Brain Cells

Question 1

What can neurons be classified based on?

Answer 1

• morphology (basic structure)
• number of neuronal processes
• for multipolar, classified based on terms of length of axons

Question 2

What are 3 types of neurons (based on morphology)?

Answer 2

bipolar (inter neuron)
unipolar (sensory)
multipolar (motor)

Question 3

How many axons and dendrites does a bipolar neuron have?

Answer 3

one axon and one dendrite

Question 4

What is the neuronal process like in a unipolar neuron?

Answer 4

a singel process which extends from the cell body

Question 5

How many axons and dendrites does a multipolar neuron have?

Answer 5

one axon
multiple dendrites

Question 6

What are the axons like in Golgi 1 neurons?

Answer 6

axons are long

Question 7

What are the axons like in Gogli 11 neurons?

Answer 7

axons are shorter
work more locally

Question 8

What are the 3 major purposes of neurons?

Answer 8

• sensation
• integration
• action

Question 9

What does sensation mean?

Answer 9

means they gather info from sense
info then goes through both spine and brain
signalling danger through pain

Question 10

What does integration mean?

Answer 10

process all info that was gathered
allow us to now take action

Question 11

What does action mean?

Answer 11

take action by sending appropriate signals to effectors

Question 12

What are the 2 ways to send signals?

Answer 12

through effectors e.g muscles
or glands

Question 13

For sensory neuorns, where are messages conveyed?

Answer 13

towards the CNS

Question 14

For interneurons, where are messages conveyed?

Answer 14

within the CNS

Question 15

For motor neurons, where are messages conveyed?

Answer 15

away from the CNS

Question 16

What does afferent mean?

Answer 16

where neurons carry info from the body into the CNS
aka sensory

Question 17

What does efferent mean?

Answer 17

where neurons carry commands from CNS to muscles and glands e.g motor

Question 18

What is resting membrane potential?

Answer 18

the stable, negative electrical charge across a cell membrane when the cell is at rest not sending signals / polarised

Question 19

What is the charge of resting membrane potential?

Answer 19

-70mV

Question 20

What does the opening of ion channels do?

Answer 20

makes the inside of neuron more negative than outside ‘extracellular space’

Question 21

How is negative polarity maintained?

Answer 21

the membrane controls environment within and around neuron
a selectively permeable membrane allows some substances through and blocks the passage of others
controls polarisation

Question 22

What is polarisation?

Answer 22

the difference in electrical charge between inside and outside of neuron

Question 23

What is an ion?

Answer 23

an electrically charged atom / molecule

Question 24

What is membrane potential a result of?

Answer 24

a balance between 2 opposing forces
- diffusion
- electrostatic pressure

Question 25

What is diffusion?

Answer 25

where molecules distribute themselves evenly through medium in which they're dissolved

Question 26

What is electrostatic pressure?

Answer 26

the force exerted by attraction or repulsion between charged molecules

Question 27

What are some examples of ions?

Answer 27

potassium (K+) Chloride (CI-) Sodium (NA+) Protein can form ion channels (A-)

Question 28

What are 2 membrane properties?

Answer 28

structure (barrier that provides cell integrity) permeability (selective)

Question 29

What does hydrophilic mean?

Answer 29

refers to molecules that can mix and interact with water

Question 30

What does hydrophobic mean?

Answer 30

refers to molecules that repel or fail to mix with water

Question 31

What does lipophilic mean?

Answer 31

molecules that are able to be dissolved in / absorb lipids (fats)

Question 32

What do molecules in the membrane partly determine?

Answer 32

the selectivity of its permeability

Question 33

What are the main molecule types?

Answer 33

proteins (transport) cholesterol (rigidity)

Question 34

What maintains balance inside the cell?

Answer 34

the sodium-potassium pump moves ions against their concentration or electrical gradients

Question 35

How do Glial cells communicate?

Answer 35

chemically

Question 36

What are the 3 ways in which Glial cells support neurons?

Answer 36

1. mobility 9support migration) 2. physical support 3. cleaning (e.g pruning synapses)

Question 37

What are the 5 main types of Glial cells?

Answer 37

Astrocyte Oligodendrocytes Schwann Cells Microglia NG2 cells

Question 38

What are astrocytes?

Answer 38

roughly half of all glia morphologically complex and densely structured chemical signalling via calcium waves

Question 39

What are Astrocytes main functions?

Answer 39

ensure that environment around neuron is conductive to electrical signals through: - nourishment - support and guidance - cleaning and protection

Question 40

What are Oligodendrocytes?

Answer 40

“Few-branch-cells” in CNS Help to speed up processing of electrical signals Achieved through myelin

Question 41

What are Schwann Cells?

Answer 41

Like oligodendrocytes but in peripheral nervous system Speed up processing of neuron by covering axon in myelin Enable axonal regeneration

Question 42

What are microglia?

Answer 42

Act as main form of immune defence in CNS Also involved in synaptic pruning