2.4 - Cell to Cell Communication Flashcards
How do electrical synapses occur?
- through gap junctions that allow direct electrical signalling between cells
TRUE OR FALSE
Electrical synapses are slow
FALSE
they are fast
Where do electrical synapses occur mainly?
uncommon, occur mainly in the CNS
Where are electrical synapses important?
in nervous system development and transmission in adult brain
Which neurons use chemical synapses?
peripheral neurons
TRUE OR FALSE:
Chemical synapses are the majority of synapses
TRUE
What is the neuroeffector junction?
synapse between neurons and effector cells
What is a neuromuscular junction?
synapse between neuron and muscle
List the 2 types of responses caused by neurotransmitters in the post synaptic cell
- Direct response: fast synaptic potential
- does not last long - Indirect response: slow synaptic potential
- longer lasting response
- uses G proteins, via 2nd messenger response system
What are the major types of neurotransmitters?
- acetylcholine
- biogenic amines
- amino acids
- neuropeptides
- purines
- gases
what are cholinergic neurons?
neurons that secrete or have receptors for ACh
Where does the synthesis of ACh occur and how?
HOW:
- synthesized from choline and acetyl CoA
- catalyzed by enzyme choline acetyl transferase CAT
WHERE:
- axon terminal
What are the 2 types of cholinergic receptors?
- muscarinic: coupled to G proteins = slower
- nicotinic: receptor operated channels = faster
Biogenic amines contain an amine group (NH2). They are derived from single amino acids. Give some examples:
- serotonin
- histamine
- dopamine
- NE
- E
What is the most abundant group of neurotransmitters in the CNS?
amino acids
Name the 4 amino acids that function as neurotransmitters in CNS
- Glutamate, aspartate = released at excitatory synapses to depolarize post synaptic cell
- glycine, GABA = released at inhibitory synapses
Purines are nucleotides that act as NTs. Where do they bind? Give some examples
- bind to purinergic receptors in CNS and other excitable tissues
- e.g. adenosine, AMP, ATP
How is Nitric Oxide synthesized?
from O2 and arginine, catalyzed by enzyme Nitric oxide synthase
Nitric Oxide needs the assistance of enzymes to degrade. TRUE OR FALSE?
false, CAN DEGRADE ON ITS OWN
What enzyme degrades ACh from the synaptic cleft?
acetylcholineesterase found on presynaptic of postsynaptic membrane or both
What happens when ACh is degraded?
choline is transported back into the presynaptic axon terminal to be used again
What are the 2 principle types of neurotransmitters in the PNS?
- ACh
- NE and E
the PNS is divided in what branches?
afferent (sensory)
efferent (motor)
