Week 3 (neurology) Flashcards
(38 cards)
What is neuroscience?
The study of the nervous system.
Includes structure, function, health, and disease.
What are neurons?
Fundamental units of the nervous system which connect with each other and other parts of the nervous system.
Describe the structure of neurons
Cell body (soma): contains organelles and cell processes radiate out from the cell body.
Dendrites (neuron’s receivers): receives impulses and carries the impulse toward cell body.
Axon (neuron’s transmitter): conducts impulses away from cell body.
What is the function of neurons?
Responsible for sending and receiving information around the body.
Convert a stimulus to nerve impulses.
Name and explain the three types of neurons and
Sensory (afferent): make up sensory division of the PNS.
Motor (efferent): connect to muscle fibres at distal end of axon.
Interneurons: between motor and sensory neurons
What is a motor unit?
Motor neuron + muscle fibres
What is the resting membrane potential of a neuron?
A neuron has a negative electrical potential of around -70mV.
What is the resting membrane potential caused and maintained by?
Caused by uneven separation of charged ions.
Maintained by differences in cell membrane permeability and a sodium potassium pump.
What is depolarisation?
When the inside of the cell becomes less negative in relation to outside. A decrease in potential difference across membrane.
Occurs when charge difference is move positive than RMP.
What is repolarisation?
Membrane potential returns to its resting state after an action potential towards a more negative value but continues past RMP.
What is hyperpolarisation?
Charge goes back to RMP.
What is a graded potential?
Localised change in membrane potential of depolarisation or hyperpolarisation,
Local event and depolarisation does not spread along neuron.
What is an action potential?
A rapid and substantial neuron membrane depolarisation.
Membrane potential changes from RMP to +30mV and back again.
When will an action potential occur?
If threshold level is reached.
mv from RMP of -70 to ~ -55mV)
What is the absolute refractory period?
When the axon is in the process of generating an action potential is unable to respond to another stimulus.
What is the relative refractory period?
Once the axon has dealt with a stimulus, it can deal with a new stimulus is of a greater magnitude than the present one.
What is a synapse?
The place where neurons connect and communicate to continue transmitting action potentials.
The site of action potential transmission from axon terminals of 1 neuron to dendrites of another.
What does a synapse between 2 neurons include?
Axon terminals of presynaptic neuron.
Receptors on postsynaptic neuron.
Space between the two structure = synaptic cleft.
What is a neuromuscular junction?
The site of action potential transmission from axon terminal of 1 neuron to the muscle.
Neurotransmitters released from motor neuron axon terminals bind to receptors on plasmalemma.
What are neurotransmitters?
Endogenous chemicals that allow neurons to communicate.
They carry messages from one neuron to the next nerve or effector organ cell.
Are released from vesicles into the synaptic cleft to carry messages across.
Why are action potentials only transmitted in one direction?
Only the post synaptic neuron contain receptors that are specific to the neurotransmitter.
Name the 2 parts of human nervous system
Central nervous system
Peripheral nervous system
Explain the sensory motor integration
PNS relays sensory information to CNS.
CNS interprets information and sends out appropriate motor signals.
What is the integration centre?
The area where sensory impulses terminate.
