Endocrine system Flashcards
(87 cards)
1
Q
endocrine system function
A
regulate physiologic functions via chemical messengers in plasma
- uses HORMONES to control and coordinate your body’s metabolism, energy level, reproduction, growth and development, and response to injury, stress, and mood
2
Q
endocrine system communication
A
via chemical hormones
- hormones released from endocrine glands
- some released from specialized cells
- hormones circulate in blood stream and bind with target organ cell receptors to affect a change in target cell
3
Q
endocrine system requires what
A
the bloodstream from the hormones to travel in
4
Q
endocrine glands
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LACK ducts because the hormones are secreted directly into the blood stream
5
Q
hormone effect depends on
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the target cell and receptor type
- where they are and contact w/ the hormone
6
Q
type of endocrine hormones
A
- amines
- peptide hormones
- steroid hormones
7
Q
Amines hormones
A
derived from tyrosine (solubility varies)
- thyroid hormone = lipid
- adrenal catecholamines = water
8
Q
Peptide hormones
A
peptides, polypeptides, and proteins
- WATER soluble ( need a receptor to pass membrane, cant pass alone)
- hypothalamus hormones
- pituitary gland hormones
- pancreas hormones
9
Q
steroid hormones
A
derived from cholesterol - LIPID soluble ( can pass through membrane alone) - adrenocortical - gonadal - vitamin D these hormones modify cholesterol
10
Q
water vs lipid soluble hormones
A
water cannot cross membrane without a receptor
lipid can cross the membrane freely
*hormone structure dictates how it communicates with the target cell
11
Q
water soluble hormone
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- small peptides removed by kidneys, so they have a shorter relative half-life
12
Q
G proteins
A
there are DIFFERENT TYPES of G proteins
- not all activate AC
13
Q
benefit of secondary messenger system
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AMPLIFICATION of signal
- a single hormone can have a HUGE effect!
14
Q
lipid soluble hormones
A
can have direct gene activation mechanism
ex. steroids, stress, testosterone, estrogen hormones
- metabolized by the liver so they have a relatively longer half-life
15
Q
half life in lipid vs. water soluble hormones
A
water soluble are small peptides and are easier to be excreted in filtration of urine and kidneys
- water soluble = shorter half-life
- lipid soluble = longer half-life
16
Q
target cell activation depends on three factors:
A
- hormone levels in the blood
- number of receptors present on target cells (less receptors = small chance of connection w hormone)
- affinity of binding between receptor and hormone
17
Q
types of hormone release mechanisms
A
- humoral stimulus
- neural stimulus
- hormonal stimulus
18
Q
humoral stimulus
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hormone release caused by altered levels of certain critical ions or nutrients
- endocrine gland has sensors for the body and makes changes
19
Q
neural stimulus
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hormone release caused by neural input
- release of epin. or nor. from the medulla gland
20
Q
hormonal stimulus
A
hormone released caused by another hormone (a tropic hormone)
21
Q
hypothalamus and pituitary
A
the hypothalamus is “the boss” of the pituitary gland
- it regulates hormone release by the pituitary
22
Q
neurohypophysis
A
posterior pituitary
- hypothalamus makes hormones that the posterior pituitary releases
- oxytocin and ADH
23
Q
Oxytocin in posterior pituitary
A
made in paraventricular cells of hypothalamus and is stored in the PP
- allows milk let down- suckling stimulates release
- uterine contractions in child birth
- positive feedback
24
Q
Antidiuretic hormone (ADH) in posterior pituitary
A
produced in hypothalamus and is stored in the PP
- makes DCT and collecting duct more permeable to water
- water reabsorbed and urine output decreased
25
adenohypophysis
anterior pituitary
| - hypothalamus regulates AP hormone release by synthesizing releasing and inhibiting hormones
26
anterior pituitary
hypothalamic hormones released into special blood vessels
| - releasing and inhibitory hormones of the hypothalamus affect AP hormone release
27
Growth hormone (somatotropic) in anterior pituitary
GHRH, stimulates and increases growth of body tissues and cell size
- promotes glycogen breakdown
- protein production in muscle increases mass
- can lead to gigantism (GHRH) or dwarfism (GHIH = somatostasin)
28
adrenocorticotrophic hormone (ACTH)
anterior pituitary (adrenal cortex hormone)
- acts on adrenal cortex to release glucocorticoids and mineralocorticoids
- secretion regulated by hypothalamus corticotrophin (CRH)
hypo. ->CRH-> AP -> ACTH -> adrenal cortex -> glucocorticoids and mineralcorticoids release
29
releasing hormone (CRH) in response to:
1. STRESS
2. cold, heat
3. hypoglycemia
4. toxemia
5. dehydration
30
adrenal glands
located near kidneys, split into:
1. adrenal cortex = corticosteroids
2. adrenal medulla = catecholamines
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adrenal glands: medulla
adrenal medulla produces catecholamines (water soluble)
| - epinephrine and norepinephrine
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adrenal glands: cortex
adrenal medulla produces corticosteroids (lipid soluble)
| - glucocorticoids (cortisol) and mineralocorticids (aldosterone)
33
Aldosterone (mineraocorticoid)
enhances Na+ resorption and K+ secretion in the renal collecting ducts and DCT
- release stimulated by the renin/angiotensisn system when BP is low or dehydration
- results in Na+ resorption and water retention
- blood volume increases
34
Cortisol (glucocorticoid)
released in response to ACTH stimulus (from pituitary)
triggered from:
- hypocalcemia = low blood sugar
- stress = very catabolic and breaks things down
* cortisol increases GLUCOSE in the bloodstream
35
negative feedback of glucocorticoids
1. abundance of glucocorticoids (cortisol) in blood stream
2. glucocorticoid receptors in hypothalamus bound
3. release of CRH stopped
4. no release of ACTH
5. no adrenal stimulation
6. no more glucocorticoids released
* negative inputs back to hypothalamus and anterior pituitary
36
hyperadrenocorticism
crushings disease
- Etiology: tumor (primary vs secondary) and iatrogenic
steroid diabetes: polyuria (increase in urination) and polydipsia (increase in thirst)
37
effects of polyuria/polydipsia (steroid diabetes) and why these occur
why? increase in glucose in blood which increases urination and overwhelms convoluted tubules
- think skin/hair loss
- swollen liver
- bone loss/weaken muscles
38
thyroid stimulating hormone (TSH)
anterior pituitary
- acts on the thyroid to release throid hormones
- regulator of metabolic activity
- secretion regulated by hypothalamus
- depends of release of thyrotropin releasing hormone (TRH)
39
thyroid gland
thyroid hormones are amine - derived from tyrosine
- lipid soluble
- thyroglobulin holds tyrosine and becomes iodinated to form active compounds
- released into blood and bound to thyroxine-binding globulin to carry to target organs
- T4 and T3
40
T4 thyroid hormone
tetraiodothyronine (4 iodine bound to thyroglobulin) = throxine
- less makes it to cells but lasts longer
41
T3 thyroid hormone
triiodothyronine (3 iodine bound to thyroglobulin)
| - more potent but lasts longer
42
iodine
taken in from your diet
| - needed for the thyroid gland to make T3 and T4 hormones
43
function of thyroid gland
increases metabolism and regulates carbs, proteins, and fat metabolism
- increases oxygen consumption
44
thyroid hormone released stimulants by TSH from anterior pituitary
1. low levels detected by the hypothalamus
2. TRH released to pituitary
3. pituitary releases TSH
4. TSH works on thyroid gland to increase activity and release T4 and T3
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if too much T3 and T4 is release:
negative feedback system starts
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thyroid hormone is especially important for
normal development and regulating basal metabolic rate and temperature regulation
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T3 and T4 negative feedback loop act on:
the anterior pituitary and the hypothalamus
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thyroid hormone positive feedback system steps
1. hypothalamus
2. TRH
3. anterior pituitary
4. TSH
5. thyroid
6. T3 and T4 is released and affects basometabolic rate
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thyroid hormone deficiency effects
hypothyroidism - reduced BMW, increased weight
- lethargy and mentally sluggish
- cold feeling
- overweight
- edema
- intellectual and physical challenges if at a young age
50
Iodine deficiency
deficiency from decreased thyroid hormone production
- hypothalamus sees low hormone and send to TRH to pituitary which send to TSH to thyroid gland
- glands grow trying to make T3 and T4
51
goiter
enlarged thyroid gland because there is no iodine to bind to T3 and T4 so loop continues
52
hyperthyroidism
graves disease
| - bulging eyes (exophthalmos)
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Calcitonin
another thyroid hormone produced from TG, NOT associated with feedback loop
- HIGH blood calcium levels stimulate calcitonin release = hypercalcemia
- calcitonin inhibits osteoclastic activity, increases Ca2+ in osteoblasts
54
causes of hypercalcemia
high blood calcium levels
- cancers
- parathyroid tumor (rare)
- bone lesions
55
causes of hypocalcemia
low blood calcium levels
- nutritonal
- calcitriol deficiency
- excessive demand (ex. birth)
- lpw or high PTH
56
Parathyroid
secreted from the parathyroid gland in response to HYPOcalcemia
- raise blood Ca2+ levels, causes Ca2+ and phosphorous to be released from bone which enhances osteocastic activity
- increases Ca2+ reabsorption in the kidneys
- causes conversion of inactive vitamin D to active form, Calcitriol
57
Calcitriol
active form of vitamin D
- lipid soluble
- increases small intestinal apical calcium channels and pumps
- increases bone absorption
- decreases PTH secretion
- decreases renal Ca2+ excrertion
58
hormones associated with bones
1. GH (growth hormone + thyroid hormone)
2. testosterone
3. estrogen
4. insulin
5. cortisol
59
testosterone
results in heavier bone growth by increasing GH secretion
| - increased osteoblast activity and epiphysial losure
60
estrogen
increased osteoblast activity
- cessation of long bone growth
- prevents osteoporosis
61
insulin
stimulates osteoblast activity (bone formation)
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cortisol
dose dependent osteoclast inhibition
| - stops/inhibits activity
63
releasing and inhibitory hormones of the hypothalamus affect
anterior pituitary hormone release
64
Prolactin
anterior pituitary hormone
- water soluble
- stimulates lactogenesis (milk production)
- lactation requires prolactin and oxytocin (milk let down)
- hypothalamus produces prolactin releasing hormone factors (PRH/PRF)
- hypothalamus produces prolactin inhibiting hormone (dopamine;PIH) to stop lactogenesis
65
Follicle stimulating hormone (FSH) and Luitenizing Hormone (LH)
anteriot pituitary hormones
- sex steroid stimulation
- hypothalamus produces gonatrophin releasing hormone (GnRH)
Males: testosterone will inhibit GnRH production
Females: Estrodial stimulates GnRH production
66
Female Hypothalamic-Pituitary-Gondal Axis Steps
1. Maturing follicle secretes estradiol
2. Estradiol stimulates hypothalamus and anterior pituitary
3. hypothalamus secretes GnRH
4. GnRH and estradiol stimulate pituitary to secrete LH and FSH
5. Oocyte complete meiosis 1; follicle radpidly enlarges and then ovulates
67
Male Hypothalamic-Pituitary-Gondal Axis Steps
1. GnRH from hypothalamus stimulates the anterior pituitary to secrete FSH and LH
2. FSH stimulates nurse cells to secrete androgen-binding protein
3. LH stimulates interstitial cells to secrete testosterone (androgen)
4. presence of ABP, testosterone stimulates spermatogenesis
5. testosterone also stimulates the libido and the development of secondary sex organs
6. testosterone has negative feedback effects that reduce GnRH secretion and pituitary sensitivity to GnRH
7. nurse cells also secrete inhibin which inhibits FSH secretion and reduces sperm production without reducing testosterone secretion
68
in males, balance of hormones is achieved during
puberty and stabilizes in adulthood
69
what does testosterone do in puberty
produce sperm by initiating spermatogenesis
- reproductive structures grow to adult size
- secondary sex characteristics
70
menopause
cessation of ovulation and menstruation
| - estrogen levels begin to decline as women reach later 40s
71
sex steroids
have some non-reprodctive effects
- help faciliatate Ca2+ uptake and reduce osteoclast activity
- maintain bone density
72
estrogen also promotes:
coagulation
increase in: plasma fibrinogen, coagulation factor, platelet activity
decrease in: anti-thrombin
73
testosterone is important for
protein synthesis and building/maintaining muscle and helps with RBC production
74
Pineal gland produces
melatonin
- water soluble
- prodcution occurs at night
75
Pancreas endocrine gland cell types
```
hormones produces by:
- alpha produce
- beta produce
glucose homeostasis:
- glucagon
- insulin
```
76
Endocrine hormones
produced by alpha and beta cells in the pancreatic islets
- glucagon and insulin hormones
- important for glucose homeostasis
77
glucagon vs. Insulin
increases blood sugar vs. decrease blood sugar
78
Insulin (water soluble)
- peptide is produced/secreted from Beta Cells
- allows glucose entry into a cell by facilitated diffusion
- lowers blood glucose
- promotes carbs and lipid storage (anabolic)
79
insulin secretion is stimulated by
1. glucose
2. parasympathetic release of acetylcholine
3. cholecystokinin
80
diabetes mellitus
not enough insulin activity
- decreased production (type 1)
- insulin resistance (type 2)
81
glucagon
opposite effects of insulin
- secreted from alpha cells when blood glucose is LOW
- catabolic
1. initiates glycogenolysis (breakdown)
2. initiates gluconeogenesis (production)
82
homeostatic balance of blood glucose by
insulin (anabolic) and glucagon (catabolic)
83
example of homeostatic imbalance
diabetes
- either lack of insulin production (type 1)
- improper response to stimulus (type 2)
84
insulin is
anabolic and is secreted by Beta cells when blood glucose is high
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glucagon is
catabolic and produced by alpha cells when blood glucose is low
86
In males, testosterone will
inhibit GnRH production, FSH feedback also involved hormone called inhibin
87
In females, Estrodial
stimulates GnRH production
