Factors affecting the heart activity and blood pressure of the swan mussel Anodonta cygnea

1975 ◽  
Vol 62 (2) ◽  
pp. 341-355
Author(s):  
B. A. Sommerville
Keyword(s):  
Heart Beat ◽  
Cavity Pressure ◽  
Heart Activity ◽  
Shell Valve ◽  
Anodonta Cygnea ◽  
Visceral Ganglion ◽  
Factors Affecting ◽  
Pericardial Cavity ◽  
Valve Movement ◽  
Pressure Changes

1. The rate of heart beat increased with temperature and was three times as high in the active as in the inactive animal. 2. The rate of shell valve movement rose and the rate of heart beat fell when the foot was extended. 3. The rates of heart beat and shell valve movement decreased when the water was saturated with carbon dioxide. This heart response remained when the visceral ganglion was destroyed. 4. Ventricular contraction occurred simultaneously over the shole chamber. The passage of blood into the posterior aorta could be restricted by the protuberances on its wall. 5. Pericardial cavity pressure rose by about 5 cm H2O at shell valve adduction and 0–25--0-6 cm H2O at ventricular diastole. 6. Pulse pressure changes of 0–25--0-6 cm H2O occurred in the auricle and 1--3 cm H2O in the ventricle and anterior aorta.

The Circulatory Physiology of Helix Pomatia

1973 ◽  
Vol 59 (2) ◽  
pp. 291-303
Author(s):  
BARBARA A. SOMMERVILLE
Keyword(s):  
Blood Flow ◽  
Helix Pomatia ◽  
Circulatory System ◽  
Mantle Cavity ◽  
Heart Beat ◽  
The Body ◽  
Pericardial Cavity ◽  
Circulatory Physiology ◽  
Pressure Changes ◽  
Characteristic Pressure

1. The pressure changes in the mantle cavity and various parts of the circulatory system of Helix pomatia have been measured. 2. There are characteristic pressure changes associated with the breathing movements, the pattern depending upon the point at which the measurement was made and, in the case of the heart, the position of the body at the time of recording. These pressure changes fail mainly within the range 2-8 cm H2O. 3. The pressure changes associated with contraction of the heart chambers fall within the range 1-2 cm H2O in pulmonary vein and auricle, 10-32 cm H2O in the ventricle, 1-3 cm H2O in the aorta and 1-8 cm H2O in the pericardial cavity. 4. An increased frequency and amplitude of heart beat was associated with an increased rate of blood flow.

Heart action of the freshwater bivalve Anodonta anatina during activity

1976 ◽  
Vol 65 (3) ◽  
pp. 685-698
Author(s):  
A. R. Brand
Keyword(s):  
Heart Rate ◽  
Systolic Pressure ◽  
Respiratory Control ◽  
Regulatory System ◽  
Heart Beat ◽  
Heart Activity ◽  
Freshwater Bivalve ◽  
Normal Behaviour ◽  
Muscle System ◽  
Pericardial Cavity

1. Heart action of Anodonta anatina (L.) was investigated by recording the electrocardiogram (ECG), heart impedance, and ventricular and pericardial cavity pressure during different aspects of the normal behaviour. The contribution of mechanical and nervous mechanisms in controlling changes in heart action is discussed. 2. Pressure recordings were generally more reliable than the other methods and it is suggested that pericardial pressure pulses indicate the stroke volume output of the ventricle. 3. During spontaneous periods of prolonged shell closure there was an initial small increase in heart activity followed by a large reduction in both heart rate and systolic pressure, indicating that total heart output was considerably reduced. When the shell reopened, heart rate increased very rapidly with an initial overshoot of the normal level; systolic pressure increased more slowly with no overshoot. 4. These major changes in heart activity appear to be associated with respiratory changes and are controlled largely by the nervous regulatory system, but some minor rhythmic variations in the amplitude of heart beat are probably caused by mechanical factors. 5. Characteristic patterns of change in heart action were recorded during burrowing. These appear to result from haemodynamic changes associated with the muscular movements of the digging cycle. Control of the heart by the nervous regulatory system is apparently of much greater importance in relation to respiratory control than in relation to the haemodynamic functioning of the fluid-muscle system in locomotion.

scholarly journals Effect of virtual mass force on prediction of pressure changes in condensing tubes

2012 ◽  
Vol 16 (2) ◽  
pp. 613-622 ◽  
Author(s):  
Hamid Saffari ◽  
Nemat Daur
Keyword(s):  
Experimental Data ◽  
Annular Flow ◽  
Fluid Model ◽  
Mass Force ◽  
Virtual Mass ◽  
Vertical Pipe ◽  
Pressure Drops ◽  
Factors Affecting ◽  
Pressure Changes ◽  
Significant Factors

Three-fluid model is used to calculate the pressure drops in a vertical pipe with the annular flow pattern for condensing steam. The three-fluid models are based on the mass, momentum, and energy balance equations for each of the fluid streams in the annular flow. There are discrepancies between predictions of three-fluid model for pressure drops and the experimental data for pressure drops when using the avail?able correlations for steam-film interfacial friction. The correlation by Stevanovic et at provides good match with experimental data, but it does not take into account some important factors affecting the pressure drops in its three-fluid model. One of these significant factors which is considered in the three fluid model used in the present paper is virtual mass (added mass) force term. Inclusion of the virtual mass force improves the pressure drop predictions such that they agree much better with the experiments.

scholarly journals Shell valve movement response of dark false mussel, Mytilopsis leucophaeta, to chlorination

1997 ◽  
Vol 31 (12) ◽  
pp. 3187-3190 ◽  
Author(s):  
Sanjeevi Rajagopal ◽  
Gerard Van Der Velde ◽  
Henk A. Jenner
Keyword(s):  
Shell Valve ◽  
Movement Response ◽  
Valve Movement

Factors affecting the accuracy of esophageal balloon measurement of pleural pressure in dogs

1992 ◽  
Vol 72 (1) ◽  
pp. 383-388 ◽  
Author(s):  
G. Dechman ◽  
J. Sato ◽  
J. H. Bates
Keyword(s):  
Soft Tissues ◽  
The Body ◽  
Pleural Pressure ◽  
Factors Affecting ◽  
Occlusion Test ◽  
Tracheal Pressure ◽  
Esophageal Balloon ◽  
Residual Capacity ◽  
Pressure Changes ◽  
Spontaneously Breathing

Simultaneous measurement of esophageal and tracheal pressures during an occluded inspiratory effort was used to assess the accuracy of the esophageal balloon for measuring pleural pressure in dogs. Esophageal balloons were inserted in five mongrel dogs, and an occlusion test was performed with the balloon tip 5, 10, 15, 20, and 25 cm above the esophageal sphincter; at lung volumes of functional residual capacity (FRC) and FRC + 600 ml; and in supine and right- and left-side lying postures. The protocol was repeated in paralyzed animals. This time the occlusion test was performed by injecting air into a plethysmograph to change the body surface pressure, simulating pressure changes produced by respiratory efforts in spontaneously breathing animals. In 47% of the tests in spontaneously breathing dogs, the slope of esophageal vs. tracheal pressure varied greater than 10% from unity. After paralysis the slope did not vary greater than 5% from unity under any circumstance. These data indicate that the poorer performance of the occlusion test in nonparalyzed dogs is due to active tension in the walls of the esophagus and stress induced in the intrathoracic soft tissues by the descent of the diaphragm during a breathing effort.

The Mechanism of Blood Circulation in Anodonta Anatina (L.) (Bivalvia, Unionidae)

1972 ◽  
Vol 56 (2) ◽  
pp. 361-379 ◽  
Author(s):  
A. R. BRAND
Keyword(s):  
Blood Circulation ◽  
Venous Return ◽  
Systolic Pressure ◽  
Circulatory System ◽  
Peripheral Circulation ◽  
Body Movements ◽  
Ventricular Systolic Pressure ◽  
Pericardial Cavity ◽  
Blood Circulatory System ◽  
Pressure Changes

1. The structure of the blood circulatory system of Anodonta anatina is described and the haemodynamics have been investigated by recording pressures in the ventricle, auricle, pericardial cavity and pedal haemocoele at rest and during burrowing. 2. Ventricular systolic pressure is usually 2-4 cm in the resting animal; during burrowing it increases to between 6 and 10 cm and this is sufficient to maintain the blood supply to the foot for most of the digging cycle. 3. Auricular and pericardial cavity pressures fall rapidly (by about 1·0 cm) during ventricular systole, confirming the operation of a volume-compensating mechanism for refilling the heart. 4. High peaks of pressure at spontaneous phasic adduction and during the adduction and retraction movements of the digging cycle are generated equally throughout all parts of the animal enclosed within the shell and do not create large gradients of pressure in the haemocoele; the longer duration of these pressure peaks in the pedal haemocoele produces small transient gradients of pressure which could result in the movement of blood out of the pedal haemocoele. 5. At spontaneous phasic adduction contraction of the pedal muscles may assist the flow of blood from the pedal haemocoele. There is some evidence that Keber's valve limits blood flow from the pedal haemocoele during active burrowing. 6. Although body movements may assist the movement of blood through parts of the peripheral circulation, they do not generate a high venous return pressure. The form of the circulatory system effectively isolates the heart from pressure changes in the pedal haemocoele.

Muscle–Nerve Sympathetic Activity in Man. Relationship to Blood Pressure in Resting Normo- and Hyper-Tensive Subjects

1978 ◽  
Vol 55 (s4) ◽  
pp. 387s-389s ◽  
Author(s):  
G. Sundlöf ◽  
B. G. Wallin
Keyword(s):  
Blood Pressure ◽  
Negative Correlation ◽  
Sympathetic Activity ◽  
Diastolic Pressure ◽  
Pressure Fluctuations ◽  
Blood Pressure Level ◽  
Heart Beat ◽  
Arterial Blood ◽  
Muscle Nerve ◽  
Pressure Changes

1. Simultaneous recordings of multi-unit muscle nerve sympathetic activity and arterial blood pressure were made in 29 subjects, 17 healthy and 12 hypertensive. The neural activity, quantified by counting the number of pulse-synchronous sympathetic bursts in the mean voltage neurogram (burst incidence), was plotted against blood pressure. The effect of spontaneous temporary blood pressure fluctuations was studied by correlating different pressure parameters of individual heart beats to the occurrence of a sympathetic burst. 2. Between subjects there were marked differences in burst incidence but no correlation was found to interindividual differences in blood pressure level. 3. When for each heart beat the occurrence of a burst was correlated to different pressure parameters there was a close negative correlation to diastolic, a low correlation to systolic, and an intermediate negative correlation to mean blood pressure. 4. In a given subject, when comparing heart beats with the same diastolic pressure, the occurrence and the amplitudes of the sympathetic bursts were higher during falling than during rising pressure. This directional dependence of the muscle—nerve sympathetic activity was slightly more pronounced in the hypertensive group, but this was considered secondary to the hypertension. 5. The findings of an intimate correlation with dynamic variations in blood pressure and the absence of correlation to the static blood pressure suggest that the sympathetic outflow to skeletal muscle is of importance for buffering acute blood pressure changes but has little influence on the long-term blood pressure.

scholarly journals Neural Control of Heart Beat in the African Giant Snail, Achatina Fulica Ferussac: II. Interconnections Among the Heart Regulatory Neurones

1987 ◽  
Vol 129 (1) ◽  
pp. 295-307
Author(s):  
YASUO FURUKAWA ◽  
MAKOTO KOBARASHI
Keyword(s):  
Neural Control ◽  
Ganglion Cells ◽  
Electrical Coupling ◽  
Cerebral Ganglion ◽  
Heart Beat ◽  
Synaptic Connections ◽  
Achatina Fulica ◽  
Visceral Ganglion ◽  
The Central Nervous System ◽  
African Giant Snail

The synaptic connections between identified heart regulatory neurones were examined in the central nervous system of the African giant snail, Achatina fulica Férussac. Two cerebral ganglion cells, the dorsal right and left cerebral distinct neurones (d-RCDN and d-LCDN), were found to have excitatory connections with several neurones in the suboesophageal ganglia (the periodically oscillating neurone, PON, the tonically autoactive neurones, TAN, TAN-2 and TAN-3, and the visceral intermittent firing neurone, VIN) and the connections are probably monosynaptic. VIN had a weak electrical coupling with PON. VIN inhibited TAN, TAN-2 and TAN-3, and the connections were considered to be monosynaptic. At the same time, TAN, TAN-2, TAN-3 and the visceral ganglion neurone (VG1) inhibited PON and VIN although the connections are unlikely to be monosynaptic. Another neurone in the pedal ganglia, the dorsal left pedal large neurone (d-LPeLN), was found to excite PON, VIN, TAN, TAN-2 and TAN-3. These connections were not monosynaptic. These results are interpreted in relation to heart regulation in Achatina.

scholarly journals Some Experiments on the Function of the Pericardial Organs in Crustacea

1953 ◽  
Vol 32 (1) ◽  
pp. 175-192 ◽  
Author(s):  
J. S. Alexandrowicz ◽  
D. B. Carlisle
Keyword(s):  
Heart Rhythm ◽  
Heart Beat ◽  
Unusual Structure ◽  
Pericardial Cavity ◽  
Isolated Hearts ◽  
Cancer Pagurus ◽  
Fluorescence Reaction ◽  
Related Compounds ◽  
Distinct Increase ◽  
Reaction Characteristic

Experiments with isolated hearts of various Crustacea (Cancer pagurus, Maia squinado, Homarus vulgaris, Squilla mantis) were performed in order to test the postulated secretory function of the pericardial organs (nerve trunks of unusual structure lying in the pericardial cavity). Tests were made with extracts of these elements added to the fluid perfusing isolated hearts.In Cancer, Homarus and Squilla the extracts caused a distinct increase in amplitude and frequency of the heart beat, and their effect proved to be very similar to that produced by adrenaline and noradrenaline tested on the same hearts. In Maia the extracts produced an increase in amplitude and decrease in frequency of the heart beat.Extracts of the pericardial organs of Cancer pagurus gave the fluorescence reaction characteristic of adrenaline and related compounds. Blood taken from the pericardial cavity gave the same reaction, but that taken from the leg arteries did not.It is assumed that the function of the pericardial organs in the Crustacea consists in liberating, through fine neuropile-like terminations of the nerve fibres, some hormone passing with the blood into the heart and producing on it a stimulating effect. There is certain evidence that the pericardial organs might release a second hormone having an inhibitory and perhaps also a stabilizing effect on the heart rhythm.

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