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Articles 31 - 39 of 39

Full-Text Articles in Physiology

The Effect Of Salinity On Habitat Selection Of Two Oregon Chiton Species (Katharina Tunicata And Mopalia Hindsii), David Carl Rostal Mar 1986

The Effect Of Salinity On Habitat Selection Of Two Oregon Chiton Species (Katharina Tunicata And Mopalia Hindsii), David Carl Rostal

Dissertations and Theses

Adult specimens of Katharina tunicata (mean weight = 10.23 grams) and Mopalia hindsii (mean weight = 10.90 grams) were tested for osmotic stress tolerance and oxygen consumption rates in a series of salinities (120%, 100%, 80%, 60%, and 40% seawater) at 11°C and 16L:8D photoperiod. K. tunicata and M. hindsii displayed similar trends in percent body weight variation and volume regulatory responses to osmotic stress. However, K. tunicata experienced a significantly higher percent body weight increase than did M. hindsii in response to hypo-osmotic conditions (80%, 60%, and 40% seawater). The mean rates of oxygen consumption per salinity for the …


The Contribution Of The Lymph Hearts In Compensation For Acute Hypovolemic Stress In The Toad Bufo Marinus, Mark Baustian Jan 1986

The Contribution Of The Lymph Hearts In Compensation For Acute Hypovolemic Stress In The Toad Bufo Marinus, Mark Baustian

Dissertations and Theses

Currently published data on the role of the lymphatic system in amphibians are inadequate and contradictory. Estimates of the rate of formation of lymph and the role of the lymph hearts in returning this fluid to the circulation are not based on actual volume determinations but rather estimates derived from changes in hematocrit using published values of plasma and blood volume. The lymph hearts are known to be vital to the maintenance of normal fluid compartment physiology and to increase their rate of activity during episodes of hypovolemic stress. Yet, significant redistribution of body fluids following hemorrage appears to occur …


The Significance Of Hypovolemia In Dehydrational Death In Anurans, Peter Blair Kimmel Jan 1985

The Significance Of Hypovolemia In Dehydrational Death In Anurans, Peter Blair Kimmel

Dissertations and Theses

The importance of hypovolemia in dehydrational death was assessed in two anuran species. Xenopus laeyis, a species which experiences a significant reduction in circulating plasma volume with dehydration, was used to evaluate the role of sympathetic reflex compensation in hypovolemia. Adrenergic blockade with propranolol or phenoxybenzamine produced no significant reduction in dehydration tolerance in this species, although β-blockade with propranolol appeared to have a minor effect. The role of hypovolemic shock in the terminal circulatory collapse that precedes death in dehydrating anurans was investigated in the toad, Bufo marinus. The activity of lysosomal proteinases (cathepsins) was used as an indicator …


Effects Of Dehydration On Hemoglobin Oxygen Affinity And Blood Cell Volume In Two Anurans, Andrew Christopher Zygmunt Aug 1984

Effects Of Dehydration On Hemoglobin Oxygen Affinity And Blood Cell Volume In Two Anurans, Andrew Christopher Zygmunt

Dissertations and Theses

Two aspects of possible adaptation in cardiovascular performance caused by increased plasma electrolytes were examined. Cells in anisotonic plasma may either act as osmometers or volume regulate. Blood flow rate is dependent upon cell viscosity, which in turn is a consequence of cell volume and membrane deform-ability. Cell volume changes which increase membrane deform-ability will thus potentially extend the limits of dehydration tolerance. It was found in R. catesbeiana and B. marinus that red blood cell is maintain constant volume during dehydration. Cells in vitro initially lose water, but then sodium, potassium and water move into the cell. Cell viscosity …


Adult Oral Diadochokinesis Rates : Preliminary Normative Data, Carol Kafton-Minkel Jan 1983

Adult Oral Diadochokinesis Rates : Preliminary Normative Data, Carol Kafton-Minkel

Dissertations and Theses

In the clinical evaluation and management of speech disorders, a speech-language pathologist may observe disturbances in a client's motor abilities that suggest possible neurological dysfunction. One possible disturbance is in oral diadochokinesis (DIO), an individual's ability to start and stop the movement of the articulators rapidly and execute repetitive, alternating, sequential movements typically associated with speech articulation. It is often recommended that a speech-language pathologist test DIO speed and compare the performance to available norms. There is, however, a lack of normative DIO data spanning all ages of adulthood. The purpose of this study was to develop preliminary normative data …


Aspects Of Anuran Metabolism: Effects Of Chronic Hypoxia On Maximal Oxygen Uptake Rates And The Fate Of Lactic Acid, Thomas Charles Solberg Aug 1982

Aspects Of Anuran Metabolism: Effects Of Chronic Hypoxia On Maximal Oxygen Uptake Rates And The Fate Of Lactic Acid, Thomas Charles Solberg

Dissertations and Theses

Some aspects of anuran metabolism are examined, with special emphasis on possible limitations to aerobic metabolism and the effect of chronic hypoxia acclimation on maximal rates of aerobic metabolism and the metabolic fate of lactic acid accumulated after anaerobic metabolism.


Anuran Activity Energetics, Scott R. Landrey Jul 1982

Anuran Activity Energetics, Scott R. Landrey

Dissertations and Theses

This thesis presents two separate experiments concerning aerobic and anaerobic amphibian energetics. The first study (Part I) investigates differential alterations in the kinetics of the anaerobic enzyme lactate dehydrogenase, in nine species of anurans with varying natural histories. The second study (Part II) studies changes in different anaerobic and aerobic physiological parameters in a single species (Rana catesbeiana) after six weeks of chronic exercised, unexercised-captive and for field frogs. The common theme of these two experiments involves the potential for physiological changes due to environmental stress. Part I examines different species to infer a possible evolutionary relationship to …


Factors Affecting Thyrotropin Secretion In Superfused Rat Anterior Pituitary Cells, Frederick Scott Bartlow Jul 1982

Factors Affecting Thyrotropin Secretion In Superfused Rat Anterior Pituitary Cells, Frederick Scott Bartlow

Dissertations and Theses

The use of static in vitro pituitary cultures has been indispensible for examining the regulation of anterior pituitary hormone secretion. While the static cultures have shown the effects of various chemical stimulators of hormone secretion, the dynamics of such secretion has not been assessed before in vitro. The in vitro superfusion method, which partially stimulates in vivo physiologic conditions, allows for the observation of the dynamics of pituitary hormone secretion.


The Metabolic Cost Of Behavioral Thermoregulation Of Body Temperature In The Northern Alligator Lizard Gerrhonotus Coeruleus, And How It Affects The Classical Concept Of Eurythermality, James Dudley Campbell Jan 1981

The Metabolic Cost Of Behavioral Thermoregulation Of Body Temperature In The Northern Alligator Lizard Gerrhonotus Coeruleus, And How It Affects The Classical Concept Of Eurythermality, James Dudley Campbell

Dissertations and Theses

The effect of total metabolic cost expenditures on the precision of behavioral thermoregulation was investigated for the purportedly eurythermic Northern Alligator lizard (Gerrhonotus coeruleus). An operant apparatus was designed to test metabolic output at different heat reinforcement magnitudes. The mean TB reflected in each trial was positively correlated to the length of reinforcement. The shuttle rate during each trial was inversely correlated to the length of reinforcement. The standard deviation and total metabolic costs did not vary significantly between trials undertaken at the same ambient temperature. Eurythermality in G. coeruleus is caused by fluctuations in preferred body temperature and …