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Advanced: Physiology

Give 1-2 paragraph or more detailed explanation for each:

1. When an adult athlete trains strenulously at high altitudes (eg. in the Rocky Mountains for a period of months, he/she is likely to experience an increase in the concentration of oxygen carying cells in the blood, which is an example of physiological acclimatization, and this will be followed by development of a large, barrel-shaped chest, which is an example of developmental acclimatization. Explain?
2) A stimulus to which afferent neurons X, Y and Z are sensitive is detected in the middle of Y's receptive field. The same stimulus simultaneously activates receptors on the periphery of the receptive fields of X and Z. Is the explanation the fact that neuron Y activates inhibitory interneurons that directly inhibit the synaptic transmission of neurons X and Z.
Explain answer?
3) What is the result of lateral inhibition in the somatic sensory system? Explain answer?
4) What causes muscle fatigue after long-duration, low intensity exercise? Explain?
5) Is the optimal length of a skeletal muscle the shortest length the muscle can achieve while attached to bone, because the amount of overlap between thick and thin filaments is maximal there? Explain?

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1) hypoxia is the principle stimulus for causing an increase in red blood cell production. ordinarily in full acclimatisation to low oxygen the hematocrit rises from a normal value of 40-45 to an average of 60, with an average increase in hemoglobin concentration from a normal of 15gram/dl to about 20 gram/dl.
<br> many natives in the andes and himalayas live at altitudes above 13000 feet, one group in peruvian andes lives at 17500 feet and works a mine at an altitude of 19000 feet. many of these natives are born at these altitudes and live all their lives. in all aspects of acclimatisation, the natives are superior to even best acclimatised low landers even though the low landers might have also lived at high altitudes for 10 or more years. acclimatisation of the natives begins in infancy. the chest size is greatly increased whereas the body size is somewhat decreased giving a high ration of ventilatory capacity to body mass. in addition there hearts particularly the right side of the heart which proviides a high pulmonary arterial pressure to pump blood through greatly expanded pulmonary capillary system are considerably larger than the hearts of low landers. the delivery of the oxygen by the blood to the tissues is also highly facilitated in these natives. the arterial oxygen pressure in the natives at high altitudes is 40 mm Hg but because of the greater quantity hemoglobin the quantity of oxygen in the arterial blood is greater than in the blood of natives at the lower altitudes. venous partial pressure (oxygen) in the high altitude natives is only 15 mm Hg less than the venous partial pressure (oxygen)for the low landers, despite the low arterial partial oxygen pressure indicating that oxygen transport to the tissues is exceedingly effective in naturally acclimatised high altitude natives.
<br>2)in a highly condensed neuron pool each input fibre provides massive number of branching terminals to hundreds or thousands of neurons in its distribution field. in the central portion of the ...