4250lec19 - Ecology and Evolutionary...
Transcript of 4250lec19 - Ecology and Evolutionary...
11/5/2015
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The Hemocoele/Mixocoele:• Not a true coelom, which
is lined with mesoderm (small remnants only)
• Instead, it’s lined with ectoderm & endoderm
• Hemolymph is thus separated from organs by basement membrane (amorphous muco-polysaccharide + collagen – very complex)
An open system• small size, short diffusion
distances
• no blood gasses to distribute
The insect circulatory systemDorsal vessel
HeartAorta
Dorsal vessel
OstiumPERICARDIALSINUS
PERIVISCERAL
SINUS
PERINEURAL
SINUS
PERINEURAL SINUS
PERICARDIAL SINUS
PERIVISCERAL SINUS
Ostium
(dorsal septum)
(ventral septum)
Alarymuscle
Not:
heartPERICARDIAL SINUS
PERIVISCERALSINUS
pleuro-sternalboundary
PERINEURALSINUS
ventral nerve cord
ventralseptum
dorsalseptum
alarymuscle
septum (diaphragm)
fenestra
X
The insect circulatory system: some details
os = ostium; v = valve (Diptera)
gut
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Pattern of circulation
wing heart
excurrent ostium incurrentostium
nervecordheart
ganglionleg
extension ofventral septum
legdorsal vessel
(aorta)
leg ampulla
antenna
antennalampulla
wingampulla
one-wayvalve of
incurrentostium
dorsal & ventral septa with fenestrae at edges
ampulla
ampulla
aorta (dorsal vessel)
brain
Accessory pulsatile organs (APO)in a cockroach
distal vessel
proximal vessel
dilator muscleof ampulla accessory
dilatormuscle
esophagus
aortal dilation
eye
corpus cardiacum& corpus alatum
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Circulation in the wing venation of three beetles
Cupedidae
Carabidae
Scarabaeidae
Lateral segmental vessels
heart septum
vessel
Some roaches & mantids(Dictyoptera)
2 thoracic, 4 abdominal
4 abdominal
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alary (aliform)muscle
aorta ordorsal vessel
dorsaldiaphragm
tergo-sternalmuscle
heart
segmental orlateral vessel
incurrentostium
segmental orlateral vessel
Segmental vesselsin Blaberus(2 pairs thoracic,
4 pairs abdominal)
Thermoregulation and the “rete mirabile”
heartaorta
convolutions (rete mirabile)
Bees & wasps(Hymenoptera)
rete mirabile
(116.6° F)
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Bumble bee circulation& thermoregulation
rete mirabile
(radiator)(tidal air)
Centralization(shortening) of the heart
heart
aorta
3 pairs of ostia
certain Diptera & mayflies(Ephemeroptera)
Number of pairs of ostia:• 3 to 9 in mayflies & roaches• 3 in higher Diptera• 1 in a highly specialized mayfly
Drosophila melanogaster
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alary (aliform)muscle
aorta ordorsal vessel
dorsaldiaphragm
tergo-sternalmuscle
heart
segmental orlateral vessel
incurrentostium
segmental orlateral vessel
Number &
placement of ostia;
nature of alary muscles
Ex. = ancestral condition
Heartbeat:• Heartbeat and alary
contraction synchronous
• Heartbeat and alary contraction asynchronous
• 14–150 beats/minute (stag beetle vs. house fly)
• Varies with O2, temperature, diet, life stage (or instar)
• myogenic not neurogenic
• also from neurosecretions of corpora cardiaca, etc.
Hemopoietic organ (“lymph glands”)
Prohemocyte
Prohemocyte
Hemolymph (“blood”):• Clear & colorless or yellowish
or greenish
• pH 6–7.5
• Na+, Cl-, Ca++, K-
• 5–40% of body weight **
• Filled with fats, organic acids, amino acids, carbs, proteins, & pigments
• 1k–275k cells/mm3
** 7–8% of a person’s weight is blood
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Cells in the hemolymph (hemocytes)
ProhemocytePlasmatocytes
Granularhemocytes
Cystocytes(coagulocytes)Spherule cell
Adipohemocyte
Oenocytoid
vermiform cell
BASOPHILIC(hematoxylin)
ACIDOPHILIC(eosin)
Yeager (1945) described 10 classes with 32 types of blood cells
neg– pos+
epithelium
basementmembrane
cuticle
oenocyte
cytoplasmicstrand
Pericardial cells(can be in phagocytic organs)
Oenocytes(epicuticle, wax & cement, enzymes)
(170-180µ)
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Blood Function:
Chrysomelidae (leaf beetle)
Coccinellidae (lady beetle)
Hemolymph functions:• Water storage
• Osmoregulation (organics)
• Transport (e.g. hormones)
• Food storage (e.g. trehalose, a disaccharide)
• Respiration (at the cellular level of diffusion)
• Protection
• reflex bleeding
• clotting
• phagocytosis
• encapsulization
• immune response (innate not “learned”)
• antifreeze (glycols)
• Mechanical (hydrostatic)
• Thermoregulation
Wound-healing and clotting
nematode parasite
entrance wound
Diptera larva
a blood clot
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Immune function of blood: Encapsulization
Hydrostatic functions of blood
Eversible male genitalia Molting & wing expansion
Hydrostatic skeleton
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Fat body3 masses
on each sideof body
fat body cells (= trophocytes,urocytes, and mycetoctyes)
(may also surround gut)
GUT
Fat body functions:• Food storage (trophocytes)
• Secretion, synthesis, & catabolism (metabolic)
• Waste storage (urocytes) –storage excretion as uric acid
• “Real” excretion
• Nutritional endosymbiosis (mycetocytes)
• Bioluminescence
Coleoptera: Lampyridae
Muscles: categories
Labium of a cricket
Metathoracic leg of a grasshopper
levator (extensor)
depressor
extrinsicmuscle
intrinsicmuscle
intrinsicmuscles
extrinsicmuscle
Muscle contraction:1. Nerve impulse
2. Secretion of acetylcholine
3. voltage change across muscle membrane
4. chemical changes in muscle:
a. flooding in of Ca++
b. changes bonding of actin & myosin
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Muscle
Ultrastructure
sarcolemma mitochondria
fibrils (myofibrils)
basementmembrane
nucleus
nerve/musclejunction
neurallamella
glialsheath
nerveaxon T-tubule
I -band
A-band
H-band
A-band
I -band
Z-disc
muscle fiber(or muscle cell)
actin filament
myosin filament
actinmolecule(filament)
myosinfilament
headsforming
cross-bridges
Flightmuscle
Visceralmuscle
I -band
Z-disc
Sar
com
ere
Muscle
Ultrastructure II
(the sarcomere isthe contractile element)
Muscle fiber (or muscle cell)
Fibril (myofibril)Sarcomere
X-sec. Myofilaments