A 40-year-old man presents with nephrolithiasis or kidney stones. The

process of stone formation as seen in this patient begins with Randall plaques

found in the basement membranes of a structure that can be found only in the

renal medulla. In which of the structures do these plaques appear?

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?

A 30-year-old woman suffered a serious contusion

of her left lower extremity while working on a local construction site.

Unfortunately, rhabdomyolysis occurs, which is characterized by the breakdown

of skeletal muscle tissue and the release of its contents, including myoglobin,

into the bloodstream. Myoglobin is a risk to the kidneys, especially when

present in high concentrations in the bloodstream. It fills the renal tubules

in the form of protein depositions and can lead to acute kidney injury. On the

second day of hospitalization, the patient experiences a decrease in urine

output. In addition, the serum creatinine level increases significantly.

Elevated serum creatinine levels indicate a decline in renal function because of

the physiological filtration of creatinine as a waste product. It should be

physiologically filtered by the kidneys and excreted from the body in the

urine. Its elevated levels are therefore a marker of impaired renal function.

The picture shows an image of a renal biopsy obtained. Which of the labelled

parts is primarily used to monitor the osmolarity of tubular fluid?

A 48-year-old woman visits her physician

complaining of recurrent vaginal yeast infection. The doctor explains the

likelihood that the woman´s problem is acid-base imbalance. The normally low pH

in the vagina is maintained by which of the following?

An investigator is studying the clearance of respiratory particles in

healthy non-smokers. An aerosol

containing radio-labeled particles that are small enough to reach the

alveoli is administered to the subjects via a special mask. A

gamma scanner is then used to evaluate the rate of particle clearance from the

lungs. The primary mechanism of particle clearance most likely involves which

of the following cell types?

In his new project, the researcher focuses on

the possible causes and factors involved in the development of stroke. In the

case of ischemic stroke, there is a lack of blood supply to a certain part of

the brain tissue, which dies due to lack of oxygen and nutrients. He is very

interested in one type of cells and its contribution to the development of this

condition. These are the cells that are part of the blood-brain barrier,

regulating blood flow through the capillaries, removing and phagocytizing dying

cells and regulating the permeability of this barrier. They are found around

the endothelium of the capillaries, even outside the nervous system, and

partially replace the tunica media, which is no longer present in the

capillaries. What are these cells called?

Individuals with Marfan syndrome have mutations

in the fibrillin gene and commonly experience aortic aneurysm. What portion of

the arterial wall is most likely to be affected by the malformed fibrillin?

A 59-year-old woman is undergoing valve

replacement surgery. During this procedure, the malfunctioning valve is removed

and replaced with either a mechanical valve or a tissue valve from an animal

donor. If the removed valve was analyzed histologically, it would include which

of the following?

A 67-year-old homeless man is brought

to the emergency department by ambulance. He was found unresponsive by the

police. Despite appropriate first aid and immediate transport to the

hospital, he dies. Examination of the heart during autopsy shows normal size

and shape. A photomicrograph of a section of the heart obtained at

autopsy is shown. How does the amount of substance indicated by the arrow

relate to the person´s age?