Cells of the Nervous System

Question 1

Neurons

Answer 1

building blocks of the nervous system

discrete, metabolic units

Question 2

Golgi Method

Answer 2

“the black method”
- used to visualize individual neurons

Question 3

Input zone

Answer 3

where neurons collect and process info, either from the environment or from other cells

• dendrites

Question 4

Integration Zone

Answer 4

where the decision to produce a neural signal is made
- inputs are combined here

Question 5

Conduction zone

Answer 5

where info can be electrically transmitted over great distances

• info as electrical signal goes down axon

Question 6

Output zone

Answer 6

axon terminals transfer info to other cells

Question 7

what kind of signals flow info through neuron

Answer 7

electric signal -> chem signal -> electric signal

Question 8

sensory neurons

Answer 8

respond to environmental stimuli (light, touch, etc.)

Question 9

interneurons

Answer 9

receive input from a neuron and send input to another neuron

Question 10

motor neuron

Answer 10

stimulate muscles or glands

Question 11

unipolar neuron

Answer 11

has a single extension from the cell body (axon that extends into dendrites)
- make up most neurons in CNS of invertebrates
- helps with direct signaling bc it is quicker
- not found in humans

Question 12

pseudounipolar neurons

Answer 12

single extension from cell body and axon splits into two branches
- are exclusively sensory neurons (dorsal root ganglia and cranial nerves)
- carry info about touch, vibration, pain, temp, etc.
- branches are axons, there are no dendrites

Question 13

bipolar neuron

Answer 13

one axon, one dendrite

• ex: form the middle layer of the retina

Question 14

multipolar neuron

Answer 14

only has one axon extending from the cell body, but multiple dendrites grow out of it, making transmitting information easier
- also helpful to gather lots of information

Question 15

dendritic arborization

Answer 15

the branching out of dendrites

• more of it means more complexity bc there are more synaptic connections possible

Question 16

dendritic spines

Answer 16

• form functional contacts with neighboring axons of other neurons
• are very plastic and their size and shape are constantly changing in response to neuronal activity

Question 17

axon hillock

Answer 17

part of the cell body that acts as an administrator (integration zone)
- sums up inhibitory and excitatory signals to see if it is enough to trigger an action potential
- if so, an electrical signal is sent down the axon

Question 18

anterograde transport

Answer 18

help move info to and from the neuron
- ex: anterograde motor proteins: kinesin

Question 19

retrograde transport

Answer 19

shuttles molecules/organelles away from axon termini toward the cell body

• ex: cytoplasmic dynein is used to send chemical messages and endocytosis products headed to endolysosomes from the axon back to the cell

Question 20

what cargo might anterograde vs. retrograde proteins carry?

Answer 20

• neurotransmitters/precursors to axon terminal
• movement of nutrients

Question 21

synaptic transmission

Answer 21

synaptic vesicles in presynaptic axon terminals contain a chemical neurotransmitter (nt)
- nt are released in response to electrical activity in the axon
- receptors in the postsynaptic membrane are specialized proteins that react when a nt molecule binds to them

Question 22

glia

Answer 22

• communicate with each other and neurons
• influence neural structure and excitability
• important for neural repair and signaling

Question 23

microglia

Answer 23

• functions: surveillance, pruning, and plasticity
• are the primary immune system of the nervous system
• patrol the cerebral microenvironment to respond to pathogens and damage
• release inflammatory factors like cytokines
• make up 10% of cells in the brain
• can change morphology depending on what it needs to do

Question 24

cytokines

Answer 24

proteins that, when released, signal the immune system to do its job
- affect the growth of all blood cells and activity of immune cells

Question 25

aberrations (abnormalities) in microglia functioning can lead to

Answer 25

excessive synapse loss and cognitive dysfunction
- ex: Alzheimer’s Disease, Schizophrenia (excessive synaptic pruning)

Question 26

macroglia

Answer 26

1. oligodendrocytes
2. schwann cells

• both have similar function (form myelin sheath) but occur in different parts

Question 27

oligodendrocytes

Answer 27

in the CNS and form myelin sheaths in brain and spinal cord

Question 28

schwann cells

Answer 28

in the PNS and form myelin sheath for cells outside of the brain

Question 29

insulation of axons (myelin sheath) help to

Answer 29

transmit electrical impulses quickly and efficiently

Question 30

myelination in cells over time

Answer 30

• more myelination occurs as neuron cell grows older (baby has none and adult is longer with more myelin)
• increases rapidly during first 6 months of life bc there is a lot of info coming in and is learning a lot
• locations near back and top of brain get myelinated fastest (vision/motion)

Question 31

Multiple Sclerosis

Answer 31

• immune system mistakenly attacks brain and nerves
• causes a loss in myelination
• leads to sclerosis (abnormal hardening of body tissue)

Question 32

astrocytes

Answer 32

help transmit info from neurons and blood

• monitor and support neurons
• regulate cerebral blood flow in adjacent capillaries to coordinate oxygen and glucose delivery with the energy demands of neurons
• can receive neuronal input and release transmitters (gliotransmission)

Question 33

can glia “talk”?

Answer 33

glia tune signal and amplify it
- regulate how neurons communicate
- release additional glutamate in return (can activate glutamate receptors on cerebellum neurons to amplify neural function - important for motor learning)