Human Physiology.

Human physiology and anatomy are closely related—anatomy is the study of form, physiology is the study of function, and form and function are intrinsically linked. The study of human physiology integrates knowledge across many levels, including biochemistry, cell physiology, and organ systems. Contemporary research in human physiology explores new ways to maintain or improve the quality of life, the development of new medical therapies and interventions, and the unanswered questions about how the human body works. The Department of Human Physiology serves its students by providing strong training in human physiology and anatomy to prepare them for careers in medicine, allied health professions, and biomedical research.

We have previously recorded a marked increase in the satiety neuropeptide cholecystokinin (CCK) amongst mountaineers sojourning to 5100 m (Bailey et al. 2000). To further elaborate on stimuli and potential mechanisms, the present study examined the independent modulatory roles of both the acute and chronic aspects of physical exercise and hypoxia on peripheral CCK metabolism.
Following ethical approval, 32 male university students with a mean (± 1 S.D.) Vo"max of 50 ± 9 ml kg -1 min -1 were randomly assigned double-blind to either a normoxic (NOR, n = 14) or hypoxic (HYP, n = 18) group. Subjects in the HYP group only participated in the acute study and were randomly assigned double -blind to two standardised cycling tests to volitional exhaustion in normobaric normoxia (Fr,o, = 0'21) and normobaric hypoxia (Fr,o, = 0'16) separated by 48 h. The hypoxic fraction was delivered from 10001 Douglas bags which were connected to the inspiratory port of a two-way non-rebreathing valve. Subjects were passively exposed to the respective conditions in the seated position 30 min prior to starting physical exercise. During the chronic study, NOR and HYP groups performed a maximal exercise test in nOl'moxia (Fr,o, = 0'21) before (PRE) and after (POST) 4 weeks of double-blind supervised normoxic (Fr,o, = 0'21) or hypoxic (Fr,o, = 0'16) training. Subjects performed three sessions per week (20-30 min per session) at 70-85% of their maximal heart rates previously determined during the PRE tests. Venous blood samples (12 h overnight fasted) were collected before and immediately after passive/active exposures and physical training. The plasma was subsequently assayed for CCK, free tryptophan and branched chain amino acids (BCAA) . Data obtained during the acute study were analysed using a two-way repeated measures ANOV A. A three-way mixed ANOV A was applied to the chronic study data. Student's t test with Bonferroni's correction and Tukey's HSD test were incorporated for a posteriori comparisons.
In contrast, chronic normoxic or hypoxic training did not affect the resting or exercise CCK response despite a marked decrease in adiposity as determined by skinfold measurements.
These data suggest that peripheral CCK metabolism is (1) more sensitive to acute compared to chronic changes in energy expenditure and (2)  The compelling evidence linking small size at birth with later cardiovascular disease (Barker, 1998) has renewed and amplified scientific and clinical interests into the determinants of fetal growth. While the effects of maternal under-nutrition on fetal growth have been extensively studied (Lechtig et al. 1975;Godfrey, 1998), little is known about the effects of materno-fetal oxygen deprivation. Previously, it was reported that high altitude, rather than maternal economic status, is associated with reduced mean birth weight and increased infant mortality in Bolivia (Giussani & Barker, 1999). This study investigated the effect of high altitude, independent of maternal economic status, on body shape at birth and the incidence of very low birth weight « 2500 g) in highland and lowland communities of Bolivia.
Bolivia is geographically and socio-economically unique. It contains several highland (> 3500 m above sea level) and lowland « 500 m) cities which are inhabited by very economically divergent populations. Birth weights, body length and head circumference were compared between a high-(n = 100) and a low-(n = 100) income region of La Paz (3649 m; largest high altitude city) and a high-(n = 100) and a low-(n = 100) income region of Santa Cruz (437m; largest low altitude city). In addition, the frequency distribution across the continuum of birth weights was plotted for babies born from high-and low-income families in La Paz and Santa Cruz.
There was no difference in gest ation length amongst all groups studied. Mean birth weights were lower in babies from La Paz than in babies from Santa Cruz in both highand low-income groups. The cumulative frequency curve across all compiled birth weights was shifted to the left in babies from La Paz compared with those from Santa Cruz irrespective of economic status (Fig. 1). The frequency of low birth weight « 2500 g) was higher in babies from La Paz than from Santa Cruz in both high-and low-income groups. In addition , there was an association between high, but not low, altitude and an increase in t he ratio of head circumference to birth weight .
These data suggest that high altitude, independent of maternal economic status, promotes very low birth weight and altered body shape at birth.