Muscles

Question 1

Cellular respiration

Answer 1

Set of metabolic reactions that convert food into energy

• aerobic respiration
• anaerobic fermentation

Question 2

Anaerobic fermentation

Answer 2

• production of ATP without O2
• ATP produced by glycolysis only
• one-step reaction
• pyruvic acid reduced to lactic acid

Question 3

Aerobic respiration

Answer 3

• presence of O2
• most ATP production
• matrix reactions (enzymes in the matrix of the mitochondria) membrane reactions (enzymes bound to cristae)

Question 4

Functions of muscles

Answer 4

Movement
Stability
Control of openings/passageways
Heat production
Glycemic control

Question 5

Excitability

Answer 5

Reaction to chemical signals, stretch, and electrical changes across plasma membrane

Question 6

Conductivity

Answer 6

Local electrical change triggers a wave of excitation that travels along the muscle fiber

Question 7

Contractility

Answer 7

Shortens when stimulated

Question 8

Extensibility

Answer 8

Capable of being stretched between contractions

Question 9

Elasticity

Answer 9

Returns to original resting length after being stretched

Question 10

Tendon

Answer 10

Attachment between muscle and bone matrix

Question 11

Fasciae

Answer 11

Connective tissue that compartmentalizes muscles

Question 12

Epimysium

Answer 12

Connective tissue around entire muscle

Question 13

Perimysium

Answer 13

Connective tissue around muscle fascicles

Question 14

Endomysium

Answer 14

Connective tissue around muscle fibers

Question 15

Sarcoplasm

Answer 15

Cytoplasm of muscle fiber

Question 16

Sarcolemma

Answer 16

Plasma membrane of muscle fiber

Question 17

Triad

Answer 17

Two terminal cisternae transverse tubule

Question 18

Sarcoplasmic reticulum

Answer 18

Stores and releases Ca+ for muscle contraction

Question 19

Transverse tubule

Answer 19

Conduct nerve impulses from sarcolemma to the interior of the cell

Question 20

Z disc

Answer 20

Attaches the thin and elastic filaments

Question 21

Sarcomere

Answer 21

Smallest functional unit of the muscle fiber

Question 22

I band

Answer 22

Contains thin filaments

Question 23

Myosin

Answer 23

Thick filament

Question 24

Actin

Answer 24

Thin filament

Question 25

Titin

Answer 25

Elastic filament

Question 26

A band

Answer 26

Contains both thick and thin filaments

Question 27

M line

Answer 27

Contains only thick filaments

Question 28

H band

Answer 28

Contains only thick filaments

Question 29

Motor unit

Answer 29

One nerve fiber and all the muscle fibers innervated by it | Average motor unit contains 200 muscle fibers for each motor unit

Question 30

Neuromuscular junction

Answer 30

Point where a nerve fiber meets the muscle fiber

Question 31

Excitation

Answer 31

Process in which nerve action potentials lead to muscle action potentials

Question 32

Excitation-contraction coupling

Answer 32

Events that link the action potentials on the sarcolemma to activation of the myofilaments thereby preparing them to contract

Question 33

Contraction

Answer 33

Step in which the muscle fiber develops tension and may shorten

Question 34

Relaxation

Answer 34

When its work is done, a muscle fiber relaxes and returns to its resting length

Question 35

Process of excitation

Answer 35

1. Arrival of an action potential 2. Release of ACh 3. Binding of ACh to the receptors 4. Opening of ligand-gated ion channels and creation of EPP 5. Opening of voltage-gated ion channels and creation of a action Potential

Question 36

Process of excitation-contraction coupling

Answer 36

6. Action potentials spreading over sarcolemma reach and enter the T tubules 7. Voltage-gated channels open in the T tubule causing calcium gates to open in the SR 8. Calcium released by SR binds to troponin 9. Troponin-tropomyosin complex changes shape and exposes active sites on action

Question 37

Process of contraction

Answer 37

10. Myosin ATPase in myosin rad hydrolyzes an ATP molecule, activating the head and “cocking” it in an extended position. It binds to an active site on the actin 11. Myosin releases the ADP and P and flexes into a bent position, tugging the thin filaments along with it

Question 38

Process of relaxation

Answer 38

12. Nerve stimulation ceases and ACh release stops 13. AChE breaks down ACh and fragments reabsorbed into synaptic knob stopping simulation 14. Active transport Ca2+ back into SR where it binds to Calsequestrin 15. Loss of Ca2+ from sarcoplasm results in troponin-tropomyosin complex 16. Muscle fiber returns to its resting length

Question 39

Rigor mortis

Answer 39

Hardening of muscles and stiffening of body beginning 3-4 hours after death. Muscle relaxation requires ATP and ATP is no longer produced after death. Fibers remain contracted until myofilaments begin to decay.

Question 40

Threshold

Answer 40

Minimum voltage necessary to generate an action potential in the muscle fiber and produce a contraction.

Question 41

Twitch

Answer 41

A quick cycle of contraction when a stimulus is at threshold or higher. Single cycle contraction/relaxation Must be added together to do work

Question 42

Isometric

Answer 42

Contraction without a change in length

Question 43

Isotonic

Answer 43

Contraction without change in length but no change in tension

Question 44

Latent period

Answer 44

2 millisecond delay between the onset of the signal and the onset of the twitch.

Question 45

Oxygen debt

Answer 45

Heavy breathing after strenuous exercise to replenish O2 reserves depleted during exercise, replenishing phosphagen system, oxidize lactic acid, and serve elevated metabolic rate.

Question 46

Slow oxidative

Answer 46

Slow-twitch, red or type I fibers - long slow twitches - abundant mitochondria, myoglobin, and capillaries giving it a deep red color - adapted for aerobic respiration and fatigue resistance

Question 47

Fast glycolytic

Answer 47

Fast-twitch, white, or type II fibers - well adapted for quick responses, but not for fatigue resistance - rich in enzymes of phosphagen and glycogen-lactic acid systems generate lactic acid, causing fatigue. - less mitochondria, myoglobin,and blood capillaries which gives pale appearance.

Question 48

Resistance training

Answer 48

Contraction of a muscle against a load that resists movement. Growth from cellular enlargement Muscle fibers synthesize more myofilaments and myofibrils and grow thicker

Question 49

Endurance training

Answer 49

Improves fatigue-resistant muscles Improves skeletal strength Increases red blood cell count and O2 transport capacity of the blood Slow twitch fibers produce more mitochondria, glycogen, and acquire a greater density of blood capillaries

Question 50

Cross training

Answer 50

Incorporates endurance and resistance exercise Necessary for optimal performance Resistance exercise does not increase fatigue resistance Endurance exercise does not increase strength

Question 51

Catabolism

Answer 51

Energy releasing decomposing reactions Breaking down larger molecules into smaller ones AB->A+B Exergonic reactions

Question 52

Anabolism

Answer 52

Energy storing synthesis reaction Combine two or more small molecules to make something larger A+B->AB Endergonic reaction

Question 53

Oxidation

Answer 53

Substance loses electrons

Question 54

Reduction

Answer 54

Substance gains electrons

Question 55

Coenzymes

Answer 55

- Crucial to these reactions - Enzymes removing electrons from intermediates and transfers them to coenzymes - Temporary carriers of extracted energy - NAD+and FAD

Question 56

Glycolysis

Answer 56

- series of enzymatic steps - converts glucose into 2 molecules of pyruvic acid - net yield of 2ATP - requires 2 molecules of NAD+ - energy extracted from glucose transferred to NAD+ - becomes 2NADH - takes place in cytoplasm