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Histo Exam 1 > Endocrine 2 > Flashcards

Endocrine 2 Flashcards

1
Q

What is the function of hormones T3 and T4?

A

act on all cells of the body to increase

a. basal metabolic rate
b. maturation processes
c. CNS activity

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2
Q

Which TH is more biologically active? How is it converted?

A

T3(5-10x more active)
T4 is converted to either T3 or rT3 (not active, little made) by the removal of iodine atom. liver converts some plasma T4 into T3

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3
Q

What proteins are responsible for transport of thyroid hormones in the blood?

A 
thyroxin-binding globin
and albumin (less)
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4
Q

The action of thyroid hormones is calorigenic effect, fuel metabolism, nervous system, cardiovascular system and sympathetic effect? what is the sympathetic effect?

A

upregulation of beta-adrenergic receptors

-increased responsiveness to catcholamines

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5
Q

When T3 and T4 (90% in this form) is released into capillaries what is recycled for reuse?

A

thyroglobulin not released in circulation and Iodine recycled

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6
Q

How are hormones stored in thyroid?

A

2-3 month supply in colloid

90% iodine stored in thyroid

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7
Q

What does TSH stimulate. List 5

A
  1. size of follicular cells
  2. # of organelles
  3. thyroglobulin, T3 and T4 synthesis
  4. thryoglobulin breakdown via receptor-mediated endocytosis
  5. T3 and T4 release
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8
Q

Parafollicular cells secret what polypeptide. What is its function. What controls this secretion. Is it dependent on pituitary control?

A

secretes calcitonin
function: lowers Ca2+ in plasma
control of secretion by feedback of calcium
independent from Pituitary control and TSH

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9
Q

what cell produces PTH? What is the function of Parathyroid hormone?

A

Chief cells
function : maintains Ca2+, P(O4)-3 &Mg2+
-stimulates vitamin D which is essential for calcium absorption

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10
Q

Where does muscarinic and nicotinic receptors found?

A

M: smooth, cardiac muscle and glands
N: motor end plate of skeletal muscle, sympathetic and parasympathetic ganglia and adrenal medulla

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11
Q

What are the structural differences between the Zona glomerulosa, zona Fasciculata, zona reticularis of the adrenal cortex?

A

ZG: large pyramidal cells with small dense nuclei with few lipid droplets in cytoplasm
-cells arranged in arches.
ZF: cells arranged in cords, large cells -filled with large lipid droplets and foamy appearance

both abundant in SER and many mitochondria
ZR:cells arranged in a meshwork pattern
-small cell-less lipid
-lipofuscin pigment
-nuvlear pycnosis
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12
Q

zona glomerulosa is responsible for a secretion of what mineralocorticoid? What does its function promote and where does the action take place?

A

aldosterone: increases Na+ absorption with water to increase blood pressure, decreases K+ and H+ released in urine.
- promotes NA retention
- DCT and CT of kidney and controlled by renin and angiotensin.

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13
Q

zona fasciculata is responsible for secretion of what glucocorticoid? How? and what is the function of this type of glucocorticoid?

A

cortisol
Increase stress-> increase ACTH->increase cortisol production

function:

  1. more sensitive to NE for smooth muscle
  2. carbohydrate metabolism
  3. decrease in glucose utilization
  4. increase blood glucose levels*
  5. gluconeogesis*
  6. protein catabolism
  7. FA mobilization from adipose tissue
  8. Anti-inflammatory
  9. prolonged high cortisol levels can cause muscle weakness
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14
Q

Zona reticularis responsible for what product

A

androgens (DHEA)

DHEA-S

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15
Q

ACTH stimulates

A
  1. cells of the zona fasciculata and reticularis
  2. synthesis and release of glucocorticoids
  3. increase in cell size and # of organelles
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16
Q

What are the 4 factors that regulate aldosterone? and how much does it increase?

A
  1. increase in potassium in ECF (greatly)
  2. increased in angiotensin 2 in ECF (greatly)
  3. increased Na+ ECF (slightly)
  4. ACTH (little effect)
17
Q

What is the mechanism of aldosterone secretion?

A

angiotensiogen->uses renin to cleave angiotensinogen to produce angiotensin 1->ACE to stimulate angiotensin 2

18
Q

If cortisol synthesis is blocked what happens to ACTH and androgen?

A

Production increase in both

19
Q

ACTH stimulates both zona fasciculata and reticularis to produce___.

A

androgens.

ACTH increase both cortisol and DHEA-S

20
Q

DHEA-S does not negatively feedback on ACTH-feedback on ACTH feedback to GnRH neurons mean?

A

puberty-androgen level increase without increase in cortisol

21
Q

What are the structural characteristics of adrenal medulla?

A

large ovoid cells in irregular cords around capillaries

  • well-developed golgi
  • dense core and homogeneous secretory granule
  • chromaffin cells
22
Q

What are the origin of adrenal medulla?

A

homologous with post-ganglionic neurons of sympathetic system

23
Q

What are the hormones produces of adrenal medulla?

A

catcholamines,

80% epinephrine, 20% NE

24
Q

What in the role of Epinephrine for metabolism and emergency situations?

A

Glycogenolysis- increase plasma glucose
CS: increase CO
RS: Increase O
SM: increase ATP

25
Q

What in the role of NorEpinephrine for metabolism and emergency situations?

A
  • maintain normal BP
  • increase in NE can lead to increase BP such as situations in heart attacks and hemorrhaging.
  • no metabolic effects
26
Q

What controls NE and E secretion?

A

hypoglycemia stimulates E secretion

-neural via sympathetic innervation

27
Q

Alpha cells . What color stain. What does it secrete? and how is the secretion controlled?

A

acidophillic, 20%

  • secrete glucagon (hyperglycemic factor)
  • causes increase of blood glucose via glycogenolysis.

control of secretion: low blood glucose levels, low FA levels, sympathetic and parasympathetic NS stimulate glucagon production

28
Q

What hormones increase blood glucose levels?

A

cortisol, epinephrine, T3, T4, and GH

29
Q

Beta cells. What color stain. What does it secrete? what happens to fat and AA uptake?

A

-basophilic stain (75%) larger than alpha cells
-secrete insulin (only hypoglycemic hormone)
to reduce blood glucose levels (storage in liver and skeletal muscles)
-storage of fat-cell permeability for glucose increase
-AA uptake and protein synthesis- increase plasma AA

30
Q

how is the secretion controlled for beta cells?

A

-high blood glucose levels, high blood FA levels, arginine, gastrin, CCK, secretin, glucagon, parasympathetic NS stimulate insulin production

31
Q

What inhibits insulin production?

A

sympathetic NS

32
Q

What type of cells don’t take up glucose?

A

cells in Nervous system

33
Q

Delta cells. stain. secretion

A

5%, don’t stain with normal stain, secrete somatostatin (GHIH)- decreases insulin and glucagon production; inhibits alpha and beta secretion

Histo Exam 1 (16 decks)

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