muscle histo

Question 1

characteristics of muscle tissue

Answer 1

1. striated or smooth
2. voluntary or involuntary
3. all specialized for contraction

Question 2

types of muscle tissue

Answer 2

1.skeletal
2. smooth
3. cardiac

Question 3

order of muscle components from largest to smallest

Answer 3

-muscle
-muscle fascicle
-muscle fibre
-myofibrils
-actin and myosin filaments

Question 4

what does the epimysium surround

Answer 4

muscle

Question 5

what does the perimysium surround

Answer 5

muscle fascicle

Question 6

what does the endomysium surround

Answer 6

muscle fibre

Question 7

function of epi,peri,endomysium

Answer 7

reduce friction between layers of muscle tissue

Question 8

muscle to tendons and apeneuroses

Answer 8

collage of fibres from endo,peri,epimusium that blend together into the tendon and apeneuroses for attachment

Question 9

tendons to bony attachment

Answer 9

collage of fibres from tendons and apeneuroses interwoven with fibres of the periosteum

Question 10

how is tendon/apeneurosis attached to periosteum

Answer 10

cemented to matrix of bone as sharpeys fibres (connect periosteum to bone)

Question 11

how is blood and nerve supplied to muscle

Answer 11

vessels and nerves form neuromuscular bundle
-branch within the CT coverings and reach individual muscle fibres

Question 12

what is the sarcolemma

Answer 12

cell membrane of skeletal muscle fibre

Question 13

what is sarcoplasm

Answer 13

cytoplasm of skeletal muscle fibre

Question 14

what are transverse tubules

Answer 14

-indentations of sarcolemma
-form network of tubes extending into sarcoplasm that ensure contraction signal is received at the same time throughout fibre

Question 15

what are myofibrils

Answer 15

protein filaments made up of actin and myosin

Question 16

what is the sarcoplasmic reticulum and what does it store and do

Answer 16

endoplasmic reticulum of skeletal muscle fibre
-stores Ca2+ and forms sleeve around each myofibril

Question 17

what are terminal cisterna

Answer 17

expansions fo sarcoplasmic reticulum on either side of T-tubules

Question 18

what is a triad

Answer 18

pair of terminal cisternae with one intervening T-tubule

Question 19

which filament is the thin filament

Answer 19

actin

Question 20

which filament is the thick filament

Answer 20

myosin

Question 21

what is a sarcomere

Answer 21

component of the myofibril for muscle contraction composed of actin and myosin

Question 22

what is G actin (globular actin)

Answer 22

molecule with active binding site capable of binding to a thick filament

Question 23

what is F actin (filamentous actin)

Answer 23

polymers of G molecule which form a filament

Question 24

what is tropomyosin

Answer 24

-covers active sites of G actin
-prevents actin myosin interactions

Question 25

what is troponin

Answer 25

-has binding site for calcium -signals for tropomyosin to move off active site with increase calcium presence

Question 26

how many thin filaments surround a thick

Answer 26

6

Question 27

parts of the sarcomere

Answer 27

z line m line h zone i band a band zone of overlap

Question 28

what is the z line

Answer 28

thin filaments attach together and delineate the sarcomere

Question 29

what is the m line

Answer 29

thick filaments attach together and extend toward z lines

Question 30

what is in h zone

Answer 30

only thick filaments (myosin)

Question 31

what is in i band

Answer 31

only thin filaments (actin)

Question 32

what is a band

Answer 32

length of thick filament -zone of overlap and h zone

Question 33

what is in zone of overlap

Answer 33

thin and thick filaments

Question 34

what are ends of sarcomere

Answer 34

z lines

Question 35

with contraction, what happens to; length of sarcomere size of h and i bands length of a band length of zone of overlap

Answer 35

-shortened -shortened -constant -increased

Question 36

what initiates muscle contraction

Answer 36

Ca2+

Question 37

how does muscle contraction happen

Answer 37

in presence of calcium, actin site becomes available, myosin head binds (cross-bridges), crossbridges rotate toward centre of sarcomere

Question 38

what causes cross bridges to detach after they rotate

Answer 38

ATP binds to myosin

Question 39

why is muscle relaxation largely passive

Answer 39

1.tissue elasticity 2. pull of antagonist muscles 3.gravity

Question 40

what is a motor unit

Answer 40

motor neuron and all muscle fibres it innervates

Question 41

what type of motor neuron is the motor neuron in motor unit

Answer 41

lower motor neuron

Question 42

how do we have precision in actions

Answer 42

ration of motor neuron to number of muslce fibres changes - more fibres = less precise

Question 43

how is there smooth contraction of muscle

Answer 43

fibres of each motor unit are intermingled within one muscle

Question 44

can only some muscle fibres from one motor unit contract while others dont

Answer 44

no - all contract or none

Question 45

how do we avoid burnout

Answer 45

some motor units contract while others rest

Question 46

what is a isotonic contraction and what are the types

Answer 46

no change in tension while muscle changes length -concentric -eccentric

Question 47

what is the difference between concentric and eccentric isotonic contraction

Answer 47

concentric -shortening, joint angle gets smaller, overcoming weight, against gravity eccentric -lengthening, joint angle gets bigger, controlled lowering of weight, gravity would otherwise pull object down

Question 48

what is a isometric contraction

Answer 48

no change in length -tension generated is not enough to exceed resistance of object to be moved and muscle does not change length

Question 49

what are the factors affecting tension

Answer 49

1. sarcomere length 2. frequency of stimulation 3. motor unit size 4. recruitment of motor units

Question 50

what happens with muscle hypertrophy

Answer 50

-more mitochondria -higher glycogen reserves -more glycogen enzymes -increased myofibrils with increased myofilaments

Question 51

how does muscle hypertrophy happen

Answer 51

repeated stimulation of muscle near maximal tension

Question 52

what are the 3 muscle fibre types and what are they for

Answer 52

1. slow oxidative - postural, antigravity muscles 2. fast glycolytic - fine control like hand and eye 3. fast oxidative-glycolytic - largest fibres - leg

Question 53

what determines the proportion of fibres within a muscle

Answer 53

function and genetics

Question 54

specifically, ratio of slow oxidative and fast glycolytic fibres are determined by what

Answer 54

genetics

Question 55

can fibres in the same motor unit be different types

Answer 55

no

Question 56

where is cardiac muscle found and what are characteristics

Answer 56

-only heart -striated, involuntary

Question 57

what are cardiocytes

Answer 57

cells that form branching network and join at the intercalated discs

Question 58

what are intercalated discs

Answer 58

-gap junctions provide intercellular communication -desmosomes provide anchorage for intermediate filaments of cytoskeleton

Question 59

what are pacemaker cells

Answer 59

set basic rate of contraction - impulses conducted through gap junctions

Question 60

what is contraction of cardiac muscle modulated by

Answer 60

autonomic nervous system

Question 61

can cardiac muscle regenerate

Answer 61

no

Question 62

what junctions hold cardiac muscle fibres together

Answer 62

tight

Question 63

where is smooth muscle and what are characteristics

Answer 63

-respiratory, circulatory, digestive, reproductive tracts - non striated, involuntary

Question 64

why is smooth muscle non-striated

Answer 64

spindle shaped cells - myofilaments are arranged irregularly

Question 65

what are pacesetter cells

Answer 65

set basic rate of contraction in smooth muscle

Question 66

what modulates smooth muscle contraction

Answer 66

ANS

Question 67

can smooth muscle regenerate and repair

Answer 67

yes