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Quantitative and Histomorphological Studies on Age-Correlated Changes in Canine and Porcine Hypophysis Lakshminarayana Das Iowa State University

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Quantitative and Histomorphological Studies on Age-Correlated Changes in Canine and Porcine Hypophysis Lakshminarayana Das Iowa State University Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1971 Quantitative and histomorphological studies on age-correlated changes in canine and porcine hypophysis Lakshminarayana Das Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Animal Structures Commons, and the Veterinary Anatomy Commons Recommended Citation Das, Lakshminarayana, "Quantitative and histomorphological studies on age-correlated changes in canine and porcine hypophysis" (1971). Retrospective Theses and Dissertations. 4873. https://lib.dr.iastate.edu/rtd/4873 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. 71-26,847 DAS, Lakshminarayana, 1936- QUANTITATIVE AND HISTOMORPHOLOGICAL STUDIES ON AGE-CORRELATED CHANGES IN CANINE AND PORCINE HYPOPHYSIS (VOLUMES I AND II). Iowa State University, Ph.D., 1971 Anatomy• University Microfilms, A XEROX Company, Ann Arbor. Michigan Quantitative and histomorphological studies on age-correlated changes in canine and porcine hypophysis py Lakshminarayana Das Volume 1 of 2 A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OP PHILOSOPHY Major Subject: Veterinary Anatoiny Approved: Signature was redacted for privacy. Signature was redacted for privacy. Signature was redacted for privacy. Iowa State University Ames, Iowa 1971 PLEASE NOTE: Several pages contain colored illustrations. Filmed in the best possible way. UNIVERSITY MICROFILMS 11 TABLE OP CONTENTS page INTRODUCTION 1 REVIEW OP LITERATURE 6 Nomenclature 6 General Morphology 19 Pars dlstalls adenohypophysls 24 pars Intermedia adenohypophysls 31 pars Infundibular is adenohypophysls 33 Radix infundibull (median eminence) 34 pars cava infundibull and pars compacta infundibull 37 pars dlstalls neurohypophysis 38 Stains and Staining Reactions 40 Morphology of the Canine I^pophysis 72 Morphology of the Porcine Hypophysis 88 Ultrastructure of the Hypophysis 97 Development of %rpophysis 115 Blood Supply of Hypophysis 130 Quantitative Changes In I^pophysls with Age 145 Qualitative Changes in Hypophysis with Age 150 MATERIALS AND METHODS I65 General I65 Design of Program 165 Collection Procedure I69 Histological Techniques 170 Ill Page Age Groups I77 Measurements and Statistical Analysis I79 Cytometry 182 OBSERVATIONS I86 Quantitative Changes in Weights of I^pophysis , 186 Dog: beagle I86 Dog: mixed breeds I90 Pig 190 Age-correlated Changes in the Relationship of the hypophysis with other Endocrine Glands 195 Dog: beagles 195 Dog: mixed breeds 200 Pig 200 Histomorphology of the Canine l^pophysis 204 Adenohypophysis 204 Neurohypophysis 220 Histomorphology of the Porcine I^pophysis 225 Adenohypophysis 225 Neurohypophysis 236 Age-correlated Changes in the Canine Hypophysis 24l Adenohypophysis 241 Statistical evaluation 261 Neurohypophysis 2 76 Age-correlated Changes in the Porcine Hypophysis 288 Adenohypophysis 288 iv Page Neurohypophysis 329 Age-correlated Changes in the Hypothalamus 341 DISCUSSION 350 Comparative Study on Quantitative Changes in Weight 350 Morphology 361 Adenohypophysis 361 Neurohypophysis 386 Age-correlated Changes 391 Correlative Studies on Age-correlated Changes in Other Endocrine Glands 408 SUMMARY 413 BIBLIOGRAPHY 423 ACKNOWIEDGMENTS 457 APPENDIX A. TABLES 459 APPENDIX B. GRAPHS 520 APPENDIX C. PHOTOMICROGRAPHS 56I 1 INTRODUCTION Throughout its life span, every organism manifests certain dynamic processes which reveal certain specific roles when they are distributed among the age intervals. In earlier stages of the life span, these processes mainly contribute towards the goal of attaining functional and reactive abilities leading to reproduction of the species. This stage commonly termed development anU/6r growth period is followed by one which denotes the period of maximum functional ability, both in reproduction and reactance to the environ­ ment. During the latter stage, different tissues and organ systems of the body are often referred to as being normal. Terms such as adult, sexually mature, matured and fully grown are often used to denote this stage. The next stage is evidenced by changes undergone by tissues and organ systems in the body as a result of the dynamics of life's processes with the passage of time. These morphological and functional deviations reduce the functional ability of organ systems, decrease the adaptability of the organism and may contribute towards its death. This stage is commonly referred to as old age or senescence. In earlier days of gerontological research, the term age changes was applied in a limited sense to the morpho­ logical and functional changes that are evident during senescence (Strehler, 1962). Since most visible changes 2 with advancement of age are evinced by organs of the repro­ ductive system, the main cause of such changes in the process of ageing was thought to be the decreased activity of gonads. This concept has since been modified. The process of ageing is no longer considered to be limited to changes during senescence but is envisaged to involve all basic underlying changes in structure and function that lead to the gradual development and subsequent dysfunction of various systems in the body (Strehler, 1962; Getty, 1966). Thus, the science of gerontology incorporates the changes that occur in the organism during its post-natal life, growth, maturity and senescence. Many of the changes in structure and function represent the sum of changes which are of extrinsic and/or intrinsic origin. Since the process of ageing is considered as a fundamental property of the organism itself and not of the environment in which it lives, basic age-correlated changes should be characterized from those of extrinsic and patho­ logical origin. Strehler (1962) emphasized that any age- associated change should belong to the criteria of univer­ sality (occur in all members of the species), intrinsicality (even though widespread, should be of intrinsic origin), progressiveness (should resemble a process but not a sudden event) and deliteriousness (should contribute towards death of the organism). Thus, it is needless to emphasize that 3 gerontological research should involve aniinals maintained with the least possible variations in management and environment. Modern gerontological research aims at elucidating basic changes in structure and function with a view to delineate effectively causes and effects of the ageing process. Such a knowledge will contribute towards advances in human geriatrics and animal population. In the former, gerontology is applied to many social and psychological problems, such as treatment of the aged persons, prevention of disease and disability and preservation of vigor and good health (Getty, 1962). In the latter case, gerontology has been envisaged to enhance the reproductive and productive period in the life span of an animal. In modern biology, the science of gerontology has achieved considerable appreciation due to its wide range of application as a basic as well as applied science. Modem cell physiology has been elucidated to such a great extent that an understanding in basic age-correlated changes is necessary for a differential study of the physiological and pathological changes. Sines these changes follow a definite pattern in a particular species, study of the ageing process in a wide variety of species will contribute much towards such differential studies. Since earlier periods, role of endocrine glands in the process of ageing has attracted the attention of gerontolo- 4 gists. As growth and fimctlonal ability of many organs are influenced by the endocrine glands, ageing of the entire organism has been considered by some authors in terms of age- associated changes in these glands (Carlson, 1952; Verzar, 1966). With the advancement of knowledge in the field of neuroendocrinology, more emphasis is being laid at present on the neuroendocrine integration mechanism than on the endocrine system Itself. Shock (1966) considered the breakdown of neural and endocrine integrative functions in the individual as one of the major causes of age-correlated impairments in performance of the organism. VJith the hypophysis being the key organ associated with the mechanism of neuroendocrine integration, age-correlated changes in it have been considered as major contributing factors towards ageing of the individual (verzar, 1966). Furthermore, several physiological distur­ bances in the body which are characteristic of advanced age, are also manifested in conditions of decreased activity in some pituitary cells, independent of age of the aninal. Hypophysectomy leads to certain peculiar phenomena which are also manifested during senility (Verzar, 1966). Thus, age- correlated changes in the structure of the hypophysis will elucidate a basic xinderstanding of similar changes in other endocrine glands as well as the animal as an entity. There is considerable variation in histomorphology of the hypophysis, and a comparative study of age-correlated 5 changes in more than one species will contribute much towards the understanding of biological ageing in this organ. With this view in mind, hypophyses of the dog and the hog have
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