Deck 24: The Endocrine Glands

Question 1

On examination, a patient is found to have a bitemporal hemianopia. An enlargement of which anatomic structure is likely to cause this condition?

Answer 1

Bitemporal hemianopia is a loss of both temporal fields of vision and is due to the interruption of the optic nerve fibers derived from the medial halves of both retinae. Pressure on the optic chiasma by a tumor of the pituitary gland is the most common cause of the condition.

Question 2

A 40-year-old woman was involved in an automobile accident in which she sustained severe head injuries. Following a slow but uneventful recovery, she was released from the hospital without any residual signs or symptoms. Six months later, the patient started to complain of frequency of micturition and was passing very large quantities of pale urine. She also said that she always seemed thirsty and would often drink 10 glasses of water in one morning. Using your knowledge of anatomy and physiology, do you think there is any connection between the urinary symptoms and her automobile accident?

Answer 2

Yes, there is a connection between the accident and the urinary symptoms. This patient is suffering from diabetes insipidus caused by traumatic damage either to the posterior lobe of the pituitary gland or to the supraoptic or paraventricular nuclei of the hypothalamus. In any event, production of vasopressin was inhibited. It should be pointed out that a lesion of the posterior lobe of the pituitary is usually not followed by diabetes insipidus, since the vasopressin (antidiuretic hormone) produced by the neurons of the supraoptic and paraventricular nuclei escapes directly into the bloodstream. The action of vasopressin is to increase nary content of catecholamines. What hormones are secreted by the cells of the suprarenal medulla, and what is their action?

Question 3

A 17-year-old boy is taken by his parents to a pediatrician because the parents are concerned about his
excessive height and his complaints of fatigue and general lassitude. His standing height is 84 in. Questioning reveals that the boy has grown very rapidly since his thirteenth birthday. As a young child, he excelled in competitive sports, but for the past 3 years, he has experienced weakness and fatigue and has ceased to compete. His nose is broad, and his mandible and facial features appear larger than normal. He has large hands and feet and takes a size 18 shoe. There is no family history of unusual tallness. The patient is of normal intelligence, and the size of his external genitalia is normal for his age. His secondary sexual characteristics are normal. Using your knowledge of anatomy and physiology, make a diagnosis. Which cell groups are likely to have undergone pathologic changes? How do you account for the excessive tallness and the presence of a large mandible, hands, and feet in the same individual?

Answer 3

This patient has the signs and symptoms of gigantism and acromegaly caused by the excessive secretion of growth hormone by the acidophil cells of the anterior lobe of the pituitary gland. The condition started before the epiphyses of the long bones fused with the diaphysis, hence the gigantism, and continued growth after the fusion had taken place, hence the acromegalic changes.

Question 4

A 25-year-old woman has been in labor for several hours. Her uterine contractions are weak, and her labor is not progressing. The obstetrician decides to give her some Pitocin, a synthetic oxytocin hormone. What is the effect of oxytocin on the uterus? In which part of the pituitary is this hormone normally released into the bloodstream?

Question 5

A 45-year-old woman visits her physician for a medical checkup. The woman has no complaints, but her husband has noted the following changes in her appearance during the previous year: She has gained a considerable amount of weight and is becoming mentally and physically slow, often falling asleep while talking to friends. Her face is puffy, and her hair is dry and has developed a tendency to fall out. The lateral third of her eyebrows is missing. Her skin is pale and dry, and her voice is becoming deep and her articulation slow. She frequently complains of the cold when others feel warm. Using your knowledge anatomy and physiology, what do you think is wrong with this patient? What do you think would be the appropriate treatment?

Question 6

A 25 -year-old woman complaining of a swelling on the front of the neck and breathlessness visited her physician. On examination, a small, solitary swelling of firm consistency was found to the left of the midline of the neck below the thyroid cartilage of the larynx. The swelling was not attached to the skin but moved upward on swallowing. About 2 weeks previously the swelling had suddenly increased in size and had become tender to touch; following this increase in size the patient became breathless.

-The following statements concerning this case would suggest a diagnosis of adenoma of the thyroid gland except which?

A) The pretracheal layer of deep cervical fascia binds the thyroid gland to the larynx, which moves upward on swallowing.
B) Each lobe of the thyroid gland is closely related to the sides of the trachea.
C) The isthmus of the thyroid gland was found to cross in front of the third, fourth, and fifth rings of the trachea.
D) The sudden increase in the size of the swelling can be explained by a hemorrhage into the adenoma.
E) The swelling was located superficial to the left sternothyroid muscle.
F) The breathlessness was caused by the adenoma pressing on the trachea, partially occluding the lumen.

Question 7

A 35-year-old woman had a partial thyroidectomy for the treatment of thyrotoxicosis. During the operation a ligature slipped off the right superior thyroid artery. To stop the hemorrhage, the surgeon blindly grabbed for the artery with artery forceps. The operation was completed without further incident. The following morning the patient spoke with a husky voice.

-The following statements about this patient would explain the husky voice except which?

A) Laryngoscopic examination revealed that the right vocal cord was slack, causing the huskiness of the voice.
B) The vocal cord is tensed by the contraction of the cricothyroid muscle.
C) The cricothyroid muscle tilts back the cricoid cartilage and pulls forward the thyroid cartilage.
D) The cricothyroid muscle is innervated by the recurrent laryngeal nerve.
E) The superior thyroid artery is closely related to the external laryngeal nerve.

Question 8

Following a total thyroidectomy for carcinoma of the thyroid gland, a 55-year-old man noticed tingling and numbness of the fingers, toes, and lips. Painful cramps of the hands and feet were also experienced. Strong muscle spasms producing adduction of the thumb, flexion of the wrist and metacarpophalangeal joints, and plantar flexion of the feet also occurred. Laboratory examination of the blood revealed a blood calcium level of $4 \mathrm{mg} / 100 \mathrm{~mL}$ . Which organ was damaged during the total thyroidectomy?

Question 9

An 18-year-old woman went to her physician because she had noticed a swelling in the midline of her neck. She said she had first noticed this swelling 3 years previously, and it had gradually increased in size. On physical examination, a small swelling was found in the midline of the neck; it measured about $0.5 \mathrm{in} .(1.25 \mathrm{~cm}$ ) in diameter. It was situated just below the body of the hyoid bone, was soft and fluctuant, and moved upward on swallowing. Nothing else abnormal was discovered.

-The physician made the diagnosis of thyroglossal cyst based on the following symptoms and signs except which?

A) The swelling was not hard.
B) The swelling was fluctuant.
C) The swelling was located in the midline of the neck.
D) It moved upward on swallowing, which indicated that it was tethered to tissue associated with the thyroid gland.
E) A thyroglossal cyst is always found below the hyoid bone.

Question 10

A 38-year-old man is admitted to the hospital for laboratory tests. When seen by his physician, he complains of increasing tiredness and muscular weakness over the previous year. He has experienced five attacks of nausea and vomiting, and diarrhea during this period. His reason for visiting his physician is that his friends have noticed that his skin is becoming darker. After a complete physical examination, a diagnosis of Addison's disease is made, and it is confirmed by laboratory tests. What is the cause of Addison's disease? The secretions of which hormones are defective in this disease? What is responsible for the weakness and increased pigmentation of the skin in this condition?

Question 11

A 29-year-old man recently experienced what he describes as severe pounding palpitations. The attacks had lasted about 20 minutes each and had been accompanied by severe sweating, headache, and paleness and coldness of the skin. While in the hospital clinic he has another attack. His pulse rate is 120 beats per minute, and his blood pressure is $240 / 140 \mathrm{~mm} \mathrm{Hg}$ . A preliminary diagnosis of pheochromocytoma is made, which is later confirmed by analysis of the uri-nary content of catecholamines. What hormones are
secreted by the cells of the suprarenal medulla, and
what is their action?

Question 12

A 51-year-old man is concerned because he has noticed during the past few weeks that he has started to urinate more frequently and is always hungry and thirsty. He is also worried because he has been treated for skin infections on six occasions during the past year. The fasting blood glucose level is measured, and a glucose tolerance test is performed. The results show that the patient has diabetes mellitus. What is the normal fasting blood glucose level? Why does glucose appear in the urine in diabetes mellitus? What is the underlying cause of diabetes mellitus?

Question 13

A 21 -year-old man sustains a severe injury to the perineum following an explosion of a road-side bomb by a terrorist. The surgeon is forced to amputate the scrotum and remove both testes. Using your knowledge of physiology, describe the changes that will take place because of the absence of testosterone. Is testosterone produced in patients with bilateral undescended testicles?

Question 14

What are the clinical signs and symptoms of menopause? What is responsible for menopause? Is it caused by a cessation of the activity of the hypothalamus, a cessation of the activity of the pars anterior, or a failure of the ovary to respond to hormonal stimulation from the pituitary?
the absorption of water in the distal convoluted tubules and collecting tubules of the kidney.