inbound678273795509876287.pdf. presentation

Physio

1. THE
DIGESTIVE
SYSTEM
L06: GENERAL PHYSIOLOGY AND TOXICOLOGY
No part of this lecture topic may be reproduced or copied
by any means, electronic or mechanical, without the
permission of the owner.

2. DIGESTIVE SYSTEM OF INSECTS
•THE DIGESTIVE SYSTEM OF INSECTS IS A HIGHLY
SPECIALIZED AND COMPLEX STRUCTURE THAT
ENABLES THEM TO PROCESS A WIDE VARIETY OF
FOOD SOURCES, RANGING FROM PLANT MATERIAL
TO OTHER INSECTS.
•IT IS DIVIDED INTO SEVERAL KEY REGIONS, EACH
ADAPTED FOR SPECIFIC FUNCTIONS IN DIGESTION
AND NUTRIENT ABSORPTION.

3. IMPORTANCE OF THE INSECT DIGESTIVE
SYSTEM
•The insect digestive system is crucial for survival and
adaptation, enabling insects to exploit diverse food
sources and thrive in various environments.
•It plays a vital role in ecological interactions, influencing
nutrient cycling and food web dynamics.

4. FUNCTIONS OF THE DIGESTIVE
SYSTEM
1. Break Down Food: The digestive
system processes complex food
substances into simpler molecules
through mechanical and enzymatic
action, allowing for efficient
digestion.

5. FUNCTIONS OF THE DIGESTIVE
SYSTEM
2. Absorb Nutrients: Nutrient
absorption occurs primarily in the
midgut, where essential components
like carbohydrates, proteins, and
lipids are taken up into the
hemolymph for energy and growth

6. FUNCTIONS OF THE DIGESTIVE
SYSTEM
3. Excrete Waste: The hindgut is
responsible for removing undigested
materials and waste products from
the body, maintaining homeostasis
and overall health.

8. MAIN COMPONENT OF DIGESTIVE
SYSTEM OF INSECT
FOREGUT
•INCLUDES THE
MOUTHPARTS, PHARYNX,
ESOPHAGUS, AND CROP.
•FUNCTIONS IN FOOD
INGESTION, INITIAL
STORAGE, AND SOFTENING.

9. MAIN COMPONENT OF DIGESTIVE
SYSTEM OF INSECT
MIDGUT
•COMPOSED OF THE
VENTRICULUS AND MAY
INCLUDE CAECA (BLIND
SACS).
•PRIMARY SITE FOR
ENZYMATIC DIGESTION AND
NUTRIENT ABSORPTION.

10. MAIN COMPONENT OF DIGESTIVE
SYSTEM OF INSECT
HINDGUT
•CONSISTS OF THE
INTESTINE, MALPIGHIAN
TUBULES, RECTUM, AND
ANUS.
•RESPONSIBLE FOR WATER
REABSORPTION, WASTE
FORMATION, AND
EXCRETION.

11. ROLE IN DIGESTION AND
ABSORPTION
THE DIGESTIVE SYSTEM WORKS IN A
SEQUENTIAL MANNER:
•FOREGUT PREPARES FOOD FOR DIGESTION.
•MIDGUT BREAKS DOWN FOOD CHEMICALLY
AND ABSORBS NUTRIENTS INTO THE
HEMOLYMPH.
•HINDGUT CONSERVES WATER AND
ELIMINATES INDIGESTIBLE WASTE, ENSURING
NUTRIENT EFFICIENCY.

12. THE
FORGUT

13. FORGUT:
COMPONENTS
Mouth:
•Specialized mouthparts
adapted for different
feeding strategies
(chewing, sucking, lapping).
Pharynx:
•Muscular structure that
aids in swallowing and
moving food into the
esophagus

14. FORGUT:
COMPONENTS
•Esophagus:
A tube that transports
food from the pharynx
to the crop.
•Crop:
Storage organ where
food is temporarily
held and softened
before further
digestion.

15. FORGUT: COMPONENTS
•PROVENTRICULUS
•THE GIZZARD-LIKE STRUCTURE THAT
GRINDS FOOD, AIDING IN THE MECHANICAL
BREAKDOWN OF FOOD PARTICLES.

16. THE MIDGUT
The midgut in insects is an essential part of their digestive system and plays a
key role in their physiology, especially in digestion and nutrient absorption.

17. FUNCTION OF
THE MIDGUT
THE MIDGUT IS RESPONSIBLE FOR THE BREAKDOWN OF FOOD PARTICLES
INTO SMALLER MOLECULES, MAKING THEM EASIER FOR ABSORPTION.
THIS IS WHERE THE BULK OF NUTRIENT EXTRACTION OCCURS, ALLOWING
THE INSECT TO ABSORB ESSENTIAL NUTRIENTS INTO ITS HEMOLYMPH
(THE INSECT EQUIVALENT OF BLOOD), WHICH THEN DISTRIBUTES THEM
THROUGHOUT THE BODY.

18. MIDGUT: COMPONENTS
•GASTRIC CAECA
•THESE ARE FINGER-LIKE
PROJECTIONS LOCATED NEAR THE
JUNCTION OF THE FOREGUT AND
MIDGUT.
•THEIR PRIMARY FUNCTION IS TO
INCREASE THE SURFACE AREA FOR
SECRETION AND ABSORPTION,
ENHANCING THE DIGESTION
PROCESS

19. MIDGUT: COMPONENTS
•Ventriculus
This is the main part of
the midgut where most
digestion and
absorption of nutrients
take place.
•It serves as the "stomach"
of the insect, housing a
variety of digestive
enzymes.

20. PERITROPHIC
MEMBRANE
•THE PERITROPHIC MEMBRANE IS
AN IMPORTANT STRUCTURE
WITHIN THE INSECT MIDGUT,
PLAYING A KEY ROLE IN DIGESTION
AND IMMUNE DEFENSE.

21. PERITROPHIC
MEMBRANE
•THE PERITROPHIC MEMBRANE IS A SEMI-
PERMEABLE MEMBRANE THAT LINES THE
MIDGUT OF MANY INSECTS.
•IT IS MADE UP OF A NETWORK OF PROTEINS
AND CHITIN (A POLYSACCHARIDE) AND
ACTS SOMEWHAT LIKE A FILTER.

22. FUNCTIONS

23. PROTECTION
•THE PERITROPHIC MEMBRANE PROTECTS THE DELICATE MIDGUT
EPITHELIUM (THE LINING OF THE GUT) FROM MECHANICAL DAMAGE
CAUSED BY ROUGH OR HARD FOOD PARTICLES.
•IT ALSO SERVES AS A BARRIER TO PATHOGENS LIKE BACTERIA, FUNGI,
AND PARASITES, PREVENTING THEM FROM DIRECTLY INTERACTING
WITH THE GUT LINING, THUS REDUCING THE CHANCES OF INFECTION.

24. REGULATING NUTRIENT ABSORPTION
•THE MEMBRANE ALLOWS SMALL MOLECULES SUCH AS DIGESTED
NUTRIENTS (AMINO ACIDS, SUGARS, FATTY ACIDS) TO PASS THROUGH,
WHILE LARGER, UNDIGESTED FOOD PARTICLES AND HARMFUL
SUBSTANCES ARE KEPT WITHIN THE GUT FOR FURTHER DIGESTION OR
ELIMINATION.
•THIS REGULATION ENSURES THAT NUTRIENTS ARE ABSORBED EFFECTIVELY
WITHOUT ALLOWING HARMFUL SUBSTANCES TO REACH THE GUT CELLS

25. ENZYMES
INVOLVED IN
THE MIDGUT

26. PROTEASES
•THESE ENZYMES BREAK DOWN
PROTEINS INTO SMALLER
PEPTIDES AND AMINO ACIDS,
WHICH ARE VITAL FOR THE
INSECT’S GROWTH AND TISSUE
REPAIR.

27. LIPASES
•THESE ENZYMES ARE
RESPONSIBLE FOR BREAKING
DOWN FATS INTO FATTY ACIDS
AND GLYCEROL, WHICH ARE
CRITICAL FOR ENERGY
STORAGE AND UTILIZATION.

28. CARBOHYDRASES
•THESE ENZYMES BREAK DOWN
CARBOHYDRATES, SUCH AS
SUGARS AND STARCHES, INTO
SIMPLE SUGARS LIKE GLUCOSE,
WHICH THE INSECT USES FOR
ENERGY.

29. THE HINDGUT
the final section of the insect digestive system and plays a crucial
role in excretion and maintaining water balance.

30. COMPONENTS OF THE
HINDGUT
ILEUM
•THIS IS THE FIRST SECTION OF
THE HINDGUT, RESPONSIBLE
FOR THE BEGINNING STAGES OF
WATER AND ION
REABSORPTION FROM THE
DIGESTIVE WASTE

31. COMPONENTS OF THE
HINDGUT
COLON
COLON CONTINUES THE
REABSORPTION PROCESS,
FURTHER CONCENTRATING
THE WASTE MATERIAL AS
IT MOVES TOWARDS THE
RECTUM.

32. COMPONENTS OF THE
HINDGUT
RECTUM
THIS IS THE FINAL SECTION OF THE
HINDGUT WHERE WATER AND SALTS
ARE REABSORBED. THE RECTUM
CONTAINS SPECIALIZED CELLS
(RECTAL PADS) THAT ARE HIGHLY
EFFICIENT IN RECOVERING WATER
AND IONS BEFORE WASTE IS
EXCRETED.

33. FUNCTION OF THE HINDGUT:
WATER AND SALT REABSORPTION:
•THE HINDGUT PLAYS A VITAL
ROLE IN OSMOREGULATION,
THE PROCESS OF MAINTAINING
THE INSECT'S INTERNAL
WATER AND IONIC BALANCE.

34. FUNCTION OF THE HINDGUT:
WASTE FORMATION AND
EXCRETION
•ONCE WATER AND SALTS ARE
REABSORBED, THE REMAINING
UNDIGESTED MATERIALS ARE
COMPACTED INTO FECES, WHICH
ARE THEN EXCRETED THROUGH
THE ANUS.

35. IMPORTANCE IN OSMOREGULATION
OSMOREGULATION REFERS TO THE CONTROL OF
WATER AND ION CONCENTRATIONS WITHIN THE
BODY, A CRITICAL PROCESS FOR MAINTAINING
PROPER CELLULAR FUNCTION.

36. IMPORTANCE IN OSMOREGULATION
THE HINDGUT IS ESSENTIAL IN PREVENTING DEHYDRATION
BY REABSORBING WATER AND SALTS, THUS MAINTAINING
THE INSECT'S INTERNAL BALANCE DESPITE VARYING
ENVIRONMENTAL CONDITIONS.

37. ROLE OF SYMBIOTIC MICROORGANISMS IN
INSECTS
•SYMBIOTIC MICROORGANISMS PLAY A CRITICAL ROLE IN
THE DIGESTIVE SYSTEMS OF MANY INSECTS,
PARTICULARLY HERBIVORES, BY HELPING THEM PROCESS
COMPLEX COMPOUNDS THAT THEY CANNOT DIGEST ON
THEIR OWN.

38. MICROORGANISMS IN THE DIGESTIVE
TRACT
•INSECTS, PARTICULARLY THOSE WITH PLANT-BASED DIETS, OFTEN HAVE
SYMBIOTIC BACTERIA, FUNGI, AND PROTOZOA LIVING IN THEIR DIGESTIVE
TRACT.
•THESE MICROORGANISMS CAN BE FOUND IN VARIOUS PARTS OF THE GUT,
WITH MANY CONCENTRATED IN THE HINDGUT OR SPECIALIZED
FERMENTATION CHAMBERS.

39. FUNCTION OF SYMBIOTIC MICROORGANISMS
BREAKING DOWN COMPLEX COMPOUNDS
HERBIVOROUS INSECTS CONSUME PLANTS THAT ARE RICH
IN CELLULOSE, A COMPLEX CARBOHYDRATE THAT IS
DIFFICULT FOR ANIMALS TO DIGEST BECAUSE THEY LACK
THE NECESSARY ENZYMES.

40. FUNCTION OF SYMBIOTIC MICROORGANISMS
FERMENTATION
IN MANY HERBIVOROUS INSECTS, MICROORGANISMS HELP
FERMENT THE PLANT MATERIAL, RELEASING ESSENTIAL
NUTRIENTS SUCH AS VOLATILE FATTY ACIDS AND OTHER BY-
PRODUCTS THAT THE INSECT CAN UTILIZE.

41. FUNCTION OF SYMBIOTIC MICROORGANISMS
NUTRIENT SYNTHESIS
SOME MICROORGANISMS SYNTHESIZE IMPORTANT VITAMINS
(E.G., B VITAMINS) AND OTHER NUTRIENTS THAT ARE
OTHERWISE UNAVAILABLE IN THE INSECT'S DIET,
CONTRIBUTING TO THE OVERALL NUTRITION OF THE INSECT.

42. EXCRETORY SYSTEM: MALPIGHIAN TUBULES
The Malpighian tubules are a key component of the insect excretory system,
playing a vital role in waste removal and maintaining water and ion balance
(osmoregulation).

43. LOCATION
MALPIGHIAN TUBULES ARE
LOCATED AT THE JUNCTION
BETWEEN THE MIDGUT AND
HINDGUT, WHERE THEY
EXTEND INTO THE INSECT’S
BODY CAVITY (HEMOCOEL).
THEY FLOAT FREELY IN THE
HEMOLYMPH, THE INSECT
EQUIVALENT OF BLOOD.

44. FUNCTION
WASTE REMOVAL
THE PRIMARY FUNCTION
OF MALPIGHIAN TUBULES
IS TO FILTER METABOLIC
WASTES, PARTICULARLY
NITROGENOUS WASTES,
FROM THE HEMOLYMPH.

45. FUNCTION
OSMOREGULATION
MALPIGHIAN TUBULES ALSO
PLAY A CRITICAL ROLE IN
MAINTAINING THE INSECT’S
OSMOTIC BALANCE BY
REGULATING THE
CONCENTRATION OF WATER
AND IONS (SUCH AS
SODIUM AND POTASSIUM)
IN THE HEMOLYMPH.

46. SUMMARY
•FILTERING METABOLIC WASTE FROM THE INSECT’S HEMOLYMPH.
•OSMOREGULATION, MAINTAINING THE BALANCE OF WATER AND
SALTS.
•CONVERTING NITROGENOUS WASTE INTO URIC ACID, ENABLING
INSECTS TO EXCRETE WASTE EFFICIENTLY WHILE CONSERVING
WATER.

47. GREEN