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.

The Circulatory Physiology of Helix Pomatia

1973 ◽  
Vol 59 (2) ◽  
pp. 275-282
Author(s):  
BARBARA A. SOMMERVILLE
Keyword(s):  
Anterior Part ◽  
Pulmonary Veins ◽  
Helix Pomatia ◽  
Mantle Cavity ◽  
Heart Beat ◽  
The Body ◽  
Semilunar Valve ◽  
Breathing Cycle ◽  
Pericardial Cavity ◽  
Contraction And Relaxation

1. Helix uses the muscular floor of the mantle cavity to effect several movements. The contraction and relaxation of these muscles is concerned primarily with filling the lung and absorption of oxygen under pressure. The movement is linked with that of the pneumostome, which is open while the floor is depressed and closed when it is raised. An exaggeration of the breathing movements serves to generate the pressure in the cephalopedal haemocoel, which propels the anterior part of the body out of the shell. 2. The rate and regularity of heart-beat vary during the breathing cycle, being slow and irregular when the pneumostome is closed and fast and regular when it is open. 3. Observation of the intact heart of Helix showed changes in the degree of filling indicating an increased blood flow from the haemocoel to the pulmonary veins and heart when the mantle cavity floor was depressed. The total volume of the heart and pericardial cavity was greater at ventricular diastole than at ventricular systole. 4. When the cardiac nerve was severed a significant but inconsistent relationship between the heart activity and the breathing cycle remained. 5. Helix pomatia, H. aspersa, Archachatina, Monodonta and Anion ater all have a semilunar valve on the common aorta directed so as to prevent blood flowing from the aorta into the ventricle. H. pomatia and H. aspersa have a second semilunar valve in the anterior aorta while in Archachatina the anterior aorta passes through a muscular constriction.

The Fate of Thorium Dioxide Injected into the Pedal Sinus of Bullia (Gastropoda: Prosobranchiata)

1965 ◽  
Vol 42 (3) ◽  
pp. 509-519
Author(s):  
A. C. BROWN ◽  
ROSALIND J. BROWN
Keyword(s):  
Mitotic Index ◽  
Sandy Beach ◽  
Mantle Cavity ◽  
The Body ◽  
Thorium Dioxide ◽  
Pericardial Cavity ◽  
Main Pathway ◽  
Heart Wall

1. The removal and ultimate disposal of foreign particles injected into the haemolymph of the sandy-beach snail, Bullia, has been studied by using the radio-opaque dye Thorotrast. 2. Particles are removed by phagocytic haemocytes which migrate by various routes to the outside of the body. The main pathway is through the heart wall into the pericardial cavity and via the renopericardial canal into the lumen of the kidney, from which the cells escape into the mantle cavity. 3. The injection of foreign particles stimulates a marked increase in the haemocyte population and also in the mitotic index. 4. The final discussion integrates the available evidence and a comparison is made between Bullia and other molluscs. The origin of the macrophages is discussed.

scholarly journals Investigation of changes in the skin blood microcirculation when performing the hatha yoga breathing technique

2022 ◽  
Vol 20 (4) ◽  
pp. 33-44
Author(s):  
A. V. Frolov ◽  
Yu. I. Loktionova ◽  
E. V. Zharkikh ◽  
V. V. Sidorov ◽  
A. I. Krupatkin ◽  
...  
Keyword(s):  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Circulatory System ◽  
Low Frequency ◽  
Brain Perfusion ◽  
The Body ◽  
Laser Doppler ◽  
Regulatory Mechanisms ◽  
Doppler Flowmetry ◽  
Breathing Exercises

Introduction. Yoga breathing exercises improve the ability to significantly reduce the respiratory rate. A decrease of the minute respiration volume results in compensatory reactions of the microcirculatory bed caused by changes in the gas composition. The reaction of the regulatory mechanisms of the microvascular bed can be evaluated by the optical non-invasive laser Doppler flowmetry method. The aim of the study was to assess the tissue microcirculation parameter changes in people performing yoga breathing exercises. Materials and methods. 25 volunteers performed yoga breathing exercises at a frequency of 3 times per minute, 2 times per minute, 1.5 times per minute, 1 time per minute for 5 minutes, and free breathing for 6 minutes before and after breathing exercises. Parameters aimed to defin the reaction of skin microcirculation in different body areas were simultaneously recorded in six sites by laser Doppler flowmetry using a distributed system of wearable analyzers. The parameters of tissue microcirculation recorded by the method of laser Doppler flowmetry were: the index of microcirculation (Im), nutritive blood flow (Imn), the amplitude of myogenic (Am), neurogenic (An), endothelial (Ae), respiratory (Ar) and cardiac (Ac) regulation circuits. Results. Yoga breathing exercises led to increase of microcirculation index at all breathing frequencies. Breathing at a frequency of 1.5 and 1/minute leads to a significant increase in nutritional blood flow. Low-frequency breathing exercises lead to an increase in blood pressure at the lowest breathing rates – 1.5/minute and 1/minute. The most significant changes were achieved at the lowest respiration rates (1 and 1.5/minute), that could be associated with hypoxic-hypercapnic mechanisms. Conclusion. The absence of significant changes in microcirculation parameters after low-frequency respiration during measurements in the supraorbital arteries in both groups characterizes the work of homeostatic mechanisms for maintaining brain perfusion in stressful situations for the body (low-frequency types of respiration, hypercapnia and hypoxia). When measured in the extremities, a change in the effect of the circulatory system regulatory mechanisms was observed; along with an increase in skin perfusion and the nutritional component, it can characterize the compensatory reaction of the microcirculation to respiration change.

scholarly journals Contractile pericytes determine the direction of blood flow at capillary junctions

2020 ◽  
Vol 117 (43) ◽  
pp. 27022-27033
Author(s):  
Albert L. Gonzales ◽  
Nicholas R. Klug ◽  
Arash Moshkforoush ◽  
Jane C. Lee ◽  
Frank K. Lee ◽  
...  
Keyword(s):  
Blood Flow ◽  
Circulatory System ◽  
The Body ◽  
Capillary Network ◽  
Transitional Region ◽  
Capillary Networks ◽  
Efficiency And Effectiveness ◽  
The Central Nervous System ◽  
Essential Function ◽  
The Brain

The essential function of the circulatory system is to continuously and efficiently supply the O2 and nutrients necessary to meet the metabolic demands of every cell in the body, a function in which vast capillary networks play a key role. Capillary networks serve an additional important function in the central nervous system: acting as a sensory network, they detect neuronal activity in the form of elevated extracellular K+ and initiate a retrograde, propagating, hyperpolarizing signal that dilates upstream arterioles to rapidly increase local blood flow. Yet, little is known about how blood entering this network is distributed on a branch-to-branch basis to reach specific neurons in need. Here, we demonstrate that capillary-enwrapping projections of junctional, contractile pericytes within a postarteriole transitional region differentially constrict to structurally and dynamically determine the morphology of capillary junctions and thereby regulate branch-specific blood flow. We further found that these contractile pericytes are capable of receiving propagating K+-induced hyperpolarizing signals propagating through the capillary network and dynamically channeling red blood cells toward the initiating signal. By controlling blood flow at junctions, contractile pericytes within a functionally distinct postarteriole transitional region maintain the efficiency and effectiveness of the capillary network, enabling optimal perfusion of the brain.

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.

Sites of encystment by the metacercariae of Echinoparyphium recurvatum in Lymnaea peregra

1992 ◽  
Vol 66 (2) ◽  
pp. 96-99 ◽  
Author(s):  
M. E. Adam ◽  
J. W. Lewis
Keyword(s):  
Intermediate Host ◽  
Experimental Infection ◽  
Mantle Cavity ◽  
The Body ◽  
Visceral Mass ◽  
Pericardial Cavity ◽  
Second Intermediate Host ◽  
Lymnaea Peregra

ABSTRACTExperimental infection of Echinoparyphium recurvatum von Linstow (Digenea: Echinostomatidae) cercariae in the snail second intermediate host Lymnaea peregra Müller shows that metacercarial encystment takes place on the lining of the mantle cavity, pericardial cavity and kidney lumen, with the mantle cavity the most preferred site. All three sites are accessible via the body openings. The metacercariae appear to be more susceptible to encapsulation in the visceral mass than in the cavity of the mantle, pericardium and the lumen of the kidney.

scholarly journals Mantle cavity water oxygen partial pressure (Po2) in marine molluscs aligns with lifestyle

2010 ◽  
Vol 67 (6) ◽  
pp. 977-986 ◽  
Author(s):  
Doris Abele ◽  
Melanie Kruppe ◽  
Eva E. R. Philipp ◽  
Thomas Brey
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Marine Invertebrates ◽  
Circulatory System ◽  
Standard Metabolic Rate ◽  
Mantle Cavity ◽  
The Body ◽  
Arctica Islandica ◽  
Oxygen Gradients ◽  
Aequipecten Opercularis

Marine invertebrates with open circulatory system establish low and constant oxygen partial pressure (Po2) around their tissues. We hypothesized that as a first step towards maintenance of low haemolymph and tissue oxygenation, the Po2 in molluscan mantle cavity water should be lowered against normoxic (21 kPa) seawater Po2, but balanced high enough to meet the energetic requirements in a given species. We recorded Po2 in mantle cavity water of five molluscan species with different lifestyles, two pectinids ( Aequipecten opercularis , Pecten maximus ), two mud clams ( Arctica islandica , Mya arenaria ), and a limpet ( Patella vulgata ). All species maintain mantle cavity water oxygenation below normoxic Po2. Average mantle cavity water Po2 correlates positively with standard metabolic rate (SMR): highest in scallops and lowest in mud clams. Scallops show typical Po2 frequency distribution, with peaks between 3 and 10 kPa, whereas mud clams and limpets maintain mantle water Po2 mostly <5 kPa. Only A. islandica and P. vulgata display distinguishable temporal patterns in Po2 time series. Adjustment of mantle cavity Po2 to lower than ambient levels through controlled pumping prevents high oxygen gradients between bivalve tissues and surrounding fluid, limiting oxygen flux across the body surface. The patterns of Po2 in mantle cavity water correspond to molluscan ecotypes.

Circulation in the Leech, Hirudo Medicinalis L

1988 ◽  
Vol 134 (1) ◽  
pp. 235-246 ◽  
Author(s):  
JAN-PETER HILDEBRANDT
Keyword(s):  
Blood Flow ◽  
Circulatory System ◽  
The Body ◽  
Diastolic Filling ◽  
Dorsal Vessel ◽  
Capillary Networks ◽  
Different Shapes ◽  
Blood Flow Velocities ◽  
Improved Model ◽  
Intravascular Pressure

In the leech, the physiological significance of high-pressure phases (HIP) and lowpressure phases (LOP) of the lateral vessels was studied by intravascular pressure recordings and observation of blood flow in different parts of the circulatory system, and by measurements of the blood flow velocities in the dorsal vessel. Different shapes of the pressure pulses were found in the anterior lateral vessel segments during HIP and LOP phases, according to the different modes of diastolic filling in both phases. Pressure recordings in the lateral abdominal vessels showed the different action of the lateral abdominal sphincters in the HIP and LOP phases of the ipsilateral lateral vessel. The LOP contractions were responsible for the blood supply to the capillary networks of the organs and the body wall, with the possible exception of the intestine. The HIP contractions caused a forward bloodflow within the lateral vessel. In the dorsal vessel, the blood pressure was about 0.9-1.9kPa in different animals. The blood flow was discontinuous with velocities of 0.5-10 mms−1. Average blood flow in the dorsal vessel was 22.9μl min−1. An improved model of the circulation in the leech is presented.

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 Fluid Dynamics of the Bivalve Molluscs, Mya and Margaritifera

1966 ◽  
Vol 45 (2) ◽  
pp. 369-382
Author(s):  
E. R. TRUEMAN
Keyword(s):  
Fluid Dynamics ◽  
High Pressures ◽  
Mantle Cavity ◽  
The Body ◽  
Mya Arenaria ◽  
Bivalve Molluscs ◽  
Muscle System ◽  
Close Interaction ◽  
Antagonistic Muscle ◽  
Pressure Changes

1. A comparison is made of the fluid dynamics of a shallow, yet actively, burrowing bivalve, Margaritifera, with the sessile, deeply buried Mya arenaria. 2. In both adduction produces high pressures (up to ioo cm.) in the mantle and the pericardial cavities which are utilized in Margaritifera for locomotory purposes, in Mya principally for siphonal extension. 3. With siphonal and pedal apertures closed the mantle cavity of Mya is virtually watertight and acts, together with the blood, as the fluid of an antagonistic muscle system, whereby adduction causes siphonal extension and siphonal retraction produces an increase in gape of the valves. The close interaction between these two muscle systems is illustrated by pressure recordings of Mya in the normal buried position. 4. Siphonal movements are shown to be associated with divarication of the valves and accompanying pressure changes. 5. Consideration is given to the haemodynamics of Mya and by contrast with the high pressures involved in locomotion or siphonal movement, maximum pressures of only 2.5 cm. were recorded from the heart, producing a sluggish circulation. The higher pressures derived from the body musculature make an important contribution to movements of the blood.

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