NEUROMUSCULAR AND SYNAPTIC TRANSMISSION D. C. Mikulecky Professor of Physiology
TWO TYPES OF SYNAPSE ELECTRICAL CHEMICAL
ELECTRICAL GAP JUNCTION: PROVIDES PATH FOR IONS TO FLOW FROM ONE CELL TO ANOTHER CELL 1 CELL 2
TYPES OF CHEMICAL SYNAPSES DISCRETE DIFFUSE
DISCRETE SYNAPSES
DIFFUSE SYNAPSES
CHEMICAL: THE SYNAPSE INCOMING NERVE POST SYNAPTIC NERVE SPACE
EVENTS IN CELLULAR COMMUNICATION INPUT SIGNAL (CHEMICAL,MECHANICAL, PHOTO, ELECTRICAL) RESPONSE (OUTPUT) SECRETION CONTRACTION/RELAXATION DIVISION PHAGOCYTOSIS RECEPTOR TRANSDUCER EFFECTOR ENZYMES,GENOME,CONTRACTILE FILAMENTS, SECRETORY GRANULES
HOW ARE WE WIRED?CONNECTIONS BETWEEN NERVE CELLS CELL BODY DENDRITES AXON HILLOCK AXON TERMINALS
THE NATURE OF CHEMICAL TRANSMISSION BETWEEN NERVES PRESYNAPTIC EVENTS POSTSYNAPTIC EVENTS IN THE SPACE
PRESYNAPTIC EVENTS THE ALL OR NONE ACTION POTENTIAL TRIGGERS THE RELEASE OF CHEMICAL TRANSMITTER
INCOMING ACTION POTENTIAL DEPOLARIZES TRIGGERS CALCIUM CHANNELS CALCIUM ENTERS THE CELL
THE SYNAPSE SYNAPTIC VESSICLES INCOMING ACTION POTENTIAL CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME
THE SYNAPSE: INCOMING ACTION POTENTAL SYNAPTIC VESSICLES INCOMING ACTION POTENTIAL CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME
CALCIUM INFLUX CAUSES VESSICLES TO BE RELEASED VESSICLES MIGRATE TO MEMBRANE EXOCYTOSIS NEUROTRANSMITTER ENTERS SPACE
THE SYNAPSE: CALCIUM CHANNELS OPEN SYNAPTIC VESSICLES INCOMING ACTION POTENTIAL CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME
THE SYNAPSE: NEUROTRANSMITTER ENTERS SPACE SYNAPTIC VESSICLES CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME
POST SYNAPTIC EVENTS IONOTROPIC (LIGAND GATED) CHANNELS VOLTAGE GATED CHANNELS ELECTROPHYSIOLOGICAL PRINCIPLES
IONOTROPIC CHANNELS BIND NEUROTRANSMITTER OPEN CHANNEL HYPER OR DE-POLARIZATION
THE SYNAPSE:NEUROTRANSMITTER BINDS TO POSTSYNAPTIC RECEPTOR SYNAPTIC VESSICLES CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME
HOW ARE WE WIRED?CONNECTIONS BETWEEN NERVE CELLS CELL BODY DENDRITES AXON HILLOCK AXON TERMINALS
POSTSYNAPTIC POTENTIALS RESTING POTENTIAL IPSP EPSP TIME
SPATIAL SUMMATION TIME SIMULTANEOUS INPUT FROM TWO SYNAPSES: ABOVE THRESHOLD
SPATIAL SUMMATION TIME SIMULTANEOUS INPUT FROM TWO SYNAPSES: ABOVE THRESHOLD
TEMPORAL SUMMATION TIME TOO FAR APART IN TIME: NO SUMMATION
TEMPORAL SUMMATION TIME CLOSER IN TIME: SUMMATION BUT BELOW THRESHOLD THRESHOLD
THE GOLDMAN-HODGKIN-KATZ (GHK) EQUATION [Ko] + [Nao] Vm = 60 LOG [Ki] + [Nai] IS THE RATIO OF SODIUM TO POTASSIUM PERMEABILITY
TEMPORAL SUMMATION TIME STILL CLOSER IN TIME: ABOVE THRESHOLD
EPSP-IPSP CANCELLATION
HOW EXCITATION OCCURS-THE ROLE OF DEPOLARIZATION AND HYPERPOLARIZATION SUMMATION CAN DEPOLARIZE THE CELL BEYOND THRESHOLD HYPERPOLARIZATION BLOCKS
NEURO TRANSMITTERS ACETYL CHOLINE DOPAMINE NOREPINEPHRINE EPINEPHRINE SEROTONIN HISTAMINE GLYCINE GLUTAMINE GAMMA- AMINOBUTYRIC ACID (GABA)
IN THE SPACE ENZYME “CHEWS UP” LIGAND MASS ACTION CAUSES LIGAND TO DISSOCIATE FROM RECEPTOR
THE SYNAPSE SYNAPTIC VESSICLES CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME
THE SYNAPSE SYNAPTIC VESSICLES CALCIUM CHANNEL ION CHANNEL RECEPTOR ENZYME