Neuroanatomy Pages 19- Flashcards Preview

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Flashcards in Neuroanatomy Pages 19- Deck (50)
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1
Q

What are sensory systems responsible for? (3)

A
  • Collecting info regarding external & internal environment
  • Conveying info from PNS to CNS
  • Sensory info is utilized by CNS in various ways
2
Q

In what ways is sensory info utilized by the CNS?

A
  • conscious appreciation of specific qualities of sensory stimulus
  • appropriate reflex response to a stimulus
3
Q

What do sensory receptors of the PNS do?

A
  • monitor changes in external & internal environment
  • serve as biological transducers- monitor stimuli
  • the info generated in PNS gets sent to CNS
4
Q

What are primary sensory neurons?

A

Sensory neurons in PNS

5
Q

Cell bodies of primary sensory neurons are located where?

A

Peripheral ganglia of spinal and cranial nerves

6
Q

Peripheral processes innervate what?

A

Peripheral sensory receptors in peripheral tissues

7
Q

Central processes project into what?

A

into the CNS

8
Q

What are the classifications of stimulus receptors and they’re functions?

A

Chemoreceptors- monitors changes in concentration of various chemical species in tissues
Photoreceptors- light
Thermoreceptors- temperature
Mechanoreceptors- physical or mechanical stimuli
Nociceptors- noxious stimuli (potentially harmful- chemical, mechanical, or thermal stimuli)

9
Q

What is the difference between a nonencapsulated and an encapsulated ending?

A

Nonencapsulated- terminals of axons that lie next to cells or free in the extracellular space
Encapsulated- consist of terminals of axons enclosed by a capsule of non-neuronal cells

10
Q

What are the 3 types of nonencapsulated ending receptors?

A
  • Free nerve endings- axon terminals distributed between cells
  • Merkel endings/discs- associated with cells located in deep layers of epidermis (hairless especially)
  • Peritrichial nerve endings- associated with axon terminals distributed along root of hair follicles
11
Q

What are the 5 types of encapsulated ending receptors?

A
  • Pacinian corpuscles- single axon terminal with layers o non-neural cells
  • Meissner’s corpuscles- one or more axons inside capsule- highly branched (long and slender capsule)
  • Ruffini endings- single axon inside delicate capsule
  • End bulbs- variable size & shape - often round - highly branched - often found at muco-cutaneous junctions
  • Others: neuromuscular spindles (skeletal muscle) & neurotendinous spindles (tendons & ligaments- Golgi)
12
Q

Where are the free nerve endings found in cutaneous areas and what do they monitor?

A
  • epidermis, dermis, subcutaneous tissue

- monitor thermal, painful (noxious), and tactile stimuli

13
Q

What do the peritrichial endings in cutaneous areas monitor?

A

Movement of hair (tactile)

14
Q

Where are Merkel endings found in cutaneous areas and what do they detect?

A

Deep layer of epidermis

Tactile

15
Q

Where are Ruffini endings found in cutaneous areas and what do they detect?

A

Dermis & subcutaneous tissue

Tactile

16
Q

Where are Meissner’s corpuscles found in cutaneous areas and what do they detect?

A

Dermal papillae of mostly glabrous (hairless) skin, especially fingertips
Tactile

17
Q

Where are Pacinian corpuslces found in cutaneous areas and what do they detect?

A

Dermis & subcutaneous tissues

Mechanoreceptors that detect vibration

18
Q

What 4 type of receptors are found in joints? Where and what kind of stimuli do they detect?

A
  • Free nerve endings- synovial membrane (proprioception), joint capsule, & periarticular CT (nociception)
  • Small pacinian corpuscles- periarticular CT around joint capsule- proprioception
  • Ruffini- joint capsular tissue- proprioception
  • Neurotendinous spindles (Golgi tendon organ)- in articular ligaments- proprioception
19
Q

What 2 types of receptors are found in skeletal muscles?

A
  • Free nerve endings- mainly CT around muscle- nociceptor

- Neuromuscular spindles- in muscle near junction with tendon - proprioception

20
Q

What 2 types of receptors are found in tendons?

A

Free nerve endings- nociceptors & proprioceptors

Golgi tendon organs- proprioceptors

21
Q

What 2 types of receptors are found in viscera?

A
  • Free nerve endings- nociceptors, chemoreceptors, stretch/distension
  • Pacinian corpuscle- fullness/distension
22
Q

What are the functions of A-alpha fibers?

A
  • motor to skeletal muscle

- sensory from neuromuscular spindle

23
Q

What is the function of A-beta fibers?

A
  • sensory from neuromuscular spindles, Ruffini endings, GTO’s, Meissner’s, and Pacinican corpuscles
24
Q

What is the function of A-gamma fibers?

A

Motor to neuromuscular spindles

25
Q

What is the function of A-delta fibers?

A
  • Peritrichial endings, pain and temperature receptors
26
Q

What are the functions of B fibers?

A
  • Preganglionic autonomic fibers

- Sympathetic & Parasympathetic

27
Q

What are the functions of C fibers?

A
  • Postganglionic autonomic fibers, pain & temperature receptors
  • Nociceptic information
28
Q

Which of the A, B & C fibers is unmyelinated?

A

C fibers

29
Q

What type of receptor is a Ia fiber, and what is it’s equivalent?

A

Neuromuscular spindle, A-alpha

30
Q

What type of receptors are Ib fibers, and what it’s equivalent?

A

Neurotendinous spindle
Ruffini Endings
A-beta

31
Q

What type of receptors are II fibers, and what it’s equivalent?

A

Neuromuscular spindle
Meissner’s & Pacinian corpuscles
A-beta

32
Q

What type of receptors are III fibers, and what it’s equivalent?

A

Pain and temperature receptors

A-delta

33
Q

What type of receptors are IV fibers, and what it’s equivalent?

A

Pain and temperature receptors

C

34
Q

Which of the two numbered fibers are nociceptive fibers?

A

III and IV

35
Q

What tissues monitor somatosensations?

A

Superficial (skin (epiderm, derm, & subcutaneous tissue)

Deep (muscle, tendons, ligs, bones)

36
Q

What are the 6 somatosenses?

A
Pain (nociception)
Temperature
Light touch= nondiscriitive (poorly localized)
Discrimitive touch= fine/2point touch
Proprioception
Vibration
37
Q

What are the two main general somatosensory pathways/systems?

A
Spinothalamic (anterolateral)
Medial Lemniscus (Dorsal/posterior column system)
38
Q

Which types of sensations is the spinothalamic system primarily concerned with?

A

Pain
Temperature
Light/ Non-discrimitive touch

39
Q

Which types of sensations is the medial lemniscus system primarily concerned with?

A

Discrimitive/fine touch
Proprioception
VIbration

40
Q

Where are primary sensory neurons typically located?

A

Ganglia of spinal & cranial nerves (DRG)

41
Q

Where are secondary sensory neurons typically located?

A

Spinal cord or brainstem

42
Q

Where are tertiary sensory neurons typically located?

A

Thalamus

43
Q

T or F. The concept of only three neurons forming the spinothalamic and medial lemniscus pathways is accurate.

A

False. It’s more convenient. The modification of the pathways can provide for modification of the experience/perception.

44
Q

Define 2 point discrimination

A

The ability to distinguish when 2 points are touched simultaneously even when close together. Fingertips=good, back=poor
Permits recognition of different textures

45
Q

Define Graphesthesia

A

Traced figure identification- ability to identify a familiar pattern when traced on the skin (quality of discriminative touch)

46
Q

Does discriminative touch require Meissner’s corpuscles?

A

Yes along with other cutaneous receptors such as Merkel cells

47
Q

Define the qualities of Proprioception.

A

Info regarding the precise position of a body part and the range of direction of movement (kinesthesia).

48
Q

Does proprioception, discrimative touch, or light touch permit one to appreciate the shape, size, and weight of objects held in hand?

A

Proprioception

49
Q

Where are receptors found for proprioception and which receptors do these include?

A

Found in articular and periarticular tissues (joint capsules, ligaments) and in muscles and tendons

  • Neuromuscular & neurotendinous spindles
  • Ruffini-like endings
  • Pacinian corpuscles
50
Q

What receptors are used to monitor vibration?

A

Mostly pacinian corpuscles