LEC 3: The Nervous System - 08.18.2014 Flashcards Preview

STRUCTURES - WEEK 1 > LEC 3: The Nervous System - 08.18.2014 > Flashcards

Flashcards in LEC 3: The Nervous System - 08.18.2014 Deck (56):
1

Neuron

nerve cell, basic unit of a nervous system

 

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2

soma

Greek for "body"

3

flow of impulse in neuron

impulse flows from soma of one neuron, down the axon, through boutons to muscle, gland, or another neuron

4

Two (2) divisions of the nervous system

1. Central nervous system (CNS)

2. Peripheral nervous system (PNS)

5

What are the components of the CNS

1. brain

2. spinal cord

Both develop from neural tube in embryo

6

What are the components of the PNS

All nervous structures outside of the CNS that connect CNS (brain, spinal cord) to body

  • includes spinal/cranial/visceral NERVES

PNS develops from neural crest cells and as outgrowth of the CNS

7

What is the position of gray matter and white matter in the brain

  • gray matter (cell bodies) are the outer portion of brain (thinking part is outer)
  • white matter (axons forming tracts/pathways) are the inner portion of the brain

8

What is the position of gray matter and white matter in the spinal cord

  • gray matter (cell bodies) are the inner portion of the spinal cord (thinking part is inner)
  • white matter (axons forming tracts/pathways) are the outer portion of the spinal cord

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9

radicle

the beginning of a nerve

10

tract

a collection of nerve cell processes (axons/fibers) found WITHIN the CNS

(gross term)

11

nucleus

a collection of nerve cell bodies (somas) found WITHIN the CNS

(gross term, do not confuse with nucleus of a cell)

12

What is the function of myelin

  • fatty myelin (white appearance) insulates axons from communicating with neighboring axons
  • myelin is itself a cell; nucleus wrapped around axon, cytoplasm (fatty) on outside

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13

Two (2) divisions of the PNS nervous system by function

1. somatic

2. visceral (autonomic)

14

somatic 

  • innervates structures (skin and most skeletal muscle) derived from somites in the embryo
  • mainly involved with receiving and responding to information from the external environment

15

visceral (autonomic)

  • innervates organ systems in the body and other visceral elements, such as smooth muscle and glands
  • concerned mainly with detecting and responding to information from the internal environment

16

PNS

1. spinal nerves

2. cranial nerves

17

nerve

a collection of nerve cell processes (axons/nerve fibers) found OUTSIDE the CNS

18

Describe the components of a nerve trunk

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A. nerve trunk (visible in gross dissection)

B. epineurium (visible in gross dissection)

C. perineurium

D. endoneurium

E. fasicle (surrounded by perineurium)

F. fasiculus (bundles of nerve fibers surrounded by endoneurium)

G. nerve fibers (neuronal axon) (surrounded by myelin)

19

tracts and nuclei

vs.

nerves and ganglia

Really another way of distinguishing CNS (tracts, nuclei) from PNS (nerves, ganglia

  • nerves are similar to tracts, but found in PNS
  • ganglia are similar to nuclei, but found in PNS

20

nerve

a collection of nerve cell processes (axons/fibers) found OUTSIDE the CNS

21

ganglion (ganglia)

a collection of nerve cell bodies (somas) found outside of the CNS

22

What are X and Y in this structure

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X. Doral root ganglion (DRG)

Y. Spinal nerve (radicle -- where a nerve begins)

NB: Doral (anterior) side, so this view is actually a superior cut

23

Afferent sensory axons/fibers

conduct impulses TOWARD the CNS in the dorsal root ganglion

 

Think: Afferent = DorsAL (toward CNS)

24

Efferent motor axons/fibers

conduct electrical impulses AWAY from CNS in the ventral root

 

Think: Efferent = VEntral (away from CNS)

25

What is the structure of a typical Afferent (sensory) axon/fiber and what does it detect

Bipolar, detects "touch" (e.g. pain, temperature, pressure, texture, tickle)

  • cell body of Afferent sensory axon/fiber sits in dorsAL root ganglion (DRG)
  • brings signal from "touch" toward the CNS

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26

dermatone

each afferent sensory axon/fiber that brings in information is limited to which dorsal root ganglion it can go to

  • skin segments related to a spinal nerve are dermatones

27

What is the structure of a typical Efferent (motor) axon/fiber and what does it affect?

Unipolar, effects "motion" (e.g. muscle contraction, gland secretion)

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28

Describe the relationship between:

  • Dorsal root ganglion (what runs through it)
  • Ventral root (what runs through it)
  • Spinal Nerve

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  • Afferent sensory axons/fibers run through DRG, carrying "touch" information from external environment to CNS (cell body sits in DRG)
    • DRG = Pure Sensory
  • Efferent motor axons/fibers run through ventral root, affecting "motion" in the form of muscle contractions, gland secretions
    • Ventral root = Pure Motor
  • Spinal nerve contains both afferent (sensory) and efferent (motor) axons/fibers

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29

What are pure fiber types and what are examples

only one fiber type (afferent OR efferent)

e.g. ROOTS of spinal nerves

30

what are mixed fiber types and what are examples

both afferent and efferent fibers together

e.g. spinal nerves and their branches

31

What is the circled structure

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Dorsal Ramus of spinal nerve (looks like a little thumb)

32

What is the circled structure

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Ventral Ramus of spinal nerve

33

What are the branches off the Dorsal Ramus and Ventral Ramus called

Rami

34

Name the labeled parts of this card and describe the orientation

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A. Ventral Root (anterior)

B. Dorsal Root Ganglion, DRG (posterior)

C. Lateral cutaneous branch of Ventral Ramus

D. Anterior cutaneous branch of Ventral Ramus

E. Dorsal Ramus

35

What does the Dorsal Ramus innervate

  • deep back muscles
  • overlaying skin

NB: Little thumb = deep back muscles and overlaying skin

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36

What does the Ventral Ramus innervate

  • innervates everything besides the deep back muscles and overlaying skin (Dorsal Ramus)
  • superficial back muscles to limbs, body wall, etc. 

37

What is the IVF

Intervertebral foramen, an opening for a spinal nerve

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38

How many cervical vertebrae and nerves are there

  • 7 cervical vertebrae
  • 8 cervical nerves

NB: Up through nerve 7 are named for vertebrae below them; nerve 8 and onward are named for the vertebrae below

39

At which vertebral levels does the spinal cord end

  • L1-L2 marks vertebral end of spinal cord
  • spine continues to grow after birth
  • roots get progressively longer as you go down spinal cord to stay connected to IVF (exit door)
  • Cord does not get longer, roots get longer

40

Name the labeled parts of this card

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A. conus medullaris

B. Cauda equina

C. filum terminale (unpaired, not nervous tissue just connective tissue)

41

What are the three layers of meninges (membranes that envelop the CNS), from inner to outer

  • form a P.A.D. over spinal cord
    • Pia Mater (tender mother)
    • Arachnoid Mater (spider mother)
    • Dura Mater (hard mother)

42

Name the labeled parts of this card

Meninges (membranes that envelop CNS)

A. Pia Mater

B. Arachnoid Mater

C. Dura Mater

P. A. D. 

43

What is between arachnoid mater and pia mater

subarachnoid space, which contains CSF

 

44

Dura Mater

Dura Mater surrounds spinal nerve/roots, eventually becomes part of epineurium of nerves

45

What is the filum terminale made of

Pia Mater

46

Epidural space

outside the dura mater (extradural); location for anesthesia placement

47

subarachnoid space

  • lumbar cistern
  • between arachnoid and pia layers
  • space is LARGE around cauda equina
  • location for withdrawing CSF or placing spinal block anesthesia

48

lumbar cistern

  • another word for subarachnoid space
  • between pia and arachnoid layers
  • location for withdrawing CSF or placing spinal block anesthesia

49

Where do you do a lumbar puncture (draw CSF) and why

  • below L2, because that's where spinal cord ends
  • L3-L4 is best
  • subarachnoid space (lumbar cistern) is largest in region below terminal end of spinal cord
  • subarachnoid space surrounding cauda equina
  • can draw CSF without touching cord

50

What are the somas and axons/fibers of the CNS called

nuclei and tracts

51

What are the somas and axons/fibers of the PNS called

ganglia and nerves

52

Which fibers are sensory

Afferent fibers

53

Which fibers are motor

Efferent fibers

54

Where are afferent fibers found

Doral Roots ("pure")

55

Where are efferent fibers found

Ventral Roots ("pure")

56

Find the following structures:

1. Dorsal Root Ganglion (DRG)

2. Ventral Root

3. Dorsal Ramus

4. Ventral Ramus

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