PhysioEX Exercise 4

Which of the following statements about metabolism is false?

All of the energy from metabolism is ultimately stored in the chemical bonds of ATP.

Thyroxine is

the most important hormone for maintaining the metabolic rate and body temperature.

Thyroid-stimulating hormone (TSH) is

produced in the pituitary gland.

An injection of TSH to an otherwise normal animal will cause which of the following?

goiter development

Thyrotropin-releasing hormone (TRH) is

secreted by hypothalamus

Which of the following statements is true?

The hypothalamus primarily secretes tropic hormones that stimulate the secretion of other hormones.

How would you treat a thyroidectomized animal so that it functions like a "normal" animal?

Provide the animal T4 supplements.

As a result of the missing hormone(s) in the hypophysectimized rat, what would be some expected symptoms?

decreased basal metabolic rate

An injection of thyroxine to an otherwise normal rat will cause which of the following?

hyperthyroidism

Why didn’t any of the rats develop a goiter after thyroxine injection?

In all cases, TSH levels were not elevated by the thyroxine injection.

Why did the normal rat develop a palpable goiter with the TSH injection?

The TSH receptors on the thyroid gland were excessively stimulated.

An injection of propylthiouracil to an otherwise normal animal will cause which of the following?

goiter development

Why did the normal rat develop a palpable goiter with the propylthiouracil injection?

The injection decreased the negative feedback mechanism on TSH.

Which rat had the fastest basal metabolic rate (BMR)?

The normal rat injected with thyroxine.

Why did the metabolic rates differ between the normal rat and the surgically altered rats?

because the surgically altered rats do have have a functioning thyroid gland. My prediction was correct.

If an animal has been thyroidectomized, what hormone(s) would be missing in its blood?

thyroxine

If an animal has been hypophysectomized, what effect would you expect to see in the hormone levels in its body?

decreased basal metabolic rate because no thyroxine production.

What was the effect of thyroxine injections on the normal rat’s BMR?

It increased BMR and made the thyroidectomized rat hyperthyroidic so the dose was too large.

What was the effect of thyroxine injections on the hypophysectomized rat’s BMR? How does the BMR in this case compare with the normal rat’s BMR? Was the dose of thyroxine in the syringe too large, too small, or just right?

The hypophysectoized rat’s BMR increased and made it hyperthyroidic. the dose was too high.

What was the effect of thyroid-stimulating hormone (TSH) injections on the normal rat’s BMR?

Overstimulation of thyroid gland to secret thyroxine which increased basal metabolic rate.

What was the effect of TSH injections on the thyroidectomized rat’s BMR? How does the BMR in this case compare with the normal rat’s BMR? Why was this effect observed?

It had no effect on the thyroidectomized rat’s BMR. It is lower than normal rat’s because there were no thyroid to be stimulated.

What was the effect of TSH injections on the hypophysectomized rat’s BMR? How does the BMR in this case compare with the normal rat’s BMR? Was the dose of TSH in the syringe too large, too small, or just right?

It increased BMR because the thyroid was stimulated by TSH. This made the rat hyperthyroidic and similar to the effect to normal rat. The dose was too large that’s why it caused hypethyroidism

Which of the following statements is false?

Insulin is a hormone secreted into the stomach to aid with starch digestion.

Which of the following statements is true?

All. plasma glucose levels are controlled by opposing actions of insulin and glucagon, plasma glucose can be converted into glycogen stored in liver and muscle cells, glucose is the primary fuel for nerve cell metabolism

A diagnosis of type 1 diabetes mellitus implies that

the pancreas is not producing sufficient insulin.

A diagnosis of type 2 diabetes mellitus implies that

the cells of the body are unresponsive to circulating insulin.

Glucagon is a hormone

that opposes the action of insulin.

A male patient has had successive fasting plasma glucose readings of 115, 110, and 122 mg/dl. The healthcare provider will inform him that

he appears to have impairment or borderline impairment of insulin-mediated glucose uptake by his cells.

To obtain an accurate spectrophotometric measurement of the glucose concentration in the sample

heparin is added to prevent blood clots.

In the spectrophotometric assay used in this experiment, the __________ as the glucose concentration in the sample increases.

optical density increases

A female patient has had successive fasting plasma glucose readings of 130, 140, and 128 mg/dl. The healthcare provider will inform her that

she has developed diabetes.

To maintain plasma glucose homeostasis

insulin-mediated transport of glucose into cells acts as negative feedback when plasma glucose levels rise.

A laboratory technician withdraws a blood sample from a vein in your upper arm knowing that

the plasma glucose concentration will be the same in both the arm vein and the index finger.

What is a glucose standard curve, and why did you need to obtain one for this experiment?

Glucose standard curve is a graphic tool to demonstrate the relationship between optical density and glucose concentration. You need it because you don’t have too many samples to compare with so you have to extrapolate.

Which patient(s) had glucose reading(s) in the diabetic range? Can you say with certainty whether each of these patients has type 1 or type 2 diabetes? Why or why not?

Patients 3 and 5 are in the diabetic range. You cannot say with certainty about whether they have type 1 or type 2 diabetes because they have the same symptomology which is high plasma glucose.

Describe the diagnosis for patient 3, who was also pregnant at the time of this assay.

She may have gestational diabetes due to her pregnancy.

Which patient(s) had normal glucose reading(s)?

Patient 1 has glood glucose under 110. Patient 2 is borderline diabetic.

What are some lifestyle choices these patients with normal plasma glucose readings might recommend to the borderline impaired patients?

Keep better control of food intake and exercise more.

Follicle-stimulating hormone (FSH)

stimulates ovarian follicle development.

Estrogen

is produced by developing ovarian follicles.

Calcitonin

works against the development of osteoporosis.

Which of the following statements is true?

The ovaries stop secreting estrogen after menopause.

Saline injections were used in this experiment to measure the effect of

a placebo on bone density.

In the ovariectomized rats used in this experiment

osteoporosis was evident prior to the injections of estrogen.

Injection of calcitonin into an ovariectomized rat will

Inhibit osteoclast activity and stimulate calcium uptake and deposition in long bones.

As the rat’s bone density increases

the X-ray scanning assay reports a less-negative T-score.

Why were ovariectomized rats used in this experiment? How does the fact that the rats are ovariectomized explain their baseline T scores?

Because there are no ovaries to produce estrogen. They are the baseline because no estrogen will be made to mitigate the onset of osteoporosis

What effect did the administration of saline injections have on the control rat? How well did the results compare with your prediction?

The baseline for T-score was -2.61, after 7 days, it became more negative because no other mechanisms could counter the osteoporosis. My prediction is wrong.

What effect did the administration of estrogen injections have on the estrogen-treated rat? How well did the results compare with your prediction?

The estrogen helped slowed the osteoporosis as seen with the less negative T-score that indicates osteopenia.

What effect did the administration of calcitonin injections have on the calcitonin-treated rat?

The effect of calcitonin was insignificant but it does help fight against osteoporosis.

What are some health risks that postmenopausal women must consider when contemplating estrogen hormone-replacement therapy?

Higher risk of uterine, breast, and colorectal cancer as well as small cell lung cancer.

Cortisol

is a hormone important in the body’s response to stress.

ACTH

is a tropic hormone that stimulates cortisol release.

CRH

has a tropic effect on the anterior pituitary gland.

Cushing’s syndrome refers to

a hypercortisolism, which could be iatrogenic.

A condition of hypocortisolism

refers to low levels of cortisol in the blood.

Under normal conditions, if the amount of secreted CRH increases, then

the amount of secreted ACTH will increase.

Under normal conditions, if the amount of secreted ACTH increases, then

the amount of secreted CRH will likely decrease.

Under normal conditions, if the amount of secreted cortisol increases, then

the amount of secreted ACTH will likely decrease.

If a hypersecreting pituitary tumor develops, then an expected outcome is

a diagnosis of Cushing’s disease.

If a hypersecreting adrenal cortex tumor develops, then an expected outcome is

abnormally low levels of CRH due to negative feedback.

A patient’s chart lists the diagnosis of Addison’s disease. Therefore, you expect

abnormally high levels of ACTH.

Which patient would most likely be diagnosed with Cushing’s disease (view Table 4.1 in Experiment Results)? Why?

Patient number 3 because he has both high level of corsisol and ACTH

Which two patients have hormone levels characteristic of Cushing’s syndrome?

Patients 2 and 5 because they have high cortisol levels and low ACTH levels

Patient 2 is being treated for rheumatoid arthritis with prednisone. How does this information change the diagnosis

This is called steroid diabetes which results in hyperglycemia.

Which patient would most likely be diagnosed with Addison’s disease (view Table 4.1 in Experiment Results)? Why?

Patient 4 because that person has low coritosl level and high ACTH level.