Muscles (Intro)

Question 1

How many muscles are there in the body

Answer 1

Over 600

Question 2

What percent of your body weight is muscles

Answer 2

40-50%

Question 3

What are the three functions of muscles

Answer 3

• Movement
• Heat production
• Posture

Question 4

What are the four characteristics of muscle tissue

Answer 4

• Excitability
• Contractility
• Extensibility
• Varying size, shape, and fibers

Question 5

Define excitability

Answer 5

Nervous system signals stimulate muscle cells

Question 6

Define contractility

Answer 6

Ability to contract (muscles pull on bones)

Question 7

Define Extensibility

Answer 7

A muscles ability to extend or stretch and return to its normal length

Question 8

What is another name for muscle cells

Answer 8

Muscle fibers

Question 9

Define sarcolemma

Answer 9

The plasma membrane of muscle fibers

Question 10

T/F: Muscle fibers are multinucleated

Answer 10

True

Question 11

Define sarcoplasm

Answer 11

Muscle fiber cytoplasm

Question 12

Define sarcoplasmic reticulum

Answer 12

A muscle fibers network of tubules and sacs

Question 13

What is the function of the sarcoplasmic reticulum

Answer 13

Continuously pumps calcium ions from the sarcoplasm into storage sacs to release later

Question 14

What is the structure and function of a T-tubule

Answer 14

• S: Inward extensions of the sarcolemma
• F: Allows electrical impulses into the interior of the cell

Question 15

What is the structure of a Triad

Answer 15

Two tubules of sarcoplasmic reticulum

Question 16

What is the structure of a myofibril

Answer 16

Numerous fine fibers packed close together in sarcoplasm

Question 17

What does each myofibril contain

Answer 17

Myofilaments