The neuron (U3 AOS 1) Flashcards
What are the three types of neurons
Sensory neurons, motor neurons and interneurons.
What is the role of a dendrite
Extension of a neuron that first receives information from other neurons and transmits it to the soma.
What is the role of the soma?
Combines the neural information from dendrites and sends it to the axon.
What is the role of the axon?
Transmits a message from the soma to other cells in the body in the form of an electrical nerve impulse.
What is the role of the myelin sheath?
It is a white, fatty covering that helps insulate the axon of one neuron from others.
This allows faster transmission of the electrical impulses across the nerve cells.
What do the axon terminals contain?
A tip called a terminal button which contain neurotransmitters.
Explain the process of the transmission of information within a neuron.
At rest, the neuron has a ‘resting potential’. When activated an ‘action potential’ travels down the neuron from the soma towards the terminal buttons via the axon.
What is an action potential?
An electrical current/impulse that travels within a neuron
Is communication within the neuron electrical or chemical?
Electrical
What is a neurotransmitter?
A chemical messenger synthesised within a pre-synaptic neuron and transmitted across the synpase.
Is communication between neurons electrical or chemical?
Chemical
How are neurotransmitters involved in the transmission of information between neurons?
They are released from the pre-synaptic neuron, pass across the synaptic gap and then land onto a receptor site of a dendrite of the post-synaptic neuron.
With reference to glutamate, outline the processes involved in successful neural transmission once the neural impulse has reached the axon terminal. In your response, refer to the lock-and-key process.
Glutamate is released into the synaptic gap from the vesicles of the pre-synaptic neuron.
Glutamate acts as a key where the complementary receptor site acts as a lock.
Glutamate then binds with the complementary receptor sites of the post-synaptic neuron.
Glutamate increases the likelihood of the post-synaptic neuron firing an action potential.
What is an excitatory effect and give an example of one.
It is an effect that stimulates the postsynaptic neuron to perform their functions. Makes neurons more likely to create an action potential.
E.g, glutamate
What is an inhibitory effect and give an example of one.
Blocks/prevents postsynaptic neurons from firing. Makes neurons less likely to fire an action potential.
E.g, GABA
What is the role of an agonist?
A substance or drug that increases the release of a neurotransmitter. This causes the post-synaptic neuron to fire an action potential.
What is the role of an antagonist?
Inhibits the release of neurotransmitters or blocks the receptor sites for neurotransmitters.
What is Parkinson’s disease?
A neurodegenerative disorder characterised by chronic and progressive changes in the brain due to deterioration to neurons leading to impaired movement.
What certain areas of the brain are affected by PD. Explain their relevance in contributing to PD.
The substantia nigra and basal ganglia and corpus striatum are affected.
The substantia nigra is responsible for neurons producing and releasing dopamine (used for controlling movement). As the neurons deteriorate because of PD, their capacity to produce dopamines diminish.
The basal ganglia and corpus striatum structures allow smooth regular movements of muscles. With diminishing dopamine levels, the communication between the two is impaired.
List 2 of each primary motor symptoms, secondary motor symptoms and non-motor symptoms of PD.
Primary motor symptoms:
- Unpredictable tremors
- Rigidity
- Bradykinesia
- Reduced coordination and balance
Secondary motor symptoms:
- Reduced control over facial muscles
- Pain and discomfort in limbs
Non-motor symptoms:
- Anxiety
- Depression
- Difficulties with communication, limiting person’s ability to socialise
- Social isolation (due to feeling embarassed)
How does PD affect someone regarding to dopamine.
The amount of dopamine available lessens and thus the dopamine available for motor activity is lower. This leads to slowness of voluntary movement and difficulty starting new movements.
