The rapid development of molecular biology and genetics has led to renewed interest in embryology, comparative embryology, and studies of the relations between ontogeny and phylogeny. In fact, genes have been identified which are involved in the formation of shapes and structures, and it is becoming apparent that their primary morphological expressions are conspicuously similar in different species. The primarily identical shapes do not become diversified until advanced individualization of embryos, and it is here that it is possible to employ the knowledge of comparative embryology, the branch of science engaged in the study of the development and differentiation of tridimensional structures in different animal groups. However, comparative embryology has been neglected during the past decades, as its development has appeared to have been completed. In our opinion, the decreased interest in comparative embryology has been caused by the fact that often the time factor was not or could not be respected. In fact, in the case of embryos of wild animals even their ontogenetic age and sometimes the duration of intrauterine development are unknown.

Sex differences are observed in various physiological, behavioral, and psychic functions, including reproductive behavior, aggres sion, emotions, and cognition. Such differences are expressed even in early childhood with preferences to definite activities. It has been generally accepted that differences between genders are formed under the influence of biological as well as environmental factors. The existence of sex differences in functions of the central nervous system has suggested that there are also morphological sex differences. In recent years several reports on sexual dimorphism in the brain of vertebrates have been published. However, the mecha nisms of sexual differentiation of the central nervous system remain unclear in most cases. It is often difficult to correlate morphological sex differences to differences in definite function or behavior. We set out to explore the sexual dimorphism of the limbic system and especially the bed nucleus of the stria terminalis and the amygdala, which are considered generally to be occupied with the control of reproductive behavior and autonomic and compli cated psychic functions. Several reports on sexual dimorphism of these structures have been published. Some of them have been directed to the total neuronal number and the volume of the nuclei, while others have concentrated on definite subpopula tions of neurons. In many cases the mechanisms of sexual differ entiation were tested, but sometimes they could not be estab lished."

Preparatory work for this monograph started in 1988 and 1989. The motive was provided by certain incongruities in the illustra- tion of descensus testis for the chapter "Entwicklung der Genital- organe" in the book Humanembryologie. The evoked discussion was reason enough for our own re- search on the phenomenon and uncertainties of testicular des- cent in human. The basis ofthese investigations was the collection of human embryos founded by Prof. Hinrichsen in 1970 at the Department of Anatomy and Embryology, Ruhr-University Bo- chum. The preparation of the material used in this paper has been done with the help of many staff members of our department to whom we feel obliged. We are especially indebted to Prof. Hin- richsen who prepared the foetuses and took the first steps of this project. We wish also to acknowledge Dr. Heinz Jiirgen Jacob for careful fixation and microdissection of specimens intended for scanning electron microscopy. Weare also grateful to Mrs. Vera Mannheim for her involvement and her sensitivity in making scanning electron micrographs, and Mrs. Antje Jaeger for provid- ing an expert and skilful photographic technique especially in the setting up of micrographs. Our thanks are also due to Mrs. Marion Kohn for skilful technical assistance and to all those technical assistants who worked in our department during the past 25 years and who were engaged in providing the serial sec- tions. The English text has been thoroughly revised by Prof. Dr.

In this treatise, current knowledge on the neurogenesis, axonal outgrowth, synaptogenesis, and regenerative capacity of descending supraspinal pathways in tetrapods is discussed. Although emphasis is on the clawed toad, Xenopus laevis, chicken embryos, opossums and rodent data, also the data available for primates including man are presented. It will be shown that 1) the outgrowth of descending supraspinal pathways is the result of a coordinated program; 2) the pattern of early descending axonal tracts is similar in all vertebrate groups; 3) the formation of descending supraspinal pathways occurs according to a developmental sequence; 4) the earliest descending supraspinal fibers arrive in a rather immature spinal cord, and 5) the regenerative capacity of descending supraspinal pathways depends on the developmental stage the particular pathways arise.

Experimental Hydrodynamics of Fast-Floating Aquatic Animals presents the latest research on the physiological, morphological and evolutionary factors in aquatic animal locomotion. Beginning with an overview on how to conduct experiments on swimming aquatic animals, assessing hydrodynamic forces, resistance and geometric parameters of animal bodies, the book then details how aquatic animals, such as fast-moving dolphins, can achieve high speeds without over-expelling their energy resources. It provides insights into investigations on how animals, including dolphins, sharks and swordfish can maneuver through water at high speeds, offering a natural model for improving human and technological underwater locomotion. This book is essential for researchers and practicing biologists interested in the study of aquatic animal locomotive physiology and its application to human technology. Advanced undergraduate and graduate students will also find this a helpful academic resource for further understanding animal hydrodynamics.

The value of the canine nose is well-documented, and working dogs are being utilized for their olfactory skills in an increasing number of fields. Not only are dogs used by police, security, and the military, but they are also now used in forensic science, in medical detection of disease, in calculating population trends of endangered species and eradicating invasive species in protected environments, and in identifying infestations and chemical contaminants. Edited and contributed to by eminent scholars, Canine Olfaction Science and Law: Advances in Forensic Science, Medicine, Conservation, and Environmental Remediation takes a systematic scientific approach to canine olfaction. It includes work from scientists working in pure and applied disciplines, trainers and handlers who have trained and deployed detection dogs, and lawyers who have evaluated evidence produced with the aid of detection and scent identification dogs. The book is divided into six sections covering The anatomy, genetics, neurology, and evolution of canine olfaction as well as diseases affecting it The chemistry and aerodynamics of odors Behavior, learning, and training Uses of canine olfaction in forensics and law Uses in conservation and remediation Uses in detection of diseases and medical conditions The various contributors describe cutting edge research, some conclusions of which are the subject of vigorous debates between various laboratories and researchers. The editors have added cross-references so that readers can consider the different perspectives that are currently being advanced and understand where consensus is being built and where more research needs to be done. A useful practical reference, Canine Olfaction Science and Law provides a wealth of information beneficial to a wide range of disciplines. It aids trainers and handlers of detection dogs as well as various professionals in healthcare, law enforcement, forensic science, and environmental conservation to gain a better understanding of the remarkable power of the canine nose while encouraging further advances in applications.

Morphogeny of the nasal skull was investigated in 92 embryos of 13 species of Cetacea. Compared to the original nasal capsule of land mammals, the nasal structures of Cetacea show many weighty transformations. As a result, the nostrils are translocated from the tip of the snout to the vertex of the head. Several structures of the embryonic nasal skull remain preserved even in adult cetaceans. The translocation of the nostrils to the highest point of the surfacing body is among the most perfect adaptations of cetaceans to the aquatic life habits. The morphogeny of the nasal skull suggests that all cetaceans are of common origin and form a single monophyletic order. The hitherto usual division of this order into two suborders, Mysticeti and Odontoceti, appears to be unsubstantiated. Rather, at least three closely related superfamilies should be distinguished within the order Cetacea, viz., Balaenopteroidea, Physeteroidea, and Delphinoidea. The results are in a

Due to their pronounced intraspecific variability and to difficulties in defining their evolutionary trends in mammalian phylogenies, peripheral blood vessels have been neglected in comparative studies. Supported by the Sonderforschungsbereich 89 (Car- diology) of the Deutsche Forschungsgemeinschaft, we have reconstructed the ontoge- of the blood vessels of the tree shrew, Tupaia belangeri, on the netic morphogenesis basis of a series of developmental stages. The arteries of the lower extremity are described and discussed here. Besides describing the morphogenesis of the arteries in Tupaia, it is the aim of this study to explain the variability of the arteries of the pelvic extremity among mammals, and especially among primates including man, on the basis of a common developmen- tal pattern. This can be shown in the following example. In the popliteal region of most adult mammals the arteria poplitea profunda is situated under the musculus popliteus. In the adult Tupaia, as well as in primates, this artery is missing but, superficial to the musculus popliteus, an arteria poplitea super- ficialis exists. It seems difficult to explain such a case of "discontinuous evolution," because it is hard to imagine the position of the artery should have shifted through the muscle. The present investigation and the literature show that early in the embryonic development of a primate, man, and of Tupaia, both the arteria poplitea profunda and the arteria poplitea superficialis are present.

1.1 Overview The precise knowledge of the three-dimensional (3-D) assembly of biological structures is still in its origin. As an example, a widely accepted concept and common belief of the structure of the airway network oflung is that of a regular, dichotomous branching pattern, also known as the trumpet model. This model, first introduced by Weibel in 1963, is often used in clinical and physiological applications. However, if this concept of dichotomy is used to model lung, a shape is obtained that is quite different from a real lung. As a matter of fact, many previous quantitative morphological and stereological investigations of lung did not concentrate on the spatial aspect of lung morphology but delivered data in a more statistical fashion. Accordingly, the functional behavior predicted by such a model becomes questionable and indeed, the morphometrically predicted lung capacity exceeds the physiological required capacity by a factor of 1.3 up to a factor of2. This problem has also been termed a paradox, as discussed by Weibel in 1983. In the rare cases where descriptive models of the mammalian bronchial tree exist, monopodial in small mammals, dichotomous in larger ones, the understanding of the historical and/or functional reasons for size-related changes in the general design is not explainable. This investigation is trying to overcome this gap by computer modeling and functional simulation.

Only five years ago, nobody in his right mind would have consid ered publishing a book on reeler as a model for brain develop ment. Although this interesting mutation has been with us for half a century, it is fair to say that, in spite of a wave of enthusiasm in the late sixties and early seventies, generated primarily by Sidman, Caviness and colleagues, studies of reeler mice fell pro gressively out of fashion during the next two decades. All that changed almost overnight when the cloning of the reeler gene, dubbed reelin, was reported in Tom Curran's laboratory in 1995. The fact that the same gene was identified at the same time independently by two other groups using positional cloning sug gested strongly that reelin was the right candidate. Although the key experiments of transgenic rescue have not been made (and perhaps will never be), the equation "reeler is reelin" has been established beyond reasonable doubt, as alterations of the reelin gene and/or its expression have been found in at least five alleles of reeler and in the mutation Shaking Rat Kawasaki (SRK), an ortholog of reeler."

Cell culture techniques allow a variety of molecular and cell biological questions to be addressed, offering physiological conditions whilst avoiding the use of laboratory animals. In addition to basic techniques, a wide range of specialised practical protocols covering the following areas are included: cell proliferation and death, in-vitro models for cell differentiation, in-vitro models for toxicology and pharmacology, industrial application of animal cell culture, genetic manipulation and analysis of human and animal cells in culture.

During pubertal development of the testes, germ cells pass initially through the complete succession of spermatogenic differentiation. Using the golden hamster as a model, this volume presents a comprehensive analysis of that establishing period of mammalian spermatogenesis. Detailed morphological and cell kinetic data of the pubertal seminiferous epithelium reveal a level of cellular organization and synchronization coming near to the adult situation. Characteristic, temporarily occurring perturbations of spermatogenic progression are related to specific delays of Sertoli or Leydig cell maturation, respectively. These results emphasize and specify the close structural and functional interdependence of germ and somatic cell development.

Conditioned taste aversion (CTA) is a robust defence device protecting animals against repeated consumption of toxic food. It is characterised by the ability of many animals to learn to avoid certain substances by their sight, smell, or taste after experiencing an unpleasant or harmful reaction to them. CTA is encountered at all levels of evolution, with similar forms of food aversion learning found in vertebrate and invertebrate species whose ancestral lines diverged more than 500 million years ago. CTA has a number of unusual properties contrasting sharply with the basic assumptions of traditional learning theories, which has brought it increasingly to the attention of neurobiologists interested in neural plasticity. In CTA, the usual time parameters between stimulus and aversion are relaxed considerably, frequently with delays of hours rather than seconds. Moreover, the critical stage of CTA acquisition may proceed under deep anaesthesia incompatible with other forms of learning. In the past decade several pivotal discoveries have considerably avanced our understanding of the neural processes underlying CTA, and opened new possibilities for their analysis at the molecular and cellular levels. This book, written by three of the world's leading researchers in the subject, comprehensively reviews the current state of research into conditioned taste aversion. The first book of its kind to provide an up-to-date summary of research into the neuroanatomy, pharmacology, electrophysiology, and functional morphology of CTA, it will be welcomed by all researchers and graduate students in the field.

Glomerular flltration represents one of the basic mechanisms in the function of an organism. Our understanding of this process is still quite fragmentary. Regulation of blood flow and pressure, together with regulation of the ultraflltration coefficient (which is an attribute of the flltration barrier), are the two fundamental mechanisms accounting for maintenance and adaptability of glomerular flltration. Regulation of glomerular blood flow is generally considered to result from an interplay between afferent and efferent glomerular arterioles, and much progress has been made recently in understanding this interplay (Navar et al. 1996). The present study provides a detailed structural description of the glomerular vascular pole of rat. The results of this study appear to be relevant for several open questions of glomerular function. First, the interaction between afferent and efferent arterioles in regulating glomerular blood is generally understood to occur between the preglomerular and the postglomerular portions of these vessels. As shown in the present study, the structural elaborations of these arterioles and the spatial relationships between them within the glomerular hilum strongly suggest an interplay also at this site. Moreover, the current understanding of glomerular blood flow regulation by tuning the interplay between afferent and efferent arterioles is exclusively based on signals whose regulatory loops are established in follow-up events outside the glomerulus (tubuloglomerular balance, tubuloglomerular feedback).

What is it that stops the process of eating? This deceptively simple question lies at the centre of Satiation: From Gut to Brain, and the book succeeds in answering it comprehensively while incorporating the latest scientific research. Unless we stop eating by choice-for medical or social reasons-an unconscious physiological process is triggered through negative feedback from ingested food as it travels from the mouth through the stomach and on to the small intestine. This process is called satiation. Recent scientific evidence has revealed that food stimuli activate this process before the actual absorption of digested food, which significantly changes the traditional perspective that satiation depends on the post-absorptive repletion of metabolic fuels. This volume presents the first detailed account of the neurobiological mechanisms of satiation. The ten chapters of the book detail the neural, endocrine, and cellular underpinnings of the process. Authors expert in different aspects of satiation have compiled a critical overview of recent advances and current problems in this field. The inclusion of a chapter on the satiation of alcohol is unique in a book on food intake, and shows the convergence of ideas on satiation in these two areas. Comprehensive in scope and accessible to a wide array of advanced students and professonals, Satiation: From Gut to Brain is an authoritative and up-to-date review of every aspect of this important physiological process. Although intended primarily for neuroscientists, nutritionists, and psychobiologists, who will find it most pertinent to their work, the book will also be useful for physiologists, pharmacologists, and psychologists concerned with eating and its disorders.

According to Jones and Smith (1973) the potential adverse effect of maternal alcoholism on the development of the offspring has been referred to in early Greek and Roman mythology. In a Carthaginian ritual, the bridal couple was forbidden to drink wine on their wedding night in order that defective children might not be conceived (Haggard and Jellinek 1942). Also, according to lones and Smith (1973,1975), the British House of Commons indicated in 1834, in a report by a select committee investigating drunk enness, that infants born to alcoholic mothers sometimes had a starved, shrivelled and imperfect look. According to Librizzi (1982) the first documented observations appeared in 1849 with the publication of the essay by Carpenter entitled "The Use and Abuse of Alcoholic Liquors in Health and Disease." He stated that habitual intemperance is the most potent of all causes of insanity because it aggravates the operation in other causes. Sullivan (1990) recorded increased abortion and stillbirth rates among chronically al coholic mothers in a Liverpool prison and an increased incidence of epilepsy in their surviving offspring. Various investigators including Ladraque (1901), Roe (1944). Le comte (1950), Christiaens et al. (1960) and Lemoine et al. (1967) have since then reported increased incidence of abnormalities and decreased weight of surviving children born to chronic alcoholic mothers."

1. 1 Purpose and Plan of This Review This review is focused on the topography and connections of some of the neuron populations that determine the manual dexterity of the macaque monkey. The populations selected for examination are the following: 1. The corticospinal neuron populations 2. The thalamocortical and corticothalamic neuron populations associated with the sensorimotor cortex 3. The ipsilateral cortical connections of the sensorimotor cortex These neuron populations have been chosen because of their obvious rel evance to the directed, intelligent use of the hands, but also because of their anatomical and functional interdependence. Corticospinal neuron populations transmit a complex, orchestrated output from a number of different regions of cerebral cortex to the neuron populations in every segment of the spinal cord, and this output includes the command information defining the intended manual action. The thalamocortical complex is especially concerned with the transmis sion and modulation or filtering of (a) visual, tactile, proprioceptive, vestibular, and auditory information to the cerebral cortex and (b) information from the cerebellum, basal ganglia, limbic system, and brain stem which is relevant to sensorimotor behavior. Finally, the extensive ipsilateral cortical connections constitute a major part of the supraspinal circuitry which coordinates the contri butions of all the cortical neuron popUlations contributing to intelligent sen sorimotor behavior and, in particular, transmits the cross talk between those cortical neuron populations which shape and control the dextrous handling of objects within reach.

Why write another small book on respiratory physiology? I have a dozen or so texts on my bookshelf that could already be used interchangeably to teach the subject. For profit, I might as well buy lottery tickets. Not that my publisher is ungenerous, you understand, it's just that the market is not that big and there are many contenders for a share. No, I write from the idealistic standpoint that I think I have something different to say, some thing that is importantly different about how gas exchange works and with an approach that is different from other authors. With few changes, basically the same text or chapters on respiratory physiology have been written, by different authors, for decades. One could almost interchange the tables of contents of most of them. Most seem to have copied the figures and concepts used by the others. Few have done more than accept and perpetu ate the conventional wisdom. In this text, I have attempted to start from fundamental principles of biology, chemistry, and physics and ask at each step, "Does it make sense?" The mechanisms and structures of gas exchange exist because, scientifically and logically, they "can't not be" as they are. The nature of our environment and the capabilities ofliving tissue are such that only certain opportunities have been available to the evolution of gas exchange."

The book shows that cell membranes vary according to the 24h cycle: it deals with circadian changes in membrane composition, principally the plasma membrane and with structural organization changes in some chloroplast thylakoids. The book deals with changes in activity or efficiency of pumps, channels, photo- and hormone receptors, in sensitivity towards external signals, in sensitivity to some drugs, including anaesthetics and in changes in signal transduction. The cell cycle is discussed on theoretical and experimental grounds, as well as its gating by circadian rhythmicity. The rhythm generating mechanism is modelized. The circadian oscillation of the plasma membrane confers a temporal parameter.

1. 1 Objectives of this Study The vertebrate middle ear has attracted the interest of morphologists for more than a century. Its difficult structure, its complicated evolutionary derivation, and its integration of branchial, cranial, and otic materials into a single func- tional unit have made it a key organ for the understanding of vertebrate structures and their evolutionary history. Gaupp's (1898, 1913) and Reichert's (1837) comparative morphological studies of the vertebrate middle ear repre- sented milestones for anatomy in the general recognition and acceptance of Darwin's theory of evolution. These fundamental studies notwithstanding, today's knowledge of avian middle ear structures is still characterized by descriptive studies focusing on character sampling to elucidate high-level phylogeny. Phylogenetic studies have considered either structural aspects of the bony stapes exclusively (Feduccia 1974, 1975a,b, 1976, 1977, 1978), or focused on the anatomy of the middle ear cavity, neglecting the sound trans- mission apparatus (Saiff 1974, 1976, 1978a,b, 1981, 1982, 1983, 1988). Other studies have investigated late-stage embryos and concentrated on the develop- ment of the skull, considering middle ear structures only as a side aspect. However, there are considerable structural differences between the middle ears of late-stage embryos, hatchlings, and adults of the same species. Although vertebrate morphology requires a meticulous knowledge of comparative middle ear data and calls upon an elaborate system of homologies, it turns out that knowledge of middle ear structural details is widely dispersed among different species and different developmental stages, making a comparison even more difficult.

In this unique book, Sir Donald Harrison draws on his wide-ranging experience as a surgeon and comparative anatomist to produce an authoritative and detailed account of the anatomy and physiology of the mammalian larynx. His investigation of the larynx has involved the study of over 1400 specimens of mammalian larynges from around the world, as well as using data from his own clinical experiences. The comparative morphology of the larynx is discussed from a developmental and functional perspective and the involvement of the larynx in respiration, locomotion and vocalisation is highlighted. Throughout the book the relationship of structure to function is drawn out and the clinical relevance of features of the human larynx is emphasised. This book will be an invaluable reference for all researchers and clinicians involved in laryngology as well as for anatomists, zoologists and anaesthesiologists.

Comprising well over half of all known animal species, insects are the most successful organisms on the planet. Indeed, it is no exaggeration to say that one cannot study agriculture, biology, and the environment, without a basic understanding of entomology. Furthermore, insects are indispensable to advances in molecular biology and genetics, and their ongoing decline in many parts of the world has stimulated much research in the crucial roles they play in global ecosystems. However, the sheer diversity of insects can be a challenge to every newcomer to entomology. Most entomology textbooks tend to focus on insect biology, leaving readers with only a superficial idea of insect diversity and evolution, while others delve into too much detail that will deter the novice. In contrast, Essential Entomology has a clear taxonomic structure that provides readers with the necessary framework to understand the diversity, life history, and taxonomy of insects in a new light. This fully revised edition provides the most up-to-date guide to insects and includes all the major developments in molecular biology and palaeontology of the last 20 years. This textbook is an essential read for undergraduate and graduate students taking courses in entomology, agriculture, and forestry. It will also appeal to a broad academic audience of ecologists, conservationists, natural resource managers, as well as to the far more numerous general readers who are interested in wildlife, nature, and the environment. With these diverse audiences in mind, the straightforward and accessible style of the first edition has been maintained, technical jargon has been kept to a minimum, and sufficient background information is provided to enable the reader to follow the text with ease.

How do bats catch insects in the dark? How do bees learn which flowers to visit? How do food-storing birds remember where their hoards are? Questions like these are addressed by neuroethology, the branch of behavioral neuroscience concerned with analyzing the neural bases of naturally occurring behaviors.This book brings together thirteen chapters presenting findings on perceptual and cognitive processes in some of the most active areas of neuroethological research, including auditory localization by bats and owls, song perception and learning in birds, pitch processing by frogs and toads, imprinting in birds, spatial memory in birds, learning in bees and in "Aplysia, " and electroreception in fish. A variety of approaches are represented, such as field studies, psychophysical tests, electrophysiological experiments, lesion studies, comparative neuroanatomy, and studies of development.Each chapter gives an up-to-date overview of a particular author's research and places it within the broader context of issues about animal perception and cognition. The book as a whole exemplifies how studying species and their particular specializations can inform general issues in psychology, ethology, and neuroscience.

Paxinos and Ashwell's Atlas of the Developing Rat Nervous System, Fourth Edition, builds on the many excellent features of previous editions that have made this book the most cited atlas of the developing rat brain. It provides the most comprehensive depiction of not only the structures in the brain and spinal cord, but also of the peripheral nervous system and target organs that are important for developmental neurobiologists, allowing the user to follow neural structures through the developing embryo in both time and space. The nomenclature and identification of structures in this edition have been thoroughly updated to ensure accuracy and compatibility.

However well the anatomy of the gastrointestinal tracts of a wide range of mammals are described and quantified, there can be no real explanation of observed patterns without consideration of the mechanical and chemical properties of the food consumed, and digestive stages involved in its processing. This book aims to integrate findings from the many different types of investigations of mammalian digestive systems into a coherent whole. Using the themes of food, form and function, researchers discuss models of digestive processes, linking this with evolutionary aspects of food utilization. Macroscopic and ultrastructural studies of the gastrointestinal tract are also presented, as are physiological, ecological and biochemical aspects of the digestion of different food types. The book ends with an integrative chapter, bringing together the themes running through the earlier sections.