9/14/21 Regulation of carbohydrate metabolism and exercise effects

Question 1

what occurs when there is increase breathing and heart rate?

Answer 1

increased O2, nutrients, eliminates CO2 and metabolic waste products, transport hormones, maintain body temp, acid-base balance

Question 2

what occurs when there is increased contraction of muscles

Answer 2

ability to extract O2, choose energy sources and eliminate metabolic waste

Question 3

what are the two types of fiber that makes up muscle?

Answer 3

fast and slow fiber

Question 4

slow fiber

Answer 4

type I myosin

Question 5

fast fiber

Answer 5

type II myosin (IIa and IIB)

Question 6

what color are slow twitch fibers and why

Answer 6

red due to large amounts of myoglobin

Question 7

what does slow twitch contain?

Answer 7

large numbers of oxidative enzymes, more mitochondria, more capillaries

Question 8

what capacity is slow twitch muscle fibers used for?

Answer 8

large capacity for aerobic metabolism, high resistance to fatigue, long distance running

Question 9

Type IIa fast twitch fiber

Answer 9

hybrid of type I and II, red, lots of mitochondria, use both aerobic and anaerobic for ATP, mid distance running

Question 10

Type IIb fast glycolytic fibers

Answer 10

white, low myoglobin levels, few mitochondria, use anaerobic metabolism for ATP, short sprints

Question 11

what are slow twitch fibers better adapted for?

Answer 11

aerobic activity

Question 12

what can fast twitch fibers maximum generate

Answer 12

tension, but can fatigue quickly

Question 13

energy source used during exercise in first hours

Answer 13

muscle glycogen provides ~50% of energy, muscle triglycerides and plasma free fatty acids ~25% each

Question 14

energy source used during exercise in second hour

Answer 14

blood glucose and plasma free fatty acids are providing more of the energy nutrients, as muscle glycogen and triglycerides are being depleted.

Question 15

energy source used during exercise in third hour

Answer 15

> 70% of energy needs are being provided by blood glucose and plasma free fatty acids.

Question 16

energy source used during exercise in fourth hour

Answer 16

hours >90 of energy fuel is provided by blood glucose and plasma free fatty acids. Muscle glycogen is fully depleted and muscle triglycerides provide >10% of energy needs.

Question 17

muscle force- velocity relationship

Answer 17

fast fibers produce greater muscular force at a faster speed than slow fibers.

fast fibers possess higher ATPase activity and more myosin cross bridges than do slow fibers. Therefore ATP is broken down more rapidly in fast fibers when compared with slow fibers.

Question 18

muscle contractility

Answer 18

measured and expressed as maximal tetanic force or as specific force generated.

Question 19

Specific force

Answer 19

the max force divided by muscle cross sectional area

Question 20

Myostatin or growth differentiation factor 8 (GDF8)

Answer 20

• an inhibitor of muscle differentiation and growth

- member of the TGF-β superfamily and binds to the activing type II receptor.

Question 21

what are the changes in muscle that occur naturally? (3)

Answer 21

1. Both endurance and resistance (weight) training result in a shift from a fast 2b myosin to 2a myosin
2. Age is associated with a loss of muscle mass (Sarcopenia).
3. Muscle loss also occurs with paralysis and with disuse atrophy (broken arm/leg).

Question 22

Skeletal Muscle Contraction

Answer 22

1. The active site on actin is exposed as calcium binds to troponin.
2. The myosin binds actin at its actin-binding site, forming the cross-bridge.
3. During the power stroke, the phosphate generated in the previous contraction cycle is released. This results in the myosin head pivoting toward the center of the sarcomere, after which the attached ADP and phosphate group are released.
4. A new molecule of ATP attaches to the myosin head, causing the cross-bridge to detach.
5. The myosin head hydrolyzes ATP to ADP and phosphate, which returns the myosin to the cocked position.

Question 23

Sources of ATP required for muscle contraction (4)

Answer 23

1. glycolysis
2. Krebs (TCA) cycle
3. Glycogenolysis
4. Fatty Acid Oxidation

Question 24

Glycogen

Answer 24

glycoprotein, consists of core protein “glycogenin”, highly branched 1,6- and 1,4 glycosidic bonds

Question 25

what are fed to individuals to last longer or extended muscle oxygen performance

Answer 25

carbohydrates

Question 26

muscle glycogen content:

Answer 26

• a determinant of capacity to do long term heavy exercise

- can be manipulated depending upon diet following glycogen depletion

Question 27

Glycogen Storage Disease Type 0

Answer 27

glycogen synthase deficiency (muscle)

Symptoms: cardiomyopathy and exercise intolerance associated with complete absence of muscle glycogen

Question 28

Glycogen Storage Disease Type IXd

Answer 28

muscle phosphorylase kinase deficiency
Symptoms: X-linked disease, relatively mild disorder characterized by variable exercise induced muscle weakness or stiffness.

Question 29

Cori Cycle

Answer 29

Muscle: glucose->lactate-> enters the liver-> glucose-> enters the blood-> goes back to muscle

Question 30

Triglycerides as an energy source and why

Answer 30

major energy reservoir, highly concentrated stores of metabolic energy because they are reduced and nonpolar– stored in anhydrous form

Question 31

what 2 things provide enough energy to sustain biological function for 24 hrs?

Answer 31

glycogen and glucose

BUT triacylglycerol stores allow survival for weeks

Question 32

what is the main source for energy at times of stress or fasting?

Answer 32

mitochondrial fatty acid beta- oxidation

Question 33

4 steps of B- oxidation

Answer 33

1. oxidation
2. hydration
3. oxidation
4. thiolysis

Question 34

simple fact about weight control

Answer 34

weight is largely a function of how much energy you consume versus how much you expend

Question 35

super athletes, doping

Answer 35

includes performance-enhancing drugs or PEDs: steroids to boost muscle growth, narcotics to suppress pain, beta blockers to slow the heart rate

Question 36

Erythropoietin (EPO)

Answer 36

naturally occurring hormone that is produced by the kidneys, which stimulates red blood cell production.
Results: thick blood, increase strain on heart, lots of O2 to tissues