The majority of the content is physiology-based, but it's also built-in an anatomical perspective.i've also included disorder of synapses Instagram @Rajamd_

1. SYNAPSE
Raja Md

2. SYNAPSE
• The site of transmission of electric nerve impulse
between Neuron & Second cell
o NEURONAL JUNCTION
CNS
PNS
• Effector
 Gland
• Neurons
Myoneural junction
Neuromuscular junction
Neuroglandular junction
Axodendritic Synapse
Axosomatic Synapse
Axoaxonic Synapse
 Muscle
• Neuron

4. CHEMICAL SYNAPSE
• Electrical activity is converted into release of chemicals known as Neurotransmitters.
• Transmission of impulse is one-way
PRESYNAPTIC TERMINAL
POSTSYNAPTIC TERMINAL
SYNAPTIC CLEFT
• contains Receptor sites for neurotransmitters.
• Synaptic gap
• Space between the pre & post - synaptic endings.
• Acts as a junction, connecting two or more neurons.
• 20 – 40 nm wide.
• Terminal boutons or Synaptic bouton
• Contains Neurotransmitters enclosed in small membrane-bound
spheres called Synaptic Vesicles
• Contains organelles, such as Mitochondria and ER
 STRUCTURE

5. PROCESS OF SYNAPTIC TRANSMISSION
1. Action potential reaches axon terminal
2. Voltage gated calcium channels opens
• There’s a rapid influx of ca 2+

6. PROCESS OF SYNAPTIC TRANSMISSION
3. Ca 2 + enters & forms Ca 2+-synaptotagmin
• Ca 2 +-synaptotagmin complex displaces
a component of the SNARE & promotes
exocytosis of the Neurotransmitter
4. Neurotransmitters diffuse rapidly across the
synaptic cleft & reach Post – synaptic
membrane

7. PROCESS OF SYNAPTIC TRANSMISSION
5. Binding of neurotransmitter ligand to receptor
protein causes chemical regulated ion channels to
open
• when opened, they produce a graded
change in the membrane potential
known as a GRADED POTENTIAL
• Influx of Na+ or Ca2+
• Produces a Graded Depolarization
• Inside of the postsynaptic membrane becomes
less negative
• Membrane potential moves toward the
threshold required for action potential.
• Influx of cl-
• Produces a Graded Hyperpolarization
• Inside of the postsynaptic membrane
becomes More negative
• Membrane potential moves away from the
threshold required for action potential.
 EXCITATORY POSTSYNAPTIC POTENTIAL (EPSP)  INHIBITORY POSTSYNAPTIC POTENTIAL (IPSP)

8. SUMMATION
 The process that determines whether or not an action potential will be generated by the combined effects
of excitatory & inhibitory signals
 There are 2 types :-

9. NEURAL CIRCUITS
• one pre-synaptic
neuron terminates into
many post-synaptic
neurons
• Many pre-synaptic
neuron terminates into
one post-synaptic
neuron
DIVERGENCE CONVERGENCE

10. SYNAPTIC PLASTICITY
• Ability of synapses to strengthen or weaken over time, in response to increases or decreases in their
activity
• Both pre-synaptic and post-synaptic mechanisms can contribute to the expression of synaptic plasticity
LONG-TERM POTENTIATION (LTP)
• persistent strengthening of synapses based on recent
patterns of activity. These are patterns of synaptic activity
that produce a long-lasting increase in signal
transmission between two neurons.
LONG-TERM DEPRESSION (LTD)
• Activity-dependent reduction in the efficacy of
neuronal synapses lasting hours or longer following a
long patterned stimulus
Dependent on a rise in Ca2+
concentration within the postsynaptic
neuron
• rapid rise in [Ca2 +] causes LTP
• Smaller & prolonged rise in the [Ca2+] causes (LTD)

11. FUNCTIONNEUROTRANSMITTERS
EXCITATORY NEUROTRANSMITTERS
INHIBITORY NEUROTRANSMITTERS
i. Acetylcholine
ii. Norepinephrine
iii. Dopamine
i. Serotonin
ii. GABA (γ aminobutyric acid)
iii. Glycine

12. ELECTRICAL SYNAPSE
LOCATION
Mechanical & Electrically link between neurons that is
formed by Gap Junction between the pre- & postsynaptic
neurons, which are separated by only 2 nanometres.
NEURAL SYSTEMS
• Allowing Myocardium to contract as a unit
• Allowing many cells to contract together, producing a stronger
contraction
• uterus during labour
• Rapid
• Bidirectional
• Synchronized
IMPULSE
• requiring fastest possible response
• Defensive reflexes
CARDIAC MUSCLE
SMOOTH MUSCLES

13. DISEASES ASSOCIATED WITH SYNAPTIC ALTERATIONS
Autism Spectrum Disorder • Alterations at the synaptic level causes
pathogenesis of this disease.
• Mutations affecting the adhesion molecules in the
synaptic cells.
Fragile X Syndrome: Mental Retardation • Alterations in synapse development and function.
Alzheimer’s Disease • A-beta amyloid formed inAlzheimer’s disease can
cause a significant decrease in synaptic plasticity.
• Decreased number of synapses in hippocampus,
cerebral cortex & subcortical regions of the
brain.
o The patients have the common symptoms of lack of
social communication & delay of language &
stereotypy.
o Most common form of mental retardation
o disease is characterized by reduced intellectual ability,
anxiety, hyperactivity, developmental delay and
hypersensitivity to stimuli
o It is a neurodegenerative disorder affecting people in
their older age

14. THANK YOU