Lecture 19 Nervous Tissue I Flashcards

1
Q

The neural plate is composed of what type of epithelium?

A

Simple columnar epithelium

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2
Q

In the neural plate, cell shape is maintained by:

A

Microtubules

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3
Q

In the neural folds, columnar cell shape changes to:

A

wedge cell shape

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4
Q

In the neural folds, the shape change is due to:

A

actin filaments

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5
Q

The wedge shape of cells in the neural fold causes:

A

Flattened neural plate to bend

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6
Q

Neuroepithelial cells from embryonic neuroectoderm give rise to _____.

A

neuroblasts

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7
Q

Neuroblasts give rise to _____ of the central nervous system (brain and spinal cord).

A

Neurons

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8
Q

______ _______ cells are derived from the neuroectoderm and give rise to neurons and neuroglial cells of the peripheral nervous system

A

Neural Crest Cells

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9
Q

Pseudostratified epithelium

A

Ventricular zone

Intermediate zone

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10
Q

Ventricular zone

A

made up of ventricular cells

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11
Q

Intermediate zone

A

Area of destruction of excess neurons via apoptosis

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12
Q

Cortical plate (mantle layer)

A

Postmitotic neurons

Future gray matter (cell bodies, dendrites, and unmyelinated axons)

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13
Q

Marginal Layer

A

Axons

Future white matter (myelinated axons

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14
Q

Characteristics of Nerve Tissue

A

Irritability

Conductibility

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15
Q

Irritability

A

Specialized to receive stimuli

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16
Q

Conductibility

A

Specialized to transmit impulses

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17
Q

Cellular components of Nerve Tissue

A

Neurons

Neuroglial cells

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18
Q

Neurons

A

Conduct impulses

Fundamental structural and functional unit of the nervous system

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19
Q

Neuroglial Cells

A

Nonconductive cells that support and protect the neurons

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20
Q

Parts of the neuron

A

Cell body (soma)
Dendrites
Axon

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21
Q

Characteristics of the cell body of a neuron

A

Contains nucleus
Nissl bodies
Extensive RER and elaborate Golgi structures
Abundant mitochondria
Abundant microtubules and intermediate filaments
Lipofucsin granules formed from lysosomes & accumulate with age of neuron
Ligand-gated channels and local potentials

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22
Q

Characteristics of Dendrites

A

Conduct impulses (local) toward cell body
Contain Nissl substance, mitochondria, & other cytoplasmic components (except Golgi)
May be stubbed w/ dendritic spines
Tend to taper distally and may branch
Ligand-gated channels and local potentials

23
Q

Characteristics of the Axon Hillock

A

Site for origin of axon
Devoid of Nissl substance
Associated with AP generation

24
Q

Characteristics of the Axon

A
Voltage-gated cation channels & APs
Contain mitochondria and microtubules
Lack RER, ribosomes, and Golgi
Constant diameter its entire length
Terminates in branching telodendrites 
Telodendrites contain synaptic vesicles & related proteins
Telodendrites form presynaptic membranes
May be enclosed within myelin sheath
25
Q

Classification of neurons according to function:

A

Sensory (afferent) neurons
Motor (efferent) neurons
Interneurons

26
Q

Sensory (afferent) neurons

A

Transmit sensory impulses from sensory receptors to CNS

27
Q

Motor (efferent) neurons

A

Transmit impulses from CNS to muscle of gland
Somatic - skeletal muscles
Autonomic - glands, cardiac, and smooth muscle (parasym and sym)

28
Q

Interneurons

A

Transmit impulses within CNS and between sensory and motor neurons

29
Q

Classification of neurons according to number of processes

A

Multipolar neurons
Bipolar
Pseudounipolar

30
Q

Multipolar neurons

A

Most common morphological type

Have single axon and multiple dendrites

31
Q

Bipolar neurons

A

Have to processes, one at end end of the spindle-shaped neuron
Found in association of special senses such as olfactory and visual

32
Q

Pseudounipolar

A

Single process from the cell body that bifurcates into central & peripheral processes
Found in ganglia alongside spinal cord (dorsal root ganglia)

33
Q

Classification of neuron according to length of axon

A

Golgi I

Golgi II

34
Q

Golgi I

A

neurons with long axon which leave the grey matter of which they are a part

35
Q

Golgi II

A

Neurons with short axons which ramify through the gray matter

36
Q

Nerve

A

Bundles of axons (fibers) in the PNS

37
Q

Tract

A

Bundle of axons (fibers) in the CNS

38
Q

Ganglion

A

Aggregation of cell bodies and dendrites in the PNS

39
Q

Nucleus

A

Aggregation of cell bodies and dendrites in the CNS

40
Q

Epineurium

A

Thick fibrous coat
Covers entire nerve
Supplied by blood and lymphatic vessels
Type I collagen and fibroblasts

41
Q

Perineurium

A

Dense CT
Covers bundles of axons (fascicles) within nerve
Epithelial-like fibroblast on inner surface joined by tight junctions (zonula occludens)
Blood nerve barrier

42
Q

Endoneurium

A

Thin layer of reticular CT
Surrounds individual fibers and Schwann cells
Type III collagen

43
Q

Membrane specializations

A

Receptors
Ion channels:
- ligand gated on dendrites & cell bodies
- potassium channels, v-gated Na channels, and v-gated Ca channels on axon

44
Q

Membrane specializations at the presynaptic membrane

A
Synaptic vesicles 
Vesicular docking proteins & synapsin filaments
Dense bodies
Mitochondria 
Voltage-gated calcium channels
45
Q

Membrane specializations at the postsynaptic membrane

A

Receptors

Ligand-gated ion channels

46
Q

In what direction does anterograde transport travel?

A

Cell body toward distal end of axon

47
Q

Anterograde transport utilizes ______.

A

Kinesin

48
Q

Slow Anterograde Transport

A

Only used in anterograde direction
Two systems:
- SCa (slow component a): preassembled microtubules and neurofilaments
- SCb (slow component b): enzymes, actin, clathrin

49
Q

Intermediate Anterograde Transport

A

50-100 mm per day

Mitochondria & other membrane-bound organelles

50
Q

Fast Anterograde Transport

A

Utilizes microtubule motors
400 mm per day
Synaptic vesicles & neurotransmitters

51
Q

In what direction does retrograde transport travel?

A

Axon toward cell body

52
Q

Retrograde transport utilizes ____ ______.

A

Cytoplasmic dynein

53
Q

Retrograde transport carries:

A

endocytosed materials & recycled proteins

54
Q

Rate of transport for retrograde transport

A

100-300 mm/day