Unit 3 Lecture 24 Flashcards Preview

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Flashcards in Unit 3 Lecture 24 Deck (12)
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1
Q

What are the two things that affect muscle performance?

A

Power and Endurance

2
Q

Power = ?

A

Speed (velocity) x strength (force)

3
Q

Endurance = ?

A

Sustained activity (aerobic and anaerobic)

4
Q

What are the three fiber types?

A

Slow, intermediate and fast fibers

5
Q

Define slow fibers (Type I or SO)

A

slow contractions - slow myosin ATPase

High resistance to fatigue- relies on aerobic metabolism (high aerobic capacity, many mitochondria, high myoglobin content, dense capillary supply for O2 delivery)

6
Q

Define intermediate fibers (Type IIA or FOG)

A

relatively fast - intermediate myosin ATPase

Resistant to fatigue - primarily anaerobic (relies on glycolysis, but has higher aerobic capacity than FG fibers)

7
Q

Define fast fibers (Type IIX, or FG)

A

Rapidly contracts - fast myosin ATPase

Low resistance to fatigue - relies on anaerobic glycolysis (low aerobic capacity, few mitochondria, low myoglobin content)

8
Q

Define myoglobin

A

Large amino acid protein that binds/ releases one O2 at a time… responsible for muscles red color

9
Q

What is the common muscle composition in humans?

A

~ 50:50 mixture of fast and slow motor units in muscle

10
Q

Define hypertrophy

A

Increase number of myofibrils in muscle fibers makes muscles stronger

11
Q

Define hyperplasia

A

To grow a muscle by adding cells (mitosis)

  • Skeletal muscle does NOT grow/strengthen through hyperplasia bc it doesn’t undergo mitosis
12
Q

Define atrophy

A

When muscles aren’t used -> weaker and lose myofibrils -> smaller muscle