Page 1 of 16 AP5045 L07 Muscular AP5045 L07 Muscular.pdf
The Muscular System
PRE-LAB QUESTIONS
1. How do banding patterns change when a muscle contracts?
When the muscle contracts, myosin and actin myofilaments will decrease its length and will
cause them to come together. The H zones shrink and narrow. The A band remains the same.
2. What is the difference between a muscle organ, a muscle fiber, a myofibril, and a myofilament?
The whole skeletal muscle is considered an organ of the muscular system. Each organ or muscle
consists of skeletal muscle tissue, connective tissue, nerve tissue, and vascular tissue. A muscle
organ is a tissue that is made up of cells and fibers that produces movement by contraction. A
muscle fiber is just a single muscle tissue. The myofibrils are long filaments that are parallel to
each other to form fibers. Muscle fibers are single multinucleated cells that combine to form
sarcomeres that are responsible for muscle contractions. Myofilament makes up the myofibrils.
3. Outline the molecular mechanism for skeletal muscle contraction. At what point is ATP used and
why?
Muscle cells can use both fatty acids and glucose for their aerobic respiration. ATP is used for
two things in muscle cells: active transport of calcium (Ca ++) and movement of motor proteins.
4. Explain why rigor mortis occurs.
The biochemical basis of rigor mortis is hydrolysis in muscle of ATP, the energy source required
for movement. Without ATP, myosin molecules adhere to actin filaments and the muscles
become rigid.
©eScience Labs, 2016
2/1/2026 AP5045 L07 Muscular AP5045 L07 Muscular.pdf
,Page 2 of 16 AP5045 L07 Muscular AP5045 L07 Muscular.pdf
The Muscular System
EXPERIMENT 1: TENDONS AND LIGAMENTS
Post-Lab Questions
1. Identify the components in the slide image below based on your observations from the
experiment.
A__Chodrocytes__
©eScience Labs, 2016
2/1/2026 AP5045 L07 Muscular AP5045 L07 Muscular.pdf
, Page 3 of 16 AP5045 L07 Muscular AP5045 L07 Muscular.pdf
The Muscular System
B___Collagen____
2. Identify the components in the slide image below based on your observations from the
experiment.
A_Collagen fiber__
B_Skeletal muscle fiber
©eScience Labs, 2016
2/1/2026 AP5045 L07 Muscular AP5045 L07 Muscular.pdf
The Muscular System
PRE-LAB QUESTIONS
1. How do banding patterns change when a muscle contracts?
When the muscle contracts, myosin and actin myofilaments will decrease its length and will
cause them to come together. The H zones shrink and narrow. The A band remains the same.
2. What is the difference between a muscle organ, a muscle fiber, a myofibril, and a myofilament?
The whole skeletal muscle is considered an organ of the muscular system. Each organ or muscle
consists of skeletal muscle tissue, connective tissue, nerve tissue, and vascular tissue. A muscle
organ is a tissue that is made up of cells and fibers that produces movement by contraction. A
muscle fiber is just a single muscle tissue. The myofibrils are long filaments that are parallel to
each other to form fibers. Muscle fibers are single multinucleated cells that combine to form
sarcomeres that are responsible for muscle contractions. Myofilament makes up the myofibrils.
3. Outline the molecular mechanism for skeletal muscle contraction. At what point is ATP used and
why?
Muscle cells can use both fatty acids and glucose for their aerobic respiration. ATP is used for
two things in muscle cells: active transport of calcium (Ca ++) and movement of motor proteins.
4. Explain why rigor mortis occurs.
The biochemical basis of rigor mortis is hydrolysis in muscle of ATP, the energy source required
for movement. Without ATP, myosin molecules adhere to actin filaments and the muscles
become rigid.
©eScience Labs, 2016
2/1/2026 AP5045 L07 Muscular AP5045 L07 Muscular.pdf
,Page 2 of 16 AP5045 L07 Muscular AP5045 L07 Muscular.pdf
The Muscular System
EXPERIMENT 1: TENDONS AND LIGAMENTS
Post-Lab Questions
1. Identify the components in the slide image below based on your observations from the
experiment.
A__Chodrocytes__
©eScience Labs, 2016
2/1/2026 AP5045 L07 Muscular AP5045 L07 Muscular.pdf
, Page 3 of 16 AP5045 L07 Muscular AP5045 L07 Muscular.pdf
The Muscular System
B___Collagen____
2. Identify the components in the slide image below based on your observations from the
experiment.
A_Collagen fiber__
B_Skeletal muscle fiber
©eScience Labs, 2016
2/1/2026 AP5045 L07 Muscular AP5045 L07 Muscular.pdf
