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BIOL 1191 > Ch. 18 - Endocrine System > Flashcards

Ch. 18 - Endocrine System Flashcards

1
Q

What are autocrine hormones?

A

local hormones that are secreted by, and bind to, the same cell

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2
Q

What are paracrine hormones?

A

local hormones that are secreted into interstitial fluid and act on nearby cells

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3
Q

What are some characteristics of lipid-soluble hormones?

A

hydrophobic, nonpolar/uncharged; often bound to transport proteins

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4
Q

What are some characteristics of water-soluble hormones?

A

hydrophilic, polar/charged; circulate freely in the plasma

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5
Q

What are some examples of lipid-soluble hormones?

A

steroids, thyroid hormone, NO

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6
Q

What are some examples of water-soluble hormones?

A
  1. amine (NE, dopamine, serotonin)
  2. peptide/protein hormones (ADH, OT, GH)
  3. eicosanoid (prostaglandin)
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7
Q

What are 3 types of stimuli that trigger hormonal secretion?

A
  1. humoral stimuli
  2. neural stimuli
  3. hormonal stimuli
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8
Q

What is humoral stimuli?

A

changing levels of certain chemicals in blood or body fluids

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9
Q

What is receptor downregulation?

A

cell response to excess hormone by decreasing number of receptors

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10
Q

What is receptor upregulation?

A

cell response to decreased hormone by increasing number of receptors

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11
Q

How does the hypothalamus secrete releasing/inhibiting hormones?

A

via hypophyseal portal system to control secretion of ant pituitary hormones

neurosecretory cells –> capillaries of hypothalamus –> hypophyseal portal veins –> capillaries of ant pituitary

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12
Q

What are hormones produced by the anterior pituitary?

A

GH, TSH, FSH, LH, PRL, adrenocorticotropic hormone (ACTH), melanocyte-stimulating hormone (MSH)

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13
Q

What controls the release of GH from the somatotrophs of the anterior pituitary? Where do these hormones come from?

A

growth hormone-releasing hormone (GHRH) and growth-hormone-inhibiting hormone (GHIH) from hypothalamus

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14
Q

What is the primary function of GH?

A

produce insulin-like growth factors (IGFs) from liver, sk muscles, cartilage, bones

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15
Q

What are some effects of IGFs?

A
  • increase cell growth and division by increasing a.a. uptake and prot synthesis & inhibiting prot breakdown
  • stimulate glycogen breakdown to increase blood glucose level & stimulating lypolysis so FA can be used for ATP prod
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16
Q

How can gH lead to diabetes?

A

excess GH causes hyperglycemia

- pancreas releases insulin continually –> beta-cell burnout (no more insulin) –> leads to diabetes mellitus

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17
Q

What stimulates GH secretion?

A

low blood glucose, low blood FA acids, high blood a.a.

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18
Q

What stimulates GHRH secretion?

A

low blood glucose, low blood FA acids, high blood a.a.

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19
Q

What stimulates GHIH secretion?

A

high blood glucose, high blood FA acids, low blood a.a.

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20
Q

What does thyrotropin-releasing hormone trigger?

A

release of thyroid-stimulating hormone (TSH) from thyrotrophs of ant pituitary

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21
Q

What does TSH stimulate?

A

synthesis and secretion of T3 and T4 hormones from thyroid gland

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22
Q

Describe the negative feedback of TRH secretion

A

high levels of T3/T4 inhibit TRH secretion

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23
Q

What does gonadotropin-releasing hormone trigger?

A

release of FSH and LH from gonadotrophs of the anterior pituitary

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24
Q

What does FSH function in?

A

oocyte maturation, estrogen production, sperm production

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25
What does LH function in?
ovulation, testosteron e production
26
What do prolactin-releasing hormone (PRH) and prolactin-inhibiting hormone (PIH) release?
prolactin from lactotrophs of ant pituitary
27
What is the function of PRL?
initiates and maintains milk production and secretion by mammary glands; released during pregnancy
28
What is the function of the corticotropin-releasing hormone (CRH) ?
stimulates release of ACTH and MSH from corticotrophs of ant pituitary
29
What is the function of ACTH?
stimulates cells of adrenal cortex to produce glucocorticoids
30
What do negative feedback loops control?
secretions of thyrotrophs, gonadotrophs, corticotrophs
31
What do inhibiting hormones (from hypothalamus) control?
secretions of somatotrophs, lactotrophs
32
What is the function of OT?
targets smooth muscle in uterus and breasts
33
What does OT do during delivery?
muscle contraction of uterus (+ feedback)
34
What does OT do after delivery?
contractions for expulsion of placenta; stimulates ejection of milk from breasts
35
What does the amount of ADH secreted depend on?
blood osmotic pressure and blood volume
36
What is the function of ADH?
decreases urine output, causes vasoconstriction
37
How do changes in blood volume affect ADH secretion?
increase in blood vol --> decrease in ADH secretion decrease in blood vol --> increase in ADH secretion
38
What causes diabetes insipidus?
hyposecretion of ADH | - leads to dehydration, excretion of large amounts of dilute urine
39
What hormones does the thyroid gland produce?
T3, T4, calcitonin
40
What part of the thyroid gland produce T3 and T4?
thyroglobulin used by follicular cells (that surround the gland)
41
What part of the thyroid gland produce calcitonin?
parafollicular cells (between the thyroid follicles)
42
What is the function of calcitonin?
lower Ca2+ levels in blood
43
What are functions of thyroid hormones?
- increase basal metabolic rate (stimulate prot synthesis, increase cell resp, make and use more ATP) - upregulate b-adrenergic receptors for E/NE - work with GH/IGF to accelerate body growth
44
What does hypothyroidism in adults produce?
sensitivity to cold, low body temp, weight gain, mental/physical lethargy
45
What is Grave's disease?
cause of hyperthyroidism; autoimmune disease that causes production of antibodies thatmimic TSH
46
What is Grave's disease?
cause of hyperthyroidism; autoimmune disease that causes production of antibodies that mimic TSH
47
What happens when T3/T4 levels drop?
- hypothalamus secretes TRH - anterior pituitary secretes TSH - thyroid follicular cells produce T3/T4 - elevated T3 levels inhibit TRH and TSH release
48
What is the function of parathyroid hormone (PTH) ?
regulator of Ca2+, Mg2+, PO4 in blood; increases [electrolytes] in blood
49
Describe mechanism of PTH functions
- increase osteoclast activity; bone resorption release Ca2+ and PO4 into blood - increases reabsorption of Ca2+ & Mg2+ by kidneys - promotes formation of calcitriol by kidneys that enhances Ca2+ & Mg2+ absorption by intestinal cells
50
What does PTH oppose?
calcitonin (inhibits osteoclast activity!)
51
What can hypoparathyroidism lead to?
low levels of electrolytes | - muscle twitches, spasms, tetany
52
What can hyperparathyroidism lead to?
high levels of electrolytes | - promotes formation of kidney stones, excessive bone resorption (easily fractured)
53
What can hyperparathyroidism lead to?
high levels of electrolytes | - promotes formation of kidney stones, excessive bone resorption (easily fractured)
54
What parts of the adrenal glands produce steroids? NE/E?
outer cortex - steroid hormones inner medulla - E/NE
55
How is the adrenal cortex divided?
3 zones 1. glucocorticoids (glucose homeostasis, stress response) 2. mineralocorticoids (mineral homeostasis) 3. androgens
56
What are the effects of glucocorticoids?
resistance to stress | anti-inflammatory/immune suppression
57
Describe resistance to stress effects of glucocorticoids
- promote protein and fat breakdown to make ATP - gluconeogenesis - convert a.a./FA to glucose to make atp - enhance vasoconstriction (increase BP)
58
Describe anti-inflammatory effects of glucocorticoids
- decrease capillary permeability, WBC numbers, WBC activity - delay tissue repair/wound healing - also used in organ transplants to treat certain autoimmune diseases
59
What is Cushing's syndrome? What does it lead to?
- high levels of circulating cortisol due to hypersecretion or exogenous hormone (use of immunosuppressive drugs) - lead to hyperglycemia, poor wound healing, susceptibility to infections, fat redistribution
60
How are glucocorticoids regulated?
1. hypothalamus releases corticotropin-releasing hormone (CRH) 2. ant ptituitary releases ACTH 3. adrenal cortex releases glucocorticoids
61
What is the function of aldosterone?
helps regulate blood pH; acts mainly on distal tubes/collecting ducts of the nephrons in the kidney
62
What are the effects of mineralocorticoids?
- regulates Na+/K+ homeostasis (Na+ reabsorption, K+ excretion) - promote water reabsorption to regulate BP/BV - promotes H+ excretion in urine to prevent acidosis
63
What would lead to aldosterone secretion?
dehydration, low Na+, low BP
64
What are the effects of androgens?
- promotes growth in boys/girls before puberty - after puberty in M, insignificant bc testosterone from testes predominates - after puberty in F, promotes libido; sole source of estrogens after menopause
65
What are the 3 stages of the stress response?
1. fight-or-flight response 2. resistance reaction (involves CRH, GHRH, TRH) 3. exhaustion (suppression of immune system, muscle wasting, ulcers)
66
What does the stress response lead to an increase in?
- increase resources (FA, glucose in blood; breakdown of protein into a.a. for repair) - increase metabolism (increase circulation/BP, respiration)
67
In the RAA pathway, what stimulates the release of renin?
1. dehydration, Na+ deficiency, hemorrhage 2. decreases BP/BV 3. triggers increased renin from juxtaglomerular cells in kidneys
68
In the RAA pathway, what stimulates the release of angiotensin II?
1. increased renin from kidneys + angiotensinogen from liver 2. both cause increased angiotensin I 3. circulates to lungs; then convert angiotensin I --> angiotensin II via angiotensin converting enzyme (ACE)
69
In the RAA pathway, what stimulates the release of aldosterone?
1. increased angiotensin II stimulates adrenal cortex | 2. increased K+ in ECF
70
What is the end result of the RAA pathway?
- increased BV and vasoconstriction of arterioles lead to increased in BP
71
In the RAA pathway, what stimulates increased levels of angiotensin I?
1. increased renin converts angiotensin from liver
72
What is DHEA?
dehydroepiandrosterone; weak androgens produced by the adrenal cortex
73
What do pancreatic alpha cells produce?
glucagon --> raise blood glucose level
74
What do pancreatic beta cells produce?
insulin --> lowers blood glucose level
75
What is type I diabetes mellitus caused by?
absolute deficiency of insulin; often due to autoimmune attack of beta cells
76
What is type II diabetes mellitus caused by?
decreased sensitivity to insulin | e.g. downregulation of insulin receptor on target cells
77
What is diabetes mellitus characterized by?
- excessive urine production - excessive thirst/eating - FA broken down for energy - excess glucose damages BV, leading to tissue ischemia, eye and kidney pathologies
78
How does diabetes mellitus lead to excessive urine production and excessive thirst?
high blood glucose causes glucose in urine, triggering osmotic diuresis (water pulled out of blood into urine along conc gradient)
79
How does diabetes mellitus lead to excessive eating?
due to lack of glucose available for cells (lack of receptors)
80
How does diabetes mellitus lead to FA being broken down for energy?
ketone bodies in blood make blood acidic
81
What hormones do the ovaries secrete?
2 estrogens (estradiol & estrone), progesterone, inhibin, relaxin
82
What is the function of estrogens and progesterone?
regulate repro cycle, maintain pregnancy, prepare mammary glands for lactation, maintain F secondary sex characteristics
83
What is the function of inhibin?
inhibits FSH secretion
84
What is the function of relaxin?
helps dilate uterine cervix during labour and delivery; increase flexibility of pubic symphysis
85
What hormones are secreted by the testes?
testosterone and inhibin
86
What is the function of testosterone?
regulate descent of testes, sperm production, maintenance of M secondary sex characteristics
87
What hormones does the thymus secrete?
secretes hormones involved in T lymphocyte maturation and activation and in various immune responses
88
What hormone does the heart release?
atrial natriuretic peptide (ANP) in response to high BP | - increases sodium and water secretion; opposite of aldosterone
89
What hormones do the kidneys release?
erythropoietin (in response to hypoxia), renin, calcitriol

BIOL 1191 (16 decks)

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