Endocrine part 2 - thyroid, parathyroid, pancreas, adrenal Flashcards

1
Q

Where is the thyroid gland located?

A

anterior to tracheal rings 2-3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What separates the right and left lobes of the thyroid?

A

isthmus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does each lobe of the thyroid gland consist of?

A

follicles filled with colloid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the characteristics of a thyroid follicle?

A
  • single layer of epithelium
  • cuboidal or columnar
  • central lumen of colloid
  • thyroglobulin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Follicular epithelium has receptors for __________________

A

thyroid stimulating hormone (TSH) from anterior pituitary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the thyroid epithelium control?

A

synthesis (exocrine) and secretion (endocrine) of thyroid hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the process of exocrine part of thyroid hormone synthesis?

A
  1. uptake amino acids and iodine
  2. thyroglobulin (TGB) synthesied on rough ER
  3. addition of idoine to tyrosine residues of TBG
  4. released into lumen via exocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Thyroid hormones are stored extracellularly as _______

A

thyroglobulin (TGB)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the process of the endocrine part of thyroid hormone synthesis?

A
  1. endocytosis/digestion of colloid
  2. colloid droplets fuse with lysosomes
  3. digestive enzymes breakdown TGB releasing T3, T4, and iodine
  4. T3 and T4 diffuse through membrane into capillary
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which thyroid hormone is secreted more and which is more potent?

A

more T4 is secreted
T3 is 3-4x more potent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the functions of thyroid hormone?

A
  • stimulates basic metabolic rate
  • augments thermogenesis
  • augments glucose production
  • required for normal development of CNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where are parafollicular/ C cells found?

A

isolated clusters between follicles or within the follicular epithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What do parafollicular/ C cells produce?

A

calcitonin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does calcitonin do?

A

decrease calcium concentration by inhibiting bone resorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does hypercalcemia do to calcitonin secretion?

A

stimulates calcitonin due to high blood levels of calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the symptoms of hyperthyroidism?

A

increased metabolic rate
weight loss
hyperactivity
heat intolerance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the disease associated with excessive production of TSH?

A

hyperthyroidism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the main symptoms of Grave’s disease?

A

exopthalamos (collagen deposition posterior to eyeball)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What causes hyperthyroidism?

A
  • excessive stimulation by adenophyophysis
  • loss of feedback control by thyroid gland (grave’s disease)
  • ingestion of T4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What causes grave’s disease?

A
  • autoimmune disorder that produces antibodies to the receptors for TSH on the follicular epithelium
  • antibodies bind to receptor and chronically stimulate it
  • results in too much circulating thyroid hormone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the symptoms of hypothyroidism?

A

low metabolic rate
feeling of being cold
weight gain
photophobia (thyroid associated eye disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What disease is caused by insufficient production of thyroid hormone?

A

hypothyroidism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What can cause hypothyroidism?

A
  • decreased iodine intake
  • loss of pituitary stimulation
  • post-therapeutic or destruction of thyroid by immune system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the treatment for hypothyroidism?

A

oral thyroid medication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Endemic goiter is caused by ________________________

A

iodine deficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How can goiter be avoided?

A

adding iodine to the diet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are the two types of secretory cells in the parathyroid gland?

A

chief cells
oxyphil cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the most abundant secretory cell in the parathyroid gland?

A

chief cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What do the chief cell secrete in the parathyroid?

A

parathyroid hormone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Which parathyroid secretory cell contains a large number of mitochondria?

A

oxyphil cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Parathyroid hormone is secreted by chief cells in response to _______________________________

A

low blood calcium level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Parathyroid hormone regulates calcium and phosphate how?

A

increasing blood Ca levels
decreasing phosphate levels

33
Q

______ acts on osteoblasts to promote osteoclast activity which increases calcium levels

A

PTH (parathyroid hormone)

34
Q

_____ acts on renal tubules to stimulate resorption of calcium

A

PTH (parathyroid hormone)

35
Q

Parathyroid hormone controls the rate of calcium uptake in the GI by regulating the production of ______________

A

vitamin D in kidneys

36
Q

What stimulates cells of intetinal mucosa to absorb calcium and synthesizes calbindin?

A

vitamin D

37
Q

What are the characteristics of hypoparathyroidism?

A
  • deficiency in secretion of PTH
  • blood calcium low
  • bone calcium not released
  • spontaneous depolarization of neurons and muscle fibers (tetany)
38
Q

What are the characteristics of hyperparathyroidism?

A
  • high blood calcium levels
  • bone loss (osteomalacia)
  • abnormal calcium deposition in arteries and kidneys
39
Q

Where are centroacinar cells found?

A

only in lumen of pancreatic acini

40
Q

Where are islets of langerhans?

A

embedded within exocrine tissue of pancreas

41
Q

How many islet of langerhans in a pancreas?

A

around 1 million

42
Q

What portal system is involved in the islets of langerhans?

A

insuloacinar portal system

43
Q

What is the pathway of blood through the islets of langerhans?

A

afferent arteriole -> fenestrated capillaries -> efferent capillaries

44
Q

Which capillaries in the islet of langerhans supply exocrine pancreatic acini?

A

efferent capillaries

45
Q

What are the three main cells in the islet of langerhans?

A

a-cells
B-cells
S-cells

46
Q

What are the characteristics of a-cells in the islet of langerhans?

A
  • 15-20%
  • secrete glucagon
  • increase blood glucose
  • stimulates glucogenesis and glycogenesis
47
Q

What are the characteristics of B-cells in the islet of langerhans?

A
  • 70%
  • secrete insulin
  • decrease blood glucose
  • stimulates intracellular glycogen synthesis
48
Q

What are the characteristics of S-cells in the islet of langerhans?

A
  • 5-10%
  • secrete somatostatin
  • inhibits both insulin and glucagon production
49
Q

What is diabetes mellitus?

A

insulin deficiency/abnormality

50
Q

What does type 1 diabetes cause?

A

decreased insulin production

51
Q

What does type 2 diabetes cause?

A

decrease number of insulin receptors or decrease in responsiveness

52
Q

What are the two main symptoms of diabetes mellitus?

A

hyperglycemia
glucosuria (glucose in urine)

53
Q

What hormone regulates the adrenal gland?

A

ACTH from the anterior pituitary

54
Q

Steroid hormones structurally related to ___________ precursor

A

cholesterol

55
Q

What are the three functional classes of adrenal hormones?

A

mineralocorticoids
glucocoricoids
sex hormones

56
Q

What are the characteristics of mineralocorticoids?

A

aldosterone
- control electrolyte and fluid balance
- regulate Na and K levels via Na pumps (in renal tubuels)
- regulates blood pressure via JGA

57
Q

What are the characteristics of glucocorticoids?

A

cortisol
- stimulates gluconeogenesis and glycogenolysis
- increases blood glucose
- increases metabolism of proteins, carbs, lipids

58
Q

What are the characteristics of sex hormones?

A

androgens
- small amount

59
Q

What are the three layers of the adrenal cortex?

A

zona glomerulosa (15%)
zona fasciculata (80%)
zone reticularis (5%)

60
Q

Which layer of the adrenal cortex secretes mineralocorticoids (aldosterone)?

A

zona glomerulosa

61
Q

Which layer of the adrenal cortex secretes glucocorticoids (cortisol)?

A

zona fasciculata

62
Q

Which layer of the adrenal cortex secretes small quanitities of androgens and glucocorticoids?

A

zona reticularis

63
Q

Which layer of the adrenal cortex contains spongiocytes?

A

zona fasciculata

64
Q

The zona glomerulosa produces aldosterone (mineralocorticoids) in response to what?

A

angiotension II
ACTH

65
Q

Which layer of the adrenal cortex is involved in electrolyte and water balance?

A

zona glomerulosa

66
Q

Which layer of the adrenal cortex have cells that contain lipid droplets in cytoplasm and have spongiocytes?

A

zona fasiculata

67
Q

What is the zona fasiculata involved in?

A
  • glucocorticoids
  • regulate CHO, protein, and fat
  • liver
  • catabolic effect in other tissues
  • suppress the immune system
68
Q

What are the characteristics of the zona reticularis?

A
  • cells arranged in irregular cords that frm an anastomosing network
69
Q

What disease has hypoadrenocorticism?

A

addison’s disease

70
Q

What disease has hyperadrenocorticism?

A

cushing’s disease

71
Q

What are the characteristics of hypoadrenocorticism (Addison’s disease)?

A
  • failure of adrenal cortex to produce hormone
  • atrophy of gland
  • decreased aldosterone
  • decreased cortisol
  • decreased blood glucose
72
Q

What are the characteristics of hyperadrenocorticism (Cushing’s disease)?

A

primary
- due to general adrenal hyperplasia or functional tumor
- excess cortisol secretion

secondary
- increased ATCH
- adrenal hyperplasia and excess cortisol secretion

73
Q

What cells are in the adrenal medulla?

A

chromaffin cells

74
Q

Chromaffin cells in the adrenal medulla secrete what?

A

epinephrine
nor-epinephrine

75
Q

What chromaffin cells in the adrenal medulla are regarded as?

A

modified sympathetic postganglionic neurons

76
Q

What are the characteristics of catecholemines?

A
  • secreted in response to intense emotional reactions
  • increase heart rate
  • dilates blood vessels to cardiac and skeletal m
  • bronchiole dilation
  • vasoconstriction of blood to GI tract, kidneys, skin
77
Q

What is pheochromocytoma?

A

benign tumor of the chromaffin cells

78
Q

What are the symptoms of pheochromocytoma?

A

elevated heart rate
elevated bp
palpitations
diaphoresis
anxiety
headaches
nausea

79
Q

What percent of pheochromocytoma are familial?

A

25%