LECTURE 6: Endocrine system & exercise Flashcards

1
Q

list four factors affecting blood hormone concentration

A
  1. rate of secretion (regulated by rate magnitude of input, inhib. vs stim. input)
  2. rate of metabolism & excretion (at kidneys/liver/target cell)
  3. availability of transport hormones
  4. plasma volume (higher concentration when dehydrated)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

list three mechanisms of actions of hormones

A
  1. altering cell membrane (allow more/less mvmt of substrates across)
  2. altering activity of cell DNA
  3. activating 2nd messengers within cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

list the three categories of hormones

A
  1. amino acid derivatives
  2. peptides & proteins
  3. steroids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

list 6 hormones released by the anterior pituitary

A

thyroid stimulating hormone/TSH, growth hormone/GH, adrenocorticotropic hormones/ACTH, prolactin, follicle stimulating hormone/FSH, leutenising hormone/LH,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

list 2 hormones released by the posterior pituitary gland

A

oxytocin, ADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

t/f: ADH levels drop linearly during exercise

A

false: ADH levels rise exponentially as intensity increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what dietary sources can tryptophan be obtained from?

A

eggs, fish, poultry, nuts, seeds, dairy etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what hormone is tryptophan a precursor for?

A

melatonin (via serotonin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what hormones does the thyroid secrete? what are their effects?

A

T3 & T4 - metabolic & permissive hormones (raise metabolic rate of most cells & facilitate effectiveness of other hormones), calcitonin - lowers plasma Ca2+ content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what hormone does the parathyroid secrete and what is it’s effect?

A

Parathyroid hormone - increases plasma Ca2+ levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

why is calcium supplementation sometimes recommended for low-impact sports?

A

when calcium is lost in sweat, plasma Ca2+ levels lower triggering a rise in PTH and breakdown of bones. chronically, this can lead to lower BMD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what hormones does the adrenal medulla secrete?

A

adrenaline, noradrenaline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

does adrenaline dilate or constrict skeletal muscle blood vessels and intestinal blood vessels?

A

dilates skeletal muscle blood vessels (acts on beta cells), constricts intestinal blood vessels (acts on alpha cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what categories of hormones does adrenal cortex secrete?

A

mineralocorticoids, glucocorticoids, sex steroids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

provide an example of a mineralocorticoid, glucocorticoid and sex steroid secreted by the adrenal cortex

A

aldosterone, cortisol, androgens & oestrogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

does aldosterone secretion rise or fall with exercise?

A

rises - to counteract fluid loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

list three factors stimulating secretion of cortisol

A

circadian rhythm, exercise, stress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

list three hormones and their functions released by the pancreas

A

insulin - lowers blood glucose (promotes uptake of glucose and AA in cells)
glucagon - raises blood glucose (promotes glucose and FFA mobilisation)
somatostatin - controls nutrient absorption in GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

does oestrogen & progesterone plasma concentration rise or fall in exercise? explain

A

rises, dependent on phase of menstrual cycle but likely due to fluid loss increasing plasma concentration.
levels rise as intensity of exercise rise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are the androgenic and anabolic effects of testosterone in men

A

androgenic –> develops secondary sex characteristics
anabolic –> promotes tissue building

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

list the two causes of relative energy deficit syndrome (RED-S)

A

inadequate energy intake
excessive training

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

t/f: plasma adrenaline is a powerful stimulator of glyconeogenesis

A

true: high intensity exercise increases plasma adrenaline levels and allows for greater glucose use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what kind of control is muscle glycogen breakdown under? describe it’s components

A

dual control - two systems control the use of muscle glucose.
1. adrenaline-cAMP: breakdown of muscle glycogen stimulated by adrenaline via beta-adrenergic receptors
2. Ca2+-calmodulin: most Ca2+ (that which isn’t used for contraction) released from SR in exercise binds to calmodulin, activating protein kinases that initiate glycogen breakdown

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

t/f: glucose is not the main fuel source for exercise at near-max intensities

A

false

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
can muscles still contract when the beta-receptors are inhibited?
yes - the calcium-calmodulin system allows muscles to contract without adrenaline
26
list 4 ways blood glucose is maintained by hormones
1. mobilisation of glucose from liver glycogen stores 2. mobilisation of FFA from adipose tissue 3. gluconeogenesis from AA, lactic acid & glycerol 4. blocking entry of glucose into cells
27
list the four fast-acting hormones that control blood glucose
adrenaline, noradrenaline, insulin, glucagon
28
list the three slow-acting hormones that control blood glucose
thyroxine, cortisol, growth hormone
29
do plasma levels of catecholamines in exercise increase, stay the same or decrease following weeks of training?
decrease - indicate body's ability to adapt to repeated stressful events
30
do plasma levels of catecholamines in exercise increase, stay the same or decrease following weeks of training?
decrease
31
does the secretion of insulin & glucagon depend on catecholamine action?
yes - catecholamine binding to alpha cells stimulates secretion of glucagon, binding to beta cells inhibits insulin secretion
32
list four ways catecholamines quickly restore blood glucose levels
1. muscle glycogen mobilisation 2. increased liver glycogenolysis 3. mobilisation of FFA from adipose tissue 4. opposing glucose uptake by tissue
33
as exercise intensity increases, do plasma insulin and glucagon levels fall or rise?
insulin falls, glucagon rises
34
how does a glucose pressure gradient develop between tissue and blood in exercise?
higher blood glucose levels (due to higher glucagon/lower insulin) creating high blood glucose concentration & high rate of muscle glucose use creating a low intracellular glucose concentration creates a pressure gradient, allowing glucose to more readily pass into the cell
35
do glucagon/insulin levels increase in endurance trained athletes?
not much, due to greater sensitivity of cells to insulin/glucagon, greater FFA metabolism with training (especially with increase in duration/intensity) & reduced SNS response to exercise (lower catecholamine levels to stimulate pancreas)
36
how do T3 & T4 contribute to blood glucose homeostasis?
act in permissive manner - allow other hormones to exert their full effect
37
to T3/T4 levels change in exercise?
no - metabolism increases in exercise but secretion increases to restore plasma levels
38
list four ways cortisol contributes to blood glucose homeostasis
1. MOSTLY permissive hormone (allows fast acting hormones to work more efficiently) 2. stimulates FFA mobilisation from adipose tissue 3. stimulates gluconeogenesis in live 4. blocks entry of glucose into tissue
39
do cortisol levels increase or decrease in low intensity exercise (less than 60%VO2max)? what about high intensity (greater than 60%VO2max)
low: decrease (rate of use is greater than rate of secretion) high: increase (stress of exercise stimulates more secretion)
40
list four ways growth hormone contributes to blood glucose homeostasis
1. supports action of cortisol 2. blocks glucose uptake in cell 3. increases FFA mobilisation 4. increases gluconeogenesis in liver
41
does plasma GH concentration increase or decrease as exercise intensity rises?
increases - at high concentrations at near-VO2max GH can start its slow effect
42
does plasma GH concentration increase or decrease with training
likely increase (especially earlier in exercise).
43
why is it uncertain whether GH levels in exercise increase or decrease with training?
GH is hard to isolate, many factors affect it's release
44
do concentrations of fast and slow acting hormones respectively increase or decrease as exercise intensity increases?
FAST: increase SLOW: decrease + small bounce up close to VO2max to provide more glucose
45
do concentrations of fast and slow acting hormones respectively increase or decrease as exercise duration increases?
FAST: increase, but mostly due to fluid loss SLOW: decrease, no bounce up due to lower intensity
46
what enzyme is FFA mobilisation dependent on?
hormone sensitive lipase (HSL)
47
why does FFA mobilisation decrease in heavy exercise despite increased hormonal stimulation for FFA mobilisation?
high lactic acid levels trap FFA in adipose cell (force FFA back into triglyceride form) high H+ levels inhibit HSL lower blood flow to adipose tissue lowers FFA release
48
what two adipokines does adipose tissue secrete (as endocrine action of adipose)?
leptin adiponectin
49
are leptin and adiponectin pro- or anti-inflammatory?
leptin - pro-inflammatory adiponectin -anti-inflammatory
50
do both adiponectin and leptin enhance insulin sensitivity & fatty acid oxidation in muscle cells?
yes, both
51
what endocrine effects of adipose tissue change when fat mass increases to obese levels?
higher leptin secretion - lower appetite suppression due to lower hypothalamic sensitivity, more pro-inflammatory effect of leptin lower adiponectin secretion - lower anti-inflammtory effects, lower insulin sensitivity of muscle cells
52
what is the primary myokine secreted by muscles (as an endocrine function)
interleukin 6 (IL-6)
53
does exercise-induced release of IL-6 have a pro- or anti-inflammatory effect?
anti-inflammatory effect - IL-6 can have both effects but when released with exercise is anti
54
what effects does the autocrine effect of myokine release have on local cells
higher glucose uptake, higher FFA oxidation
55
what paracrine/endocrine effects does myokine release have on the body?
promotes blood vessel growth in muscle promotes liver gluconeogenesis and TAG breakdown
56
what stimulates increased erythropoietin (EPO) release?
hypoxia
57
what does erythropoietin to do the blood?
increases RBC content
58
what organ secretes EPO?
kidneys
59
what does ESA stand for?
erythropoietin stimulating agent
60
what does rhEPO stand for?
recombinant erythropoietin
61
what is the difference between rhEPO & ESAs?
rhEPO is an exogenous form of EPO that directly increases RBC levels, ESAs are exogenous stimulators of EPO release in the body.
62
does altitude increase or decrease EPO secretion?
increases
63
what is the form of classic altitude training?
LHTH - Live high train high
64
what is the form of contemporary altitude training?
LHTHL - live high train high & low
65
what does altitude do to stimulate EPO secretion?
hypoxia
66
does growth hormones (as a PED) affect contractile proteins or collagen?
collagen
67
does testosterone affect collagen or contractile protein growth?
Contractile protein