Chapter 9: Muscular System

Question 1

Muscular System Functions

Answer 1

Body Movement
Maintenance of Posture
Respiration 
Production of Body Heat
Communication
Construction of organs and vessles
Heart beat

Question 2

Properties of Muscle

Answer 2

Contractility
Excitability
Extensibility
Elasticity

Question 3

Contractility

Answer 3

Muscle shorten with force

Question 4

Excitability

Answer 4

respond to a stimulus

Question 5

Extensibility

Answer 5

muscle can be stretched beyond its normal resting length and still contract

Question 6

Elasticity

Answer 6

recoil to original resting length after stretched

Question 7

Skeletal (voluntary)

Answer 7

Locomotion, facial expressions,posture, respirations

Question 8

Smooth (involuntary)

Answer 8

Walls- holllow organs, blood vescles, glands, skin,

Some functions: propel, urine, mix foods (Digestive), pupils, regulate blood flow.

Question 9

Cardiac (involuntary)

Answer 9

• Heart
• Autorhythmic
• Control - endocrine and autonomic nervous system

Question 10

Skeletal Muscle Structure

Answer 10

A. Muscle cells(muscle fibers), connective tissue, blood vessels, nerves.
B. Fibers long, cylindrical multinucleated
C. Smaller diameter in small muscles; larger in large muscles. 1mm to 4cm long
D. Develop from myoblasts; numbers “constant” from birth
E. Straited - light and dark banding

Question 11

Sarcolemma

Answer 11

Surrounds the muscle cell

Question 12

Endomysium

Answer 12

Also around muscle cell

Question 13

Permiysium

Answer 13

surrounds group of muscle fibers (fasciculus)

Question 14

Epimysium

Answer 14

surrounds the muscle

Question 15

Fascia

Answer 15

connective tissue sheet

Question 16

Fascia steps:

Answer 16

• forms layer under the skin
• holds muscles together - separates them into functional groups
• allows free movements of muscles
• carries nerves, blood vessels, and lymphatics
• continuous with tendons and peritoneum

Question 17

Motor neurons

Answer 17

stimulate muscle fibers to contract

Question 18

Axons branch

Answer 18

each muscle fibers is innervated

Question 19

Muscle Fiber Anatomy

Answer 19

Nuclei - inside sarocolemma(plasma membrane of muscle fibers)
Muscle cell is packed with myofibers within muscle cytoplasm

Question 20

“thin”

Answer 20

Actin myofilaments

Question 21

“thick”

Answer 21

Myosin myofilaments

Question 22

Sacromeres

Answer 22

repeating units of myofilaments

Question 23

Tropomyosin

Answer 23

long protein covers active binding sites on Actin - prevents Myosin from binding

Question 24

Troponin

Answer 24

binds to actin, topomyosin, and Ca++

Question 25

Tropomyosin/troponin complex

Answer 25

regulates interaction of active sites on actin

Question 26

Myosin molecules

Answer 26

"golf clubs" | - wound molecules wound together- 2 heads

Question 27

Myosin heads

Answer 27

binds to active sites on actin - form cross- bridges hinge region - bends during contraction breaks down ATP, releasing energy. Energy used to bend hinge.

Question 28

Z disk

Answer 28

attachment for actin myofilaments

Question 29

M line

Answer 29

filaments holding myosin in pleace