Unit 4: Muscular System Pt. 2

Question 1

What causes rigor mortis?

Answer 1

After death, calcium diffuses everywhere and triggers contractions, forming cross-bridges which run out of ATP to break resulting in frozen muscles

Question 2

Why does rigor mortis wear off?

Answer 2

Muscle proteins begin to break down (myosin, actin)

Question 3

The amount of ______ generated depends on the _____ of the muscle

Answer 3

Tension
Length

Question 4

Overly contracted muscles are when

Answer 4

Thick filaments are too close to the Z discs, causing a weak result

Question 5

Overly stretched muscles are when

Answer 5

There is too little overlap, meaning cross-bridges cannot form and there is a weak result

Question 6

The greatest force of contraction happens

Answer 6

At optimum resting length

Question 7

What is a muscle twitch

Answer 7

brief stimulus at the threshold voltage produces 1 quick contraction and relaxation

Question 8

What are the phases of a muscle twitch

Answer 8

Latent
Contraction
Relaxation

Question 9

Define MMU and how it affects intensity/strength

Answer 9

Multiple Motor Unit Summation
More motor units = more fibers contract = more intensity

Question 10

Define Wave Summation and how it affects intensity/strength

Answer 10

Muscles are rapidly stimulated without time to relax in between
Calcium builds up in sarcoplasm

Question 11

Define isometric muscle contraction

Answer 11

Length of muscle stays the same while tension develops

Question 12

Define isotonic muscle contraction

Answer 12

Tension on muscle stays the same without length change

Question 13

What are the 2 types of ATP sources

Answer 13

Anaerobic fermentation
Aerobic respiration

Question 14

Which ATP source creates more ATP?

Answer 14

Aerobic

Question 15

Anaerobic fermentation requires _______ and produces ______

Answer 15

No oxygen
Lactic acid

Question 16

Aerobic respiration requires ______ and produces ______

Answer 16

Continuous oxygen
H2O and CO2

Question 17

Where does the first immediate energy come from?

Answer 17

Phosphagen System

Question 18

What is the phosphagen system?

Answer 18

ATP is formed by transferring phosphate from another molecule (ADP or creatine phosphate) to ADP

Question 19

What takes over creating ATP after the phosphagen system?

Answer 19

Anaerobic fermentation produces ATP from glycogen-lactic acid system and glucose from blood

Question 20

What energy system is used for long-term energy?

Answer 20

Aerobic respiration

Question 21

What allows aerobic respiration to take place?

Answer 21

Increased cardiovascular and respiratory activity drawing in more O2

Question 22

What limits aerobic respiration?

Answer 22

Loss of electrolytes and fluids
Loss of glycogen and blood glucose

Question 23

What causes muscle fatigue?

Answer 23

Less oxygen means more inefficient anaerobic respiration
Less ATP available as glycogen depletes
Less electricity as Na-K pumps shut down
Loss of electrolytes (like calcium)

Question 24

Define oxygen debt

Answer 24

The need to breathe heavily to replace O2 reserves and glucose after exercise

Question 25

The speed of a contraction depends on

Answer 25

How fast myosin ATPase can split ATP and the electrical activity of neurons

Question 26

What are the 3 types of skeletal muscle fibers

Answer 26

Slow oxidative Fast oxidative Fast glycolytic

Question 27

Describe slow oxidative tissue (color, ATP source, speed)

Answer 27

More red myoglobin Aerobic respiration (Stored O2) Best for endurance, fatigue-resistant

Question 28

Describe fast oxidative tissue (color, ATP source, speed)

Answer 28

Red myoglobin, less dark Mostly aerobic, some anaerobic Faster energy but less fatigue-resistant

Question 29

Describe fast glycolytic tissue (color, ATP source, speed)

Answer 29

White color with no myoglobin Anaerobic respiration Best for short, intense movement but fatigues fast

Question 30

Describe Myasthenia Gravis, its risk groups, and symptoms

Answer 30

Autoimmune disorder which causes antibodies to block ACh receptors, which blocks communication with muscle cells Thymus tumor, younger women, older men Trouble moving face and eye muscles Muscles weaken with activity and strengthen with rest

Question 31

Describe Duchenne Muscular Dystrophy, its risk groups, and symptoms

Answer 31

X-linked disorder which affects gene that makes protein dystrophin so muscle fibers cannot anchor Genetic, mostly passed from mother to son Fatigue, learning disabilities, rapidly weakening muscles

Question 32

Describe Botulinim Toxin

Answer 32

Toxic bacteria from contaminated food which prevents the release of ACh, resulting in paralysis