How Nerves work Flashcards
What are the 3 sub-divisions of the Nervous system?
The Brain, the spinal cord and the peripheral nerves
What does the soma contain?
The nucleus
What does the initial segment contain?
Information for making action potentials
What are the dendrites for?
A route for information from other neurones
What does the axon do?
Takes the action potential elsewhere
What is the typical resting membrane potential?
-70mV
What generates the resting membrane potential?
Sodium/Potassium pumps in the cell membrane
What are the characteristics of action potentials?
All or Nothing
Self-propagating
What are the properties of Graded potentials?
Decremental
Only transmit over short distances
Summating
Inhibitory or Excitatory
What channels open to allow an action potential to fire?
Voltage gated sodium channels
How does the cell repolarise?
Opening K channels
What must reach a certain threshold before firing an action potential?
A graded potential
What kind of neurones detect changes or sensory stimuli?
Afferent
What kind of neurones decide what to do about incoming stimulus?
Interneurones
What kind of neurones carry signals to effector tissues and cells?
Efferent Neurons
Why do large axons transmit signals faster?
Because resistance is decreased
What is myelination formed out of in the CNS?
Oligodendrocytes
What is myelination that isn’t formed in the CNS made of?
Schwann cells
Why do myelinated cells transmit signals faster?
Because they are insulated
What is an example of a disease that effects myelination?
Multiple Sclerosis
What structure forms a synapse at a muscle?
Motor end plate
What do the ACh receptors in a muscle lie on?
The sarcolemma
What does the action potential trigger at the NMJ?
Calcium ion release
What do Calcium ions release at the NMJ?
Acetylcholine
