Here I would like to inform you on physiology of impulse transmission in insects. I hope this would increase your understanding -------------------------------------------------

1. WEL COME
SSNAIK
TNAU

2. TERM PAPER PRESENTATION
ON
ENT 803
ADVANCES IN INSECT PHYSILOGY
CPPS,TNAU,
COIMBATORE-641 003
NAME :SABHAVAT SRINIVASNAIK
ID. NO: 2015 800 506
YEAR: I Ph. D (2015)
DEPT.: AGRICULTURAL ENTOMOLOGY

3. INTRODUCTIONPART I
PART II
PART III
INDEX
INSECT NERVOUS SYSTEM
(STRUCTURE)
IMPULSE TRANSMISSION
(FUNCTION)

4. INTRODUCTIONPART I

5.  Protozoa to Chordata- highest evolved organism- human being
 A unicellular organism -single cell – functions- No 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
Introduction…
(Pant and Ghai, 1981)

6. Introduction…
Living organism
-RF Chapman, 1998 and J. Simpson, 2013
Structure Function
PhysiologyNervous system
Impulse transmission

7. INSECT
NERVOUS
SYSTEM
PART II
-
struc
ture

8. INSECT NERVOUS SYSTEM
Soma/Cell body
Nucleus
Dendrite
Axon
Glial cells-N. lamella
Protoplasm
Collateral
Arborisations
Stimuli
Neurons – ganglion
Strands of neurons-nerve
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 impaulses from the cell body to
other neurons, muscles, and organs

9. Introduction…
i) Synaptic cleft
(Chemical transmission)
Vesicles
20-25 nm
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

10. Chapman, 1998
GLIAL CELLS- “BLOOD BRAIN BARRIER CONCEPT”
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
Used during development of CNS
Used in making repairs

11. INSECT NERVOUS SYSTEM
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
A. STRUCTURAL BASIS

12. INSECT NERVOUS SYSTEM
B. FUNCTIONAL BASIS
Internuncial (association) neurons : Unipolar
cells (often with several collaterals and/or
branching axons) (conduct signals within
CNS)
Motor neuron: conducts impulse from CNS to
effector organs-Efferent neurons,Efferent neurons,
monopolar, situated in the ganglia andmonopolar, situated in the ganglia and
conduct impulse from CNS to effectorconduct impulse from CNS to effector
organs like muscles and glandsorgans like muscles and glands
Afferent (sensory) neurons : Bipolar or
multipolar cells have dendrites -
associated with sense organs or receptors
(carry information towards CNS).

13. INSECT NERVOUS SYSTEM
Nervous system divided in to three major sub-systems
i. Central nervous system (CNS)
ii. Visceral nervous system (VNS)
iii. Peripheral nervous system (PNS)

14. INSECT NERVOUS SYSTEM
i) Central 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

15. INSECT NERVOUS SYSTEM
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
1. Brain

16. INSECT NERVOUS SYSTEM
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.

17. House fly
Silverfish

18. INSECT NERVOUS SYSTEM
ii. Visceral nervous system/sympathetic
consists of three separate systems
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

19. INSECT NERVOUS SYSTEM
iii. Peripheral Nervous Systemiii. Peripheral Nervous System
 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

20. IMPULSE
TRANSMISSION
PART III
-
Function/Ph
ysiology

21. 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

22. IMPULSE TRANSMISSION…
1. Axonic conduction
Positive ions
Negative ions
Sodium channels
Axon
Donnan equilibrium

24. Visual/ Chemical/ Mechanical
Sensory neuron
Environment
Insect
1. Axonic conduction……….

25. IMPULSE TRANSMISSION…
1. Axonic conduction
1.Resting potential The state during which no nerve impulse is being
conducted although the neuron is capable of doing so
2. Action potential The state during which the neuron is actively involved in
conducting a nerve impulse
3. Recovery potential The state during which the neuron is unable to conduct a
nerve impulse since it must recover from the last impulse

26. Resting neuron
 A charge difference is maintained
 Na+ is pumped out and K+ is pumped in
 So exterior become (+) and interior become (–)
 This is called resting membrane potential
Restoring neuron
 K+ channel opens ( Na K ATP ase)
 K+ ions goes out
 So again interior become (–) and exterior become (+)
1. Axonic conduction

27. 2. Synoptic transmission

28. 2. Synoptic transmission

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

30. dendrite
receives information
cell body
contains nucleus &
organelles
axon
transmits nerve impulse
axon terminal
transmits to next neuron
synapse
junction between two neurons
Directionofnerveimpulse

31. INETARCTION OF DIFFREENT SYSTEMS

32. Please keep watch......
AXONIC TRANSMISISON

33. References
• Chapman, R. F. 1998. The insects: structure and function. Cambridge
university press.
• N. C. Pant and Miss Swaraj Ghai. 1981. Insect physiology and anatomy,
ICAR, New Delhi
• Internet

34. Thank You
Presented by
Sabhavat Srinivasnaik
ID.NO:2015800506
I Ph. D (Agrl. Entomology)
Keep the farmers smile…… beca
we are
scientific----------------------------------
-