The eco-physiological significance of the circulatory mechanics of Lymnaea stagnalis L.

The ultrastructure of the heart and kidney of the pilid gastropod mollusc Marisa cornuarietis, with special reference to filtration throughout the Architaenioglossa

“…The variation in the structure of the wall of the ventricle in the three groups may be correlated with factors unrelated to filtration, such as the degree of activity of a particular species and the need for a relatively high blood pressure (Dale, 1974), but may nevertheless have a secondary effect on filtration. In more active snails with a higher blood pressure the musculature of the ventricle will be well developed, and the possibility of ultrafiltration through its wall may be sacrificed to achieve maximum efficiency of the ventricle as a pump, Its contribution to filtration appears to vary in the three architaenioglossan families.…”

The ultrastructure of the heart and kidney of the pilid gastropod mollusc Marisa cornuarietis, with special reference to filtration throughout the Architaenioglossa

“…The variation in the structure of the wall of the ventricle in the three groups may be correlated with factors unrelated to filtration, such as the degree of activity of a particular species and the need for a relatively high blood pressure (Dale, 1974), but may nevertheless have a secondary effect on filtration. In more active snails with a higher blood pressure the musculature of the ventricle will be well developed, and the possibility of ultrafiltration through its wall may be sacrificed to achieve maximum efficiency of the ventricle as a pump, Its contribution to filtration appears to vary in the three architaenioglossan families.…”

The anatomy of neurosecretory neurones in the pond snail Lymnaea stagnalis (L)

“…Some of these factors may well have contributed to the development of peripherally releasing terminals in the Dark Green Cells. Blood pressure in Lymnaea is low (Dale 1974) and although the dynamics of blood flow through the various tissues is unknown, circulation through the tissues of the mantle and the foot is likely to be sluggish, particularly in the mantle, which has no arterial supply (Bekius 1972;W alter 1969). Release into the central neurohaemal areas surrounding the brain would be inefficient if a rapid onset of action of the hormone was necessary, since blood from the head sinus returns to the heart, via the kidney-lung portal system, before circulating to the foot, and to reach the mantle would have to circulate first through the heart and viscera into the visceral sinus, which is the only source of blood to the mantle.…”

The ultrastructure of the heart and kidney of the pilid gastropod mollusc Marisa cornuarietis, with special reference to filtration throughout the Architaenioglossa

“…The variation in the structure of the wall of the ventricle in the three groups may be correlated with factors unrelated to filtration, such as the degree of activity of a particular species and the need for a relatively high blood pressure (Dale, 1974), but may nevertheless have a secondary effect on filtration. In more active snails with a higher blood pressure the musculature of the ventricle will be well developed, and the possibility of ultrafiltration through its wall may be sacrificed to achieve maximum efficiency of the ventricle as a pump, Its contribution to filtration appears to vary in the three architaenioglossan families.…”

The anatomy of neurosecretory neurones in the pond snail Lymnaea stagnalis (L)

“…Some of these factors may well have contributed to the development of peripherally releasing terminals in the Dark Green Cells. Blood pressure in Lymnaea is low (Dale 1974) and although the dynamics of blood flow through the various tissues is unknown, circulation through the tissues of the mantle and the foot is likely to be sluggish, particularly in the mantle, which has no arterial supply (Bekius 1972;W alter 1969). Release into the central neurohaemal areas surrounding the brain would be inefficient if a rapid onset of action of the hormone was necessary, since blood from the head sinus returns to the heart, via the kidney-lung portal system, before circulating to the foot, and to reach the mantle would have to circulate first through the heart and viscera into the visceral sinus, which is the only source of blood to the mantle.…”

The ultrastructure of the heart and kidney of the pilid gastropod mollusc Marisa cornuarietis, with special reference to filtration throughout the Architaenioglossa

“…The variation in the structure of the wall of the ventricle in the three groups may be correlated with factors unrelated to filtration, such as the degree of activity of a particular species and the need for a relatively high blood pressure (Dale, 1974), but may nevertheless have a secondary effect on filtration. In more active snails with a higher blood pressure the musculature of the ventricle will be well developed, and the possibility of ultrafiltration through its wall may be sacrificed to achieve maximum efficiency of the ventricle as a pump, Its contribution to filtration appears to vary in the three architaenioglossan families.…”

The anatomy of neurosecretory neurones in the pond snail Lymnaea stagnalis (L)

“…Some of these factors may well have contributed to the development of peripherally releasing terminals in the Dark Green Cells. Blood pressure in Lymnaea is low (Dale 1974) and although the dynamics of blood flow through the various tissues is unknown, circulation through the tissues of the mantle and the foot is likely to be sluggish, particularly in the mantle, which has no arterial supply (Bekius 1972;W alter 1969). Release into the central neurohaemal areas surrounding the brain would be inefficient if a rapid onset of action of the hormone was necessary, since blood from the head sinus returns to the heart, via the kidney-lung portal system, before circulating to the foot, and to reach the mantle would have to circulate first through the heart and viscera into the visceral sinus, which is the only source of blood to the mantle.…”