Chapter 3 Structure and Functions of the Muscular System

Question 1

what are the three functions of the muscular system

Answer 1

adequate posture
body movement
necessary bodily functions

Question 2

what are the three types of muscles

Answer 2

skeletal muscles:
attach to bones
voluntary
cardiac muscles:
located in the walls of the heart
involuntary
smooth muscles:
located in blood vessels and walls of the intestine
involuntary

Question 3

6 features of muscles

Answer 3

nervous control, contractibility, extensibility, elasticity, atrophy, hypertrophy

Question 4

what are the three forms of muscle fiber arrangement

Answer 4

fusiform:
produce low force,
designed for mobility,
run the length of the muscle belly
pennate:
run at angles to the tendons,
do not provide much mobility,
designed for strength and power
radiate:
radiate from the main tendon
capable of producing strength and power while being mobile.

Question 5

what are the three types of pennate muscles

Answer 5

unipennate:
fibers only found on one side of the central tendon (e.g. semimembranosus)
bipennate:
fibers run off either side of the central tendon (e.g. rectus femoris)
multipennate:
fibers branch out from several tendons, which enables body to produce greatest force (e.g. deltoid)

Question 6

structure of skeletal muscles

Answer 6

epimysium
perimysium
fasciculus
endomysium
muscle fiber

Question 7

epimysium

Answer 7

connective tissue that covers skeletal muscle thickens to form tendons as it nears the ends of muscles.

Question 8

perimysium

Answer 8

connective tissue that surrounds the fasciculus

Question 9

fasciculus

Answer 9

is a bundle of muscle fibers

Question 10

endomysium

Answer 10

connective tissue that binds fibers to form bundles

Question 11

muscle fibre

Answer 11

a single muscle fiber

Question 12

what does the sarcoplasm contain

Answer 12

mitochondria
myoglobin
fat, carbohydrate, and protein
adenosine triphosphate ATP
enzymes
actin and myosin

Question 13

what is a sarcomere

Answer 13

a contractible unit, and each one is designated by a line at either end called the Z line each sarcomere consists of two protein myofilaments called actin and myosin

Question 14

actin

Answer 14

a thin filament that attaches to the Z line

Question 15

myosin

Answer 15

a thick filament situated between each of the actin filaments.

Question 16

I band

Answer 16

where only actin is found

Question 17

A band

Answer 17

both actin and myosin are found it is equal to the length of the myosin filaments

Question 18

H zone

Answer 18

only myosin is found the gap between the ends of the actin

Question 19

describe the process of muscle contraction

Answer 19

muscle contraction begins with calcium release, activating cross bridges to bind actin, leading to filament sliding and muscle shortening. ATP powers detachment, enabling relaxation