Prothorax
Ocelli Proto cerebrum Deuterocerebrum
Antenna Trito cerebrum
C Cardiaca C Aliata
Mouth
Esophagus
Prothoracic gland
Thoracic ganglia
Ventral nerve chain
Ventral glands
FIGURE 11-19   Generalized central nervous system and endocrine systems of an insect. The nervous system contains three major groups of neurosecretory cells: the median (mnc), lateral (lnc), and subesophageal (snc), which are connected with the corpora cardiaca via NCCI and NCCII nerves; phasmid insects have additional neurosecretory cells in the tritocerebrum (tnc) connected to the corpora cardiaca via NCCIII nerves. The corpora cardiaca are a neurohemal organ for the release of neurosecretions; they arise from stomodeal ectoderm (shown by black arrows). The corpora aliata are classical endocrine glands that arise from ectodermal invaginations near the maxillae (black arrows). The prothoracic gland is another important classical endocrine gland; it arises (black arrow) from ventral glands (which are present in primitive insects).   (Modified from Jenkin 1962; after Knowles 1963.)                                                                                                 >
Neurosekretorické buňky mozku
Corpus
cardiacurrí
(CC)
Corpus^ allatum" (CA)
'PITH Nízká koncentrace /        vOř
JH^kukla       I          ^prothorakální žláza
Vysoká koncentrace JH*larva
L             Ekdyson (ec)
Larva      *%
Dospělec
Obr.   14.5.  Hormonálni řizeni svlékání hmyzu.
______.Produkce  ekdysonu  z  prothorakálnich  žláz   je
^^>         stimulována protoracikotropním hormonem (PTTH)
^V)V€MLM\ HPKnaKJ „^^a^^^*^ v mozku a vylévaného z kar-diálních tělisek (CC). Ekdyson iniciuje svlé-kací děje. Zda se vytvoří kutikula kuklová nebo opět larvální, rozhodne koncentrace ju-venilního hormonu (JH). Ten je produkován v tělískách přilehlých   (CA).
PTTH neurosecretory cells have cell bodies in the brain...
Bíain
. ..and axon terminals in the corpora allata
The corpora allata
also contain
non neural endocrine
cells that secrete JH.
Corpus cardiacujn
Corpus allalum
I'll II
Prolhoracic gland
The prothoracic gland secretes ecdysone.
-
The tracheae are branched tubes that extend from openings called spiracles in the body wall.
Inka cells, located on
the tracheae, secrete PETHandETH-
TABLE 14.6  JVIajor hormones and neurohormones that control insect metamorphosis
Hormone
Type of molecule
Type of signal
Site of secretion
Major target tissue
Action
Prothoracicotropic
hormone (PTTH)
Ecdysone (molting hormone)
Protein (-5000 molecular weight)
Steroid
Neuroendocrine
Endocrine
Brain, with axon terminals extending to corpora allata
Prothoracic glands in larva/nymph; ovary in adult
Prothoracic glands
Epidermis in
larva/nymph; fat body in adult
Juvenile hormone (JH)	Terpene (fatty-acid derivative)	Endocrine	Corpora allata	Epidermis in larva/ nymph; ovary in adult
Eclosion hormone (EH)	Peptide	Neuroendocrine	Brain	Inka cells, possibly others
Pre-ecdysis triggering hormone (PETH)	Peptide	Endocrine	Inka cells of tracheae	Neuronal circuits in brain
Ecdysis triggering hormone (ETH)	Peptide	Endocrine	Inka cells of tracheae	Neuronal circuits in brain
Bursicon	Large protein (-35,000 molecular weight)	Neuroendocrine	Brain and nerve cord	Cuticle and epidermis
Initiates molting (ecdysis) by stimulating release of ecdysone from prothoracic glands
When activated to 20-hydroxyec-dysone, promotes cellular mechanisms to digest ofd cuticle and synthesize new one; stimulates production of yolk proteins in adult
Opposes formation of adult structures and promotes formation of larval/nymphal structures; functions as a gonadotropin in the adult
Promotes PETH and ETH secretion from Inka cells
Coordinates motor programs to prepare for shedding the cuticle
Coordinates final motor programs for escaping from old cuticfe
Tans and hardens new cuticle
Sources-: After Randall, Burggren, and French 2002;and Žitňan et al. 2003.