Human Phys 2.5 Flashcards
What does an electrical synapse allow?
Current to flow from one excitable cell to the other via low resistance pathways (gap junctions)
Where are electrical synapses found?
Cardiac muscle and some types of smooth muscles
What is transmission of gap junctions?
Bidirectional
Is there a synaptic delay in gap junctions?
No
What is a chemical synapse?
A gap between the Presynaptic membrane and postsynaptic membrane called the synaptic cleft (information is transmitted between them via neurotransmitters)
What can the change in potential on the postsynaptic side be?
Excitatory (depolarized, closer to 0)
Inhibitory (hyperpolarized, further from 0)
What is the direction of a chemical synapse?
Unidirectional (from Presynaptic to postsynaptic)
Is there a synaptic delay in chemical synapse?
Yes
Motor end plate
Part of the muscle fiber in direct contact with the nerve
Neuromuscular junction
Connection between a nerve and muscle fiber
Neuromuscular transmission
- Nerve releases acetyl choline and it binds to a nicotinic receptor
- Binding opens gate and allows Na+ to go in
(Ligand gated ion channel)
ACh-channel is large enough to allow passage of Na+, K+, and Ca2+, so why do more Na+ ions pass through?
There is a large concentration of Na+
Easier for Na+ to enter than K+ to leave because cell is negatively charged
End plate potential
Local positive potential ( responsible for generation of action potential)
What can the end plate potential increase resting potential by?
50-75 mV
What happens as long as acetyl choline is present?
It continues to stimulate the motor end plate
