Chapter 2C

Question 1

neurochemicals

Answer 1

Neurochemicals are chemicals in the brain and nervous system that play a key role in transmitting signals between neurons.
* These chemicals can be classified as
neurotransmitters and neuromodulators.

Question 2

the neural synapse

Answer 2

A neural synapse is the tiny gap between two nerve cells where they communicate. When one cell sends a signal, it releases chemicals called neurotransmitters into the gap. These chemicals travel to the next nerve cell and pass on the message, allowing the brain and nervous system to work properly.

Question 3

binding

Answer 3

Neurotransmitters have a distinct shape and will only bind
with receptor sites with a complementary shape – like a key fitting into a lock.

Question 4

the synaptic gap diagram

Answer 4

in book

Question 5

lock and key model of synaptic transmission

Answer 5

transmitter molecules will affect the postsynaptic membrane only if their shape fits the shape of a certain receptor molecules in that membrane-much as a key has to fit into a lock.

Question 6

neurotransmitters

Answer 6

A neurotransmitter is a chemical substance that carries a message to other neurons to enable rapid neural communication. it has an effect on one post-synaptic neuron at a time
* The effect can be:
- Excitatory neurotransmitters will stimulate or activate post-synaptic neurons to perform their
functions (i.e. they make neurons more likely to fire).
- Inhibitory neurotransmitters will block or prevent post-synaptic neurons from firing (i.e. they
make neurons less likely to fire).

Question 7

GABA- an inhibitory neurotransmitter

Answer 7

GABA is the primary inhibitory neurotransmitter in the CNS. It works to make post-synaptic neurons less
likely to fire. GABA is important as it counterbalances the excitatory activity of glutamate and ensures the
CNS maintains itself at a calm and balanced state. Without GABA and other inhibitory neurotransmitters,
the CNS may get out of control, resulting in seizures, epilepsy, and mental disorders such as anxiety.

Question 8

Glutamate - excitatory neurotransmitter

Answer 8

Glutamate is the primary excitatory neurotransmitter in the CNS. It enhances the likelihood of effective
neural transmission as it makes neurons more likely to fire an action potential. it is involved in most aspects of normal brain functioning
such as memory, learning, perception, and movement, as these all require efficient communication between
neurons.

Question 9

neuromodulators

Answer 9

• These neurochemicals have an effect on a larger scale than
  a neurotransmitter. They act on multiple synapses at once,
  and have a longer lasting effect. they are called modulators because they modify how neurons respond to trasmitters, changing their responsiveness to enhance the ecitatory or inhibitory effects on neurotransmitters. the two main neuronmodulaters are seritonin and dopamine

Question 10

dopamine - a neuromodulator

Answer 10

• Dopamine is produced in a number of areas in the brain – the substantia nigra and the ventral
  tegmental area – both located in the midbrain.
• It has both an inhibitory or excitatory effect on the post-synaptic neuron, depending on the
  receptor sites present.
• Dopamine has a role in producing smooth muscle movements. It also is released during
  learning and acts as a pleasurable reward for a behaviour. For this reason, it can also motivate
  people to repeat dopamine producing behaviours for the pleasurable outcome

Question 11

dopamine and parkinsons disease

Answer 11

• A lack of dopamine produced in the substantia
  nigra can lead to Parkinson’s disease. This has an
  impact on movement and causes slowed movement,
  muscle rigidity, tremors, poor balance and poor
  posture.

Question 12

dopamine and addiction

Answer 12

• The release of dopamine can act as a reward. In some
  cases, people will repeat a behaviour many times to
  experience that pleasurable feeling again. This can lead to
  addiction of certain behaviours – gaming, gambling, risky
  behaviours are examples.

Question 13

serotonin - a neuromodulator

Answer 13

• A large area of neurons in the brainstem (called the raphe
  nuclei) produce serotonin and sends it throughout the
  brain.
• It has an inhibitory and excitatory effect on the postsynaptic neuron.
• Serotonin has a significant role in maintaining positive,
  stable moods.
• It also has a role in maintaining our sleep-wake cycle and
  is also involved in digestion, appetite and arousal.

Question 14

serotonin and mental health

Answer 14

• If serotonin levels are too low, it can lead to
  depression, feelings of being inadequate. Many
  medications for depression target serotonin receptors
  in the brain or work to increase serotonin levels.
• A link between poor sleep and serotonin levels has
  also been found – highlighting the importance of
  sleep for mental health.