Unit 1B Flashcards
(106 cards)
1
Q
What are two of the most important hormones made in the hypothalamus and secreted from the posterior pituitary?
A
ADH and Oxytocin
2
Q
How is oxytocin transported?
A
paraventricular nucleus in hypothalamus, axons, posterior pituitary, axon terminal
*diagram in slides
3
Q
How is ADH transported?
A
supraoptic nucleus in hypothalamus, axons, posterior pituitary, axon terminal
*diagram in slides
4
Q
What is the pituitary gland’s main function?
A
secrete hormones made to control other things like the thyroid and pancreas
5
Q
What is oxytocin’s function in females?
A
-uterine contractions
-a positive feedback loop in labor
-milk ejection
- emotional bonding
6
Q
What is oxytocin’s function in males?
A
-unsure, but we know they have it
-related to sexual and emotional bonding
7
Q
What is ADH’s funciton?
A
-decreasing urine production by retaining fluid in the body
-maintains blood volume
-stimulates thirst
-constricts blood vessels increasing blood pressure
8
Q
What is another name for ADH
A
vasopressin
9
Q
What are hypophysiotropic hormones?
A
regulatory hormones synthesized in the hypothalamus
10
Q
How are hypophysiotropic hormones transported?
A
through the primary plexus, through the hypophyseal portal, secondary portal and then the anterior pituitary
11
Q
What is a releasing hormone?
A
Hormones that increase secretion/release of anterior pituitary hormones
12
Q
How do releasing hormones travel ?
A
hypothalamus, blood, secondary plexus, anterior pituitary
13
Q
What are examples of releasing hormones?
A
-thyrotropin-releasing
-prolactin-releasing
- gonadotropin-releasing (GnRH)
- corticotropin-releasing
- growth hormone-releasing (GHRH)
14
Q
How do GHRHs travel
A
hypothalamus secretes GHRH, anterior pituitary releases gh stimulating igf production in liver, blood, all organs
15
Q
What are inhibiting hormones?
A
hormones that decrease secretion of anterior pituitary hormones
16
Q
What are examples of inhibiting hormones?
A
-prolactin-inhibiting hormone
-growth inhibiting hormone
17
Q
What does growth inhibiting hormone do?
A
stops release of gh
18
Q
What are tropic hormones?
A
hormones that exert control over endocrine glands
19
Q
What are examples of tropic hormones?
A
-TSH
-Prolactin
- FSH
-LH
-GH
-ACTH
20
Q
What does TSH do?
A
controls thyroid
21
Q
What does prolactin do in females?
A
-controls mammary glands and their growth
-causes milk production
-levels are cyclic and increase during pregnancy
- decreases chances of getting pregnant while breastfeeding.
-naturally high levels inhibit secretion of FSH and GnRH
22
Q
What does prolactin do in males
A
-not too sure
-could help reproductive function by increasing testosterone levels
-fairly constant levels
-hypersecretion could cause erectile dysfunction, but could be due to prolactinoma (tumor)
23
Q
How is prolactin controlled?
A
released by PRH or inhibited by PIN or dopamine in Hypothalamus
24
Q
What is FSH?
A
follicle-stimulating hormone
25
What is LH?
luteinizing hormone
26
What do FSH and LH do?
target gonads (testes and ovaries) with goal of making gametes
27
How are FSH and LH controlled ?
release is triggered by GnRH in Hypothalamus
28
What does FSH do in females?
- stimulates development of ovarian follicles and maturation of oocytes as well as secretion of estrogen
29
What does FSH do in males?
Stimulates sustentacular cells to secrete androgen-binding protein which keeps testosterone levels high in testes
30
What does LH do in females?
peaks monthly to trigger ovulation and subsequent secretion of progesterone
31
What does LH do in males?
stimulates interstitial cells in testes to secrete testosterone
32
What does GH do?
- targets bones, muscle, blood glucose, and nutrients
- requires TH to be produced so a messed up thyroid will affect GH
Induces liver to secrete mitogenic IGF
33
What does ACTH do?
targets adrenal glands
34
What is ACTH?
adrenocorticotropic hormone
35
What is an example of ACTH?
cortisol
36
When is TH released
the hypothalamus releases TH in cold temps, high altitudes, low TH levels, hypoglycemia, pregnancy
37
How does TH work?
1. hypothalamus releases TH
2. It binds to receptors of follicles and triggers the release of Th (T3 and T4)
3. Th are then transported in the blood by carrier proteins which have longer half-life
4. T3 and T4 increase cellular metabolism
5. T4 is often converted to T3 at target cells by taking away a thyroid globin
38
What are the differences between T3 and T4?
-the number of iodines
-T3 is stronger
T4 is made in more abundance
39
How is TH a negative feedback loop?
- increases in the cause a decrease in its release (Th inhibits the release of TRH from the hypothalamus
- TH inhibits the release of TSH from anterior pituitary
-TH causes the release of GHIH further inhibiting TSH release
40
What do follicular cells do?
produce and release TH
41
Where are follicular cells and follicular lumen found?
thyroid glands
42
What is the follicular lumen?
contains colloid with enzymes important to the production of TH
43
What do parafollicular cells do?
-produce calcitonin
- secreted by humoral stimuli in response to high blood calcium levels in order to decrease blood calcium levels
44
How are thyroid hormones formed?
At follicular cell
1. iodide ion transported for cell to colloid at follicular lumen
2. iodide molecules form I2 at the follicular cell membrane near the lumen
3. thyroglobulin synthesis occurs inside follicular cells and is released into colloid by exocytosis
At the colloid
4. I2 are enzymatically attached to thyroglobulin forming MIT, TI, DIT, or T2
At follicular cell
5. a vesicle containing thyroglobulin with attached T3 and T4 fuses with a lysosome and enzymes cleave T3 and T4 from thyroglobulin
6. T3+ thyroxine (higher levels of T4) go from the follicular cell into the blood
45
What do TH do?
- crucial to the development of CNS in the fetus
-increases metabolic rate and protein synthesis in target cells
-stimulates Na+, K+, ATP passes through body
- stimulates increased amino acid and glucose uptake
-increases the number of cellular respiration enzymes in mitochondria
- up-regulates beta-adrenergic receptors in tissues (especially heart and nervous tissue
- calorgenic action
46
What is calorgenic action?
generates heat and raises temperatures
47
What does TH do in the liver?
increases blood glucose by increasing gluconeogenesis + glycogenolysis + decreases glycogenesis
48
What does TH do in adipose tissue?
glucose sparing effect (saves glucose for brain by increasing lipolysis + decreasing lipogenesis)
49
What does Th do in the lungs and heart?
-lungs: increases breathing rate
-Heart: increases heart rate and force of contraction
- both help meet increased O2 demand for aerobic cellular respiration
50
What are the types of hormone imbalances?
-hypothyroidism (congenital hypothyroidism and postnatal hypothyroidism)
-hyperthyroidism
51
Explain Congenital hypothyroidism
-results in a poorly developed nervous system and can cause severe mental impairment
-typically occurs when pregnant women don't have enough iodine
-iodized salt helps eliminate this in most countries
-this is why pregnant women need lots of T3 and T4
52
Explain postnatal hypothyroidism
- typically due to low iodine consumption or autoimmune thyroiditis (Hashimoto's disease)
- symptoms include cold sensitivity, weight gain, and difficulty concentrating
-leads to increased TH levels and or goiter
-could be treated by pharmaceutical T4
53
Explain hyperthyroidism
-typically due to thyroid tumor or autoimmune disease (graves disease)
- symptoms include heat intolerance, weight loss, increased anxiety, and heart rate
- could be treated with drugs that inhibit TH synthesis, surgical removal, destroying a part of the thyroid gland, beta-blocker drugs to decrease sympathetic response.
54
What is the negative feedback loop of IGF and GH
- increased GH and IFG inhibit the release of GHRH from the hypothalamus leads to the inhibited release of GH from the anterior pituitary
55
What are the steps in the GH IGF feedback loop?
1. hypothalamus releases GHRH into the hypothalamus-hypophysial portal system
2. Anterior pituitary releases GH because of GHRH
3. GH stimulates hepatocytes to release IGF into the blood
56
What is IGF
insulin-like growth factor
57
What is the relationship between GH and IFG
-work synergistically to enhance response
(igf has longer 1/2 life)
58
What does IGF do in the bone and muscle cells?
-all cells have receptors for IGF and GH or both
- causes an increase in cell division, cell differentiation, amino acid uptake, and protein synthesis
- bone and muscle are particularly responsive to GH and IGFs which cause bone elongation and muscle hypertrophy
59
What does IFG do in the liver?
- increase in glycogenolysis and gluconeogenesis and decreases in glycogenesis
- results in diabetogenic increase in blood glucose levels
60
What is glycogenesis
turns glucose into glucagon reduces glucose
61
What is glycogenolysis?
turns glucagon into glucose increasing glucos
62
-What does IGF do in adipose tissue?
- increases lipolysis and decreases lipogenesis releasing nutrients
-increases levels of glycerol and fatty acid in blood in order to provide molecules necessary for generating ATP for growth
63
How do GH levels change over time?
- more abundant in adolescence and levels start to drop off when you get older
-affected by nutrient levels, stress, exercise, time of day
64
What are the disorders having to do with GH Secretion
-GH deficiency (pituitary dwarfism)
-pituitary gigantism
-acromegaly
- GH insensitivity syndrome
65
What is pituitary dwarfism?
-inadequate gh production due to hypothalamic/ pituitary problem
-results in short stature and low blood sufar
66
What is GH insensitivity syndrome?
mutation to GH receptor causes failure to produce IGF
67
What is pituitary gigantism?
-too much gh prior to adulthood
-results in excessive growth, increased blood sugar, and enlarged internal organs
- can bee fatal at early age if untreated
68
What is acromegaly?
-excessive GH production in adults
- results in enlargement of bones in the face, hands, and feet, increased glucose release, and enlarged internal organs
- typically due to a loss of feedback control of GH
69
What does the adrenal medulla do?
- sympathetic axons stimulate the release of catecholamines (largely epinephrine, some norepinephrine, and a little dopamine)
- nervous system stimulation triggers a response to decreasing blood pressure, pain, physical injury, abrupt emotional upset, hypoglycemia
- This results in an increased heart rate, anxiety, sweat, and blood glucose concentrations.
70
What are the adrenal cortex zones?
-zona glumerosa
-zona fasciculata
-zona reticularis
*image in slides
70
What does the zona glumerosa do?
releases mineralocorticoids
71
What is an example of a mineralocorticoid?
aldosterone
72
What does aldosterone do?
releases sodium and water retention. decreases K+/H+ secretion
73
What does the zona fasciculata do?
releases glucocorticoids
74
What is an example of a glucocorticoid?
cortisol
75
What does cortisol do?
-effects metabolism of glucose resulting in increased blood sugar
- facilitates body's response to stress and acts as an anti-inflammatory/ anti-immune function
76
What does the zona reticularis do?
releases gonadocorticoids
77
What is an example of a gonadocorticoid?
dehydroepiandrosterone (DHEA)
78
What does DHEA do?
releases weak androgens increased secretion in males at beginning of puberty, and converted to estrogen in females
79
What are corticoids?
steroids released from cortex
80
What does cortisol do?
increases blood levels to resist stress and repair injured tissue
-most cells spare cortisol intake to save it for the brain
-increases glycogenolysis and gluconeogenesis
-decreases glycogenesis
- decreases lipogenesis in adipose tissue
-stimulates protein catabolism in all cells except hepatocytes
- decreases glucose uptake
81
How is cortisol regulated?
-through a negative feedback loop
1. hypothalamus releases CRH into hypothalami-hypophyseal portal system
(stimulated by stress, late stages of sleep, and low levels of cortisol)
2. in response to CRH the anterior pituitary releases ACTH
3. ATCH stimulates the adrenal cortex to release glucocorticoids into the blood
4. cortisol stimulates target cells (effectors)
*image in slides
82
How are pancreatic hormones secreted?
Through humoral stimuli
83
What is a normal blood sugar range
70-110 mg/deciliter
84
What do pancreatic hormones do?
maintain blood glucose levels
85
What do high levels of blood glucose do?
-can damage blood vessels and kidneys
-insulin is secreted to lower levels which causes increased levels of glycogen using glucose from blood and liver, decreased breakdown of fat by adipose cells, increased uptake of amino acids in protein by all cells, increased glucose uptake and increased protein transport by all cells
86
What do low blood glucose levels do?
- can cause lethargy, mental + physical impairment, and death
- glucagon is secreted causing an increased breakdown of glycogen making glucose available in blood by liver and increased breakdown of fat by adipose tissue
87
What is Diabetes Mellitus?
inadequate glucose uptake from blood resulting in chronically elevated glucose, which can cause blood vessel damage, increased risk for heart disease and stroke
- is leading cause of retinol blindness, kidney failure, and non-traumatic amputations in the US
88
What is type 1 diabetes mellitus?
- absent/diminished release of insulin from the pancreas
- tends to occur in children or younger individuals
-may have an autoimmune component
-requires daily insulin injections
89
What is type 2 diabetes mellitus?
-decreased insulin release/ effectiveness
-tends to occur in older people, but could effect young adults
-treat with diet, exercise, medication
90
What is gestational diabetes?
-diabetes that is seen in pregnant women
- higher risk for developing type 3 later on
- if untreated could cause risk to fetus or delivery complications
91
What is hypoglycemia?
-low blood sugar levels
-below 60mg/dl
92
What causes hypoglycemia?
- insulin overdose
-prolonged exercise
- alcohol use
- liver or kidney dysfunction
deficiency of glucocorticoids and gh
-genetics
-some medications
93
What are some symptoms of hypoglycemia?
-hunger
-dizziness
-confusion
-sweating
-sleepiness
94
Where is the pineal gland located?
in epithalamus
95
What does the pineal gland do?
secretes melatonin in cyclic levels that are highest at night
-regulates circadian rhythm which causes drowsiness and affects mood
- influences GnRH secretion
effects on reproductive physiology
light can inhibit melatonin
-melatonin peaks at the middle of the night
96
Where is the parathyroid gland?
-small structures on thyroid
-between 2-6 of them, usually 4
*image on slides
97
What does the parathyroid gland do?
secrete PTH which works with calcitonin to maintain blood calcium levels (PTH and calcitonin are antagonistic)
-liberates PTH from bone, decreases loss in urine, activates calcitriol hormone
98
What structures also have endocrine functions?
- thymus
-heart atria
- kidney
-liver
-stomach
-small intestine
-adipose tissue
99
What does the thymus do in regard to endocrine function?
- epithelial cells secrete thymic hormones
- grows in childhood and shrinks in adulthood
-maturation site for T-lymphocyte white blood cells
100
What does the Heart atria do in regard to endocrine function?
- secretes atrial natriuretic peptide (ANP)
- ANP lowers blood pressure, increases urine output, and increased red blood cell production
100
What does the kidney do in regard to endocrine function?
-releases erythropoietin (EPO)
- secretion occurs in response to low blood o2 and increases red blood cell production
101
What does the liver do in regard to endocrine function?
-secretes IGF and inactive hormone angiotensinogen
-angiotensinogen is converted to angiotensinogen II by enzymes from kidney and lung blood vessels and helps raise blood pressure when it falls by causing vessel constriction, decreasing urine output, and stimulating thirst
102
What does the stomach do in regard to endocrine function?
secretes gastrin which increases motility in stomach for digestion
103
What do the small intestine do in regard to endocrine function?
-secretes secretin and choleocytokin into blood
-secretin stimulates the secretion of bile and pancreatic juice
-CCK stimulates the release of bile frome gall bladder
104
What does adipose tissue do in regard to endocrine function?
- controls appetite by binding neurons to hypothalamus
-less body fat= less leptin= appetite
- excess adipose raises cancer risk
-excess adipose delays puberty
-abnormally low adipose interferes with menstruation
