Endocrine Organs Flashcards

1
Q

Name 6 endocrine glands

A

Pineal, pituitary, thyroid/parathyroid, adrenal, ovaries/testes, and placenta

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2
Q

Part of the brain that is not a gland but still secretes hormones?

A

Hypothalamus

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3
Q

Function of the pineal gland

A

To secrete melatonin

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4
Q

List the 3 components of the 3 tiered chain of command or “axis”; Aka name the order in which the hormones go

A

Hypothalamic neurons, pituitary gland, and endocrine glands

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5
Q

Name the 3 specific axes

A
  1. Hypothalamic-pituitary-thyroid axis
  2. Hypothalamic-pituitary-adrenal axis
  3. Hypothalamic-pituitary-gonadal axis
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6
Q

Path of hypothalamic-pituitary-thyroid axis

What does it regulate

A

Hypothalamus releases thyrotropin releasing hormone to pituitary which secretes TSH to activate thyroid gland to secrete thyroxine.
Thyroxine regulates metabolic rate and temperature

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7
Q

Path of hypothalamic-pituitary-adrenal axis

What does it regulate

A

Hypothalamus releases CRH to pituitary which secretes ACTH which activates adrenal glands

Regulates secretion of cortisol

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8
Q

Path of hypothalamic-pituitary-gonadal axis

A

Hypothalamus releases GnRH to pituitary which secretes FSH and LH into circulation to reach ovaries/testes

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9
Q

Name an organ that is part of the growth axis

Explain

A

Liver

Hypothalamus releases somatostatin to regulate pituitary secretion of somatotropin (GH) which stimulates liver secretion of somatomedin (another growth hormone)

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10
Q

What part of the thyroid gland is midline

A

Isthmus

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11
Q

Thyroid gland synthesizes, stores, and secretes what two things?

Function (3)

A

T3 (triiodothyronine) and T4 (thyroxine)

Increase metabolic rate, stimulating mitochondrial function and mitochondrial proliferation

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12
Q

What other hormone does thyroid gland synthesize, store and secrete?

Function?

A

Calcitonin

Promotes calcium storage in bone by inhibiting bone resorption

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13
Q
  1. Thyroid gland consists of which type of tissue when in store mode?
  2. When in secretory phase?
A
  1. Simple cuboidal epithelium

2. Simple columnar epithelium

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14
Q

Two principal endocrine cell types?

A

Follicular cells (thyrocytes) and parafollicular cells (clara or C cells)

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15
Q
  1. Two functions of follicular cells?

2. Function of parafollicular cells?

A
  1. Form the simple epithelium and synthesize/release thyroid hormone
  2. Synthesize/release calcitonin
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16
Q

Location of parafollicular and follicular cells in relation to each other?

A

Parafollicular cells are deep to follicular cells

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17
Q
  1. T3 is composed of what 2 things?

2. T4?

A
  1. Monoiodotyrosine + diiodotyrosine

2. Diiodotyrosine + diiodotyrosine

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18
Q

Polymerized form of tyrosine

Then post transitionally modified via __ and __

A

Thryoglobin

RER and golgi (then secreted into lumen)

19
Q

Iodide is transported through ___ to be converted to iodine

Tyrosine residues are iodinated to form?

A

Thryocyte

MIT or DIT ~ then further conversion to form T3 and T4

20
Q

How does thyroxine (thyroid hormones) signal?

A

By binding to an intracellular receptor (THR)

21
Q

How does THR regulate gene expression?

A

THR dimerizes with retinoid X receptor and binds to a specific promotor region DNA sequence

22
Q

What inhibits the hypothalamic-pituitary-thyroid axis?

A

Elevates T3/T4 levels (negative feedback inhibition)

23
Q

Natural activator and 2 natural inhibitors of the thyroid

A

Cold activates it; heat and stress inhibit it

24
Q

Does sympathetic innervation stimulate or inhibit the thyroid? How?

A

Stimulates; by increasing blood flow or by noradrenergic stimulation of follicular cells to secrete T3 and T4

25
Q

Calcitonin has what effect on blood levels of calcium

A

Reduces blood levels of calcium by inhibiting bone resorption and decreasing retention by kidney

26
Q

Function of parathyroid hormone

A

Increases blood levels of calcium by activating bone resorption, increasing calcium retention by kidney and increasing absorption from GI

27
Q

Where are the parathyroid glands located

A

Posterior side of thyroid gland usually but could also be on lateral surface

28
Q

Another name for hyperthyroidism

A

Graves disease

29
Q

What is graves disease

Hallmark symptoms?

Other symptoms

A

Autoimmune disease that binds and activates TSH

Esophthalmos (protruding eyes), myxedema (puffy skin) and goiter

Fatigue, weight loss, increase appetite, heat intolerance (using a lot more energy)

30
Q

People with graves disease have an increase in TSH because ?

A

They have deficient thyroxine production (which means less inhibition, so more TSH released)

31
Q

Adrenal glands from outer to inner (3)

A

Capsule, adrenal cortex, adrenal medulla

32
Q

3 zones of the adrenal cortex from outer to inner

A

Zona glomerulosa, zona fasciculata, and zona reticularis

33
Q

What type of cells are in the adrenal medulla?

Function

A

Chromaffin cells

Post-ganglionic sympathetic neurons that secrete epinephrine/norepinephrine into the blood

34
Q

Main function of the zona glomerulosa

A

Synthesizes mineralcorticoids (aldosterone)

35
Q

Function of the zona fasciculata and reticulata?

A

Synthesizes glucocorticoids (cortisol)

36
Q

What has the ability to increase expression of the enzyme that converts NE to E?

A

Glucocorticoids (secreted by cortex, can diffuse into medulla)

37
Q

Two main functions of ACTH

A

Stimulates adrenal cortex to synthesize/secrete glucocorticoids and can also act as a growth factor to induce adrenal hypertrophy

38
Q

Elevated glucocorticoids promotes what two things

A

Gluconeogenesis and glycogeneolysis

39
Q

Name two other ways that glucocorticoids act in the body

A

Suppress growth and can be used to help some immune system responses

40
Q

Steroid hormones and glucocorticoids act as transcription factors. What does that mean

A

They bind promoter regions on DNA and regulate gene expression

41
Q

Cushing syndrome

  1. Caused by
  2. What does it cause
A
  1. excess ACTH (secondary to pituitary tumor)

2. Adrenal hyperplasia, inappropriate hair growth in females/masculinization, obesity, and osteoporosis

42
Q

Addisons disease

  1. Caused by
  2. Hallmark symptoms
A
  1. Adrenal hypofunction, autoimmune resulting in adrenal cortex degeneration/failure
  2. Weakness, hypotension, hypoglycemia, Na+ wasting and K+ elevation
43
Q

Pheochromocytoma

  1. Originate from
  2. Hyperfunction syndrome is?
  3. What does it cause
  4. Where else can it occur
A
  1. Chromaffin cells
  2. Excess production of NE or E
  3. Hyperglycemia, hypertension, arrhythmias
  4. Prevertebral/paravertebral sites due to ectopic sites of chromaffin cells in sympathetic ganglia
44
Q
  1. Adrenal medulla originates from?

2. Adrenal cortex originates from

A
  1. Neural crest cells

2. Mesoderm that initially lies lateral to the dorsal aorta