Unit 2 Muscle

Question 1

skeletal muscle embryonic origins

Answer 1

mesoderm

somites

Question 2

cardiac muscle embryonic origins

Answer 2

splanchnic mesoderm

Question 3

smooth muscle embryonic origins

Answer 3

somatic mesoderm

splanchnic mesoderm

Question 4

types of muscle tissue

Answer 4

skeletal
cardiac
smooth

Question 5

muscle fibers

Answer 5

elongated

only skeletal and smooth

Question 6

skeletal muscle

Answer 6

attach to bones or skin
single, very long, cylindrical, multinucleate with striations
voluntary
contract rapidly, tire easily, powerful

Question 7

skeletal muscle tissue

Answer 7

packaged into skeletal muscles; organs that are attached to bones and skin

Question 8

skeletal muscle fibers

Answer 8

longest of all muscle and have striations

Question 9

terminology

Answer 9

muscle fiber = muscle cell
syncytium = multinucleate
sarco = meat

Question 10

epimysium

Answer 10

dense irregular CT surrounding entire muscle; may blend with fascia

Question 11

perimysium

Answer 11

fibrous CT surrounding fascicles

Question 12

endomysium

Answer 12

fine areolar CT surrounding each muscle fiber

Question 13

muscle fiber

Answer 13

sarcolemma
sarcoplasm
myofibrils
sarcoplasmic reticulum
T tubules

Question 14

sarcolemma

Answer 14

muscle fiber plasma membrane

Question 15

sarcoplasm

Answer 15

muscle fiber cytoplasm

contains many glycosides for glycogen storage, myoglobin for O2 storage

Question 16

myofibrils

Answer 16

densely packed rodlike elements

accounts for approx. 80% muscle fiber volume

Question 17

myofibril features

Answer 17

striations
sarcomeres
myofilaments

Question 18

striations

Answer 18

stripes formed from repeating series of dark and light bands along length of each myofibril

Question 19

A band

Answer 19

dark regions
H zone
M line
thick and thin filament

Question 20

H zone

Answer 20

lighter region in middle of dark A band

thick filaments

Question 21

sarcoplasmic reticulum

Answer 21

1. network of smooth ER tubules surrounding each myofibril
2. run longitudinally
3. terminal cisterns from perpendicular cross channels at A-I band junction
4. regulation of intracellular calcium levels

Question 22

M line

Answer 22

line of myomesin (protein) that bisects H zone vertically

Question 23

I bands

Answer 23

lighter regions
Z line (disc)
thin filament

Question 24

Z line

Answer 24

coin-shaped sheet of proteins on midline of light I band

Question 25

sarcomere

Answer 25

smallest contractile unit A band with 1/2 I band at each end (Z line-Z line) M line bisects H band myomesin anchors adjacent thick filaments

Question 26

sliding filament model

Answer 26

thin actin filament reversibly and slide over thick myosin filament requires ATP expenditure, presence of calcium

Question 27

muscle contraction

Answer 27

1. total length of sarcomere decreases 2. Z discs move closer together 3. I band length decreases 4. A band length doesn't change

Question 28

myofilaments

Answer 28

orderly arrangement of actin and myosin within sarcomere

Question 29

actin myofilaments

Answer 29

thin, extend across I bad, partway to A band | anchored by Z line

Question 30

myosin myofilaments

Answer 30

thick, extend length of A band | connected at M line

Question 31

T tubules

Answer 31

1. tube formed by profusion of sarcolemma deep into cell interior at A-I band junction between terminal cisterns 2. allow electrical nerve transmissions to reach deep into interior of each muscle fiber

Question 32

triad | skeletal

Answer 32

area formed from terminal cistern of one sarcomere, T tubule, and terminal cistern of neighboring sarcomere

Question 33

``` T tubules (alt. def.) ```

Answer 33

1. deep invagination of the sarcolemma (skeletal/cardiac) | 2. allow depolarization of membrane to quickly penetrate to the interior of the cell

Question 34

repair of skeletal muscle

Answer 34

fibers are most-mitotic | finite satellite cells can be exhausted

Question 35

satellite cells | skeletal

Answer 35

within basal lamina myogenesis divide to produce myoblasts to fuse and replace fibers

Question 36

cardiac muscle

Answer 36

striated, involuntary forms myocardium branched with 1-2 nuclei cells joined by intercalated discs

Question 37

diad | cardiac

Answer 37

T tubules single cisterna of SR located at Z lines, one per sarcomere

Question 38

intercalated discs

Answer 38

desmosomes | gap junctions

Question 39

cardiac SR

Answer 39

less elaborate than skeletal single terminal cisterna diads

Question 40

cardiac T tubules

Answer 40

wider, less numerous | one per sarcomere

Question 41

cardiac muscle repair

Answer 41

post mitotic | cells are replaced with non-contractile CT

Question 42

smooth (visceral) muscle

Answer 42

non striated, involuntary small tapered cells with centrally located nuclei SR is reduced/absent no sarcomeres bundles of crisscrossing myofilaments form bundles, sheets linked via gap junctions fusiform

Question 43

smooth muscle repair

Answer 43

mitotic | replace lost cells or increase mass

Question 44

hyperplasia

Answer 44

increase number

Question 45

hypertrophy

Answer 45

increase size

Question 46

smooth muscle specializations

Answer 46

caveolae | dense bodies

Question 47

caveolae

Answer 47

invagination of smooth muscle cells ion channels associated with SR

Question 48

dense bodies

Answer 48

act like Z disc