scholarly journals Respiration in the Desert Locust

1960 ◽  
Vol 37 (2) ◽  
pp. 224-236 ◽  
Author(s):  
P. L. MILLER
Keyword(s):  
Carbon Dioxide ◽  
Central Nervous System ◽  
Nervous System ◽  
Schistocerca Gregaria ◽  
Thoracic Ganglion ◽  
Desert Locust ◽  
Maximum Volume ◽  
Metathoracic Ganglion ◽  
The Central Nervous System

1. Normal (dorso-ventral) and three auxiliary ventilating mechanisms (neck, prothoracic and abdominal longitudinal) are described in the non-flying Schistocerca gregaria. 2. Neck and prothoracic ventilation together contribute 14% of the maximum volume of air pumped by the insect. Head ganglion receptors must be stimulated for these forms to appear. 3. The metathoracic ganglion may contain a pacemaker controlling the frequency and amplitude of all forms of ventilation. Each head and thoracic ganglion contains carbon-dioxide receptors which modify the activity of the pacemaker. There is no control from the abdomen in the intact insect, or from receptors outside the central nervous system. 4. Oscilloscope recordings from the isolated central nervous system demonstrate a rhythm, which is modified and possibly initiated by carbon dioxide. 5. It is suggested that carbon dioxide normally provides a more important ventilatory stimulus than oxygen lack.

The Effects of Curare in the Cockroach

1970 ◽  
Vol 52 (3) ◽  
pp. 583-592
Author(s):  
K. J. FRIEDMAN ◽  
A. D. CARLSON
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Motor Nerve ◽  
Nerve Fibres ◽  
Affected Area ◽  
Metathoracic Ganglion ◽  
The Central Nervous System ◽  
Mechanical Studies

1. The nature of insect curarization has been investigated in the cockroach, P. americana. Mechanical studies of leg contraction revealed that dTC, whether injected into the abdomen, injected into a leg or applied to the metathoracic ganglion, produces failure of contraction. 2. The contraction failure caused by injecting dTC into a leg or by applying dTC to the metathoracic ganglion could be reversed by washing the drug out of the affected area. 3. The central nervous system does not appear to be essential for curare-induced contraction failure. The contraction of metathoracic legs deprived of their metathoracic ganglion is abolished in the presence of curare. 4. Since curare produces contraction failure when applied to the metathorax and when injected into a leg, the site of curare action must be present in both these locations. The motor nerve fibres are present in both these locations and it is proposed that contraction failure is due to the action of curare on these fibres.

scholarly journals Tracheal Pulsation in the Flea

1938 ◽  
Vol 15 (3) ◽  
pp. 327-338 ◽  
Author(s):  
G. M. HERFORD
Keyword(s):  
Carbon Dioxide ◽  
Central Nervous System ◽  
Nervous System ◽  
The Other ◽  
The Central Nervous System ◽  
Effect Of Oxygen

1. The phenomenon of tracheal pulsation has been demonstrated in three different species of fleas. 2. It is shown to be independent of the other body rhythms, such as those of the heart and gut. 3. Experiments are described showing the effect of oxygen, carbon dioxide, evacuation and of sectioning the central nervous system. 4. Three theories are put forward to explain the phenomenon, and their relative merits are discussed.

scholarly journals Respiration in the Desert Locust

1960 ◽  
Vol 37 (2) ◽  
pp. 264-278 ◽  
Author(s):  
P. L. MILLER
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Desert Locust ◽  
Tracheal System ◽  
First Instar ◽  
The Central Nervous System ◽  
Cross Links ◽  
Flight Muscles ◽  
Peripheral Action ◽  
Negative Induction

1. During normal flight of the desert locust, auxiliary ventilating mechanisms do not appear, and dorso-ventral abdominal pumping continues at increased frequency and amplitude. When flight stops hyperventilation together with auxiliary forms appear briefly. Removal of the abdomen has shown that pterothoracic and neck ventilation are adequate for sustained flight. 2. Spiracles 2 and 3 open wide during flight: when flight is weaker they make incipient closing movements. A central inhibitory reflex controls their activity, in addition to the peripheral action of carbon dioxide on spiracle 2. The incipient closing movements are shown not to have a functional significance; they are probably the expression of two competing mechanisms, and may arise by negative induction. 3. Spiracles 1 and 4-10 remain synchronized with ventilation, and thereby permit adequate ventilation of the central nervous system. 4. The isolation of the pterothoracic tracheal system is enhanced by the occlusion of two pairs of cross-links. The occlusion of a further three pairs in the prothorax and head ensures that the head has priority on the inspired air. 5. The occlusion of all the cross-links takes place after the first instar, at which time spiracle synchronization first regularly appears and a directed airstream becomes possible. 6. In flight there are two largely independent ventilating systems. The first, a two-way system, ventilates the flight muscles through the open spiracles 2 and 3 and is pumped by the flight movements. The second, a one-way system, ventilates primarily the central nervous system and is pumped by the abdomen, in through the dorsal orifice of spiracle 1, and out through spiracles 5-10.

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