Review: Sperm: Comparative morphology and function related to altered reproductive strategies and fertility in mammals

2018 ◽  
Vol 34 (6) ◽  
pp. 558-565
Author(s):  
Shannon Kate Thompson ◽  
Naseer A. Kutchy ◽  
Samantha Kwok ◽  
Zulfi N.A. Rosyada ◽  
Ikhide G. Imumorin ◽  
...  
Keyword(s):  
Reproductive Strategies ◽  
Comparative Morphology ◽  
And Function

Bivalve Morphology and Function

1985 ◽  
Vol 13 ◽  
pp. 88-101 ◽  
Author(s):  
Adolf Seilacher
Keyword(s):  
Fossil Record ◽  
Soft Part ◽  
Biotic Interactions ◽  
Comparative Morphology ◽  
Internal Constraints ◽  
Developmental Constraints ◽  
Constructional Morphology ◽  
Evolutionary Pathways ◽  
And Function ◽  
New Framework

This part of our course builds on the assumption that evolutionary change, although being stochastic in principle, is channeled by external and internal constraints to such a degree that it becomes quasi-predictable – or at least understandable. On this basis it makes sense to use the old methods of comparative morphology in the new framework of constructional morphology (Seilacher, 1970) in order to recognize patterns and to interpret them as trends and evolutionary pathways. For such an approach, bivalves are particularly suited:1. they deviate little from a common design (for instance they never lost their shell).2. their preservable hard parts adequately reflect the developmental biography of each individual.3. their shell form expresses the compromise between developmental constraints and functional paradigm with little interference from soft part anatomy, physiology and biotic interactions.4. they are diversified enough to provide many examples of parallel adaptations for model testing, particularly if we include the fossil record.

The life-cycle ofProsorhynchus crucibulum(Rudolphi, 1819) Odhner, 1905, and a comparison of its cercaria with that ofProsorhynchus squamatusOdhner, 1905

Parasitology ◽  
1973 ◽  
Vol 66 (1) ◽  
pp. 133-164 ◽  
Author(s):  
R. A. Matthews
Keyword(s):  
Egg Production ◽  
Comparative Morphology ◽  
Scophthalmus Maximus ◽  
Connective Tissues ◽  
Second Intermediate Host ◽  
And Function ◽  
First Time ◽  
Advanced Development ◽  
Conger Conger ◽  
Host Tissues

The adult ofP. crucibulumis redescribed to form a basis for comparison with the cercaria and metacercaria. Particular emphasis is given to the structure and function of the rhynchus, digestive system and reproductive system. Some features, notably prepharyngeal glands and spematophores, have not previously been recorded in this species.The sporocyst and cercaria which were found inMytilus edulisare described for the first time. Out of 6907 mussels examined from Borth Rocks, Cardigan Bay, 0·26% were infected withP. crucibulumand 0·06 % withP. squamatus. The cercaria of the latter is redescribed on a comparative basis with that ofP. crucibulum, to avoid confusion. The two cercariae are clearly distinguished by three features – flame-cell formula, shape of the excretory vesicle, and structure of the tail stem (this being bilobed inP. crucibulumand trilobed inP. squamatus). The significance of the two types of tail in securing attachment to the second intermediate host is discussed.Metacercariae ofP. crucibulumwere obtained experimentally in ‘O’ group specimens ofScophthalmus maximus. Three other species of fish, namelyLimanda limanda, Onus mustelusandGobius minutuswere also successfully infected. The metacercariae did not develop in the following fish:S. rhombus, Pleuronectes platessa, Cottus bubalisandBlennius pholis. Possible mechanisms which might account for host specificity within Pleuronectidae andScophthalmusare suggested.The development of the metacercaria in the connective tissues and musculature ofS. maximuswas followed over a period of 10 months. Within 1 month of infection the hyaline cyst of parasitic origin breaks down, enabling the parasite to feed directly on the host tissues. This feature is thought to account for the advanced development of the metacercaria, which 1 month after infection could clearly be identified with the adult on the basis of comparative morphology, and at 2 months resembles the adult in every respect except the development of the vitellaria. Egg production only occurs within the intestine ofConger conger, the definitive host.

Myelinated Nerve Fixation Techniques: Problems and Comparative Morphology

1990 ◽  
Vol 48 (3) ◽  
pp. 164-165
Author(s):  
James E. Van Over ◽  
Theresa A. Fassel ◽  
Christopher C. Hauser ◽  
Hani S. Matloub
Keyword(s):  
Femoral Nerve ◽  
Comparative Morphology ◽  
Nerve Function ◽  
Sprague Dawley ◽  
Myelinated Nerve ◽  
Sprague Dawley Rats ◽  
Cacodylate Buffer ◽  
Fixation Techniques ◽  
And Function ◽  
Peripheral Nerve Trauma

The morphology of peripheral nerve trauma is necessary to understand the resulting alterations in nerve function. Specific traumas, such as Vibration Syndrome, directly effect nerve function. Earily changes in myelinated axons closely resemble artifact damage due to preperations for electron microscopy. If the correlation between structure and function in traumatic conditions is to be studied, it is imperative to establish a fixation technique that yields consistently good results. It is also important to characterize fixation artifacts and correlate these changes to traumatic damages.Several techniques were compared in an attempt to illustrate the quality of morphology obtained from each fixation. Femoral nerve was microsurgically harvested from Sprague Dawley rats. The nerve was then cut into 1 mm segments and fixed by a variety of methods. The basic fixation was for 2.5 hr in 2.5% glutaraldehyde (GA), followed by 3 10-minute washes in 0.1 M cacodylate buffer pH 7.2, and 2.5 hr post-fixation in 1.0% OSO4 with an additional three washes in buffer.

Comparative Morphology and Function of Hepatic Caeca in Four Enteropneusts

1994 ◽  
Vol 75 (4) ◽  
pp. 371-378 ◽  
Author(s):  
Todd S. Bridges ◽  
Keith H. Woodwick
Keyword(s):  
Comparative Morphology ◽  
And Function

— Zur Morphologie und Funktion des — Helodiden-Aedoeagus (Col.)1

1972 ◽  
Vol 3 (2) ◽  
pp. 81-119 ◽  
Author(s):  
Tord Nyholm
Keyword(s):  
Distal Part ◽  
Comparative Morphology ◽  
Structure And Function ◽  
The Other ◽  
Gradual Change ◽  
Median Lobe ◽  
Initial Form ◽  
The Family ◽  
Different Types ◽  
And Function

AbstractThe structure and function of the aedeagus were investigated in 9 genera of the family Helodidae, most thoroughly in Helodes and Cyphon. On the basis of this investigation, the different types of tegmen and penis represented within the family are described. The tegmen of the Helodidae, which is either entirely devoid of a sclerotized "basal piece" or possesses only rudiments of such, may be divided into three main types; in addition there are a few quite aberrant cases. The penis (median lobe), more interesting from the standpoint of comparative morphology, is extremely diversified. A separation between two main types could however be maintained: one represented by genus Helodes alone, the other by all remaining genera. The Helodes type is more primitive, though at the same time rather specialized in certain details. The second penis type is still more specialized. Its main characteristic is a separate triangular sclerite (a "trigonium") situated ventrally in the distal part of penis. In certain genera it is cleft medially into a pair of moveable appendages ("prosthemata"). A splitting of the penis apex into two lobes ("parameroids") occurs in most species of Helodes, but also among the majority of remaining genera. The evolution of the penis from a supposed primitive initial form towards the Helodes type on one side and the highly specialized type represented by certain species of Cyphon on the other, is outlined and discussed. The importance of a gradual change of the copulatory method for this evolution is particularly stressed. The morphology of the aedeagus as basis for the systematics of the Helodidae is briefly treated. The investigation was also extended to cover representatives of other families, generally regarded as related to the Helodidae. Most of them possess an aedeagus of a rather primitive trilobed type. Deviating from this pattern are the Dascillidae, with the penis completely cleft into one dorsal and one ventral sclerite, and also the Psephenidae. In this family, the penis is supplied with a separate sclerite, apparently homologous with the "trigonium" of the Helodidae and with a similar evolution.

Fine structure of the phasmid of second-stage juveniles of Heterodera schachtii (Tylenchida: Nematoda)

1985 ◽  
Vol 63 (3) ◽  
pp. 534-542 ◽  
Author(s):  
James G. Baldwin
Keyword(s):  
Phylogenetic Analysis ◽  
Fine Structure ◽  
Comparative Morphology ◽  
Heterodera Schachtii ◽  
Sheath Cell ◽  
Second Stage ◽  
Plant Parasite ◽  
Junctional Complexes ◽  
And Function ◽  
Cell Sheath

The phasmid of infective second-stage juveniles of Heterodera schachtii consists of an external pore, cuticle-lined duct, socket cell, sheath cell, and single dendrite receptor. Specimens vary in detail and two discrete types, designated A and B, can be distinguished, with A being larger and relatively more complex. In both types of phasmids the socket cell is roughly cup shaped, envelops the duct, and partially encloses and forms junctional complexes with the sheath cell. The sheath cell fills the cup of the socket cell and occurs near the proximal end of the duct. In the A phasmid the sheath cell is deeply invaginated, forming a receptor cavity which is continuous with a maze of extracellular channels penetrating the cell; secretions accumulate in the channels and receptor cavity. Conversely, the sheath cell of the B phasmid lacks a receptor cavity and is nonsecretory. The sheath cell of both types of phasmid encloses and forms junctional complexes with a single dentritic process. In the A phasmid the process terminates within the receptor cavity whereas in the B type the tip is embedded within the sheath cell. A typical basal body or rootlets were not observed, although a ciliary region with a circle of eight doublets surrounding three or four singlets occurs slightly proximal to the terminus. Knowledge of phasmid structure of H. schachtii provides a basis for study of phasmid development and function in a plant parasite; it also contributes to understanding comparative morphology for phylogenetic analysis of Heteroderidae.

COMPARATIVE MORPHOLOGY OF SALIVARY GLANDS OF HUMANS AND LABORATORY ANIMALS

2020 ◽  
pp. 79-92
Author(s):  
А. А. Мужикян ◽  
В. В. Шедько ◽  
К. О. Заикин ◽  
Я. А. Гущин ◽  
М. Н. Макарова ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Relative Size ◽  
Comparative Morphology ◽  
Structural Features ◽  
Myoepithelial Cells ◽  
Laboratory Animals ◽  
Histological Structure ◽  
Normal Morphology ◽  
And Function ◽  
Treatment Procedures

В статье обобщены и представлены сравнительные данные о нормальной морфологии околоушной, поднижнечелюстной и подъязычной слюнных желез у человека и некоторых лабораторных животных, наиболее часто попадающих в поле зрения морфологов в сфере биомедицинских исследований. Приведенные в данном обзоре сведения показывают схожесть общих принципов строения и функции больших слюнных желез у человека, крысы, мыши, кролика, морской свинки и хомяка. Однако морфология все же достаточно вариабельна, что объясняется, прежде всего, филогенетическими особенностями, связанными с образом жизни человека и животных, а также характером питания. При этом, если анатомически железы преимущественно однотипны, немного различаясь формой и относительными размерами, то более существенным становятся межвидовые отличия в топографическом расположении желез и их микроскопическом строении. Выявленные в ходе исследования различия в составе секрета той или иной железы у человека и изученных животных были обусловлены, главным образом, особенностями строения ацинусов и выводных протоков, особенностями расположения миоэпителиальных клеток в ацинусах и выводных протоках. Таким образом, при доклинических исследованиях лекарственных средств необходимо учитывать не только физиологические особенности саливации и биохимический состав слюны, но и структурные характеристики слюнных желез у разных видов животных. Представленные в данном обзоре сведения о строении, топографии и синтопии слюнных желез могут быть полезны при выполнении хирургических манипуляций, лечебно-диагностических процедурах и моделировании патологий, а знание особенностей гистологического строения позволит избежать затруднений при постановке диагноза, а также неверной интерпретации данных. The article summarizes comparative data on the normal morphology of the parotid, submandibular, and sublingual salivary glands of humans and some laboratory animals most commonly used in biomedical research. The information presented in this review shows the similarity of the general principles of the structure and function of the large salivary glands of humans, rats, mice, rabbits, guinea pigs and hamsters. However, morphology is still quite variable, which is explained, first of all, by phylogenetic features associated with the lifestyle of humans and animals, as well as the type of nutrition. When the anatomy of the glands is principally the same, only slightly different in shape and relative size, the interspecies differences in the topographic location of the glands and their microscopic structure became more significant. The differences in the composition of the secretion of human glands and glands of studied animals were mainly due to the structural features of the acini and excretory ducts and the location of myoepithelial cells in these structures. Thus, in preclinical studies of drugs, it is necessary to take into account not only the physiological characteristics of salivation and the biochemical composition of saliva but also the structural features of the salivary glands of various animal species. The information on the anatomy, topography, and syntopy of the salivary glands presented in this review can be useful in performing surgical procedures, in diagnostic and treatment procedures, and for modeling pathologies. Information about the histological structure will help to avoid difficulties in making a diagnosis, as well as incorrect interpretation of the data.

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