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1. HLTH 108 > Nervous tissue > Flashcards

Flashcards in Nervous tissue Deck (47)
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1
Q

overview of nervous system:

A

network of specialised cells for communication btw host and environment

  • regulates body functions
  • maintains homeostasis (helped by endocrine system)
  • responsible for all behaviours, memories, movement
2
Q

list basic functions:

A

sensory, integrative, motor

3
Q

sensory:

A

sense changes in internal/external environments through sensory receptors
- sensory (afferent) neurons

4
Q

integrative:

A

process/ store sensory info, make decisions regarding appropriate responses
- association/ interneurons

5
Q

motor:

A

responds to stimuli by initiating action

- motor (efferent) neurons

6
Q

list parts of CNS

A

central nervous system:

  • brain
  • spinal cord
7
Q

list parts of PNS

A

peripheral nervous system:

  • cranial nerves
  • spinal nerves
  • ganglia
  • plexuses
  • receptors
8
Q

3 types of PNS

A
  • somatic nervous system
  • autonomic nervous system
  • enteric nervous system
9
Q

list two categories of cells in nervous system:

A

neurons, neuroglia (glial cells)

10
Q

general features/ function: neurons

A

functional unit of nervous sytem

  • propagates electrical impulses
  • 3 main types: multipolar, bipolar, unipolar
11
Q

features/ function: neuroglia

A

supportive cells
- 6 major types
(4 in CNS, 2 in PNS)

12
Q

main parts of neurons:

A

dendrites (afferent)
cell body (integration)
axon (efferent)

13
Q

features/ function: dendrites

A

RECEIVING signals from other neurons (less: intergrating)

  • typically many dendrites with numerous branches
  • diameter tapers away from cell body
  • not myelinated
  • passively conduct graded potentials from synapses -> towards cell body
14
Q

features/ function: cell body

A

soma or perikaryon

  • variable in size/ shape
  • INTERGRATING signals
  • cytoplasm has many organelles
15
Q

organelles of cell body:

A

nucleus, nissl bodies (ER), golgi apparatus, mitochondria, microtubules

16
Q

features/ function: axons

A

PROPAGATING signals from neuron-neuron

  • 1 axon per neuron, relatively few branches (exc. near terminal end)
  • uniform diameter entire way
  • often myelinated, increase conduction velocity
  • propagates action potentials away -> cell body toward -> synapses at axon terminal
17
Q

features/ function: synapse

A

junction btw two neurons/ neuron and effector organ

  • electrical
  • chemical

postsynaptic potentials in other neuron/ organ:

  • excitatory
  • inhibitory
18
Q

list different classifications of neurons: and why?

A

based on no. of structures directly attached to cell body:
unipolar
bipolar
multipolar

19
Q

features: multipolar neuron

A

most common

  • cell body btw many dendrites
  • axon
20
Q

features: bipolar neuron

A
  • cell body middle

- dendrite, axon

21
Q

features: unipolar neuron

A

sensory neuron

- one structure (axon)

22
Q

trigger zone:

A

needs to be activated from multiple dendrites of same signal to then pass stronger signal down axon

23
Q

list glial cells in PNS:

A

schwann cells
satellite cells

similar functions to glial cells in CNS

24
Q

list glial cells in CNS

A

oligodendrocytes
astrocytes
microglia
ependymal cells

similar functions to glial cells in PNS

25
Q

features/ function: Oligodendrocytes

A

found in CNS

  • produces myelin
  • 1 cell has many processes, wraps myelin around multiple axons
26
Q

features/ function: Schwann cells

A

found in PNS

  • produces myelin
  • 1 cell forms myelin around 1 segment of 1 axon
27
Q

features/ function: myelin

A

80% lipid, 20% protein

  • electrical insulation of axon
  • increases velocity of impulse propagation
  • larger diameter axons have thicker/ more effective myelin sheaths (up to 100s of layers)
  • provides track for regrowth to occur
28
Q

features/ function: astrocytes

A

found in CNS

  • most abundant cell in CNS
  • structural/ metabolic support
  • maintains extracellular chemical balance
  • principal role in nervous system repair
29
Q

features/ function: satellite cells

A

found in PNS

  • flattened cells surrounding neuron cell bodies within ganglia
  • similar role to astrocytes (metabolic/ structural support)

aka: mantle cells, amphicytes

30
Q

features/ function: ependymal cells

A

found in CNS

  • lines ventricles of brain/ central canal of spinal cord
  • columnar/ cuboidal epithelium
  • ependymocytes: in choroid plexuses produce CSF
  • ciliated ependymocytes: help circulate CSF
31
Q

features/ function: microglia

A

found in CNS

  • from precursor cells in bone marrow (monocyte)
  • similar to macrophages elsewhere in body

main active immune defence in the CNS:

  • scavenging
  • phagocytosis
  • cytotoxicity
  • antigen presentation
  • promotes repair
32
Q

list layers of cerebral cortex:

A
I: molecular layer
II: outer granular layer
III: outer pyramidal layer
IV: inner granular layer
V: inner pyramidal layer
VI: layer of pleiomorphic cells
33
Q

distinguish layers: cerebral cortex

A

no boundaries, hard to distinguish

34
Q

list layers of cerebellar cortex:

A

I: molecular layer
II: Purkinje cell layer
III: granular cell layer

35
Q

list connective tissue associated with peripheral nerves:

A

endoneurium, perineurium, epineurium

36
Q

endoneurium:

A

surrounds each axon

37
Q

perineurium:

A

forms complete sleeve around bundle of axons

38
Q

epineurium:

A

dense sheath covering entire peripheral nerve

39
Q

features in molecular layer (cerebral cortex):

A

contains relatively few nerve cell bodies

- composed largely of dendrites, axon terminals, neuroglia

40
Q

features in outer granular layer (cerebral cortex):

A

typically contains very small cells (granule cells)

41
Q

features in outer pyramidal layer:

A

contains cell bodies of small pyramidal cells

42
Q

features in inner granular layer (cerebral cortex):

A

-

43
Q

features in inner pyramidal layer:

A

contains cell bodies of large pyramidal cells

44
Q

features in layer of pleiomorphic cells:

A

contains cells of assorted size and shape

45
Q

features in molecular layer (cerebellar cortex):

A

dendrites of Purkinje cells, axons of granule cells, neuroglia

46
Q

features in Purkinje cell layer:

A

-

47
Q

features in granular cell layer (cerebellar cortex):

A

packed with nuclei of many cerebellar granule cells