a. Trace the pathway of light through the eye and explain the function of each structure. Briefly, compare the different ways in which a vitamin A deficiency and increased intraocular pressure could cause vision impairment. Which of these two is most likely to be reversible? Explain.

b. Describe the structure and function of receptors involved in taste and olfaction. Explain how and why each of the following situations would affect someone’s perception of flavor: 1) a medication results in chronic dry mouth, 2) an upper respiratory infection results in nasal congestion.