FORM AND FUNCTION (Metabolic Demands: Muscle)

Question 1

Key features of the metabolic demands of skeletal muscle:

Answer 1

-adaptability
-rapid ATP production
-fatigue

Question 2

Adaptability:

Answer 2

-can switch between metabolic pathways based on activity demands

Question 3

Rapid ATP production:

Answer 3

-skeletal muscle can quickly produce ATP to meet immediate energy needs when switch to intense activities from rest

Question 4

Fatigue:

Answer 4

-metabolic by-products can lead to muscle fatigue during intense activities

Question 5

3 main energy pools:

Answer 5

-ATP-Creatine phosphate (immediate)
-glycolytic (fast and short-term)
-oxidative (slow and long-term)

Question 6

ATP-Creatine phosphate system:

Answer 6

-provides energy for short, high-intensity burst (<10seconds)
-rapid regeneration of ATP from Creatine Phosphate
-Creatine kinase catalyzes the reversible reaction
-Creatinine is by-product of creatine

Question 7

ATP-Creatine phosphate ‘equation’:

Answer 7

-resting muscle: ATP+creatine=creatine phosphate and ADP
-creatine kinase get=creatine and ATP in active muscle (ATP used for muscle contraction)

Question 8

Creatinine:

Answer 8

-by-product of creatine
-used as an indicator for kidney function (not functioning properly)
*not directly involved in metabolism but is part of the system

Question 9

Glycolytic vs. oxidative:

Answer 9

-glycolytic: glycolysis (anaerobic)
-oxidative phosphorylation: TCA cycle and ETC (mitochondria)

Question 10

Glucose: anaerobic pathway

Answer 10

-get 2 ATPs
-lactate produced can cause muscle fatigue and metabolic acidosis (and death)

Question 11

Glucose (pyruvate) or FFA (beta oxidation): aerobic pathway

Answer 11

-relies on TCA and the ETC (mitochondria)
-predominantly used in prolonged, low-intensity activities
-requires oxygen

Question 12

Oxygen for aerobic pathway:

Answer 12

-myoglobin (oxygen-binding protein)
-blood supply

Question 13

Fiber types:

Answer 13

-type I (slow twitch)
-type IIA (fast twitch, oxidative)
-type IIB (fast twitch, glycolytic)

Question 14

Fast vs. slow:

Answer 14

-refers to speed of contraction
-related to Vmax (ability of the myosin head)

Question 15

Type I:

Answer 15

-slow twitch
-aerobic
-high endurance =fatigue resistance
-red (due to heme group in myoglobin)

Question 16

Type I morphological characteristics:

Answer 16

-high mitochondrial content
-high fat content
-low glycogen content

Question 17

Type IIA:

Answer 17

-fast twitch
-oxidative
-mix of aerobic and anaerobic
-moderate endurance (fatigue resistant)

Question 18

Type IIA morphological characteristics:

Answer 18

-intermediate mitochondria
-fat and glycogen content

Question 19

Type IIB:

Answer 19

-fast-twitch
-glycolytic
-predominantly anaerobic
-low endurance=fatigue sensitive
-white

Question 20

Type IIB morphological characteristics:

Answer 20

-low mitochondrial and fat content
-high glycogen content

Question 21

Motor units and fiber type:

Answer 21

-usually only have one fiber type

Question 22

Force and fatigability of different types of motor units:

Answer 22

-highest: type IIB
-middle/low: type IIA
-low: type I

Question 23

If continue stimulation: force and fatigability:

Answer 23

-fast twitch (Type IIB): can no longer maintain the force even with continuous stimulation
-Type IIA: maintain force for minutes but not hours
-slow twitch: maintain a 100% force with the continuous stimulation

Question 24

Percentage of each fiber type:

Answer 24

-varies from muscle to muscle
-varies from species or breeds

Question 25

Quarter horse vs. Arabian:

Answer 25

-quarter: sprinting, higher Type II fast twitch
-Arabian: endurance, higher Type I slow twitch

Question 26

Skeletal muscle: adaptation

Answer 26

-sarcomeres increase during growth
-hypertrophy and hyperplasia

Question 27

Hypertrophy:

Answer 27

-increases actin/myosin in parallel to increase force
*not adding new muscle fibers, but adding sarcomeres in PARALLEL

Question 28

Hyperplasia:

Answer 28

-rare
-more force is generated form more muscle fibers being made
-requires satellite cells with intact endomysium for successful repair after injury
>satellite cell can make another muscle fiber if endomysium is intact

Question 29

Type of training:

Answer 29

-learning/coordination
-endurance (submaximal, sustained efforts)
-strength (brief, maximal efforts)
*skeletal muscle show specific adaptations based on type of activity

Question 30

Learning/coordinated training:

Answer 30

-ex. typing
-increased rate and accuracy of motor skills (CNS)

Question 31

Endurance training:

Answer 31

-submaximal, sustained efforts
-ex. marathon training
-increased oxidative capacity in all involved motor units with limited cellular hypertrophy

Question 32

Strength training:

Answer 32

-brief, maximal efforts
-ex. weightlifting
-hypertrophy and enhanced glycolytic capacity (ex. more enzymes) or motor units employed