Lecture 9.1

Question 1

main function of muscle

Answer 1

create motion, stabilize body positions and maintain posture, store substances within organs using sphincters, move substances through the body by peristaltic contractions, generate heat through thermogenesis

Question 2

how is muscle tissue and nervous tissue similar

Answer 2

both are excitable, or “irritable”
they have the ability to respond to stimulus

Question 3

how are muscle tissue and nervous tissue different

Answer 3

muscles are contractible, extensible, and elastic

Question 4

what prefixes indicate muscle tissue

Answer 4

myo, mys, and sarco

Question 5

properties of skeletal muscle

Answer 5

organs attached to bones and skin, elongated cells called muscle fibers, striated, multinucleate, voluntary , require nervous system stimulation for contraction

Question 6

skeletal muscle fibers are also called what

Answer 6

skeletal muscle cell

Question 7

properties of cardiac muscle

Answer 7

only in the heart (bulk of heart walls), branched short cells, striated, uni or binucleate, does not require nervous system for stimulation, involuntary

Question 8

properties of smooth muscle

Answer 8

in walls of hollow organs (stomach, urinary, etc), non striated, uninucleate, can contract with or without nervous system stimulation, involuntary

Question 9

each muscle is served by one artery, one nerve, and one or more veins. where do they enter and exit

Answer 9

near central part and branch through connective tissue sheaths

Question 10

each muscle is served by one artery, one nerve, and one or more vein. by what and how is a skeletal muscle fiber controlled

Answer 10

supplied by a neuron ending that controls its activity

Question 11

when contracting, what happens to the metabolic rate of muscle and how does that affect nutrient requirement and waste generation

Answer 11

high metabolic rate when contracting, uses large amounts of ATP, huge nutrient and oxygen needed, generates a lot of waste

Question 12

connective tissue sheaths of muscle and their properties

Answer 12

epimysium - dense irregular connective tissue surrounding the entire muscle (may blend with fascia)
perimysium - fibrous connective tissue surrounding fascicles
endomysium - fine areolar connective tissue surrounding each individual muscle fiber

Question 13

fascicles

Answer 13

groups of 10-100 muscle fibers, form the grain in meat (pulled pork analogy)

Question 14

where does skeletal muscle attach

Answer 14

insertion - movable bone
origin - less moveable or immovable bone

Question 15

what is the difference between direct and indirect attachment of skeletal muscle

Answer 15

direct - epimysium fused to periosteum of bone or perichondrium of cartilage
indirect - connective tissue wrappings extend beyond muscle as rope-like tendon or sheetlike aponeurosis

Question 16

what is muscle fascia and what does it do

Answer 16

covers many muscles

Question 17

what is an example of fascia from the powerpoints

Answer 17

fascia lata - envelopes the entire group of quadriceps and hamstring muscles

Question 18

what is typically found traversing deep fascia

Answer 18

veins, arteries, and nerves

Question 19

what is an aponeurosis

Answer 19

a thick flat fascia that connects two muscle bellies

Question 20

epicranial aponeurosis connects what two muscles

Answer 20

occipitalis and frontalis which connects to form the occipitofrontalis

Question 21

sarcolemma definition

Answer 21

plasma membrane of muscle cell

Question 22

sarcoplasm defintion

Answer 22

cytoplasm of muscle cell

Question 23

where are glycosomes found and why are they important

Answer 23

found is the sarcoplasm, they contain glycogen
(when sarcoplasmic glucose falls, glycogen stores can be hydrolyzed to provide glucose for ATP)

Question 24

what is myoglobin, where is it found, why is it important

Answer 24

globular protein found only in muscle cells, binds oxygen that diffuses into the muscle cell from the interstitial fluid, releases oxygen when mitochondria needs to make ATP, function as quick oxygen reserve sarcoplasmic oxygen levels decline from high contractile rate leading to decrease blood flow

Question 25

myofibril definition

Answer 25

densely packed rod like elements, about 80% of cell volume, contains sarcomeres (contractile units)
exhibit striations

Question 26

what are striations

Answer 26

repeating series of dark A bands and light I bands

Question 27

Transverse (T) tubules defintion

Answer 27

tunnels of sarcolemma that run from the surface of the muscle cell to the inner regions
open to the outside of the fiber and filled with interstitial fluid
muscle action potentials travel along sarcolemma and down into the T-Tubules

Question 28

Sarcoplasmic reticulum definition

Answer 28

similar the smooth ER of typical cell, stores and releases calcium ions among many other functions

Question 29

Triad definition

Answer 29

formed from a T-Tubule and two terminal cisterns

Question 30

Terminal cisterns definition

Answer 30

dilated end sacks of the sarcoplasmic reticulum that butt against the T-tubules
allow for quick release of Calcium from the SR into the sarcoplasm when stimulated

Question 31

sarcomeres definition

Answer 31

smallest contractile unit (functional unit) of skeletal muscle fibers
align like boxcars of a train
composed of thick and thin myofilaments made of contractile proteins
contains an A band with 1/2 of an I band at each end
Z-disc form sarcomere boundary

Question 32

what are thin filaments of the sarcomere made of

Answer 32

actin myofilaments
twisted double strand of fibrous protein F actin
F actin consist of G (globular) actin subunits

Question 33

what binding site is found on G actin in thin filaments

Answer 33

active site for myosin head attachment during contraction

Question 34

what regulatory proteins are found on the thin filament

Answer 34

tropomyosin and troponin

Question 35

what are thick filaments made of

Answer 35

composed of protein - myosin
each composed of two heavy and four light polypeptide chains

Question 36

what composes the myosin tail in thick filaments

Answer 36

two interwoven heavy polypeptide chains - think shaft of golf club

Question 37

what composes the myosin head in thick filaments

Answer 37

two smaller, light polypeptide chains per head that act as cross bridges during contraction
think head of golf club

Question 38

what binding sites are on the myosin head

Answer 38

binding site for G actin of thin filaments
binding sit for ATP
myosin head is an ATPase

Question 39

Titan (an elastic filament) performs what function in the sarcomere

Answer 39

holds thick filaments in place, helps recoil after stretch
also resists excessive stretching

Question 40

what is the purpose of dystrophin

Answer 40

links thin filaments to proteins of sarcolemma

Question 41

what is the purpose of nebulin, myomesium, and C-proteins

Answer 41

bind filaments or sarcomeres together, important in maintenance of alignment