Exercise 4: Endocrine System Physiology

Activity Q 1.4: What does it mean if a hormone is a tropic hormone?

A tropic hormone stimulates or inhibits another endocrine gland to secrete hormones.

Activity 4.2 Q: Explain the differences between Cushing's syndrome and Cushing's disease?

Cushing's syndrome is primary hypercortisolism resulting from an adrenal gland tumor. Cushing's disease is secondary hypercortisolism resulting from a pituitary tumor.

Activity Q 2.4: The amount of the corn syrup in the american diet has been described as alarmingly high. Predict the likely trends in the fasting plasma glucose levels of our children as they mature.

Our current diet trends are contributing to an increase in the prevelance of Type 2 diabetes in children.

Activity Q 2.3: What recommendations would you make to a patient with fasting plasma glucose levels in the impaired/borderline impaired range who was in the impaired/borderline impaired range for the oral glucose tolerance level?

Patients in the borderline range should be counseled to alter their diet and exercise. Their diet should limit the ingestion of simple sugars and their exercise level should be increases.

Activity Q 2.2: What are potential sources of variability when generating a glucose standard curve?

Some potential sources include experimental error in measurement of the reagents and inherent variability of the spectrophotometer measurements.

Predict Q 1.1: Make a prediction about the basal metabolic rate (BMR) of the remaining rats compared with the BMR of the normal rat you just measured.

The BMR of both remaining will be lower than the normal rat's BMR.

Activity Q 4.1: Discuss the benefits and drawback of giving glucocorticoids to young children that have significant allergy-induced asthma.

The benefits of glucocorticoid therapy include dilation of the airway. the drawbacks are the side effects associated with long term treatment. These include high blood pressure, bone thinning, high blood pressure, high blood sugar levels, suppression of the immune response and weight gain.

Predict Q 3.3: What effect will the calcitonin injections have on the calcitonins-treated rat's vertebral bone density?

The calcitonin injections will not change that rat's vertebral bone density.

Activity Q 1.1: What happened to the carbon dioxide the rat produced while in the sealed chamber?

The carbon dioxide is absorbed by the soda lime in the bottom of the glass chamber.

Activity Q 3.2: In hormone replacement therapy, how is the hormone dose determined by the presenting physicians?

The dosage of hormone replacement will be determined by the current levels of hormones found in the body by using blood tests.

Predict Q 3.2: What effect will the estrogen injection have on the estrogen-treated rat's vertebral bone density?

The estrogen injections will increase the rat's vertebral bone density.

Activity Q 1.2: What would happen to the fluid levels of the manometer if the rats in the sealed chamber were engaged in physical activity?

The fluid levels would increase due to the additional oxygen utilized for the exercising rat.

Activity Q 1.3: Describe the role of the hypothalamus in the production of thyroxine.

The hypothalamus secretes TRH which stimulates the release of TSH by the pituitary gland.

Activity Q 1.6: What is the role of the hypothalamus in the production of thyroid stimulating hormone (TSH)?

The hypothalamus secretes TRH which stimulates the release of TSH.

Predict Q 1.3: What do you think will happen to the metabolic rates of the rats after you inject them with TSH?

The normal rat will become hyperthyroidic and develop a goiter.

Predict Q 1.2: What do you think will happen to the metabolic rates of the rats after you inject them with thyroxine?

The normal rat will become hyperthyroidic but will not develop a goiter.

Predict Q 1.4: What do you think will happen to the metabolic rates of the rats after you inject them with PTU?

The normal rat will become hypothyroidic and develop a goiter.

Predict Q 2.1: How would you measure the amount of plasma glucose in a patient sample?

The optical density of the sample will be measured and the glucose concentration will be extrapolated from the glucose standard curve.

Activity Q: 2.1 How would you know if your glucose standard curve was aberrant and thus inappropriate for patient diagnosis?

The optical density should be proportional to the concentration of glucose producing a roughly straight line. Aberrant glucose standard curve would not produce a straight line.

Predict Q 3.1: What effect will the saline injections have on the control rat's vertebral bone density?

The saline injections will not change the rat's vertebral bone density.

Activity Q 1.5: How could you treat a thyroidectomized rat so that it functions like a "normal rat"? how do you verify that your treatments were safe and effective?

Thyroidectomized rats could be treated with thyroxine to replace the hormone that is not available because the thyroid gland is missing.