Brain Cells Flashcards
What can neurons be classified based on?
- morphology (basic structure)
- number of neuronal processes
- for multipolar, classified based on terms of length of axons
What are 3 types of neurons (based on morphology)?
bipolar (inter neuron)
unipolar (sensory)
multipolar (motor)
How many axons and dendrites does a bipolar neuron have?
one axon and one dendrite
What is the neuronal process like in a unipolar neuron?
a singel process which extends from the cell body
How many axons and dendrites does a multipolar neuron have?
one axon
multiple dendrites
What are the axons like in Golgi 1 neurons?
axons are long
What are the axons like in Gogli 11 neurons?
axons are shorter
work more locally
What are the 3 major purposes of neurons?
- sensation
- integration
- action
What does sensation mean?
means they gather info from sense
info then goes through both spine and brain
signalling danger through pain
What does integration mean?
process all info that was gathered
allow us to now take action
What does action mean?
take action by sending appropriate signals to effectors
What are the 2 ways to send signals?
through effectors e.g muscles
or glands
For sensory neuorns, where are messages conveyed?
towards the CNS
For interneurons, where are messages conveyed?
within the CNS
For motor neurons, where are messages conveyed?
away from the CNS
What does afferent mean?
where neurons carry info from the body into the CNS
aka sensory
What does efferent mean?
where neurons carry commands from CNS to muscles and glands e.g motor
What is resting membrane potential?
the stable, negative electrical charge across a cell membrane when the cell is at rest not sending signals / polarised
What is the charge of resting membrane potential?
-70mV
What does the opening of ion channels do?
makes the inside of neuron more negative than outside ‘extracellular space’
How is negative polarity maintained?
the membrane controls environment within and around neuron
a selectively permeable membrane allows some substances through and blocks the passage of others
controls polarisation
What is polarisation?
the difference in electrical charge between inside and outside of neuron
What is an ion?
an electrically charged atom / molecule
What is membrane potential a result of?
a balance between 2 opposing forces
- diffusion
- electrostatic pressure
What is diffusion?
where molecules distribute themselves evenly through medium in which they’re dissolved
What is electrostatic pressure?
the force exerted by attraction or repulsion between charged molecules
What are some examples of ions?
potassium (K+)
Chloride (CI-)
Sodium (NA+)
Protein can form ion channels (A-)
What are 2 membrane properties?
structure (barrier that provides cell integrity)
permeability (selective)
What does hydrophilic mean?
refers to molecules that can mix and interact with water
What does hydrophobic mean?
refers to molecules that repel or fail to mix with water
What does lipophilic mean?
molecules that are able to be dissolved in / absorb lipids (fats)
What do molecules in the membrane partly determine?
the selectivity of its permeability
What are the main molecule types?
proteins (transport)
cholesterol (rigidity)
What maintains balance inside the cell?
the sodium-potassium pump
moves ions against their concentration or electrical gradients
How do Glial cells communicate?
chemically
What are the 3 ways in which Glial cells support neurons?
- mobility 9support migration)
- physical support
- cleaning (e.g pruning synapses)
What are the 5 main types of Glial cells?
Astrocyte
Oligodendrocytes
Schwann Cells
Microglia
NG2 cells
What are astrocytes?
roughly half of all glia
morphologically complex and densely structured
chemical signalling via calcium waves
What are Astrocytes main functions?
ensure that environment around neuron is conductive to electrical signals
through:
- nourishment
- support and guidance
- cleaning and protection
What are Oligodendrocytes?
“Few-branch-cells” in CNS
Help to speed up processing of electrical signals
Achieved through myelin
What are Schwann Cells?
Like oligodendrocytes but in peripheral nervous system
Speed up processing of neuron by covering axon in myelin
Enable axonal regeneration
What are microglia?
Act as main form of immune defence in CNS
Also involved in synaptic pruning
