Endocrine 1 pituitary CLASSICAL ALGORITHM PITUITARY ANTERIOR POSTERIOR

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Endocrine. 1* pituitary

Endocrine. 1* pituitary

CLASSICAL ALGORITHM • PITUITARY • ANTERIOR • POSTERIOR • THYROID • PARATHYROID • PANCREAS

CLASSICAL ALGORITHM • PITUITARY • ANTERIOR • POSTERIOR • THYROID • PARATHYROID • PANCREAS (endo. ) • ADRENAL • CORTEX • MEDULLA • DEGENERATION (aka, “involution”) • INFLAMMATION • NEOPLASM • BENIGN • MALIGNANT

BETTER ALGORITHM • PITUITARY • ANTERIOR • POSTERIOR • THYROID • PARATHYROID • PANCREAS

BETTER ALGORITHM • PITUITARY • ANTERIOR • POSTERIOR • THYROID • PARATHYROID • PANCREAS (endo. ) • ADRENAL • CORTEX • MEDULLA • NON-NEOPLASTIC • HYPER-function • HYPO-function • NEOPLASTIC • FUNCTIONAL • NON-FUNCTIONAL • Functional endocrine malignancies are RARE. Why? *****

FEEDBACK SYSTEMS • CORTEX, SUBCORTEX? • HYPOTHALAMUS • ANTERIOR PITUITARY • ENDOCRINE GLAND •

FEEDBACK SYSTEMS • CORTEX, SUBCORTEX? • HYPOTHALAMUS • ANTERIOR PITUITARY • ENDOCRINE GLAND • END ORGAN • HYPOTHALAMUS Positive and negative feedback systems are the principles of of the endocrine system and there effects upon each other and target organs. The concept of the so called pituitary as being the MASTER gland, has long been abandoned!

Ant. Pit Wi. Fi Post. Pit Wire d Generally, “releasing” hormones are between the

Ant. Pit Wi. Fi Post. Pit Wire d Generally, “releasing” hormones are between the hypothalamus and adenohypophysis, and “stimulating” hormones are between the pituitary and other major endocrine glands. Build up of a hormone to tell the hypothalamus and pituitary to DECREASE production is called NEGATIVE FEEDBACK. Build up of a hormone to tell a gland to INCREASE production is called POSITIVE FEEDBACK. It is important to understand the difference between POSITIVE and NEGATIVE feedback. Feedback systems are the basis of endocrinology.

Anterior pituitary lobe = adenohypophysis = Rathke’s pouch = pars distalis. Hormones released here

Anterior pituitary lobe = adenohypophysis = Rathke’s pouch = pars distalis. Hormones released here also made here. Anterior lobe is Wi. Fi. Posterior pituitary lobe = neurohypophysis = infundibulum = pars nervosa. Hormones released here are made in the hypothalamus. Posterior lobe is Hard. Wired.

HORMONES • POLYPEPTIDE (2 nd MESSENGER) • STEROID (DIRECT on NUCLEUS) Overall cellular mechanisms

HORMONES • POLYPEPTIDE (2 nd MESSENGER) • STEROID (DIRECT on NUCLEUS) Overall cellular mechanisms of action of the two major classes of hormones, polypeptide and steroid. Second Messenger: 1) -glycerol 2) c-amp, c-gmp 3) NO, CO

ACIDOPHILS BASOPHILS CHROMOPHOBE S A I AXONS P AXONS and “PITUI-”cytes

ACIDOPHILS BASOPHILS CHROMOPHOBE S A I AXONS P AXONS and “PITUI-”cytes

A I P All three lobes of the pituitary: Anterior, intermediate, and posterior lobes.

A I P All three lobes of the pituitary: Anterior, intermediate, and posterior lobes. Note that the pituitary also has a “portal” circulation, i. e. , artery capillari es veins capillaries, rather than just a c v. Why? Ans: to create a “secondary” circulation between the pituitary and the hypothalamis releasing factors!

The differentiation between acidophils and basophils is usually not too difficult unless the stain

The differentiation between acidophils and basophils is usually not too difficult unless the stain is really lousy. Chromophobes are uncommon, and have minimal cytoplasm and no granules. Chromophobe cytoplasm stains close to basophil cytoplasm in color, but is less granular and has is a minimal cytoplasm. Can you find a few chromophobes here?

ANTERIOR PITUITARY • ACIDOPHILS (growth) Hormones from basophils go • GROWTH Hormone to other

ANTERIOR PITUITARY • ACIDOPHILS (growth) Hormones from basophils go • GROWTH Hormone to other endocrine glands, • PROLACTIN thyroid, adrenal cortex, ovary, • BASOPHILS testis. Cells from acidophils do NOT. (trophs) Acidophils make GROWTH • TSH related hormones. • ACTH Basophils make hormones • LH, FSH which STIMULATE OTHER endocrine glands. Chromophobes make NOTHING.

The posterior pituitary (aka, pars nervosa or neurohypophysis) looks like typical brain tissue. Why?

The posterior pituitary (aka, pars nervosa or neurohypophysis) looks like typical brain tissue. Why? Ans: It IS typical brain tissue. The pituicytes are glial cells. Herring bodies are massively dilated terminal axons from the hypothalamus, which RELEASE the hypothalamic made hormones.

POSTERIOR PITUITARY The posterior pituitary does not make these hormones, it just releases them.

POSTERIOR PITUITARY The posterior pituitary does not make these hormones, it just releases them. The hypothalamus actually makes the hormones and transfers it down the stalk to the neurohypophysis • OXYTOCIN (contracts uterine smooth muscle) • VASOPRESSIN (ADH) (vasoconstriction, gluconeogenesis, platelet aggregation, release of Factor-VIII and v. Wb factor, concentrates urine, main effects on kidney and brain)

PITUITARY PATHOLOGY • CLINICAL FEATURES, mimic the endocrine effects, visual effects, or mass effects)

PITUITARY PATHOLOGY • CLINICAL FEATURES, mimic the endocrine effects, visual effects, or mass effects) • FUNCTIONING ADENOMAS • HYPO-PITUITARISM • POSTERIOR PITUITARY SYNDROMES • HYPOTHALAMIC (SUPRASELLAR) TUMORS

CLINICAL FEATURES • HYPER: growth(a), lactation(a), thyroid(b), adrenal cortex(b) • HYPO: growth, thyroid, adrenal

CLINICAL FEATURES • HYPER: growth(a), lactation(a), thyroid(b), adrenal cortex(b) • HYPO: growth, thyroid, adrenal cortex • MASS EFFECT: visual fields, brain

Note the extreme proximity of the pituitary stalk (infundibulum) to the optic chiasm

Note the extreme proximity of the pituitary stalk (infundibulum) to the optic chiasm

G A L A C T O R R H E A

G A L A C T O R R H E A

GIGANTISM (excess somatotropin [GH] BEFORE epiphyseal closure) Recognize this famous pituitary giant? What kind

GIGANTISM (excess somatotropin [GH] BEFORE epiphyseal closure) Recognize this famous pituitary giant? What kind of cells of the pituitary might be proliferating here? (acidophil or basophil)

ACROMEGALY: (excess somatotropin What kind of cells of the pituitary might be proliferating here?

ACROMEGALY: (excess somatotropin What kind of cells of the pituitary might be proliferating here? (acidophil or basophil) [GH] AFTER epiphyseal closure)

STRIAE MOON FACIES BUFFALO HUMP What kind of cells of the pituitary might be

STRIAE MOON FACIES BUFFALO HUMP What kind of cells of the pituitary might be proliferating here? (acidophil or basophil) Which layer of the adrenal cortex (G, F, R), do you think is primarily involved?

Normal pituitary. With Turkish saddle, i. e. , sella turcica.

Normal pituitary. With Turkish saddle, i. e. , sella turcica.

Find the pituitary adenoma

Find the pituitary adenoma

BITEMPORAL HEMIANOPSIA What part of the optic nerves/chiasm/tracts would have to be injured to

BITEMPORAL HEMIANOPSIA What part of the optic nerves/chiasm/tracts would have to be injured to produce this?

Usually the bitemporal hemianopsia is NOT perfectly symmetrical. Why? Because pituitary tumors are under

Usually the bitemporal hemianopsia is NOT perfectly symmetrical. Why? Because pituitary tumors are under no law to grow perfectly midline.

HYPO-pituitarism • Pituitary tumors, functional or not. • NON-pituitary tumors, primary or metastatic •

HYPO-pituitarism • Pituitary tumors, functional or not. • NON-pituitary tumors, primary or metastatic • Pituitary surgery, of course • Radiation, of course • “Apoplexy”, i. e. , sudden hemorrhage • Sheehan’s syndrome (Post-partum ischemic necrosis) • Cysts (Rathke’s cleft) • Empty sella syndrome, (is NOT a disease) • Genetic defects (pit-1 gene mutations)

The usual differential of hypopituitarism, hopefully, all logical. ESS is: Primary ESS happens when

The usual differential of hypopituitarism, hopefully, all logical. ESS is: Primary ESS happens when a small anatomical defect above the pituitary gland increases pressure in the sella turcica and causes the gland to flatten out along the interior walls of the sella turcica cavity. Primary ESS is associated with obesity and hypertension in women. The disorder can be a sign of idiopathic intracranial hypertension. Secondary ESS is the result of the pituitary gland regressing within the cavity after an injury, surgery, or radiation therapy. Individuals with secondary ESS due to destruction of the pituitary gland have symptoms that reflect the loss of pituitary functions, such as amenorrhea, infertility, fatigue, and intolerance to stress and infection.

POSTERIOR pituitary • DIABETES INSIPIDUS • SIADH (Syndrome of Inappropriate Andi. Diuretic Hormone)

POSTERIOR pituitary • DIABETES INSIPIDUS • SIADH (Syndrome of Inappropriate Andi. Diuretic Hormone)

DIABETES INSIPIDUS • ADH deficiency • Head trauma, tumors, inflam. hypothal/pit • Hyperdiureses with

DIABETES INSIPIDUS • ADH deficiency • Head trauma, tumors, inflam. hypothal/pit • Hyperdiureses with LOW sp. gr. Vasopressin increases water permeability of kidney collecting duct by inducing translocation of aquaporin-CD water channels in the kidney nephron collecting duct plasma membrane.

Inappropriate ADH • ADH EXCESS (SIADH) • Hyponatremia (hypervolemia), cerebral edema, neurologic symptoms •

Inappropriate ADH • ADH EXCESS (SIADH) • Hyponatremia (hypervolemia), cerebral edema, neurologic symptoms • Neoplasms, esp. Small Cell CA. • NON-neoplastic lung diseases • Posterior pituitary injury (SIADH) is characterized by excessive release of ADH, or vasopressin, from the posterior pituitary gland or another source