the major peripheral nerve that arise from the cervical plexus. Describe the general functions.
    • Phrenic nerve - diaphragm 
    • Accessory nerve/hypoglossal nerve -muscles and skin of head and neck
  21. State the major peripheral nerve that arise from the brachial plexus. Name the general function of these nerves.
    • Axillary nerve
    • Radial/medial/ulnar nerves
    • functions: innervates muscles and skin of the upper limb
  22. State the major peripheral nerve that arise from the lumbar plexus. State the general function of these nerves.
    • Femoral Nerve
    • function: innervates the thigh, abdominal wall and psoas muscle.
  23. State the major peripheral nerve that arise from the sacral plexus. State the general function of these nerves.
    • Common fibular nerve
    • tibial nerve
    • Sciatic nerve
    • Function: serves the buttock, lower limb, pelvic structure and perineum.
  24. Name the 5 components of the reflex arc.
    • Receptor: detects stimulus
    • Sensory Neuron: transmits afferent impulses to CNS
    • Integration center: within the CNS; either monosynaptic or postsynaptic path
    • Motor Neuron: conducts efferent impulses from the integration centre to the effector 
    • Effector: muscle or gland that responds ti efferent impulses
  25. To smoothly coordinate skeletal muscle activities, the nervous system must receive proprioceptor input regarding:
    • a) length of a muscle: input is provided by muscle spindles
    • b) tension in a muscle: input is provided by tendon organs
  26. Input information regarding the length of is muscle is collected from?
    length comes from muscle spindles.
  27. The input for the amount of tension in a muscle and its associated tendons is provided by?
    tension input is from tendon organs
  28. Describe the stretch reflex
    • maintains muscle tone in large postural muscles, and adjusts it reflexively 
    • causes muscle contraction in response to increased muscle length
    • monosynaptic
    • ipsilateral
  29. all stretch reflexes are ______, while all other reflexes are __________
    • monosynaptic 
    • polysynaptic
  30. describe the flexor reflex
    • initiated by a painful stimulus
    • ipsilateral and polysynaptic
    • protective function to prevent further damage 
    • brain can override the automatic withdrawal
  31. describe the crossed-extensor reflex
    • typical occurs as the same time as a flexor reflex in a lower limb to maintain body balance
    • ipsilateral withdrawal reflex and contralateral extensor reflex
  32. this reflex indicates damage to the primary motor cortex or corticospinal tract. The big toe dorsiflexes and other toes fan out.
    Babinski's sign
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PNS and reflex (chapter 13)
2014-12-09 20:48:56

chapter 13, A&P I
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