Chapter 10: The Muscular System and Homeostasis

Question 1

Cardiac Muscle

Answer 1

• Striated
• One nucleus
• Contract involuntarily
• Found in the walls of the heart

Question 2

Skeletal Muscle

Answer 2

• Striated
• Many nuclei
• Contract voluntarily
• Usually attached to bones of the skeleton

Question 3

Muscle Fibres

Answer 3

Skeletal muscle cell.

Question 4

Myofibrils

Answer 4

The subunits of muscle fibres. Hundreds of thousands of these make up a muscle fibre.

Question 5

Myofilaments

Answer 5

What makes up myofibrils, contains protein structures that are responsible for muscle contraction.

Question 6

Actin Myofilament

Answer 6

Two strands of protein (actin) molecules that are wrapped around each other.
- Thin

Question 7

Myosin Myofilament

Answer 7

Two strands of protein molecules wound around each other.

• 10 times longer than actin filament
• Thick
• One end being a long rod, the other end splits into to heads.

Question 8

Sliding Filament Model

Answer 8

An explanation for muscle contraction based on movement (sliding) of actin filaments in relation to myosin filaments.

Question 9

Smooth Muscle

Answer 9

• Non-striated
• One nucleus
• Contract involuntarily
• Found in the walls of internal organs, eye …

Question 10

Atrophy

Answer 10

A reduction in the size, tone, and power of a muscle. Usually due to injuries.

Question 11

Hypertrophy

Answer 11

Exercise-induced increase in muscle mass due to an increase in the size, not number, of individual skeletal muscle fibres.

Question 12

Muscle Twitch

Answer 12

Muscular contraction that lasts a fraction of a second.

Question 13

Slow-Twitch Fibre

Answer 13

Muscle fibre that produces most of its energy aerobically; contracts slowly, but can maintain a steady, prolonged production of ATP when oxygen is available.

Question 14

Fast-Twitch Fibre

Answer 14

Muscle fibre that produces most of its energy anaerobically; adapted for the rapid generation of power. Can result in lactate buildup causing rapid fatigue.