Here I am explaining about the Insect Nervous system and Impulse transmission

1. TERM PAPER-I PRESENTATION
ON
INSECT NERVOUS SYSTEM AND IMPULSE
TRANSMISSION
Course In-Charge
ENTO 606
Dr.G.Sridevi, PS & Head (AINP on PR)
Dr.K.Kavitha, Senior Scientist (AINP on PR)
SABHAVAT SRINIVASNAIK
ID.No: RAD/2021-25
In-Service I Ph.D
DEPARTMENT OF PATHOLOGY
COLLEGE OF AGRICULTURE, RAJENDRANAGAR
PROFESSOR JAYASHANKAR TELANGANA STATE AGRICULTURAL UNIVERSITY

2. Preamble
Axonic transmission
Synoptic transmission
Insect nervous system structure
CONTENTS
Insecticide molecules and Target
Insect Nervous system function
References
Summary & Conclusion

3. PREAM

4. PREAMBLE
 Protozoa to Chordata- highest evolved
organism- human being
 A unicellular organism-single cell-
functions- less coordination
 A multicellular organism-well organised
mass of matter
 Contains different chemical compounds
 It performs chemical activities and physical
activities
 Charged organism–state of equilibrium with
its environment.
 “Coordination-Insect nervous system”
 Nervous system- poorly insulated current
system
 Producing the harmonised behaviour by
coordinating 300 skeletal muscles
 Temporal and spatial manner
 Insecticides act on nervous system
Chapman,1983 & Simpson, 2013
Structural and Functional Unit: Neuron

5. STRUCTURE
Neuron
Glial cells
Nervous system

6. INSECT NERVOUS SYSTEM STRUCTURE-NEURON
Soma/Cell body/Perikaryon
Nucleus
Dendrite
Axon
Glial cells-N.lamella
Protoplasm
Collateral
Arborisations
Stimuli
Neurons-ganglion
Branched projections of a neuron
that conduct the impulses received
from other neural cells to the cell
body
Long slender projection of a nerve cell
that conducts nerve impulses from the
cell body to other neurons, muscles,
and organs Chapman,1983 & Simpson, 2013

9. INSECT NERVOUS SYSTEM STRUCTRE-SYNAPSES

10. INSECT NERVOUS SYSTEM STRUCTRE-SYNAPSES
i) Synaptic cleft-20-25 nm
(Chemical transmission)
Vesicles
ii) Gap junction-3.5 nm
(Direct transmission)
Post synaptic neuron
Pre synaptic neuron
Synapse
The junction between the terminal of a neuron and either another neuron or a
muscle or gland cell, over which nerve impulses pass
 Electron lucent
 Electron dense
 Physical synapses
 Functional synapses
 Retinula cell of fly =200 Physical synapse
 Single to many cells/
 Among them one =functional

11. INSECT NERVOUS SYSTEM STRUCTURE-GLIAL CELLS
 Each neuron consist of glial cells
 Synaptic contact occur where there is no glial cells
 Glial cells pass nutrient materials to neurons
 It reserves glycogen
 Making repairs to the neurons
 Ionic balance and protection- Blood Brain Barrier concept

12. INSECT NERVOUS SYSTEM STRUCTURE-GLIAL CELLS

13. INSECT NERVOUS SYSTEM STRUCTURE-GLIAL CELLS

14. INSECT NERVOUS SYSTEM STRUCTURE-GLIAL CELLS

15. CLASSIFICATION OF NEURONS -STRUCTURAL BASIS
Neuron with a proximal axon & many distal dendrites
Neuron with a single axon
Neuron with a proximal axon and a long distal dendrite
1
1
2
1
2
3
4
5
6

16. Internuncial (association) neurons
Unipolar cells (often with several collaterals
and/or branching axons) (conduct signals
within CNS)
Motor neurons: conducts impulse from CNS
to effector organs-Efferent neurons, monopolar,
situated in the ganglia and conduct impulse
from CNS to effector organs like muscles and
glands
Afferent (sensory) neurons
Bipolar or multipolar cells have dendrites -
associated with sense organs or receptors
(carry information towards CNS).
CLASSIFICATION OF NEURONS –FUNCTIONAL BASIS

17. INSECT NERVOUS SYSTEM
Nervous system divided in to three major sub-systems
1. Central nervous system (CNS)
2. Visceral nervous system (VNS)
3. Peripheral nervous system (PNS)

18. INSECT NERVOUS SYSTEM-CNS
Contains double series of nerve centers (ganglia).These ganglia are connected
by longitudinal tracts of nerve fibers called connectives. Transverse tracts of
nerve fibers called commissures

19. INSECT NERVOUS SYSTEM-CNS
1.Brain
Formed by the fusion of first three
cephalic neuromeres
a) Protocerebrum
Large, innervate compound eyes
and ocelli
b) Deutocerebrum:
Found beneath protocerebrum,
innervate antennae
c) Tritocerebrum:
Bilobed, innervate labrum
Main sensory centre controlling
insect behaviour

21. INSECT NERVOUS SYSTEM-CNS
3.Thoracic ganglia
4. Abdominal ganglia
Median chain of segmental ganglia beneath
oesophagus
Formed by the last three cephalic
neuromeres which innervate mandible,
maxillae and labium.
2. Sub-oesophageal ganglia
Three pairs found in the respective thoracic
segments, largest ganglia, innervate legs
and muscles.

22. (a)Dictyopterus (Coleoptera: Lycidae) and Pulex (Siphonaptera: Pulicidae)
(b)Blatta (Blattodea: Blattidae) and Chironomus (Diptera: Chironomidae)
(c) Crabro and Eucera (Hymenoptera: Crabronidae and Anthophoridae)
(d)Musca,Calliphora and Lucilia ( Diptera: Muscidae and Calliphoridae)
(e)Hydrometra (Hemiptera: Hydrometridae) and Rhizotrogus (Scarabaeidae).

23. INSECT NERVOUS SYSTEM-VNS
1. Stomodeal / stomatogastric
Frontal ganglion and connected with
aorta, foregut and midgut
2. Ventral visceral
Associated with the ventral nerve cord
3. Caudal visceral
Associated with the posterior segments
of abdomen and reproductive organs

24. INSECT NERVOUS SYSTEM-PNS
 Sensory neurons of the cuticular
sensory structures (the sense
organs) that receive mechanical,
chemical, thermal or visual stimuli
from an environment
 All the motor neuron axons that
radiate to the muscles from the
ganglia of the CNS and visceral
nervous system

25. FUNCTIO

26. INSECT NERVOUS SYSTEM-IMPULSE TRANSMISSION
A nerve impulse is an electric
current that travels along
dendrites or axon due to ions
moving through voltage gated
channels in the neurons
plasma membrane
Types
1.Axonic conduction
2.Synaptic conduction

27. IMPULSE TRANSMISSION-AXONIC CONDUCTION
Positive ions
Negative ions
Sodium channels
Axon
Donnan equilibrium

28. IMPULSE TRANSMISSION-AXONIC CONDUCTION

29. IMPULSE TRANSMISSION-AXONIC CONDUCTION
Visual/ Chemical/ Mechanical
Sensory neuron
Insect

30. IMPULSE TRANSMISSION-AXONIC CONDUCTION
Resting neuron
 A charge difference is maintained
 Na+ is out and K+ is in
 Exterior is (+) and interior is (–)
 This is called resting membrane potential
Restoring neuron
 K+ ions comes in (NaK ATPase)
 Na+ ions goes out
 So again interior become (–) and exterior become (+)

31. IMPULSE TRANSMISSION-SYNAPTIC CONDUCTION

32. SYNAPTIC CONDUCTION
 Axonal-dendritic (axon to dendrite)
 Axonal-somatic (axon to soma)
 Axonal-axonal (axon to axon)
Location of synapses
Proteins-Acetyl choline
 Synaptotagmin
 Synaptobrevin
 Synap-25
 Syntaxin

33. IMPULSE TRANSMISSION-SYNAPTIC CONDUCTION
Cholinergic-Acetylcholine
Adrenergic-Norepinephrine

34. IMPULSE TRANSMISSION-SYNOPTIC CONDUCTION

35. IMPULSE TRANSMISSION-SYNOPTIC CONDUCTION

36. DIRECTION OF IMPULSE TRANSMISSION
Dendrite
receives information
Cell body
contains nucleus & organelles
Axon
transmits nerve impulse
axon terminal
transmits to next neuron
Synapse
junction between two neurons
Direction
of
nerve
impulse

37. INTERACTION OF DIFFERENT N.SYSTEMS

38. INSECTICIDES & THEIR TARGETS
 DDT
 Synthetic pyrethroids
 Oxadizines
 Cyclodienes- GABA gated Cl channels
 Carbamates- Ach Esterase
 Organophosphates - Ach Esterase
 Neonicotinoids- Nicotine Ach Receptors
 Phenyl pyrazoles- GABA Gated Cl Channel
 Spinosyns-nAchR+GABA Gated Cl Channel
 Avermectins- GABA gated Cl Channel
 Formamidines-Octopamine receptors
Na gated channels
 Diamides –Ryanodine receptors

39. IMPULSE TRANSMISSIO

40. AXONIC TRANSMISSION

41. SYNOPTIC TRANSMISSI

42. SUMMARY & CONCL

43. SUMMARY & CONCLUSION
Insect nervous system is responsible for harmonised behaviour of the insect
Neuron is the structural and functional unit-Dendrites, Axons and Synapses
Glial cells are involved in Blood Brain Barrier concept
Axonic and synaptic conduction
2 types of synapses: Cholinergic and Adrenergic
Neurotransmitters, Neuromodulators and Neurohormones
DDT, Synthetic pyrethroids,Oxadizines acts on Na gated channels
Cyclodienes, Carbamates, Organophosphates, Neonicotinoids, Phenyl
pyrazoles, Spinosyns, Avermectins and Formamidines acts on synaptic cleft

44. REFERENCES
Chapman, R.F.1983.The insects: structure and function, 3rd edn. Cambridge
University Press, Cambridge, 788 pp
Pant, N.C and Swaraj Ghai. 1981. Insect physiology and anatomy, ICAR, New
Delhi
Gerald, K.2002. Cell and Molecular Biology (4th ed.). John Wiley & Sons.864p
Matsumura F.1986.Toxicology of insecticides, 2nd edn. Plenum, New York, 503
pp
Nation, J.L.2001. Insect physiology and biochemistry. Plenum, Boca Raton.
496 pp
Raghumoorthi,K.N.,Balasubramani,V.,Srinivasan,M.R and
Natarajan,N.2011.Insect an Introduction.222P
Scharf, M.E.2003.Neurological effects of insecticides. In:Pimental,D (ed)
Encyclopedia of pest management. Marcel-Dekker, New York.
Srivastava,R.P and Saxena,R.C.1989.Textbook of insect toxicology. Himanshu
publications.166p

45. THANK YOU