1. Which types of ion channels are found on the nerve cell membranes? 

There are two types of ion channels found on the nerve cell membranes namely, voltage-gated and ligand-gated ion channels.

1. Name 3 differences between voltage-gated and ligand-gated ion channels.
   • Voltage-gated ion channels react to changes in the membrane potential of a cell. These changes are detected by a voltage sensor component in the protein which then controls the gating (opening and closing) of the channel. In contrast, ligand-gated ion channels control the gating of the channel by reacting to the binding of a ligand or a neurotransmitter to the ionotropic channel receptor. 
   • Voltage-gated ion channels are more readily found through the body than when compared to ligand-gated ion channels. Voltage-gated ion channels are found on the axons of nerve cells and on the outer surface of cell bodies and dendrites. Ligand-gated ion channels are also found on the outer surface of cell bodies as well as on both sides (pre and postsynaptic) of synapses. 
   • Examples of Voltage-gated ion channels include sodium, potassium and calcium channels. In contrast, Ligand-gated ion channels act as ionotropic receptors and so they make use of g-aminobutyric acid, acetylcholine, glutamate and serotonin as their neurotransmitters. 

3. Compare ionotropic and metabotropic receptors.

IONOTROPIC	METABOTROPIC
There is no formation of second messengers.	Second messengers are formed in order for the transduction system to come into working.
They work in the same way as ligand-gated ion channels. The binding of a neurotransmitter or a hormone to the inotropic channel receptor is what causes it to open or close.	They work in the same way as G Protein-coupled receptors. The neurotransmitter or hormone must bind to the extracellular section of the receptor protein this allows intracellular processes to occur and the inactive G-protein is activated and the formation of second messengers occurs.
There are only 4 receptors that we know of; GABAA, Nicotinic, EAA and 5-HT3	All the other receptors found in the body.
Responsible for the opening of ion channels.	Responsible for metabolic changes.
Ionotropic receptor activation involves quick stimulation and a quick, short lasting effect.	Metabotropic receptor activation causes the effect to last longer and it can take longer for stimulation to occur.

4. Classify the CNS receptors into ionotropic and metabotropic and know the transduction mechanism of each receptor.

Ionotropic receptors include GABA_A, Nicotinic, EAA, 5-HT₃, BD. 

Metabotropic receptors are divided into two groups based on their transduction systems; Adenylyl cyclase system & Phospholipase C system. 

In the Adenylyl cyclase system there are receptors which are positively bound (b₁₊₂, D₁) and when they are stimulated the formation of 2^ndmessengers occurs and ATP is converted to c-AMP. In the Adenylyl cyclase system there are also receptors which are negatively bound (D₂, a₂, 5-HT_{IA + B}, M₂, GABA_B) and when they are stimulated the formation of c-AMP is suppressed. 

In the Phospholipase C system there are only receptors that are positively bound (a₁, 5-HT₂, M₁, H₁) and when they are stimulated phospholipase C is involved in the conversion of PIP₂ to DAG and IP₃. 

5. Explain the difference between an EPSP and an IPSP and give examples of each.

EPSP stands for Excitatory/Activating Post Synaptic Potential meaning that when activated it will activate additional action potentials. This occurs when the neuronal membrane is hyper polarized. Examples of receptors that will bring about this effect include Nicotinic, EAA, 5-HT₃, BD. 

IPSP stands for Inhibiting Post Synaptic Potential meaning that when activated it will prevent further action potentials from occurring. This occurs when the neuronal membrane is depolarized. Examples of receptors that will bring about this effect include GABA_A. 

6. What is the role of calcium in the development of a synaptic potential?

When an action potential arrives at the axon terminal it results in the depolarization of the membrane. This then causes an influx of calcium into the presynaptic membrane which causes neurotransmitter release from the synaptic vesicles into the synaptic cleft. The neurotransmitters can then diffuse across the cleft and bind to receptors on the postsynaptic membrane which will in turn produces an effect. Thus calcium is essential for neurotransmitter release which is needed in order to produce an effect.