10/21 Class Lecture Chapter 9

Question 1

how much muscle tissue makes up the body mass

Answer 1

half of bodys mass

Question 2

prefixes for muscle

Answer 2

Myo, mys, and sarco

Question 3

skeletal muscle characteristics

Answer 3

Organs attached to bones and skin 
Elongated cells called muscle fibers
striated 
voluntary 
Contract rapidly; tire easily; powerful
Require nervous system stimulation

Question 4

special characteristics of muscle tissues

Answer 4

excitability
contractility
extensibility
elasticity

Question 5

excitability

Answer 5

(responsiveness): ability to receive and respond to stimuli electricity, causes muscles to “jump”

Question 6

contractility

Answer 6

ability to shorten forcibly when stimulated responds through contractility, shorts with force- why muscle is usefull

Question 7

extensibility

Answer 7

ability to be stretched, expands but not forcibly (muscle pulls, it does not push)

Question 8

elasticity

Answer 8

ability to recoil to resting length, flexible tissue

Question 9

what are the reasons for the muscle characteristics

Answer 9

the muscle functions

Question 10

Functions of muscles

Answer 10

Movement of bones or fluids (e.g., blood)
Maintaining posture and body position
stabilizing joints
heat generation
Protects organs, forms valves, controls pupil size, causes “goosebumps”

Question 11

what is a skeletal muscle served by

Answer 11

one artery, one nerve, and one or more veins

Question 12

how are skeletal muscles structured

Answer 12

connective tissue sheaths of skeletal muscle

Question 13

epimysium

Answer 13

dense irregular connective tissue surrounding entire muscle; may blend with fascia (broad sheet of muscle)

Question 14

perimysium

Answer 14

fibrous connective tissue surrounding fascicles (groups of muscle fibers)

Question 15

endomysium

Answer 15

fine areolar connective tissue surrounding each muscle fiber, most microscopic

Question 16

skeletal muscle attachments

Answer 16

insertion
origin
action
innervation

Question 17

insertion

Answer 17

moveable bone

Question 18

origin

Answer 18

immovable (less movable) bone

Question 19

action

Answer 19

what is does (ex. Flexes forearm)

Question 20

innervation

Answer 20

what nerve

Question 21

direct skeletal muscle attachment

Answer 21

epimysium fused to periosteum of bone or perichondrium of cartilage

Question 22

indirect skeletal attachment

Answer 22

connective tissue wrappings extend beyond muscle as ropelike tendon or sheetlike aponeurosis

Question 23

sarcolemma

Answer 23

plasma membrane

Question 24

sarcoplasm

Answer 24

cytoplasm

Question 25

what is in sarcoplasm

Answer 25

glycosomes

myoglobin

Question 26

glycosomes

Answer 26

glycogen storage for energy

Question 27

myloglobin

Answer 27

for O2 storage (store a few minutes worth) as you get in shape they can store more to a degree

Question 28

modified structures of skeletal muscle fibers

Answer 28

myofibrils, sarcoplasmic reticulum, and T tubules

Question 29

what does the skeleton need for contract

Answer 29

calcium

Question 30

what are myofibrils

Answer 30

Densely packed, rodlike elements
~80% of cell volume bascially 2 proteins
Contain sarcomeres
Exhibit striations

Question 31

sarcomeres

Answer 31

contractile units

Question 32

What are the striations

Answer 32

• perfectly aligned repeating series of dark A bands and light I bands A is the dArk band, I is the lIght band

Question 33

Parts of muscle tissues striations

Answer 33

H Zone, M Line, Z disc, thick and thin filaments, sacromeres, myosin, actin

Question 34

H zone

Answer 34

lighter region in midsection of dark A band where filaments do not overlap

Question 35

M line

Answer 35

line of protein myomesin bisects H zone, m as in middle, anchoring point for the thick filaments

Question 36

z discs

Answer 36

coin-shaped sheet of proteins on midline of light I band that anchors thin filaments and connects myofibrils to one another tube shaped strucutres, anchoring point for thin filaments

Question 37

thick filaments

Answer 37

run entire length of an A band

Question 38

thin filaments

Answer 38

run length of I band and partway into A band

Question 39

myosin

Answer 39

proteins fibers darker filaments

Question 40

actin

Answer 40

lighter filaments

Question 41

sarcomere characteristics

Answer 41

Smallest contractile unit (functional unit) of muscle fiber
Align along myofibril like boxcars of train, all next to eachother linked together
Contains A band with ½ I band at each end
Composed of thick and thin myofilaments made of contractile proteins

Question 42

actin myofilaments

Answer 42

thin filaments
Extend across I band and partway in A band
Anchored to Z discs

Question 43

myosin myofilaments

Answer 43

thick filaments
Extend length of A band
Connected at M line

Question 44

Sarcoplasmic reticulum

Answer 44

Network of smooth endoplasmic reticulum surrounding each myofibril
Most run longitudinally
Pairs of terminal cisterns form perpendicular cross channels
Highly organized
Functions in regulation of intracellular Ca2+ levels
Stores and releases Ca2+ and reabsorb it which allows the muscle to contract

Question 45

what is contained in T Tubules

Answer 45

triads and transverse

Question 46

characteristics of T Tubules

Answer 46

Continuations of sarcolemma
Lumen continuous with extracellular space
Increase muscle fiber’s surface area
Penetrate cell’s interior at each A band–I band junction
Associate with paired terminal cisterns to form triads that encircle each sarcomere