biology questions 30

3 questions for Biology

Question 1

Using what you know about osmotic pressure explain how higher levels of sodium in the kidney affect water retention. What hormone is responsible for the initiation of Na+ reabsorption by liver tubules? The hormone ADH also leads to water reabsorption from secretion flow but doesnâ€™t change ion concentrations to do so. How is this accomplished? Are these hormones secreted by the same tissues?

Must use the words/phrases:concentrations, passively, osmotic pressure, paracrine

Question 2

In humans, the hypothalamus regulates non–shivering thermogenesis through adrenal and thyroid hormone secretion. Would you expect to see this mechanism of thermoregulation in clod-blooded animals? Why? What are two examples of thermoregulating behavior in humans?

Must use the words/phrases:ectoderm/endotherm, heat-generating, environment,

Question 3

The excretory tubules of nephrons clear blood of toxic molecules through a 4-step process: 1) passive filtration, 2) active reabsorption (of nutrients), 3) active secretion, and 4) excretion, in that order. Imagine a carcinogen capable of mutating some step in this secretion flow. If a patient (non-diabetic) then shows high levels of glucose in their urine what step(s) of this filtration process have most likely received the mutation? What structure, through a â€œbeatingâ€ motion, is responsible for the flow of secretion in the tubules of flatworms?

Must use the words/phrases: small, selective transportation, flame bulb, waste, tubules, cilia