INTERNAL STRUCTURES OF INSECT

1. INTERNAL STRUCTURES OF INSECT

2. DIGESTIVE SYSTEM • Related with i) digestion; ii) absorption; 3) water balance; 4) excretion • Main division: 1) foregut 2) midgut 3) hindgut

3. FOREGUT • Mouth: mandibles break down food to small pieces. inside mouth salivary glands excrete enzymes to: 1) aid breakdown of food; 1) add moisture • Phariynx: region that is circled by muscles – force food from mouth to esophagus • Esophagus: at tube-like connecting the crop(tembolok)

4. FOREGUT • Crop: storage area for food. Insect eats beyond repletion, so need storage before pushed into midgut • Proventriculus: sometimes grinding organ (with small teeth; sometimes only as a valve between fore & midgut

5. FOREGUT • MOUTH  PHARYNX  ESOPHAGUS ENZYMES FROM SALIVARY GLANDS CROP (TEMBOLOK) PROVENTRICULUS

6. MIDGUT • Ventriculus: Enzymes breakdown food chemically, initiate nutrient uptake (absorption amino acid, carbo, lipids, vit., mineral) • Single layer epithelial cells, convoluted (berlingkar) & folded: provide absorption space • The lining is peritrophic membrane: 1) as a sieve (penapis) which allows enzymes & b/down poducts to move thru it. 2) protect midgut • Gastriscaeca (sekumgastrik): involved in harbouring m/organisms

7. Function of midgut?? • 1) • 2)

8. HINDGUT • Water absorption and waste excretion • Waste products are concentrated and packaged for excretion • Consists of 1) intestine (ileum+colon); 2)rectum; 3) anus • From intestine pass to rectal pads: further salt & water retained

9. Malphigian tubules: junction of mid & hindgut • Function: kidneys of insect: absorbs salts, water and wastes from the surrounding hemolymph. The wastes then are released from the organism in the form of solid nitrogenous compounds. • Waste in form of uric acid (dry and nontoxic) • Feces Leaf chewing insects very distinctive – take the shape of the intestine

10. Function: • 1) filter hemolymph • 2) recover lost metabolites, water & salt • 3) excrete waste • Ileumkolon  rectum rectum anus (waste in form of acid uric- dry & nontoxic • T. Malphigian border of mid & hindgut

11. Insect Nutrition • Diverse • Some insects eat variety plants spp. Or maybe restricted to single plant • Eg: Manduca sexta: eats Solanaceae (tobacco, tomato,potatoes)

12. What do insects need? • 1)FAT (=LIPID) • For hormone production • 2) CARBOHYDRATE(SUGAR) • For energy • 3) PROTEINS • Need amino acid, for development (eg arganine, leucine, lysine etc) • 4) Vitamins • Vitamin A for vision • Vit B1 (thiamine:energy),B2 (riboflavin:energy),B6(pyridoxine:amino acid metabolism)

14. RESPIRATORY SYSTEM(TRACHEAL SYS.) • Gas exchange • Insect blood doesn’t contain haemoglobin • Has massive plumbing with tubes carry air to cells • GAS (outside)spiracles tracheal trunk (pimary trachea) 2o & 3otrachea tracheol

16. SPIRACLE • Air comes thru • Opening on the body • Open and close (have muscles) to minimize water loss • Mechanism: • Co2 high in body muscles relax  spricales open Co2 escape + Oxygen in • O2 in body approx. outside  muscles recover  spricales pull shut

17. TRACHEAL TRUNK • Spiral of tough filaments (resist collapse) • Branches to secondary & tertiary trachea • Smaller tubes : tracheols • Tracheols are intimately associatied with cells • Eg: muscles cells: tracheols enter deep into the cells: close to mitchondria (where o2 needed) • O2 diffuses from tracheols to cells, Co2 from tissues to tracheols

18. AQUATIC ADAPTATION • Some without spiracles, they have modified gills • The gills with thin layer of cuticles with lots of tracheoles • Some have ‘snorkel’ : a tube with spiracles- the tube above water for air intake

20. CIRCULATORY SYSTEM • No arteries, veins or capillaries • The organ sits in open cavity filled with insect blood called ‘HEMOLYMPH’

21. FUNCTIONS • Transport of nutrient and hormones • Storage for substance like acid amino • Water reservoir • Hydrostatic pressure for movement • Protection from foreign organism which invade

22. HEMOLYMPH • Consists of: • 1) 90% PLASMA:   • a watery fluid: usually clear, sometimes greenish or yellowish • high concentrations of amino acids, proteins, sugars, and inorganic ions.   • 1) 10% HEMOCYTES: • various cell types • involved in the clotting reaction, phagocytosis, and/or encapsulation of foreign bodies.   • does NOT contain hemoglobin (or red blood cells).   • Oxygen is delivered by the tracheal system, not the circulatory system.

23. DORSAL VESSELS (SALUR DARAH) • HEART • divided segmentally into chambers • that are separated by valves (ostia) to ensure one-way flow of hemolymph.   • A pair of alary muscles are attached laterally to the walls of each chamber.   • Peristalsis: these muscles force the hemolymph forward from chamber to chamber • AORTA • In front of the heart, • lacks valves or muscle.   • continues forward to the head and empties near the brain.   • Hemolymph bathes the organs and muscles of the head as it emerges from the aorta • then back over the alimentary canal,through the body until it reaches the abdomen and re-enters the heart.

24. PERICARDIAL SINUS DORSAL DIAPHRAGM PERIVISCERAL SINUS PERINEURAL SINUS VENTRAL DIAPHRAGM To facilitate circulation of hemolymph, the body cavity is divided into three compartments:

26. REMEMBER!!!! • DOES NOT CARRY OXYGEN!!! • So blood flow is not critical like us human HEMOLYMPH FROM BODYENTER OSTIA( HEART MUSCLE RELAXPERISTALSIS BATHES HEAD AND ALL ORGANS & BACK TO ABDOMEN AORTA (LACK MUSCLES & VALVE) MOVE FORWARD CHAMBERS

27. SENSORY SYSTEM • Exoskeleton need sensory organ • To evaluate changes in the environment • First info receive by SENSILLA: specialized cuticullar structure equipped with nerve cells and neuron • Usually hair-like

28. PHOTORECEPTOR • Light/vision • Vision can be restricted in insects • Some to differentiate light from dark • Some can distingusih shape & images • 3 types of photoreceptor: • 1) ocelli • 2)stemmata • 3) compound eye

29. OCELLI • Many adults and nymph of hemimetabolous • Related to flight, most flightless insects don’t have • Sensitive to light intensity • Cannot perceive images or shape

30. STEMMATA • Only on larvae of holometabolous • Larvae of holometabolous almost never have compound eyes • capable only of detecting light. • cannot focus or allow reception of images.

31. COMPOUND EYES • Consists of numerous hexagon shaped facets/lense called ommatidium • 2 major components: 1) lenses; 2) light receiving syst.

32. MECHANISM • Lens guide light to a group of pencil-shaped like cells tie up together called rhabdom • These photoreceptor absorp the light then convert to eletrical signal which is conveyed in brain • RHODOPSIN: chemical pigment to absorb light, with the help of Vitamin A

33. Insect eyes cannot focus until sharp image • The best insect eye resolves less detail than human eye • But sensitive in movement • So what they perceive ? Shape & form • Broken shapes are differentiated solid

34. Some can see colours • Pigments in ommatidia sensitive to different array of colours • Insect sees from 700 nm (red) range down to 3o0 (violet) • Bees see flower blue

35. CHEMORECEPTOR • Smell/taste (olfaction) • Well developed compared to photoreceptor • A) Close range, • chemical signals in solution form (taste) • Found in legs • Eg: honeybee: taste sweet, sour, salty and bitter • Eg: red admiral butterfly 200x sensitive to sugar than hman tongue

36. CHEMORECEPTOR • B) distant range (jarak jauh) • Airborne chemical signal = smell • Found on antennae • detect odours great distance, miles • Useful for finding mates • PHEROMONES: chemical signals • Smells much more sensitive than human

37. MECHANORECEPTOR • Touch/pressure/vibration or sound • Sense of pressure/touch usually on legs: often contact to ground • Many insects are deaf: sound not really important • Tympanum: on legs for cricket, on abdomen for cicadas • Hair sensilla in antenna: eg Johnston’s organ

39. THERMORECEPTOR • Changes in temperature • Bed bug use thermoreceptor to locate warm blooded verteb.

40. HYGRORECEPTOR • changes of humidity • Blood feeding parasites • Warm, moist breath good indicator of host

42. NERVOUS SYSTEM • INSECT SIMPLE CREATURE???? • What happen when you attack the fly????? • 3 components • 1)brain central • 2)ventral nerve cord nervous system (CNS) • 3)peripheral nervous system (extend outside the central nervos system to serve the limbs and organs • Each of the components consists millions of neurons

43. VENTRAL NERVE CORD

44. WHAT IS NEURON? • Nerve cell • For information transfer • Composed of • 1) dendrite (enter the cell body) • 2) cell body (nucleus found) • 3) axon( leaving the body) • Repeating unit of neuron form a nervous system • Individual nerve cells connect with one another through special junctions, called synapses.

45. 3 categories, depending on their function within the nervous system: • 1) Afferent (sensory) neurons • bipolar or multipolar cells • dendrites associated with sense organs or receptors.   • carry information toward the central nervous system. A D

46. 2) Efferent (motor) neurons • unipolar cells • conduct signals away from the central nervous system • stimulate responses in muscles and glands. A D

47. 3) Interneurons • unipolar cells (often with several collaterals and/or branching axons) that conduct signals within the central nervous system.

49. BRAIN • Nerve cord to the head is the BRAIN • 3 pairs of ganglia region: • 1)protocerebrum: associated with vision; they innervate the compound eyes and ocelli. 2)deotocerebrum: pair lobes with sensory pathway to antennae • 3)tritocerebrum: lobes with connective to 1st ganglion of ventral nerve cord

50. VENTRAL NERVE CORD • 1) subesophageal ganglion • innervates mandibles, maxillae, and labium, hypopharynx, salivary glands, and neck muscles. • 2) thoracic ganglia • ) control locomotion by innervating the legs and wings. • 3) abdominal ganglia • control movements of abdominal muscles.