Transcript Physiology as the science. Bioelectrical phenomena in nerve cells. Physiology of

Physiology as the
science. Bioelectrical
phenomena in nerve
cells. Physiology of
synapses, interneuron
connections
Author
ass.prof. N.M. Volkova
Neurons
• Communication
throughout the
nervous system
takes place via
neurons—cells
that are highly
specialized to
receive and
transmit
information from
one part of the
body to another.
The Neuron
Soma
Dendrites
Myelin
Sheath
Axon
Axon
Terminals
Glial cells
• Along with
neurons, the
human nervous
system is made
up of other types
of specialized
cells, called glial
cells between
neurons and
blood vessels in
the brain.
Glia and Blood-Brain Barrier
Action Potentials
Voltage depending ion gate
The Synapse
• The point of
communication
between two
neurons
• is called the
synapse.
• The
transmission of
information
between two
neurons occurs
in one of two
• ways: electrically
or chemically.
Chemical Signals
• One neuron will transmit info to another neuron or to a
muscle or gland cell by releasing chemicals called
neurotransmitters.
• The site of this chemical interplay is known as the synapse.
– An axon terminal (synaptic knob) will abut another cell, a
neuron, muscle fiber, or gland cell.
– This is the site of transduction – the conversion of an
electrical signal into a chemical signal.
Synaptic
Transmission
• An AP reaches the
axon terminal of the
presynaptic cell and
causes V-gated Ca2+
channels to open.
• Ca2+ rushes in, binds
to regulatory proteins &
initiates NT exocytosis.
• NTs diffuse across the
synaptic cleft and then
bind to receptors on
the postsynaptic
membrane and initiate
some sort of response
on the postsynaptic
cell.
Important
Neurotransmitters
• Acetylcholine -learning,
memory, muscle
contractions
• Dopamine – movement,
thought processes,
rewarding sensations
• Serotonin - emotional
states, sleep
• Norepinephrine - physical
arousal, learning, memory
• GABA - Inhibition of brain
activity
• Endorphins Pain
perception Positive
emotions
Video