Synapses Flashcards
Cellular communication occur through
-synapses( direct comunication)
-by blood in endocrine system(indirect communication)
Types of synapses
-chemical synapses between (one way conduction)
A neuron-neuron synapse
B neuron muscle fiber synapse(NMJ)
-Electrical synapse(bi directionally)
Cardiac cells, smooth muscle(gap junction)
Neurites
All extentions from soma
Information is transmitted in CNS in the form of———called———-
Action potentials -nerve impulses
Pre synaptic terminal have
1 mitochondria to provide ATP
2 voltage gated Ca channels
3 transmitter vesicles
How neuro transmiter is released
As action potential reaches the axon terminal then the pre synaptic membrane depolarizes opening of voltage gated Ca channels ca entery and binds to release sites on the terminal membrane of presynaptic neuron and transmitter vesicle forming snare complex opening them and release of neuro transmitter
Effect of neurotransmitter on post synaptic neuron
Either inhibtory or excitatory depending on characterstic of receptor
Receptor parts
Binding component
Intra cellular component
Receptor types
-inotropic receptor
-Metabotropic receptor
Effects of excitatoery neuro transmitter
Opening sodium cahnnels
Decreased conductance through k and cl
Through second messenger decrease no of inhibitatory neuro transmitter
Excitatory neuro transmitter excites the post synaptic neuron
rapid influx of sodium ions to inside of the membrane due to;
Excitatory post synaptic potential
large sodium concentration gradient and large electrical negativity inside the neuron,
Effect of Inhibitory Synapses on the Postsynaptic Membrane—Inhibitory Postsynaptic Potential (IPSP).
- Opening of Cl channels and Cl influx
- Opening of K channels and K outflux
Muscle fibers are innervated by large mylinated motor neurons that originate from anterior horn of spinal cord
Motor unit
Motor end plate
A single motor neuron and the whole muscle fibers that it innervates
Neuro muscular junction
