The ___ is the site of attachment of the embryo.

A. enhanced sodium ion loss in urine: Increasing the excretion of sodium would not address the underlying hydrogen ion excess or bicarbonate deficit. In fact, the kidneys typically attempt to retain sodium to maintain blood volume during the fluid loss associated with diarrhea. Electrolyte loss is a consequence of the illness rather than a corrective compensatory mechanism for pH.

B. increased respiratory rate and depth: The body compensates for metabolic acidosis by stimulating peripheral chemoreceptors to increase alveolar ventilation. This process, known as Kussmaul breathing, enhances the elimination of carbon dioxide from the blood. Reducing partial pressure of carbon dioxide shifts the carbonic acid-bicarbonate buffer equation to decrease the concentration of free hydrogen ions.

C. increased renin secretion: Renin secretion is a response to decreased blood pressure and volume resulting from fluid loss in diarrhea. While the subsequent production of aldosterone helps regulate electrolytes and blood pressure, it is not the primary mechanism for correcting systemic pH. Renin serves a hemodynamic rather than an immediate acid-base compensatory function.

D. hypoventilation: Decreasing the rate and depth of breathing would cause the retention of carbon dioxide, leading to an increase in carbonic acid. This would result in respiratory acidosis, which would exacerbate the existing metabolic acidosis instead of correcting it. Hypoventilation is a compensatory response for metabolic alkalosis, not acidosis.

A. myogenic mechanism: This is an autoregulatory response where vascular smooth muscle in the afferent arteriole contracts when stretched. This mechanism actually resists changes in blood flow and limits excessive filtration during high blood pressure. It acts as a protective brake rather than a promoter of filtrate formation.

B. colloid osmotic pressure of the blood: The presence of large plasma proteins like albumin creates an osmotic pull that keeps water within the glomerular capillaries. This pressure opposes filtration by drawing fluid back into the vascular space. High colloid osmotic pressure reduces the net filtration pressure at the glomerulus.

C. capsular hydrostatic pressure: As filtrate accumulates within the confined space of the glomerular capsule, it exerts a physical pressure against the filtration membrane. This back-pressure opposes the movement of more fluid out of the capillaries. It is a resistive force that must be overcome to form new filtrate.

D. glomerular hydrostatic pressure: This is the blood pressure within the glomerular capillaries, which is maintained at a higher level than other capillary beds. It provides the primary outward force that pushes water and solutes through the filtration membrane into the capsular space. It is the dominant promoter of glomerular filtration.