Chapter 5 Flashcards
What is synaptic transmission?
The process of information transfer at a synapse.
Where do electrical synapses occur?
Specialized sites called gap junctions
What are secretory granules?
larger vesicles (about 100 nm in diameter) in axon terminals that contain soluble protein that appears dark in the electron microscope. They are sometimes referred to as dense-core vesicles.
What are membrane differentiations?
Dense accumulations of protein adjacent to and within the membranes on either side of the synaptic cleft.
On the presynaptic side, proteins jutting into the cytoplasm of the terminal along the intracellular face of the membrane sometimes look like a field of tiny pyramids. The pyramids, and the membrane associated with them, are the actual sites of neurotransmitter release, called active zones. Synaptic vesicles are clustered in the cytoplasm adjacent to the active zones.
What is the postsynaptic density?
The protein thickly accumulated in and just under the postsynaptic membrane. It contains the neurotransmitter receptors, which convert the intercellular chemical signal (i.e., neurotransmitter) into an intracellular signal (i.i., a change in membrane potential, or a chemical change) in the postsynaptic cell.
What is a neuromuscular junction?
A chemical synapse that occurs between the axons of motor neurons of the spinal cord and skeletal muscle.
What is another name for the motor end-plate?
the post-synaptic membrane
What is the job of transporters?
concentrating amino acid and amine neurotransmitters inside the vesicle.
What causes voltage-gated calcium channels in the active zones to open?
The depolarization of the terminal membrane
What is the process by which vesicles release their contents?
Exocytosis
What are transmitter-gated ion channels?
membrane-spanning proteins consisting of four or five subunits that come together to form a pore between them
What is an excitatory postsynaptic potential (EPSP)?
A transient postsynaptic membrane depolarization caused by the presynaptic release of neurotransmitter. Synaptic activation of ACH-gated and glutamate-gated ion channels causes EPSPs.
What is an inhibitory postsynaptic potential (IPSP)?
A transient hyperpolarization of the postsynaptic membrane potential caused by the presynaptic release of neurotransmitter. Synaptic activation of glycene-gated or GABA-gated ion channels cause an IPSP.
What is neuropharmacology?
The study of the effects of drugs on nervous system tissue
What are inhibitors?
Drugs that inhibit the normal function of specific proteins involved in synaptic transmission
