Lecture 2

Question 1

challenges of studying neurons

Answer 1

-the size
-obtaining nervous tissue that is sufficiently thin (very soft)
-neurons are generally colourless

Question 2

parts of a prototypical neuron

Answer 2

soma
axon
nerve terminal
dendrite
dendritic spine
nucleus
cellular membrane
cytoskeleton

Question 3

soma

Answer 3

-mitochondria
-site of cellular respiration
-krebs cycle
-ATP - cell’s energy source

Question 3

axon

Answer 3

-electrical transmission of signal output
-branches (collaterals) bifurcating at right angles (90 degrees)

Question 3

axon hillock

Answer 3

-start of the axon that emerges from the soma
-site of initiation of action potentials

Question 4

axon (or nerve) terminal

Answer 4

synaptic transmission

Question 5

differences between axon and soma

Answer 5

-ER does not extend into axon
-protein composition of the axon is unique

Question 6

differences between nerve terminals and axons

Answer 6

-no microtubules in terminal
-presence of synaptic vesicle
-abundance of membrane proteins
-large number of mitochondria

Question 7

electric synapses

Answer 7

gap junctions

Question 8

chemical synapses

Answer 8

release of neurotransmitters

Question 9

dendrites

Answer 9

-“antennae” of neurons
-processing of information received through synapses

Question 10

dendritic spines

Answer 10

-dendrites of certain neurons are stubbed with small mushroom or spine-shaped structures
-recieve signals from nerve terminals of other neurons
-postsynaptic compartment contains synaptic receptors
-associated with memory and learning

Question 11

cell membrane

Answer 11

-barrier that encloses the cytoplasm
-different regions of the neuron cell membrane will contain different types of membrane proteins
-supports electrical and chemical transmission of information

Question 12

different neuron membranes

Answer 12

-presynaptic membrane
-postsynaptic membrane
-axonal membrane

Question 13

cytoskeleton

Answer 13

-not static, very dynamic
-3 types of filaments (microtubules, microfilaments (actine), neurofilaments)

Question 14

microtubules

Answer 14

-movement of organelles
-railroad for molecular motors

Question 15

microfilaments (actine)

Answer 15

dynamic change of shape

Question 16

neurofilaments

Answer 16

support and stability

Question 17

anterograde axoplasmic transport

Answer 17

-from soma to nerve terminal
-requires kinesins interacting with microtubules
-consumes ATP
-used to visualize the postsynaptic connections of neurons of interest
-answers the question: “a neuron speaks to who?”

Question 18

retrograde axoplasmic transport

Answer 18

-from nerve terminal to soma
-requires dyneins
-consumes ATP
-used to visualize the presynaptic neurons connected to neurons of interest
-answers the question: “a neuron is listening to who?”

Question 19

anterograde tracing

Answer 19

-labels nerve terminals
-phageolus vulgaris leucoagglutinin
-dextrans
-dil

Question 20

retrograde tracing

Answer 20

-labels cells that innervate a targetted area
-dextrans
-dil
-horseradish peroxydase (HRP)
-virus

Question 21

unipolar

Answer 21

a single neurite

Question 22

bipolar

Answer 22

two neurites

Question 23

multipolar

Answer 23

multiple neurites

Question 24

somatic classification

Answer 24

can be oval/spherical or pyramidal cells

Question 25

dentritic classification

Answer 25

-number of dendrites -lengths -branching patterns

Question 26

golgi type I

Answer 26

projection neurons (long axon)

Question 27

golgi type II

Answer 27

loccal neurons (short axon)

Question 28

sensory neurons connectivity

Answer 28

sensory receptors

Question 29

motoneurons connectivity

Answer 29

muscle or gland

Question 30

interneurons connectivity

Answer 30

contact other neurons within CNS

Question 31

glia function

Answer 31

-neuronal support -insulation -nourish neurons -can shape cell signalling

Question 32

astrocytes

Answer 32

-formed by many projections: star shaped -most numerous glia in the brain -fill the space between neurons -influence neurite growth -regulate ionic extracellular concentrations -shape synaptic transmission

Question 33

oligodendrocytes (CNS)

Answer 33

wrap around multiple axons

Question 34

schwann cells (PNS)

Answer 34

wrap around a single axon

Question 35

role of myelin

Answer 35

-insulate axons -increases the speed of electrical transmission

Question 36

node of ranvier

Answer 36

-region where the axonal membrane is exposed, high density of sodium channels -allows for saltatory transmission

Question 37

microglia

Answer 37

-phagocyte -immune system -elimination of cellular waste and dead cells

Question 38

neurons

Answer 38

-process information -sense environmental changes -communicates percieved changes to other neurons -command corporal responses