EXAM #2: ENDOCRINE PANCREAS ANATOMY Flashcards

1
Q

What are pancreatic islets embryologically derived from?

A

Endoderm

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2
Q

What hormone is secreted by Beta cells in the pancreas?

A

Insulin

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3
Q

What hormone is secreted by Alpha cells in the pancreas?

A

Glucagon

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4
Q

What hormone is secreted by Delta cells in the pancreas?

A

Somatostatin

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5
Q

What is contained in an immature secretory vesicle of the beta cells? What happens in this vesicle?

A

Proinsulin, which is cleaved into Insulin and Protein C

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6
Q

How does Clathrin differentiate between an immature vesicle and mature vesicle in the Beta cell?

A
Immature= clathrin coated 
Mature= no clathrin
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7
Q

Which has a longer half-life, insulin or protein c?

A

Protein C

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8
Q

Is GLUT-2 dependent or independent of insulin?

A

Independent

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9
Q

What is the mechanism of insulin release from the beta cells?

A

1) Glucose in via GLUT-2
2) Glycolysis increases ATP
3) ATP binds K+ sensitive channel, inactivating it and leading to membrane depolarized (Sulfonylurea Receptor)
3) Ca++ enters voltage gated channels
4) Insulin is released via exocytosis

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10
Q

What drugs target the K+ channel necessary for insulin release?

A

Sulfonylurea class drugs i.e.

  • Gliclazide
  • Glimepiride
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11
Q

What transporter is necessary for glucose entry in target cells?

A

GLUT-4

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12
Q

Is GLUT-4 dependent or independent of insulin?

A

Dependent

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13
Q

What does insulin do to target cells?

A
  • Causes insertion of GLUT-4 transporters into membrane

- Glucose enters the cell

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14
Q

What is the embryologic origin of the adrenal cortex?

A

Mesoderm

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15
Q

What is the embryologic origin of the adrenal medulla?

A

Neural crest cells

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16
Q

What is required for the differentiation of neural crest cells to chromaffin cells in the adrenal medulla?

A

Cortisol

17
Q

What is the mnemonic to remember the parents vessels of the suprarenal arteries?

A

IPAR

Inferior phrenic= superior suprarenal a.
Aorta= middle suprarenal a.
Renal= inferior suprarenal a.

18
Q

What is the origin of the cortical and medullary arteries?

A

Supracapsular arterial plexus (plexus under the capsule from the suprarenal a)

19
Q

What capillaries receives the hormones from the adrenal cortex?

A

Sinusoidal capillaries in the cortex

20
Q

Where does the right suprarenal vein empty?

A

IVC

21
Q

Where does the left suprarenal vein empty?

A

Left renal vein

22
Q

What are the three zones of the adrenal cortex?

A

GFR:

Glomerulosa
Facsiculata
Reticularis

23
Q

What is the mnemonic to remember the hormones released from the zones of the adrenal cortex?

A

Salt, sugar, sex

Aldosterone= G
Cortisol= F
Androgens= R
24
Q

Histologically, what do you NOT see in the adrenal cortex would be expected b/c of the glands high output of secretory products?

A

Secretory vesicles; steroid hormones diffuse across membrane unlike peptide hormones

25
Q

ACTH has a stimulatory effect on which two parts of the adrenal cortex?

A

Fasiculata and reticularis, NOT Glomerulosa

26
Q

What is the expected gross finding in the setting of ACTH excess i.e. Cushing’s?

A

Cortical hypertrophy contributed by Fasiculata and Reticularis ONLY

27
Q

What hormone has a major inhibitory effect on ACTH and cortisol secretion?

A

Glucocorticoids

28
Q

What segmental levels of the SNS innervate the adrenal medulla?

A

T8-L1

29
Q

Catecholamines are derived from what amino acid?

A

Tyrosine

30
Q

List the steps in catecholamine synthesis?

A

1) Tyrosine
2) DOPA
3) Dopamine
4) NE
5) Epinephrine

31
Q

What enzyme converts NE to Epi? What hormone activates this enzyme?

A

Phenylethanolamine-N-methyltransferase, which requires cortisol

32
Q

In catecholamine synthesis, which is the only product that is NOT made in the cytoplasm?

A

NE

*Dopamine to NE enzymatic step occurs in the secretory vesicle

33
Q

When catecholamine synthesis increases, what binding protein also increases?

A

Chromogranin

34
Q

What is the Organ of Zuckerkandl?

A

Ectopic adrenal-medulla tissue in the region of the aortic bifurcation

35
Q

A tumor of the Organ of Zuckerkandl i.e. a pheochromocytoma, is expected to increase the output of what?

A

Norepinehprine

*Without cortisol from the adrenal cortex, cannot convert NE to Epi

36
Q

In Congenital Adrenal Hyperplasia, with the enzyme that produces cortisol deficient, describe the sequence of events that results in ambiguous genitalia in the female?

A

1) Decreased cortisol and shunting down the other pathways
2) Adrogens increased
3) Decreased cortisol leads to increased ACTH causing positive feedback and increased androgens

*Leads to ambiguious in the female patient