scholarly journals Fine Structure and Function in Stentor polymorphus

1958 ◽  
Vol 4 (6) ◽  
pp. 807-830 ◽  
Author(s):  
J. T. Randall ◽  
Sylvia Fitton Jackson
Keyword(s):  
Fine Structure ◽  
Living Organism ◽  
Structural Features ◽  
The Body ◽  
Interconnected System ◽  
Fine Structure And Function ◽  
The Individual ◽  
And Function ◽  
Theoretical Considerations ◽  
Vacuolated Cytoplasm

The fine structure of the ciliate Stentor has been studied by means of the electron microscope and the results have been correlated with observations made on the living organism by means of light microscopy; special reference has been made to structural features which may be responsible for contraction and extension in Stentor. Descriptions have been given of the structure of the macronucleus, the vacuolated cytoplasm, mitochondria and the pellicle; a detailed study has also been made of the adoral membranelles. About 250 membranelles encircle the peristomal cap and each is composed of 3 rows of cilia, with 20 to 25 cilia in each row; a fibrillar root system connected with the membranelles depends into the endoplasm for about 20 µ and each is essentially in the shape of a fan, the terminal ends of each root bifurcating to connect to neighbouring roots. The membranelles thus form a cohesive unit and this morphological arrangement may have a bearing on the motion and coordination of the whole system. Two structural features extending throughout the length of the animal have been identified per cortical stripe in the body wall of Stentor; first, km fibres lying just beneath the pellicle are composed of stacks of fibrillar sheets and are identical with the birefringent fibres observed in the living animal. The individual fibrils of the sheets are in turn connected to the kinetosomes of the body cilia; thus the km fibres are homologous to kinetodesmata. Secondly, M bands lie beneath the km fibres and form an interconnected system in contact with the surrounding vacuolated cytoplasm; the thickness of the M bands is greatest at the base of a contracted animal. The contractile and extensile properties of these organelles have been discussed in the light of experimental results and theoretical considerations.

Genealogy of the Cerebral Subject

Being Brains ◽  
2017 ◽  
Author(s):  
Fernando Vidal ◽  
Francisco Ortega
Keyword(s):  
Nineteenth Century ◽  
Functional Neuroimaging ◽  
The Body ◽  
Self Help ◽  
Brain Structure And Function ◽  
Cerebral Subject ◽  
The Individual ◽  
And Function ◽  
Cerebral Self ◽  
The Brain

The first chapter proposes to trace the distant roots of the cerebral subject to the late seventeenth century, and particularly to debates about the seat of the soul, the corpuscularian theory of matter, and John Locke’s philosophy of personal identity. In the wake of Locke, eighteenth century authors began to assert that the brain is the only part of the body we need to be ourselves. In the nineteenth century, this form of deterministic essentialism contributed to motivate research into brain structure and function, and in turn confirmed the brain-personhood nexus. Since then, from phrenology to functional neuroimaging, neuroscientific knowledge and representations have constituted a powerful support for prescriptive outlooks on the individual and society. “Neuroascesis,” as we call the business that sells programs of cerebral self-discipline, is a case in point, which this chapter also examines. It appeals to the brain and neuroscience as bases for its self-help recipes to enhance memory and reasoning, fight depression, anxiety and compulsions, improve sexual performance, achieve happiness, and even establish a direct contact with God. Yet underneath the neuro surface lie beliefs and even concrete instructions that can be traced to nineteenth-century hygiene manuals.

scholarly journals FINE STRUCTURE OF THE EYE OF A CHAETOGNATH

1964 ◽  
Vol 21 (1) ◽  
pp. 115-132 ◽  
Author(s):  
Richard M. Eakin ◽  
Jane A. Westfall
Keyword(s):  
Fine Structure ◽  
Photoreceptor Cell ◽  
Sensory Cell ◽  
Pigment Cell ◽  
Evolutionary Relationship ◽  
Cell Process ◽  
Rods And Cones ◽  
Fine Structure And Function ◽  
And Function ◽  
Relationship Of

Electron microscopy reveals a star-like pigment cell at the center of the eye of the arrow-worm, Sagitta scrippsae. Between the arms of the pigment cell are clusters of photoreceptor cell processes, each process consisting of: (1) a tubular segment containing longitudinally arranged microtubules about 500 A in diameter and 20 µ in length; (2) a remarkable conical body, composed of cords and large granules, situated at the base of the tubular segment; and (3) a connecting piece which, like that of rods and cones, connects the process with the sensory cell proper and through which runs a fibrillar apparatus consisting of nine peripheral double tubules. Beneath the connecting piece lies a typical centriole with a striated rootlet. The receptor cell process is deeply recessed into the sensory cell which may possess a corona of microvilli at its inner surface. A nerve fiber arises from the outer end of the cell and passes into the optic nerve. Additional features are some supporting cells, an external layer of flattened epithelial cells, and an over-all investment of basement membrane and thick fibrous capsule. The fine structure and function of these elements of the eye are discussed in relation to earlier studies with the light microscope. The ciliary nature of the photoreceptor cell process in S. scrippsae points to a probable evolutionary relationship of chaetognaths to echinoderms and chordates.

Fine structure and function of kupffer cells

1990 ◽  
Vol 14 (3) ◽  
pp. 237-246 ◽  
Author(s):  
Robert S. McCuskey ◽  
Patricia A. McCuskey
Keyword(s):  
Fine Structure ◽  
Kupffer Cells ◽  
Structure And Function ◽  
Fine Structure And Function ◽  
And Function

Fine structure and function of hepatocytes during development

1990 ◽  
Vol 14 (2) ◽  
pp. 92-105 ◽  
Author(s):  
Shinsuke Kanamura ◽  
Kazuo Kanai ◽  
Jun Watanabe
Keyword(s):  
Fine Structure ◽  
Structure And Function ◽  
Fine Structure And Function ◽  
And Function
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