Human Physiology Lec-5: Synaptic Transmission and Neural Integration

Neurotransmission Mechanisms

• The presynaptic neuron can actively transport the neurotransmitter back into itself through a process called reuptake.

Synapse Types

• A chemical synapse occurs between a presynaptic axon terminal and a postsynaptic cell's dendrite.

Synaptic Delay

• The primary cause of the synaptic delay (0.5-5 msec) is the time it takes for the neurotransmitter to bind to the receptor and initiate a response in the postsynaptic cell.

Ionotropic Receptors

• A fast response involves ionotropic receptors, where the neurotransmitter binds to a channel-linked receptor.

Calcium Regulation

• The influx of Ca++ is stopped within a few milliseconds when a series of action potentials arrives at the axon terminal due to Ca++ channels being inactivated.

Synapse Definition

• Traditionally, the term synapse in physiology refers to the functional connection between two neurons.

Electrical Synapses

• The function of electrical synapses is to allow ions to flow directly from one cell to another, providing rapid communication.

Synapse Types

• Most neurons use chemical synapses to communicate.

Gap Junctions

• Gap junctions, also known as electrical synapses, transmit signals between adjacent cardiac muscle cells or adjacent smooth muscle cells.

Neurotransmitter Role

• The role of neurotransmitters at chemical synapses is to transmit signals from the presynaptic neuron to the postsynaptic neuron.