Chapter 2: Nervous System Functioning Part 2 Flashcards
What are the 2 types of effects on neurotransmitters?
- Excitatory effect
- Inhibitory effect
What is the excitatory effect of neurotransmitters?
It stimulates or activates presynaptic neurons to perform their functions.
What is the inhibitory effect of neurotransmitters?
It blocks or prevents presynaptic neurons from firing.
What is glutamate (Glu)?
It is the primary excitatory neurotransmitter in the CNS, which enhances info transmission by making postsynaptic neurons more likely to fire.
What is glutamate associated with and what are the consequences when there is the wrong amount (give an example)?
- The release of Glu is associated with enhanced learning and memory.
- When there is too much or too little of Glu it can harm neurons and brain functioning (Eg. Abnormally high concentrations of glutamate can result in over-excitation of receiving neurons)
What is gamma-amino butyric acid (GABBA)?
It is the primary inhibitory neurotransmitter in the CNS, which works to make postsynaptic neurons less likely to fire.
What roles do GABBA and Glu play in the CNS?
They play important roles in regulating CNS arousal
Give an example of the consequences of low levels of GABBA:
It can lead to anxiety symptoms such as those experienced by people with phobias
What is GABBA able to counterbalance?
The inhibitory action of GABBA is able to counterbalance the excitatory activity of glutamate and vice versa.
Describe the lock-and-key process of neurotransmission:
Because each neurotransmitter has a chemically distinct shape, when one is released by a presynaptic neuron it searches for the correctly shaped receptor site on the dendrites of the postsynaptic neuron to bind to.
-Like a key in a lock, a neurotransmitter’s shape must perfectly match the shape of the receptor site
What is the effect of binding in the lock-and-key process?
Binding ‘unlocks’ the postsynaptic neurons’ responses so that neurotransmitters can cause changes to the neuron, resulting in either an excitatory or inhibitory effect.
What is Parkinson’s disease and why is it called a neurodegenerative disease?
A chronic and neurodegenerative condition that affects both motor and non-motor functions. It is neurodegenerative because the loss of neurons worsens over time.
List 4 key motor symptoms of Parkinson’s:
- Tremors
- Slowness of movement (Bradykinesia)
- Muscle rigidity
- Postural instability
List 2 key non-motor symptoms of Parkinson’s:
- Speech impairment
- Mental illnesses (Eg. Depression, anxiety)
What are tremors?
The continuous involuntary shaking of the body.
What is muscle rigidity?
Muscles seem unable to relax and are tight, even when at rest.
What is postural instability?
Involves difficulty maintaining an upright posture and a steady balanced position.
What is speech impairment?
Problems with verbal fluency, which can reduce the volume, clarity, and speed of speech.
What is the effect of dopamine in Parkinson’s?
- Parkinson’s causes a degeneration of the neurons in the substantia nigra, which produces dopamine neurotransmitters
- Because dopamine is responsible for the smooth, coordinated functioning of the body’s muscles and movements when at rest or during periods of activity, those with Parkinson’s experience a reduction in these functions since there are fewer messages sent to the motor cortex.
What is the fight-flight-freeze response?
Is initiated by the sympathetic nervous system and prepares the body to confront a stressful situation to optimise the chance of survival.
What are the types of neurons in the spinal cord and what is their function?
Interneurons communicate messages between sensory and motor neurons at the spinal cord.
Give 3 examples of physiological stress reactions:
- Headaches
- Stomach ulcers
- Colds/flu
Give an example for each of the 3 types of psychological stress reactions:
Behavioural: Changes to sleeping patterns
Emotional: Irritability
Cognitive: Decreased concentration
