Blind-ending tubules and branching patterns of the rat ductuli efferentes

1992 ◽  
Vol 232 (3) ◽  
pp. 423-431 ◽  
Author(s):  
Robert F. Guttroff ◽  
Paul S. Cooke ◽  
Rex A. Hess
Author(s):  
John W. Roberts ◽  
E. R. Witkus

The isopod hepatopancreas, as exemplified by Oniscus ascellus. is comprised of four blind-ending diverticula. The regenerative cells at the tip of each diverticula differentiate into either club-shaped B-cells, which serve a secretory function, or into conoid S-cells, which serve in the absorption and storage of nutrients.The glandular B-cells begin producing secretory material with the development of rough endoplasmic reticulum during their process of maturation from the undifferentiated regenerative cells. Cytochemical and morphological data indicate that the hepatopancreas sequentially produces two types of secretory material within the large club-shaped cells. The production of the carbohydrate-like secretory product in immature cells seems to be phased out as the production of the osmiophilic secretion was phased in as the cell matured.


Zoomorphology ◽  
2021 ◽  
Author(s):  
Stephan Scholz ◽  
Torben Göpel ◽  
Stefan Richter ◽  
Christian S. Wirkner

AbstractIn this study, the hemolymph vascular system (HVS) in two cambarid crayfishes, i.e. the Marbled Crayfish, Procambarus virginalis Lyko, 2017 and the Spiny Cheek Crayfish, Faxonius limosus (Rafinesque, 1817), is investigated in regard of areas of non-genetic phenotypic variation. Despite their genetic identity, specimens of P. virginalis show variability in certain features of the HVS. Thus, we describe varying branching patterns, sporadic anastomoses, and different symmetry states in the vascular system of the marbled crayfish. We visualize our findings by application of classical and modern morphological methods, e.g. injection of casting resin, micro-computed tomography and scanning electron microscopy. By comparing our findings for P. virginalis to the vasculature in sexually reproducing crayfishes, i.e. F. limosus and Astacus astacus, we discuss phenotypic variation of the HVS in arthropods in general. We conclude that constant features of the HVS are hereditary, whereas varying states identified by study of the clonal P. virginalis must be caused by non-genetic factors and, that congruent variations in sexually reproducing F. limosus and A. astacus are likely also non-genetic phenotypic variations. Both common causal factors for non-genetic phenotypic variation, i.e., phenotypic plasticity and stochastic developmental variation are discussed along our findings regarding the vascular systems. Further aspects, such as the significance of non-genetic phenotypic variation for phylogenetic interpretations are discussed.


Author(s):  
Sandeep Bagla ◽  
Rachel Piechowiak ◽  
Abin Sajan ◽  
Julie Orlando ◽  
A Diego Hipolito Canario ◽  
...  

Abstract Purpose: Genicular artery embolization (GAE) has been proposed as a novel technique to treat painful synovitis related to osteoarthritis. An in-depth understanding of the genicular arterial anatomy is crucial to achieve technical success and avoid nontarget-related complications. Given the lack of previous angiographic description, the present study analyzes genicular arterial anatomy and proposes an angiographic classification system. Materials and Methods: Angiographic findings from 41 GAEs performed during two US clinical trials from January 2017 to July 2019 were reviewed to analyze the anatomical details of the following vessels: descending genicular artery (DGA), medial superior genicular artery (MSGA), medial inferior genicular artery (MIGA), lateral superior genicular artery (LSGA), lateral inferior genicular artery (LIGA), and anterior tibial recurrent artery (ATRA). The diameter, angle of origin, and anastomotic pathways were recorded for each vessel. The branching patterns were classified as: medially, M1 (3/3 arteries present) vs M2 (2/3 arteries present); and laterally, L1 (3/3 arteries present) vs L2 (2/3 arteries present). Results: A total of 91 genicular arteries were embolized: DGA (26.4%), MIGA (23.1%), MSGA (22.0%), LIGA (14.3%), and LSGA/ATRA (14.3%). The branching patterns were: medially = M1, 74.4% (n = 29), M2, 25.6% (n = 10); and laterally = L1, 94.9% (n = 37), L2, 5.1% (n = 2). A common origin for MSGA and LSGA was noted in 11 patients (28.2%). A direct DGA origin from the popliteal artery was reported in three patients (7.7%, n = 3). Conclusions: A thorough understanding of the geniculate arterial anatomy is important for maximizing postprocedural pain reduction while minimizing complications, procedure time, and radiation exposure during GAE.


Author(s):  
A. J. Southward

SUMMARYThe jelly-fish Aurelia aurita possesses external and internal ciliary currents that play a large part in food collection and in the transport of food, reproductive products and excretory matter.Adults feed on relatively small organisms, which are collected in mucus on all external surfaces and eventually passed to the inner surfaces of the oral arms.The inner surfaces of the oral arms bear two ciliated tracts which operate simultaneously in opposite directions. The lateral tract carries food materials proximally towards the gastric pouches, but is capable of rejecting inedible matter. The basal tract carries excretory matter distally, away from the gastric pouches and canals to the exterior.Rejection reactions are also found in the gastric pouches and radial canals, parts of which have currents moving in opposite directions on the roof and on the floor. These opposing currents appear to be derived from the system in the ephyra stage, where the circulation in the wide gastric cavity and blind-ending canals is maintained partly by centripetal currents on the floor and centrifugal currents on the roof.The directions of the main currents remain constant throughout the larval stages to the adult, although slight variations are introduced by morphological changes. The currents also remain the same during spawning, when the eggs and sperm leave the gastric pouches by the normal excretory path.Many of the ciliary currents found in Aurelia are present in other semaeostome and rhizostome medusae, but only in Aurelia do the umbrella surfaces and currents play a large part in food collection.


Hand ◽  
2021 ◽  
pp. 155894472199973
Author(s):  
Shruthi Deivasigamani ◽  
Ali Azad ◽  
S. Steven Yang

Background The abductor pollicis longus (APL) is classically described as inserting on the base of the first metacarpal. This study analyzed APL insertional anatomy and quantified the size of various elements of the extensor side of the thumb to determine associations with size and function. Methods Twenty-four formalin-preserved upper limbs were dissected. The insertional anatomy of the APL, extensor pollicis brevis, and extensor pollicis longus were characterized, and the capacity of APL tendon slips to perform palmar abduction of the first digit was quantified based on slip size and insertion. Results The mean number of APL tendon slips observed was 2.3. Abductor pollicis longus insertion sites included the base of the first metacarpal, trapezium, abductor pollicis brevis, and opponens pollicis. Only 4 specimens had a solitary metacarpal slip, while 83% of specimens had insertions onto at least 1 thenar muscle. A total of 62.5% of APL tendons exhibited some form of branching that we categorized into “Y” and “Z” patterns. In assessing palmar abduction capacity, we found that APL tendon slips inserting into the base of the first metacarpal were larger in cross-sectional area than nonmetacarpal slips and reproduced complete palmar abduction of the digit in the absence of nonmetacarpal slips. The abduction capacity of APL tendon slips was not correlated to the cross-sectional area. Conclusions There is significant variability in APL tendon slips, branching patterns, and insertional anatomy. These findings provide further understanding of the function of the APL and its surgical implications.


2010 ◽  
Vol 518 (22) ◽  
pp. 4649-4673 ◽  
Author(s):  
Anushree Tripathi ◽  
Lucía Prensa ◽  
Carolina Cebrián ◽  
Elisa Mengual

2000 ◽  
Vol 78 (12) ◽  
pp. 1531-1544 ◽  
Author(s):  
Eric Nicolini ◽  
Daniel Barthélémy ◽  
Patrick Heuret

The growth and branching patterns of the main axis of 6-year-old sessile oak, growing in a natural regeneration in the north of France, were analysed each year retrospectively according to three increasing canopy density conditions: large gap, small gap, and dense canopy. Increasing gap size is associated with an increase in the total height, basal diameter, branching probability, and global polycyclism rate of the trees. At the growth unit or annual shoot level, from dense canopy to large gaps these botanical entities also show an increase in their total length, number of nodes, polycyclism, and branching rate as well as mean number of branches and mean internode length. A discussion of our results revealed some endogenous features of growth and branching patterns in young sessile oak trees. It is also shown that increasing canopy density generally tends to reduce the expression of the endogenous architectural sequence of differentiation of young sessile oak trees. Young trees growing below dense canopy thus seem to be "delayed" in their sequence of differentiation and appear to be in a "waiting" status, whereas young trees growing in large gaps exhibit an architecture very similar to trees growing in nurseries under nonlimiting growth conditions.Key words: architecture, Quercus petraea, growth, morphology, canopy density.


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