ch 10.1 - 10.3, muscle tissue

Question 1

muscle tissue

Answer 1

primary tissue responsible for contraction and movement

Question 2

types of muscle tissue

Answer 2

skeletal, cardiac, muscle

Question 3

common properties of muscle tissue

Answer 3

excitability, contractility, extensibility, elasticity

Question 4

excitability (responsiveness)

Answer 4

ability to receive and respond to stimuli

Question 5

contractility

Answer 5

the ability of cells to shorten

Question 6

extensibility

Answer 6

ability of the muscle to stretch

Question 7

elasticity

Answer 7

ability of the muscle to recoil to its resting length

Question 8

functions of skeletal muscle

Answer 8

• producing movement
  -mainting posture and body position

Question 9

skeletal muscle

Answer 9

muscles of the body that are attached to bones

Question 10

3 layers of connective tissue in skeletal muscles

Answer 10

epimysium, perimysium, endomysium

Question 11

epimysium

Answer 11

layer of collagen fibers that surrounds entire muscle and separates it from surrounding to tissues
- connected to the deep fascia (dense connective tissue layer)

Question 12

perimysium

Answer 12

surrounds individual fascicles (muscle fiber bundles)
- contains collagen + elastic fibers, blood vessels and nerves

Question 13

endomysium

Answer 13

surrounds individual muscle cells and loose interconnects them

Question 14

what does endomysium contain

Answer 14

capillary networks
myosatellite cells (stem cells that repair damage)
nerve fibers

Question 15

at the end of each muscle

Answer 15

collagen fibers of the epi,peri, and endomysium come together to form a tendon or broad sheet called an aponeurosis

Question 16

what do tendons and aponeuroses do

Answer 16

attach skeletal muscles to bones

Question 17

myofibrils

Answer 17

made of protein myofilaments (actin + myosin) that forms sarcomeres

Question 18

muscle fibers

Answer 18

muscle cell

Question 19

muscle fasicles

Answer 19

bundle of muscle fibers

Question 20

skeletal muscle fiber (cells) characteristics

Answer 20

• large
• multinucleate
• striated
• develop by fusion of embryonic cells called myoblasts

Question 21

sarcolemma

Answer 21

plasma membrane of a muscle fiber that surrounds the sarcoplasm (cytoplasm of muscle fiber)

Question 22

what initiates a contraction in skeletal muscle fiber

Answer 22

a sudden change in the membrane potential

Question 23

transverse tubules (t-tububles)

Answer 23

narrow tubes continuous w/ the sarcolemma, which extend deep into the sarcoplasm

Question 24

t-tubules function

Answer 24

quickly transmit electrical impulses from the sarcolemma into the cell interior to ensure a coordinated contraction of the entire cell

Question 25

sarcoplasmic reticulum (SR)

Answer 25

tubular network similar to smooth ER that surrounds each myofibril

Question 26

sarcoplasmic reticulum (SR) function

Answer 26

- forms chambers (terminal cisternae) that attach to T tubules - specialized for storage and release of calcium

Question 27

triad

Answer 27

a pair of terminal cisternae plus a T tubule

Question 28

myofibrils

Answer 28

organized collection of myofilaments that are responsible for muscle contraction - surrounded by SR

Question 29

myofilaments

Answer 29

bundles of contracticle protein filaments - actin and myosin

Question 30

2 types of myofilaments

Answer 30

thin - composed of actin thick - composed of myosin

Question 31

sacromeres

Answer 31

repeating structural and functional units of a myofibril - smallest contractile units of muscle fiber

Question 32

bands of the sacromere

Answer 32

A bands (dark bands) I bands (light bands)

Question 32

z disc

Answer 32

separates sarcomeres

Question 33

A bands

Answer 33

dark bands which run the length of the thick filaments

Question 34

subdivisions of A band

Answer 34

M line, H band, and zone of overlap

Question 35

M line

Answer 35

vertical line in center of A band; contains proteins that stabilize the position of the thick filaments

Question 36

H band

Answer 36

made only of thick filaments and extends on either side of the M line

Question 37

zone of overlap

Answer 37

region where the thick and thin filaments overlap

Question 38

I bands

Answer 38

light bands that contain only thin filaments - extends from A band of one sarcomere to the A band of the next sarcomere

Question 39

Z lines

Answer 39

bisect the I bands and mark the boundaries between adjacent sarcomeres

Question 40

titin

Answer 40

elastic protein which extends from the tops of thick filaments to the Z line

Question 41

titin function

Answer 41

- keeps filaments in proper alignment - aids in restoring resting sarcomere length

Question 42

thin filament contains what 4 proteins

Answer 42

F-actin nebulin tropomyosin troponin

Question 43

filamentous actin (F-actin)

Answer 43

twisted strand composed of 2 rows of globular G-actin molecules

Question 44

nebulin

Answer 44

holds the F-actin strands together

Question 45

tropomyosin

Answer 45

covers the active sites on G-actin and prevents actin-myosin interaction

Question 46

troponin

Answer 46

globular protein that holds tropomyosin in place and binds to calcium ions

Question 47

troponin

Answer 47

globular protein that holds tropomyosin in place and binds to calcium ions

Question 48

thick filaments contain

Answer 48

myosin

Question 49

each myosin molecule consists of

Answer 49

tail: binds to other myosin molecules, points towards the M line head: made of 2 globular protein subunits, protects toward the nearest thin filament

Question 50

sliding filament theory

Answer 50

during a contraction, the thin filament slides toward the center of the sarcomere (M line) alongside the thick filaments - a sarcomere shortens as the thick and thin filaments slide past one another

Question 51

steps of contraction

Answer 51

1. brain stimulates muscle contraction + sends action potential 2. terminal cisternae relases Ca to bind to troponin 3. troponin becomes flat when Ca binds + tropomyosin slips off which activates exposed active sites on G- actin protein 4. Myosin heads bind to exposed active sites 5. power stroke/muscle contracts