Neurons

Question 1

Outline the steps of neurotransmission

Answer 1

1 > An electrical impulse travels down the pre-synaptic neuron.

2 > The electrical impulse stimulates the vesicles containing neurotransmitters to migrate towards the pre-synaptic membrane.

3 > The vesicles release the neurotransmitters into the synaptic cleft via exocytosis.

4 > The neurotransmitters diffuse across the synaptic cleft and attach to specific protein receptor sites on the post-synaptic membrane.

5 > This then activates the post-synaptic neuron.

6 > Once the receptors on the post-synaptic membrane have been activated, they produce either an excitatory or inhibitory effect.

7 > If the neurotransmitter is excitatory it makes the post-synaptic neuron more likely to fire as there is an increase in positive charge.

If the neurotransmitter is inhibitory it makes the post-synaptic neuron less likely to fire as there is an increase in negative charge.

8 > The net effect of the neurotransmitters is then calculated through a process of summation.

Question 2

Describe the 3 neurons

Answer 2

SENSORY =
has a receptor cell attached onto the dendrites.
the cell body is found attached to the axon & myelin sheath.
Long dendrites, Short axons (LS).

RELAY =
the most normal looking neuron.
NO myelin sheath.
Short dendrites, Short axons (SS)

MOTOR =
looks like it’s holding TNT at the pre-synaptic terminal.
very long dendrites.
Short dendrites, long axon (SL)

Question 3

Define neuron

Answer 3

Nerve cells that picks up info from sense receptors (e.g. skin), and carry nerve impulses TO the CNS (spinal cord and brain)

Question 4

Using your knowledge of different types of neurotransmitters, explain what effects acetylcholine will have on neural transmission

Answer 4

Acetylcholine is an excitatory neurotransmitter.

This means that it allows positively charged particles to enter the post-synaptic neuron, creating a positive electrical charge, making a nerve impulse more likely to occur.

Question 5

Outline fight or flight

Answer 5

A person enters a dangerous/ stressful situation

The amygdala (part of the limbic system) is activated which sends a distress signal to the hypothalamus
T
he hypothalamus activates the sympathomedually pathway (SAM pathway)- the pathway running to the adrenal medulla and the sympathetic nervous system (SNS)

The SNS stimulates the adrenal medlla

The adrenal medulla releases the hormones adrenaline and nonadrenaline into the bloodstream

Adrenaline causes physiological changes to prepare the body for fight or flight