Law: c=v/r
Voltage: separation of
Chemical Synapses: most common
oppositely charged ionic Electrical Synapses: much less Pumps: a type of transport
1. Neurotransmitter molecules
particles common, presynaptic neuron
protein for moving Action Potential:
released from synaptic knob
Current: movement of physically bound together, 1. Excitation
2. Diffusion of neurotransmitter across substances across a
charged particles gap junctions are present
Resistance: opposition to
cleft
where there is no delay in concentration gradient, 2. Reaching threshold
3. Binding of some neurotransmitters voltage
movement of charged passing electrical signals, requires ATP, contains
to receptors
particles located in limited regions of both Na-K pumps and Ca 3. Depolarization
4. Synaptic delay
brain and eyes 4. Repolarization
5. Single postsynaptic neuron often pumps
stimulated by more than neuron Leak Channels: 5. hyperpolarization
always open, e.g.,
Peripheral Nervous sodium ion and
System (PNS) potassium ion
(includes brain and channels
spinal cord)
The Nervous System
Chemically-Gated:
normally closed, open Membrane potential difference
Channels in response to binding in charges across the plasma
of neurotransmitter membrane
Central Nervous Chemical concentration
gradient: unequal distribution
System (CNS) of ions between two areas
(Nerves)
RMP: resting membrane
potential: -70mV
Sensory (afferent) nervous Voltage-Gated: normally closed but opens in response to
system Motor (efferent) Nervous changes in electrical charge. Has three states
- Responsible for System 1. Resting State: Inactivation gate open, activation
receiving - Initiates and gate closed, entry of Na+ prevented
sensory transmits motor 2. Activation state: inactivation gate open,
information output from CNS
- Transmit info to activation gate open, Na+ moving through
CNS channel
3. Inactivation state: activation gate open,
inactivation gate closed, entry of Na+ prevented EPSP: neuron becomes
more positive
IPSP: neuron becoming
Somatic Sensory Visceral Sensory Somatic Motor Neurons: Autonomic Motor
more negative
Neurons: stimuli is Neurons: stimuli is transmits motor output Neurons: transmits
consciously not consciously from CNS to voluntary motor output from CNS All or None Law:
perceived perceived skeletal muscles without conscious the nerve will
control respond
completely or not
at all
Receptors: EX: being able to
Receptors: eyes, press the Receptive Segment: dendrites and cell body,
internal organs Ex. Our hearts mainly chemically gated channels
nose, tongue, accelerator on
and blood your car beating Initial Segment: axon hillock, voltage gated Na+
ears etc.
vessels and K+ channels
Conductive segment: axon, voltage gated Na+
and K+ channels
Transmissive segment: synaptic knobs, voltage
gated Ca2+ channels and pumps