Final answer:
The relationship between hypoventilation and cerebral blood vessel resistance involves the balance of carbon dioxide and oxygen levels. Hypoventilation typically leads to hypercapnia, which can dilate cerebral vessels, decreasing resistance. In cases of hypoxia due to severe hypoventilation, vasoconstriction might occur, increasing resistance.
Step-by-step explanation:
Hypoventilation leads to increased levels of carbon dioxide in the blood. As a result, the systemic arterial concentrations of hydrogen ions increase, which can cause the blood to become more acidic. This condition stimulates peripheral chemoreceptors, prompting a need to increase ventilation to remove the excess carbon dioxide and lower the acidity, thereby increasing the systemic pH level. However, the question about the effect of hypoventilation on cerebral blood vessels resistance is more complex. Generally, increased carbon dioxide (hypercapnia) can cause cerebral blood vessels to dilate, which would decrease resistance. Nonetheless, hypoventilation, if severe, might lead to insufficient oxygen levels (hypoxia) which could potentially cause vasoconstriction and increase resistance.
Venoconstriction does not seem to be directly related to the question of the effect of hypoventilation on cerebral blood vessel resistance. However, it is an important aspect to consider in the overall understanding of blood circulation and blood pressure regulation. Venoconstriction typically leads to an increase in venous blood flow by reducing the surface area in contact with the blood but can increase the pressure in veins.