STUDY GUIDE M - UNIT 3

Question 1

What two things create the most demand for ATP in skeletal muscles?

Answer 1

Resetting myosin heads and calcium pumping.

Question 2

What is myokinase? What reaction does it catalyze?

Answer 2

Enzyme that transfers phosphate from one ADP to another to form ATP.

Question 3

What is creatine kinase? What reaction does it catalyze?

Answer 3

Enzyme that transfers phosphate from creatine phosphate to ADP to form ATP.

Question 4

What is glycolysis? Net ATP?

Answer 4

Anaerobic breakdown of glucose → 2 net ATP.

Question 5

How is creatine phosphate regenerated at rest?

Answer 5

By reverse action of creatine kinase using ATP.

Question 6

What is glycolysis? Net ATP?

Answer 6

Anaerobic breakdown of glucose → 2 net ATP.

Question 7

Benefits of glycolysis?

Answer 7

Fast & doesn’t need oxygen.

Question 8

What is aerobic respiration?

Answer 8

Oxygen-dependent breakdown of fuel → 30 ATP/glucose.

Question 9

Benefits of aerobic respiration?

Answer 9

High ATP yield, supports long-duration activity.

Question 10

In low O₂, pyruvate becomes…?

Answer 10

Lactate.

Question 11

Is lactate the cause of muscle pain?

Answer 11

No, it’s not the direct cause.

Question 12

Primary ATP sources by time?

Answer 12

• 1st 5 sec: Phosphagen system
• 1 min: Glycolysis
• After 1 min: Aerobic respiration

Question 13

What is oxygen debt?

Answer 13

Extra O₂ needed post-exercise to restore ATP, creatine phosphate, and O₂ levels.

Question 14

Type I (slow) fibers characteristics?

Answer 14

Slow, fatigue-resistant, aerobic, many mitochondria.

Question 15

What are Type IIb (fast) fibers?

Answer 15

Fast, powerful, fatigue quickly, anaerobic, fewer mitochondria.

Question 16

Muscle type with mostly fast fibers?

Answer 16

Eye, hand muscles (quick movement).

Question 17

Muscle type with mostly slow fibers?

Answer 17

Postural muscles (e.g., back).

Question 18

Endurance athletes have more…?

Answer 18

Slow fibers (Type I).

Question 19

Sprinters/weightlifters have more…?

Answer 19

Fast fibers (Type IIb).

Question 20

Primary determinant of fiber type?

Answer 20

Genetics.

Question 21

What is muscle tension?

Answer 21

Force generated when muscle contracts.

Question 22

What is a twitch?

Answer 22

Single, brief contraction-relaxation cycle.

Question 23

Three twitch phases?

Answer 23

Latent (no tension), contraction (tension ↑), relaxation (tension ↓).

Question 24

More motor units = stronger contraction. What’s this called?

Answer 24

Recruitment.

Question 25

Is muscle contraction all-or-none?

Answer 25

Yes for each fiber, but whole muscle strength is graded by recruitment.

Question 26

Motor unit recruitment order?

Answer 26

Small → Large; conserves energy.

Question 27

What Does Slow Stimuli Do (<10/sec)?

Answer 27

Discrete twitches.

Question 28

What Has Increased Frequency?

Answer 28

Temporal (wave) summation → incomplete tetany → complete tetany.

Question 29

What is fatigue?

Answer 29

Reduced ability to produce tension after prolonged use.

Question 30

What is muscle tone?

Answer 30

Constant low-level contraction for posture.

Question 31

Isometric vs. Isotonic contraction?

Answer 31

1. Isometric: Tension ↑, length same. 2. Isotonic: Length changes. 2a. Concentric: Muscle shortens. 2b. Eccentric: Muscle lengthens.

Question 32

Why does overly stretched or contracted muscle generate less tension?

Answer 32

Fewer optimal cross-bridges.

Question 33

Optimal length for max contraction = ?

Answer 33

Resting length.

Question 34

Name for length–tension relationship?

Answer 34

Length–tension curve.

Question 35

4 factors affecting muscle tension?

Answer 35

Fiber type, length, frequency, number of motor units.

Question 36

Main cause of fatigue?

Answer 36

Depletion of glycogen.

Question 37

Endurance exercise effects?

Answer 37

↑ capillaries, mitochondria, myoglobin; better ATP use.

Question 38

Resistance training effects?

Answer 38

Hypertrophy: ↑ fiber size, myofibrils, mitochondria.

Question 39

Primary way muscle grows?

Answer 39

Hypertrophy.

Question 40

What else contributes slightly?

Answer 40

Hyperplasia (new fibers).

Question 41

Result of disuse?

Answer 41

Atrophy (↓ muscle size & strength).

Question 42

What Are Some Aging Effects?

Answer 42

↓ mass, motor neurons → ↓ strength & endurance.

Question 43

Where is cardiac muscle found?

Answer 43

Heart walls.

Question 44

Cardiac cell shape & nuclei?

Answer 44

Short, branched, 1–2 nuclei.

Question 45

What connects cardiac cells?

Answer 45

Intercalated discs (gap junctions + desmosomes).

Question 46

Is it striated?

Answer 46

Yes—sarcomeres present.

Question 47

What Is The Cardiac Cells' ATP source?

Answer 47

Exclusively aerobic respiration.

Question 48

Ca²⁺ source?

Answer 48

Extracellular & sarcoplasmic reticulum.

Question 49

Contraction stimulus?

Answer 49

Autorhythmic (pacemaker cells); nervous system modulates rate/force.

Question 50

Function of extrinsic eye muscles?

Answer 50

Move eyeball.

Question 51

Rectus muscles & actions?

Answer 51

- Superior: Up - Inferior: Down - Medial: In - Lateral: Out

Question 52

Oblique muscles?

Answer 52

1. Superior (via trochlea): Down/lateral 2. Inferior: Up/lateral

Question 53

Two anterior neck groups?

Answer 53

Suprahyoid (elevate hyoid), Infrahyoid (depress hyoid).

Question 54

Sternocleidomastoid (SCM) action?

Answer 54

1. Both: Neck flexion 2. One: Rotation to opposite side

Question 55

Posterior neck muscles action?

Answer 55

Extend head/neck.

Question 56

Semispinalis capitis name origin?

Answer 56

Partially hidden (semi-) & near head (capitis).

Question 57

Splenius capitis action?

Answer 57

1. Both: Extend neck 2. One: Turn to same side

Question 58

Function of erector spinae?

Answer 58

Maintain posture, extend vertebral column.

Question 59

3 muscle groups?

Answer 59

Iliocostalis, Longissimus, Spinalis.

Question 60

Role of scalenes?

Answer 60

Elevate ribs during inhalation.

Question 61

Intercostal muscles?

Answer 61

1. External: Elevate ribs (inhalation) 2. Internal: Depress ribs (forced exhalation)

Question 62

Most important breathing muscle?

Answer 62

Diaphragm—dome-shaped, separates thorax & abdomen.

Question 63

Diaphragm innervation?

Answer 63

Phrenic nerve (C3–C5).

Question 64

External oblique?

Answer 64

Rotate trunk, compress abdomen; “V” fibers.

Question 65

Internal oblique?

Answer 65

Rotate trunk, compress abdomen; “A”/tent fibers.

Question 66

Transversus abdominis?

Answer 66

Compresses abdomen; horizontal fibers.

Question 67

Order from superficial to deep?

Answer 67

External → Internal → Transversus

Question 68

Rectus abdominis?

Answer 68

Flexes spine; partitioned by tendinous intersections; in rectus sheath; linea alba runs vertically.