Endocrine System Overview Flashcards
(71 cards)
1
Q
What are the primary endocrine organs?
A
pituitary, pineal, parathyroid, thyroid, adrenal, thymus
PPPTAT
2
Q
What are the secondary endocrine organs?
A
pancreas, liver, ovaries, adipose tissue, testes, hypothalamus
PLOATH
3
Q
The nervous system is an electrical communication system. So, what is the endocrine system?
A
a chemical communication system
4
Q
Compared to the nervous system, what is the speed of endocrine signaling?
A
slower
5
Q
Compared to the nervous system, what is the duration of endocrine signaling?
A
longer
6
Q
What are the signaling molecules of the endocrine system?
A
hormones
7
Q
How does the endocrine system maintain homeostasis?
A
- controls and regulate cell and organ activity
- acts on target cells
8
Q
What does the endocrine system coordinate during rest and exercise?
A
integration of physiological systems
9
Q
How does the endocrine system maintain homeostasis during exercise?
A
- controls substrate metabolism
- regulates fluid and electrolyte balance
10
Q
What is a gland?
A
an organ/body that secretes substance
11
Q
Describe exocrine glands.
A
- contain ducts
- carry substances directly to a specific surface
12
Q
Describe endocrine glands.
A
- ductless
- secrete substances directly into blood
13
Q
What is a hormone?
A
signaling molecule that travels through the blood stream
* “chemical messenger”
14
Q
Are peptide hormones hydrophilic or hydrophobic?
A
hydrophilic
15
Q
How do peptide hormones travel in the blood?
A
travel dissolved in plasma
16
Q
What are the two types of peptide hormones?
A
- Protein or Peptide
- Amino Acid Derived
17
Q
Describe protein peptide hormones.
A
- most non-steroid hormones
- from pancreas, hypothalamus, and pituitary gland
18
Q
Describe amino acid derived hormones.
A
- thyroid hormones (T3, T4)
- adrenal medulla (NE, Epi)
19
Q
Describe the MOA for peptide hormones.
A
- hormone binds to surface receptor
- secondary messengers are released in cytoplasm
- secondary messengers enter nucleus to cause cellular response
20
Q
Are steroid hormones hydrophilic or hydrphobic?
A
hydrophobic
21
Q
How do steroid hormones travel in the blood?
A
travel bound to carrier proteins
22
Q
What are steroid hormones derived from?
A
cholesterol
23
Q
Steroid hormones are secreted by what 4 major glands?
A
- adrenal cortex (cortisol, aldosterone)
- ovaries (estrogen, progesterone)
- testes (testosterone)
- placenta (estrogen, progesterone)
24
Q
Describe the MOA for steroid hormones.
A
- steroid hormone crosses the lipid bilayer of target cell
- binds to steroid receptor within cytoplasm
- bound complex moves into nucleus to cause cellular response
25
What is a half life?
the time it takes a quantity to reduce to half of its original value
26
Do peptide or steroid hormones have longer half-lives?
steroid hormones have longer half-lives compared to peptide hormones
27
How do hormones enact effects?
by binding to receptors
28
Do all cell types have every hormone receptor?
No, not every cell type has a receptor for every hormone
29
Is plasma concentration a good measure of hormone activity?
NO, plasma concentration is a poor indicator of hormone activity
30
Why is plasma concentration a poor indicator of hormone activity?
* cells change sensitivity to hormones
* number of receptors on cell surface can change
31
What causes hormone desensitization?
down-regulation
* decreasing number of receptors during high plasma concentration
32
What causes hormone sensitization?
up-regulation
* increasing number of receptors during high plasma concentration
33
What are the major endocrine glands responsible for metabolic regulation?
* anterior pituitary gland
* thyroid gland
* adrenal gland
* pancreas
34
Where is the pituitary gland located?
attached to the inferior hypothalamus
35
What are the lobes of the pituitary gland?
anterior, intermediate, posterior
36
What triggers the release of hormones from the pituitary gland? What type of factors are released?
* hypothalamic hormones
* both inhibiting and releasing
37
How does exercise affect all pituitary hormones?
exercise increases the secretion of all anterior pituitary hormones
38
What are major points about GH?
* anabolic hormone
* mobilizes fat as primary substrate
39
GH ?? gluconeogenesis in the liver, but it ?? blood glucose uptake by some tissues.
* stimulates gluconeogenesis in the liver
* prevents blood glucose uptake by some tissues
40
How is GH related with exercise?
Increased exercise = increased GH
* proportional
41
How is GH related to age?
increased age = decreased GH
* inversely
42
T4
thyroxine
43
T3
triiodothyronine
44
How are T3 and T4 related?
T4 is the precursor to T3 (more active form)
45
What is the main function of thyroid hormones?
* set level of metabolism in many tissues
* high thyroid hormones = high metabolism
46
What are important affects of increased thyroid hormones?
increased...
* metabolic rates
* protein synthesis
* number and size of mitochondria
* glucose uptake by cells
* rates of glycolysis and gluconeogenesis
* FFA mobilization
47
What are important points to know about thyroid hormones?
* steroid-like hormones but actually amine hormones
* T3 and T4
48
How are exercise and thyroid hormones related?
increased exercise increase TSH release
49
What does the adrenal cortex release?
corticosteroids
* glucosteroids, mineralcorticoids, and gonadocorticoids
50
What is a major glucosteroid released by the adrenal cortex?
cortisol
51
What are 3 major things cortisol does?
* stimulates gluconeogenesis
* increase lipolysis, FFA mobilization
* causes protein breakdonw (catabolism)
52
What is a major cause of cortisol secretion??
stress
53
How does acute exercise affect cortisol levels?
it increases cortisol levels
54
How does exercise training affect cortisol levels?
decreases cortisol levels
55
What does the adrenal medulla release?
catecholamines
* NE (20%) and Epi (80%)
56
What are major affects of catecholamine release?
increased....
* glycogenolysis
* FFA metabolism
* blocking of glucose uptake in some cell types
57
How does exercise affect catecholamine levels?
exercise increases the levels of plasma catecholamines
58
What is insulin primary role?
lower blood glucose
59
How does insulin lower blood glucose?
* counters hyperglycemia, opposes glucagon
* facilitates glucose transport into cells
* enhances synthessis of glycogen, protein and fat
* inhibits gluconeogenesis
60
What is the primary role of glucagon?
raises blood glucose
61
How does glucagon increase blood glucose?
* counters hypoglycemia, opposes insulin
* promotes glycogenolysis, gluconeogenesis
62
What is significant about glucose being a polar molecule?
* can't cross cell membrane
* requires a transport protein (GLUT)
63
GLUT1
most tissues, non-inducible (constitutive expression)
64
GLUT2
on the pancreas
65
GLUT4
predominantly in muscle (cardiac, smooth, skeletal), inducible
66
What does adequate glucose utilization require?
* glucose released by the liver (gluconeogenesis/glycogenolysis)
* glucose uptake by muscles
67
How does GH influence circulating glucose levels?
* increases FFA mobilization
* decreases cellular glucose uptake
68
How do T3 and T4 influence circulating glucose levels?
increases glucose catabolism and fat metabolism
69
As exercise intensity increases...
* catecholamines?
* glycogenolysis?
* muscle glycogen vs. liver glycogen?
* catecholamine release increase
* glycogenolysis rate increases
* muscle glycogen is used before liver glycogen
70
As exercise duration increases...
* liver glycogen?
* muscle glucose uptake?
* liver glucose release?
* glycogen stores?
* glucagon levels?
* more liver glycogen is used
* increase muscle glucose uptake
* increased liver glucose release
* decreased glycogen stores
* increased glucagon levels
71
During exercise...
* insulin concentrations?
* cellular insulin sensitivity?
* insulin concentrations decreases (spare glucose uptake specifically for active muscles)
* cellular insulin sensitivity increases
* more glucose is take up and less insulin is used
