Basic Neuroscience Flashcards
In ENS, what is the effect of intensifying the stimulus?
The size of twitch contractions get bigger
In electrical nerve stimulation, what happens when the ulnar nerve is stimulated?
The ADM muscle contracts
In ENS, what happens when the frequency of the stimulus increases?
The muscle contraction goes from twitching to tetonic
In what 2 clinical settings do we use ENS?
To measure nerve conduction velocity (e.g. check for carpal tunnel syndrome)
To test for myasthenia gravis (abnormal nerve-muscle transmission as muscle receptor cells are damaged)
What are the two classifications of the nervous system?
Structure and Function
What are the 2 nervous system types when functionally classified?
Somatic and Autonomic
Which functional nervous system interacts with the external environment?
(deals with sensation - eyes, ears, balance and skin and Motor - skeletal muscle/movement)
Somatic NS
Which functional nervous system regulates the internal environment/homeostasis (heart, blood vessels, lungs, kidneys, digestive system, glands, liver)?
Sympathetic NS and Parasympathetic NS
Which functional nervous system do the sympathetic and parasympathetic systems fall under?
The Autonomic NS
What is the basic functional unit of the nervous system?
Neurone
What are the supporting cells called that support the neurones in the nervous system?
Neurolgia - they outnumber neurones by 10:1 and they act as nutrition for cells
What does the cell body with dendrites act as in the neurone?
The input
What does the myelin sheath do in the neurone?
Speed up electrical impulses
What does the axon do in the neurone?
Impulses travel along it
It can be a really long nerve fibre e.g. big toe to spinal cord
Does the white matter or grey matter in the brain contain axons/tracts of nerve fibres?
The white matter (you can see the myelin which is why it is white)
Does the white matter or grey matter in the brain contain the nerve cell bodies and the main sites of nerve cells (cortex, basal nuclei)?
Grey matter
Does the nervous system have internal connective tissue for support?
No - it has supporting cells called neuroglia
Neuroglia outnumber neurones by 10:1
By how much do neuroglia outnumber neurones in the nervous system?
10:1
Can the neuroglia be different shapes and sizes?
Yes they are
Astro ones are star shaped
Micro ones are small
List the 4 types of neurones
No axon
Bipolar
Unipolar
Multipolar
Neurons with no axons are called amacrine cells. Where do they transmit their signals from?
Their dendrites
Do neurons ever have more than one axon?
No
How many processes do unipolar, bipolar and multipolar neurones have?
Uni = one Bi = two Multi = lots
Inputs arrive at the neurone via the d…………….., action potentials then go along the a…………. and the s……………… t……………. release outputs (neurotransmitters) to another neurone or muscles/tissues
Input = dendrites
APs along AXON
Output = SYNAPTIC TERMINALS
Nerve cells can communicate with what 3 things?
Nerve cells
Muscle
Glands
Oligodendrocytes in the CNS and schwann cells in the peripheral NS do what?
Wrap around the axon and produce myelin
MS sufferers have problems with this
Which NS do the schwann and oligodendrocytes cells work on?
CNS = OLIGO Peripheral = schwann
Nerve cells communicate with each other by sending an a………….. p………….. (electrical signal) from the p…………… c…… across the s…………../j………………. to the ………………….. …….. .
A……………… P…………………are known as changes in membrane potential
Action Potential
Pre-synaptic Cell
Synapse/Junction
Post-synaptic cell
A resting cell membrane is known as p………………..
Polarised (resting cell membrane)
Is a polarised (resting) cell membrane negative or positive compared to the outside?
It has a negative charge - the inside is -70mv to -80mv
When a resting cell membrane becomes depolarised, what has happened to it?
It has been stimulated
What are the chain of events once the cell has been depolarised?
Sodium channels open and sodium floods in
The electrical potential in the cell becomes positive
How does a cell re-polarise?
Sodium channels close
Potassium channels open and potassium moves out
Electrical potential turns normal and negative again
If a cell membrane receives a small electrical stimulus below the threshold, is there an action potential?
No - a fixed size of AP is needed - a certain level of stimulus
What does the presynaptic neurone release?
Neurotransmitters
In the presynaptic neurone, what contains/releases NTs?
Vesicles
Once released from the vesicles in the presynaptic neurone, what do the NTs cross to get to the postsynaptic neurone?
They diffuse across the synapse/synaptic junction
Once the AP has caused the NTs to cross the synapse after being released by the vesicles in the presynaptic neurone, where do they bind to and go?
They bind to receptors in the post-synaptic neuron
What part of the post-synaptic neurone is often an ion channel, that allows NTs to depolarise the membrane to cause an Action Potential?
Chemical synapse receptor
What are the body’s executive controllers?
Systems begin with N and E
The nervous and endocrine systems
There are 2 types of NS classification; functional and structural. What NS fall into each of these?
Functional: Somatic/Autonomic
Structural: CNS/PNS
What is the basic unit in the NS?
Neurone
What transmits action potentials/impulses?
Neurones
Where do neurones release NTs?
Synapses
