M&n Week 4: Pathology Of The Pituitary

Front 1

What anatomical structure is the adenohypophysis derived from?

Back 1

Rathke's pouch
(located in the roof of the mouth)

Front 2

What type of tumor develops from small cells that remain along the line of embryologic ascent of the pituitary gland?

Back 2

Craniopharyngioma

Front 3

What is the neurohypophysis derived from?

Back 3

Hypothalamus
(downward growth of axons to the median eminence of the pituitary stalk and the posterior pituitary)

Front 4

What type of cells are acidophils and where are they located?

Back 4

Acidophils secrete polypeptide hormones:
1. Somatotrophs ---> GH
2. Lactotrophs --> prolactin

*Located in the anterior pituitary

Front 5

What type of cells are basophils and where are they located?

Back 5

Basophils secrete glycoprotein hormones:
1. Thyrotrophs --> TSH
2. Corticotrophs --> ACTH
3. Gonadotrophs --> LH, FSH
(Gonadotrophs also identified as chromophobes)

*Found in anterior pituitary

Front 6

Which hormones are secreted by the posterior pituitary?

Where are these hormones formed?

Back 6

1. ADH (vasopressin)
2. Oxytocin

*Formed in the hypothalamus (paraventricular and supraorbital nuclei)

Front 7

Which hormone inhibits prolactin?

Back 7

Dopamine

Front 8

Which hormones can stimulate prolactin if present in high concentrations?

Back 8

1. Thyrotropin releasing factor (TRF)
2. Estrogen

Front 9

How is the release of ADH stimulated?

Back 9

1. Increase in serum osmolality
2. Decrease in blood volume

Front 10

What is the most common cause of hyperpituitarism?

Which hormones are usually secreted?

Back 10

Monoclonal neoplasm (pituitary adenoma).

Prolactin, GH, ACTH most commonly secreted

Front 11

Pituitary adenomas are most often seen in which individuals?

Back 11

Young adults
(slightly more frequent in males)

Front 12

T or F

Overtly malignant pituitary neoplasms are rare.

Back 12

TRUE

(and when they do occur, they are generally nonfunctional)

Front 13

Name the rare syndrome that occurs due to extensive, spontaneous necrosis or sudden hemorrage of a pituitary adenoma.

Back 13

Pituitary apoplexy

Front 14

Which hormone is the most common secretory product of pituitary adenomas?

Back 14

Prolactin

Front 15

What is the effect of high levels of prolactin on pituitary gonadotrophin release?

What are the consequences of hyperprolactinemia in men and women?

Back 15

SUPRESSES gonadotropin release

Men --> infertility, impotence
Women --> anovulation and secondary amenorrhea

Front 16

How can hyperprolactinemia (due to pituitary adenoma) be treated nonsurgically?

Back 16

Dopamin agonists
(Bromocryptine)

Front 17

Syndrome that occurs before puberty, and is due to an increase in GH, causing exaggerated skeletal growth.

Back 17

Gigantism

Front 18

Syndrome that occurs after puberty and is caused by GH excess.

What are the physical characteristics associated with this syndrome?

Back 18

Acromegaly

Enlargement and coarsening of the face, hands, and feet.
Facial features: prominent forehead, protruding jaw, thick lips, and enlarged tongue

Front 19

What are some metabolic problems associated with acromegaly?

Back 19

1. Hypertension
2. Glucose intolerance
3. Osteoporosis

Front 20

How are gigantism and acromegaly treated?

Back 20

Surgery and/or radiation

Front 21

Which disease is caused by ACTH excess?

Back 21

Cushing's disease

Front 22

What is the most common anterior lobe hormone deficit?

Back 22

Growth hormone

Front 23

What usually causes hypopituitarism?

What disease results from this abnormality?

Back 23

Extensive destruction of the anterior lobe

*Panhypopituitarism (Simmond's disease)

Front 24

Growth hormone deficiency before puberty can have what physical consequences?

Back 24

1. Pituitary dwarfism
2. delayed sexual maturity

(After puberty, growth hormone deficiency is generally asymptomatic)

Front 25

In children, a gonadotropin deficiency may have what consequence?

Back 25

Delayed puberty

Front 26

What is the result of a gonadotropin deficiency in adult males and females?

Back 26

Females --> Amenorrhea, loss of secondary sex characteristics, atrophy of ovaries and external genitalia

Males --> aspermia, loss of secondary sex characteristics, and testicular atrophy

Front 27

A TSH deficiency causes what sort of symptoms?

Back 27

Symptoms of hypothyroidism

Front 28

A ACTH deficiency causes what sort of symptoms?

Back 28

Symptoms of hypoadrenalism

Front 29

Name the tumor which is derived from remnants of Rathke's pouch, and is usually benign and slow-growing.

Which individuals are the most likely candidates for this tumor?

Back 29

Crangiopharyngioma

*Children and young adults

Front 30

Craniopharyngiomas histologically resemble what type of tissue?

Back 30

Embryonic tooth enamel (ameloblastoma)

Front 31

What type of tumors arise in the pineal gland from germ cells that were embryologic "left-overs?"

Back 31

Germinomas

Front 32

What is the most frequent cause of hypopituitarism?

Back 32

Non-functioning adenoma
(leading to the destruction of the anterior lobe)

Front 33

Name the type of tumor consisting of sparsely granulated cells.

Back 33

Chromophobe adenoma
(can destroy anterior pituitary lobe, leading to hypopituitarism)

Front 34

Name the type of tumor that contains cells with a clear cytoplasm.

Back 34

Null cell adenoma
(can destroy anterior pituitary lobe, leading to hypopituitarism)

Front 35

Name the type of tumor that contains cells packed with mitochondria.

Back 35

Oncocytoma
(can destroy anterior pituitary lobe, leading to hypopituitarism)

Front 36

What syndrome results from an infarct of the anterior lobe secondary to hypotension or shock?

Back 36

Sheehan's syndrome

Front 37

Sheehan's syndrome is classically caused by..?

Back 37

Obstetric hemorrhage and hypotension
(potpartum pituitary necrosis)

Front 38

How does the pituitary gland change during pregnancy?

What is a potential risk associated with this?

Back 38

*During pregnancy, the pituitary gland doubles in size, compromising the portal veins

*Can lead to postpartum pituitary necrosis --> "Sheehan's syndrome"

Front 39

What might be the first sign of postpartum pituitary necrosis?

Back 39

Inabililty to lactate
(or may be identified when there is failure to resume menses. Lack of energy and loss of muscle strength is also present).

Front 40

Syndrome caused by the absence of a pituitary gland in an otherwise enlarged or normal sella.

Back 40

Empty sella syndrome

Front 41

Which syndrome results in renal retention of water with hypervolemia, hemodilution, and an inability to dilute urine?

Back 41

Syndrome of Inappropriate ADH (SIADH)

Front 42

What is the typical cause of Syndrome of Inappropriate ADH (SIADH)?

Back 42

Ectopic production of ADH by various neoplasms
(excessive ADH)

Front 43

Which disease results from deficient ADH secretion?

Back 43

Diabetes insipidus

Front 44

Which tissue is often destroyed in Diabetes insipidus?

Back 44

Posterior pituitary

Front 45

List 3 ways to diagnose Diabetes insipidus.

Back 45

1. Low urine osmolality
2. High serum osmolality
3. Increased urine concentration following administration of synthetic ADH

Front 46

Which disease results from sufficient ADH production, but an end-organ unresponsiveness to the hormone?

Back 46

Nephrogenic Diabetes insipidus

Front 47

What symptoms may result from an expanding pituitary mass?

Back 47

1. Visual impairment (bitemporal hemianopsia)
2. Headaches
3. Nausea
4. Vomiting

Front 48

From what embryologic tissue does Rathke's pouch arise?

Back 48

Oral ectoderm
(Arises from an infolding of this tissue which loses its connection ot the early oral cavity to become the adenohypophysis)

Front 49

Which structures laterally surround the pituitary gland?

Back 49

Contents of the cavernus sinus
(ICA, CN III, IV, V, VI)

*Cranial nerve deficits may be seen with pituitary enlargement

Front 50

Which sinus cavity is located directly below the pituitary gland?

Back 50

Sphenoid sinus

Front 51

What are the 3 divisions of the pituitary?

Back 51

1. Anterior lobe (adenohypophysis)
2. Posterior lobe (neurohypophysis)
3. Intermediate zone

Front 52

Which arteries provide blood supply to the pituitary gland?

Which division of the pituitary is supplied directly and which is supplied indirectly?

Back 52

Hypophyseal branches of the Internal carotid A
(superior and inferior branches)

*Posterior gland supplied DIRECTLY
*Anterior gland supplied INDIRECTLY

Front 53

How are hypophysiotropic factors carried from the hypothalamus to the anterior pituitary?

Back 53

Via hypophyseal portal system

Front 54

Where is the second capillary plexus located along the hypophyseal portal system?

Back 54

Anterior pituitary

Front 55

Dopamine inhibits which pituitary hormone?

Back 55

Prolactin

Front 56

Somatostatin inhibits which pituitary hormones?

Back 56

GH and TSH

Front 57

Which hormone stimulates LH and FSH?

Back 57

GnRH

Front 58

Which hormone stimulates ACTH?

Back 58

CRH

Front 59

What type of cells are found in the supraoptic/ paraventricular nuclei of the hypothalamus?

What do they secrete?

Back 59

Magnocellular

*Secrete oxytocin and ADH (associated with posterior pituitary)

Front 60

What type of cells are found in the median eminence?

Back 60

Parvicellular

The axons of the parvocellular neurosecretory cells of the PVN project to the median eminence, at the base of the brain, where their neurosecretory nerve terminals release peptides into blood vessels in the hypothalamo-pituitary portal system. The blood vessels carry the peptides to the anterior pituitary gland, where they regulate the secretion of hormones into the systemic circulation.

Front 61

Which hormones are secreted from the anterior pituitary?

Back 61

1. FSH
2. LH
3. ACTH
4. TSH
5. Prolactin
6. GH

(FLAT PiG)

Front 62

How are ADH and oxytocin transmitted from the hypothalamus to the posterior pituitary?

Back 62

Via neurofiber tracts
(neurophysin carrier protein)

Front 63

What are the 2 functions of oxytocin?

Back 63

1. Milk "let-down" reflex
2. Uterine contractions

*Letdown reflex – in lactating (breastfeeding) mothers, oxytocin acts at the mammary glands, causing milk to be 'let down' into subareolar sinuses, from where it can be excreted via the nipple

Front 64

What is the function of ADH?

Back 64

Controls resporption of water in the collecting duct to facilitate urine concentration

Front 65

What type of neural cells are found within the neurohypophysis and have elongated nuclei, which is embedded in a network of wavy nerve fibers?

Back 65

Pituicytes

Front 66

List 3 general causes of hyperpituitarism.

Back 66

1. Hypothalamic hypersecretion
2. Loss of negative feedback
3. Autonomous pituitary secretion

Front 67

What is a pituitary microadenoma?

What is the treatment?

Back 67

Adenoma <1 cm
*CANNOT produce mass effect

These tumors are NOT secreting and they do NOT produce a mass effect, so no treatment is necessary

Front 68

What is the difference between a micro and a macroadenoma?

Back 68

Macroadenomas can produce mass effects (even if non-functional), while microadenomas cannot.

Macroadenomas are treated, while microadenomas are not

Front 69

T or F

Prolactin-producing cells are both acidophilic and chromophobic.

Back 69

TRUE

Front 70

List 4 targets of prolactin.

Back 70

1. Breast tissue
2. Liver
3. Testis
4. Prostate

Front 71

Which hormone stimulates milk production?

Back 71

Prolactin

Front 72

Why does hypothyroidism lead to hyperprolactinemia?

Back 72

Because high concentrations of TRH stimulates prolactin secretion

Front 73

Prolactinomas can lead to what type of visual field deficit?

Back 73

Bitemporal hemianopsia
(due to compression of crossing fibers in the optic chiasm)

Front 74

What is a common lab test for GH adenomas?

Back 74

IGF-1
(indirect of GH --> hepatic prodoction of IGF-1)

Front 75

What type of functional cells secrete GH?

Back 75

Somatotrophs
(acidophils)

Front 76

ACTH stimulates the production of which hormones?

Back 76

(adrenal hormones)
Glucocorticoids and androgens

Front 77

What is the difference between Cushing syndrome and Cushing disease?

Back 77

Cushing syndrome --> excess glucocorticoids due to medications or adrenal tumor

Cushing disease --> excess glucocorticoids as result of ACTH-producing pituitary adenoma

Front 78

What type of adenoma is most prone to pituitary apoplexy?

Back 78

Null cell adenomas

Front 79

List 2 very general causes of hypopituitarism.

Back 79

1. Hypothalamic lesion/tumor
2. Destruction/compression of adenohypophysis

Front 80

How are invasive pituitary adenomas defined?

Back 80

Tumors that invade the dura or erode the sella turcica

Front 81

List 2 suprasellar causes of hypopituitarism.

Back 81

1. Craniopharyngioma
2. Germinoma

Front 82

"Empty sella" syndrome is more common in what type of individuals?

Back 82

Obese, mutliparous women.