Final answer:
Excitatory neurotransmitters have an excitatory effect on the postsynaptic cell, causing depolarization and generating excitatory postsynaptic potentials (EPSPs). Acetylcholine and glutamate are examples of excitatory neurotransmitters.
Step-by-step explanation:
The **excitatory neurotransmitters** are a type of neurotransmitters that have an excitatory effect on the **postsynaptic cell**. When these neurotransmitters bind to receptor sites on the postsynaptic membrane, they open ion channels, such as ligand-gated channels, which allow positive ions, like sodium (Na+), to enter the cell. This **depolarizes** the postsynaptic membrane and generates an **excitatory postsynaptic potential (EPSP)**, making the postsynaptic neuron more likely to fire an action potential.
Two examples of excitatory neurotransmitters are **acetylcholine** and **glutamate**. Acetylcholine is released at the neuromuscular junction and causes the opening of Na+ channels in the postsynaptic muscle cell, leading to muscle contraction. Glutamate is the primary excitatory neurotransmitter in the central nervous system and plays a crucial role in synaptic transmission and neuronal communication.