The document discusses several topics related to electrical and synaptic signaling in the nervous system. It begins by defining neurons and describing their basic structures like dendrites, axons, and synapses. It then covers membrane potential, ion transport, and equations like the Nernst and Goldman equations that relate to ion concentrations. The document also discusses myelination, the stages of neurotransmission at synapses, and the structures involved in synaptic transmission.

1. ELECTRICAL AND SYNAPTICAL SIGNALING
NAME - SATYANARAYAN PRAJAPATI
MOLECULAR BIOLOGY
BARKATULLAH UNIVERSITY BHOPAL
DEPARTMENT OF BIOCHEMISTRY AND GENETICS

2. s.no1 Neurons
2 STRUCTURE OF NEURONES
3 AXON
4 CLASSIFICATION OF NEURONES
5 MEMRANE POTENTIAL
6 Ion concerntration
7 ION TRANSPORTATION FOR MAINTAIND CON. EQUILIBRIUM
8 NERNST EQUATION
9 Goldman equation
10 Stages in neurotransmission at the synapse
11 Myelin sheath signaling
12 Direction of propogation
13 SYNAPTICAL TRAMS,ISSION
14 Synaptical structure

3.  Neurons
◦ The basic functional units of the nervous system
◦ The structure of neurons
 The multipolar neuron
 Common in the CNS
 Cells Body (soma)
 Shorts, branched dendrites
 Long, single axon

4.  THERE ARE THREE STRUCTURE
1.DENDRIDE
2.AXON
3.SYNAPSIS.

5.  The Cell Body
◦ Large nucleus and nucleolus
◦ Mitochondria (produce energy)
◦ RER and ribosomes (produce neurotransmitters)
◦ Cytoskeleton
 Neurofilaments and Neurotubules in place of microfilaments and
microtubules
 Neurofibrils: bundles of neurofilaments that provide support for dendrite
and axon
◦ Nissel Bodies
 Dense area of RER and ribosomes
 Make neural tissue appears gray (gray matter)
◦ Dendrites
 Highly branched
 Dendritic spines
 Receive information from other neurons*

6. ◦ Axon
 Is long and slender
 Carries electrical signal (action potential) to target
 Axon structure is critical to function
◦ Structure of the Axon
 Axoplasm
 Cytoplasm of axon
 Contains neurofibrils, neurotubules, enzymes, organelles
 Axolemma
 Specialized cell membrane
 Convers the axoplasm
 Axon Hillock
 Thick section of cell body
 Attaches to initial segment

7.  Structural Classifications of Neurons
◦ Anaxonic Neurons
 Found in brains and sense organs (without neurons)
◦ Bipolar Neurons
 Found in special sensory organs (sight, smell, hearing)
◦ Unipolar Neurons
 Found in sensory neurons of PNS
◦ Multipolar Neurons
 Common in the CNS
 Include all skeletal muscle motor neurons

9.  Membrane potential is a potential gradient that forces
ions to passively move in one direction: positive
ions are attracted by the 'negative' side of
the membrane and negative ions by the 'positive' one.
 The resting membrane potential of a neuron is about -
70 mV (mV=millivolt) - this means that the inside of
the neuron is 70 mV less than the outside.
 At rest, there are relatively more sodium ions outside
the neuron and more potassium ions inside that neuron.

10.  Ionic Mechanisms of Action Potentials
• Voltage-Dependent Conductances
• Na+ is critical for the action potential in nerve cells.
• action potentials are repeatedly initiated as the extracellular
concentration of Na+ is modified. As the concentration of sodium
in the extracellular solution is reduced, the action potentials
become smaller.
• Na+ & k + highly needed energy.

13.  an equation that will allow us to calculate the value of the equilibrium potential
based on the nature of ion (i.e., valence of the ion), as well as the ion
concentration gradient that exists across the membrane.
 We will use K+ for this derivation and will later extend the equation to other ions.
We begin by determining the free energy (ΔG) available from the chemical and
electrical gradients. The chemical gradient (ΔGChemical) and the electrical gradient
(ΔGElectrical) can be defined as:
 ΔGChemical =RT ln [K+ ]o equ..1
[K+ ]I
 ΔGElectrical = zFV equ..2

14.  where R is the gas constant,
 T is the absolute temperature,
 F is the Faraday constant,
 V is the voltage, and z is the valence of K+ (+1).
 At equilibrium, ΔGElectrical and ΔGChemical are equal.
 Therefore,
equ..3
Substituting for ΔGChemical and ΔGElectrical, we get
equ..4

15.  Solving for V, we get
above equation is nernst equation.
 The Nernst equation allows us to calculate the potential that will be established across the
membrane based on the valence and concentration gradient of K+ (provided that only
K+ channels are present).
 This potential is also referred to as the Nernst potential.
 The Nernst potential for any given ionic species is the membrane potential at which the ionic
species is in equilibrium; i.e., there is no net movement of the ion across the membrane

16.  two or more ions contribute to the membrane potential, the Nernst potential no longer yields the Vm. In
this case, use the Goldman-Hodgkin-Katz (GHK) equation to calculate the Vm.
 at the equilibrium potential for any one ion. For a typical mammalian neuron, the membrane potential is
generally around −70 mV.
 This is because in most cells at rest, there are both K+ and Na+ selective channels in the plasma
membrane
 it turns out that in many cells, K+, Na+, and Cl− make the largest contribution to the resting membrane
potential. Therefore, the contribution of all three ions (Na+, K+, and Cl−) to Vm must be taken into account.
 When more than one ion channel is present in the membrane, the membrane potential can be calculated
by using the Goldman-Hodgkin-Katz equation (GHK equation):

17.  Synthesis of the neurotransmitter. This can take place in the cell body, in the axon,
or in the axon terminal.
 Storage of the neurotransmitter in storage granules or vesicles in the axon
terminal.
 Calcium enters the axon terminal during an action potential, causing release of the
neurotransmitter into the synaptic cleft.
 After its release, the transmitter binds to and activates a receptor in the
postsynaptic membrane.
 Deactivation of the neurotransmitter. The neurotransmitter is either destroyed
enzymatically, or taken back into the terminal from which it came, where it can be
reused, or degraded and removed.

18.  There are two type of signaling
o Countinous signaling
o Soltatary signaling (jumping)

19. •Node of ranvier rich in Na ion channel .
•In node of ranvier voltage gated channel are present Na ion and k ion as well as
•Mye lin the made of lipid ,lipid work an insulator ,which transmit the
electrochemical signals .
•During the time of propogation Soltatory signaling is faster then continous
signaling
•Nerve conduction is faster in soltatory not in countinous

20. Direction of propogation
The direction of propagation ,when dendrites get the signal so signal is unidirectional.
When the researcher takes single axon and gives the stimulus in mid of axon, so direction
will be bi direction

21. •Synaptic transmission is the biological process by which a neuron communicates with a target
cell across a synapse. Chemical synaptic transmission involves the release of a neurotransmitter
from the pre-synaptic neuron, and neurotransmitter binding to specific post-synaptic receptors.
•In chemical synapsi ca ion gatted channel is present ieither iof na ion gated channel .

23. THANKYOU