endocrinology

Question 1

4 ways to maintain plasma glucose

Answer 1

1. mobilize glucose form the liver
2. mobilize FFA from adipose tissue
3. gluconeogenesis at the liver
4. block glucose entry into some cells

Question 2

during exercise the body tries to protect (2)

Answer 2

1. muscle glycogen

2. blood glucose

Question 3

does skeletal muscle share its glycogen stores with the rest of the body if the body is in great great need?

Answer 3

NO.

Question 4

glucose moves via _____ diffusion across the cell, this means? Glucose is also ____ driven

Answer 4

• facilitated diffusion
• -> has carrier proteins
• gradient (only moves DOWN a gradient)

Question 5

what are the 2 glucose transporters? which one is primary?

Answer 5

• GLUT 1

- GLUT 4 (primary)

Question 6

GLUT 4 glucose transporter has insulin- responsive transporters in ? (3)

Answer 6

1. skeletal muscle fibers
2. cardiac muscle fibers
3. adipose cells

Question 7

how does muscle act as an endocrine organ?

Answer 7

it produces cytokines via contraction of skeletal muscle (myokines).
- IL-6 which helps modify the inflammatory response and activates muscle, liver, adipose, and blood vessels to help maintain blood glucose

Question 8

what effect does IL-6 have at the muscle?

Answer 8

increases glucose uptake and fat oxidation

Question 9

what effect does IL-6 have at the liver?

Answer 9

increases hepatic glucose production through gluconeogensis and glycogenolysis

Question 10

what effect does IL-6 have at the adipose tissue?

Answer 10

increases lipolysis

Question 11

what effect does IL-6 have in blood vessels?

Answer 11

growth and proliferation (increase in cappilarization)

Question 12

explain the pathway of insulins formation of glycogen

Answer 12

insulin binds to receptor–> phosphorylation of internal protein subunits –> activates signal cascade–> activates glycogen synthase–> glycogen (stored in cell)

Question 13

what step is essential for insulin to create to glycogen and why ?

Answer 13

activation of glycogen synthase (enzyme) because it creates the GRADIENT

Question 14

what is the problem of insulin creating glycogen

Answer 14

it is happening EVERYWHERE not just in the muscle so we need to stop this during exercise or else or else it will take up so much glucose that we will run out of blood glucose very quickly

Question 15

the pancreas regulates glucose into all tissues except what?

Answer 15

the brain

Question 16

glucose that is not catabolized is destined to become? (2)

Answer 16

1. glycogen

2. triglycerides

Question 17

is it better to store calories as triglycerides or CHO? and why

Answer 17

triglycerides because they take up less space = smaller

Question 18

with high blood sugar, ____ stimulates what?

with low blood sugar, _____ stimulates what?

Answer 18

• insulin, glycogen formation to lower blood sugar and stimulates glucose uptake from blood to lower blood sugar
• glucagon, glycogen breakdown to increase blood sugar

Question 19

insulin and glucagon are secreted from?

Answer 19

the pancreas

Question 20

can muscle release glucagon like the pancreas can?

Answer 20

NO

Question 21

increased insulin secretion causes most tissues results in? (4)

Answer 21

1. increased glucose uptake (except brain, liver, exercising muscle)
2. increased amino acids uptake
3. increased protein synthesis
4. decreased protein breakdown

Question 22

increased insulin secretion causes adipose tissue results in (2)

Answer 22

1. increase FA and triglycerol synthesis

2. decrease lypolysis

Question 23

increased insulin secretion causes liver and muscle to? (2)

Answer 23

1. increase glycogen synthesis

2. decrease glycogenolysis

Question 24

increased insulin secretion cause the liver to (2)

Answer 24

1. increased FA and triacylglycerol synthesis

2. decreased glycogenolysis

Question 25

as insulin goes up during exercise what do we stop?

Answer 25

the beta cells in the pancreas from releasing insulin

Question 26

what is the main glucose receptor in skeletal muscles

Answer 26

GLUT 4

Question 27

insulin regulates blood glucose by promoting uptake of glucose by cells - 3 characteristics

Answer 27

1. activates GLUT transporter molecules 2. various GLUT isoforms result in different kinetics 3. GLUT-4 most predominant in skeletal muscles

Question 28

insulin also promotes?

Answer 28

lipogenesis in adipose tissue

Question 29

insulin levels decrease during exercise. - Favors ___ out of the liver - -allows for greater? - Active muscles may take up glucose without?

Answer 29

- favors glucose out of the liver - greater mobilization of FFA - without assistance form insulin

Question 30

during exercise do we effect the receptors inside the cell? why?

Answer 30

NO. we don't effect the receptors inside the cells because we still them during exercise so we instead favour glucose going out of the liver to allow muscles to still take up glucose but other cells will not

Question 31

what 5 hormones are involved in mobilizing fuels for working muscle? what 2 are "highlighted"

Answer 31

glucagon and epinephrine are highlighted | - also growth hormone, thyroxine, cortisol

Question 32

glucagon is secreted by?

Answer 32

alpha cells of the pancreas

Question 33

glucagon promotes?

Answer 33

glycogenolysis in the liver gluconeogenesis in the liver | --> release glucose into the blood

Question 34

what plays a big role in the sympathoadrenal response during exercise?

Answer 34

exercise intensity!

Question 35

what is the sympathoadrenal response

Answer 35

spike in epi and norepi during exercise!

Question 36

at what percent vo2 max do we see spike in norepi ? what % do you we see a spike in epi?

Answer 36

- norepi= 50% - epi= 75% (above threshold) (relative to the individual)

Question 37

during exercise, we just need _____ receptors for glucose transport not ____

Answer 37

- GLUT4 | - insulin

Question 38

exercise results in ___ translocation INDEPENDENT of insulin

Answer 38

GLUT 4

Question 39

what are the 3 possible signals for GLUT4 Translocation during exercise

Answer 39

1. calcium 2. AMP/AMPK 3. NO

Question 40

the 3 signals for GLUT4 activation during exercise are activated by what?

Answer 40

muscle contraction

Question 41

what calcium in the muscle cell do during contraction?

Answer 41

- enhances actin myosin cross bridge and cascading event s

Question 42

What are factors affecting the SUPPLY of glucose during exercise, ultimately affecting glucose uptake

Answer 42

1. capillary perfusion | 2. blood glucose concentration

Question 43

what are factors affecting the TRANSPORT of glucose and thus the uptake of glucose during exercise

Answer 43

1. Surface membrane GLUT abundance 2. Glucose gradient 3. GLUT activity

Question 44

what are factors affecting the METABOLISM of glucose and thus the uptake of glucose during exercise

Answer 44

1. hexokinase activity | 2. substrate flux

Question 45

acute glucose uptake by muscles is influenced by ?

Answer 45

intensity and duration | greater with both

Question 46

what does exercise training do to influence glucose uptake | --> how does it get affected by muscle fiber type

Answer 46

it influences the available pathways for bringing glucose into the cell - shift to slow twitch fibers which have more GLUT 4 (greater concentration)

Question 47

what do ppl with type 2 diabetes have to do before exercising?

Answer 47

they have to reduce the amount of insulin they take because there would be a massive increase in glucose uptake so blood glucose levels would drop (during exercise insulin receptors are NOT blocked, just insulin release is, SO you still have insulin increasing glucose uptake)

Question 48

can you get increased glucose uptake with resistance training and aerobic training?

Answer 48

YES both

Question 49

what are normal blood glucose levels

Answer 49

< 7

Question 50

what are 3 hormonal changes during exercise that = improved glucose uptake to support work?

Answer 50

1. enhance fuel availability for muscles 2. improve glucose transport to muscles 3. increased sensitivity of insulin receptors

Question 51

liver _____ and muscles ____ in regards to glucose | --> if this is stable then we have stable blood glucose

Answer 51

liver PROVIDES and muscles UTILIZES

Question 52

what stimulates the thyroid gland?

Answer 52

TSH

Question 53

what 3 things does the thyroid gland secrete?

Answer 53

1. T3 - triiodothyronine (more active in resting state) 2. T4 - thyroxine 3. Calcitonin

Question 54

T3 and T4 are known as ?

Answer 54

thyroid hormones

Question 55

both T3 and T4 have ______ effects on cellular metabolism. particularly on ______

Answer 55

Permissive, Epinephrine

Question 56

does the calcitonin play a role in blood glucose regulation?

Answer 56

NO

Question 57

what 3 things do thyroid hormones enhance? and it also increases what?

Answer 57

1. cellular uptake of glucose 2. glycolysis & gluconeogenesis 3. mobilaization and oxidation of FA - -> increases protein synthesis

Question 58

how do thyroid hormones increase protein synthesis

Answer 58

by increase intracellular enzymes , size and # of mitochondria

Question 59

cortisol acts ______ to maintain plasma glucose

Answer 59

permissively (glucagon and GH) | --> not sure whats with the glucagon and GH

Question 60

with what 3 mechanisms does cortisol maintain plasma glucose

Answer 60

1. blunts insulins effect 2. mobilizes FFA 3. Promotes protein breakdown --> gluconeogenesis

Question 61

heavy exercise does what to cortisol levels?

Answer 61

increases them slightly

Question 62

moderate exercise does what to cortisol levels

Answer 62

no change

Question 63

prolonged exercise to exhaustion does what to cortisol levels?

Answer 63

increase them

Question 64

give an example of how duration influences fuel availability via endocrine control

Answer 64

prolonged exercise to exhaustion increases cortisol levels (stress!)

Question 65

when will there be the greatest spike in cortisol levels and testosterone levels? (before exercise , right after, or 1 hr recovery)

Answer 65

right after *see graph in slides

Question 66

growth hormone promotes growth of what tissues?

Answer 66

ALL tissues

Question 67

what 3 things does growth hormone do to enhance the growth of all tissues ?

Answer 67

1. tissue uptake of amino acids = protein synthesis 2. induces gluconeogenesis 3. increase lipolysis

Question 68

what causes growth hormone release?

Answer 68

- EIGR (exercise induced growth hormone response) --> caused by neural input, lactate and possibly NO

Question 69

during exercise what happens to GH levels?

Answer 69

they increase!

Question 70

what 4 things does GH do during exercise?

Answer 70

1. Supports the role of CORTISOL 2. Blunts the effects of INSULIN 3. Enhances Gluconeogenesis (aids in maintaining blood glucose) 4. Increases FFA mobilization

Question 71

what are the 4 ways to maintain plasma glucose?

Answer 71

1. mobilize glucose from the liver 2. mobilize FFA from adipose tissue 3. gluconeogenesis at liver 4. block glucose entry into some cells