Lecture 19 Nervous Tissue I

Question 1

The neural plate is composed of what type of epithelium?

Answer 1

Simple columnar epithelium

Question 2

In the neural plate, cell shape is maintained by:

Answer 2

Microtubules

Question 3

In the neural folds, columnar cell shape changes to:

Answer 3

wedge cell shape

Question 4

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

Answer 4

actin filaments

Question 5

The wedge shape of cells in the neural fold causes:

Answer 5

Flattened neural plate to bend

Question 6

Neuroepithelial cells from embryonic neuroectoderm give rise to _____.

Answer 6

neuroblasts

Question 7

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

Answer 7

Neurons

Question 8

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

Answer 8

Neural Crest Cells

Question 9

Pseudostratified epithelium

Answer 9

Ventricular zone

Intermediate zone

Question 10

Ventricular zone

Answer 10

made up of ventricular cells

Question 11

Intermediate zone

Answer 11

Area of destruction of excess neurons via apoptosis

Question 12

Cortical plate (mantle layer)

Answer 12

Postmitotic neurons

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

Question 13

Marginal Layer

Answer 13

Axons

Future white matter (myelinated axons

Question 14

Characteristics of Nerve Tissue

Answer 14

Irritability

Conductibility

Question 15

Irritability

Answer 15

Specialized to receive stimuli

Question 16

Conductibility

Answer 16

Specialized to transmit impulses

Question 17

Cellular components of Nerve Tissue

Answer 17

Neurons

Neuroglial cells

Question 18

Neurons

Answer 18

Conduct impulses

Fundamental structural and functional unit of the nervous system

Question 19

Neuroglial Cells

Answer 19

Nonconductive cells that support and protect the neurons

Question 20

Parts of the neuron

Answer 20

Cell body (soma)
Dendrites
Axon

Question 21

Characteristics of the cell body of a neuron

Answer 21

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

Question 22

Characteristics of Dendrites

Answer 22

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

Question 23

Characteristics of the Axon Hillock

Answer 23

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

Question 24

Characteristics of the Axon

Answer 24

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

Question 25

Classification of neurons according to function:

Answer 25

Sensory (afferent) neurons Motor (efferent) neurons Interneurons

Question 26

Sensory (afferent) neurons

Answer 26

Transmit sensory impulses from sensory receptors to CNS

Question 27

Motor (efferent) neurons

Answer 27

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

Question 28

Interneurons

Answer 28

Transmit impulses within CNS and between sensory and motor neurons

Question 29

Classification of neurons according to number of processes

Answer 29

Multipolar neurons Bipolar Pseudounipolar

Question 30

Multipolar neurons

Answer 30

Most common morphological type | Have single axon and multiple dendrites

Question 31

Bipolar neurons

Answer 31

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

Question 32

Pseudounipolar

Answer 32

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

Question 33

Classification of neuron according to length of axon

Answer 33

Golgi I | Golgi II

Question 34

Golgi I

Answer 34

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

Question 35

Golgi II

Answer 35

Neurons with short axons which ramify through the gray matter

Question 36

Nerve

Answer 36

Bundles of axons (fibers) in the PNS

Question 37

Tract

Answer 37

Bundle of axons (fibers) in the CNS

Question 38

Ganglion

Answer 38

Aggregation of cell bodies and dendrites in the PNS

Question 39

Nucleus

Answer 39

Aggregation of cell bodies and dendrites in the CNS

Question 40

Epineurium

Answer 40

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

Question 41

Perineurium

Answer 41

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

Question 42

Endoneurium

Answer 42

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

Question 43

Membrane specializations

Answer 43

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

Question 44

Membrane specializations at the presynaptic membrane

Answer 44

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

Question 45

Membrane specializations at the postsynaptic membrane

Answer 45

Receptors | Ligand-gated ion channels

Question 46

In what direction does anterograde transport travel?

Answer 46

Cell body toward distal end of axon

Question 47

Anterograde transport utilizes ______.

Answer 47

Kinesin

Question 48

Slow Anterograde Transport

Answer 48

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

Question 49

Intermediate Anterograde Transport

Answer 49

50-100 mm per day | Mitochondria & other membrane-bound organelles

Question 50

Fast Anterograde Transport

Answer 50

Utilizes microtubule motors 400 mm per day Synaptic vesicles & neurotransmitters

Question 51

In what direction does retrograde transport travel?

Answer 51

Axon toward cell body

Question 52

Retrograde transport utilizes ____ ______.

Answer 52

Cytoplasmic dynein

Question 53

Retrograde transport carries:

Answer 53

endocytosed materials & recycled proteins

Question 54

Rate of transport for retrograde transport

Answer 54

100-300 mm/day