A 7-year-old girl

presents with complaints of increased urination (polyuria), increased thirst

(polydipsia), and increased hunger (polyphagia). Despite the increase in hunger,

she has lost weight, and she complains at times of having difficulty seeing her

computer screen or the board at school. Tests reveal elevated glucose in her

urine (glucosuria), and she is diagnosed with type 1 diabetes mellitus. The

glucosuria in this patient is due to an increased amount of glucose filtered by

the corpuscle due to elevated blood sugar, which overwhelms the ability of the

tubular system to recapture this glucose. The portion of the tubular system

that recaptures glucose from her ultrafiltrate (provisional urine) has which of

the following histologic characteristics?