Exercising Muscle Part 1: Muscle Types, Functions, and Sarcomeres

Question 1

what are the three major types of muscle?

Answer 1

• skeletal
• cardiac
• smooth

Question 2

which types of muscles are striated?

Answer 2

skeletal and cardiac muscle

Question 3

which types of muscles are unstriated

Answer 3

smooth muscle

Question 4

which types of muscles are under voluntary control?

Answer 4

skeletal muscle

Question 5

which types of muscles are under involuntary control?

Answer 5

cardiac and smooth muscle

Question 6

what are the six major functions of muscle?

Answer 6

• body movement
• maintenence of posture
• respiration
• constriction of organs and vessels
• heartbeat
• production of body heat (thermogenesis)

Question 7

what are the four major properties of muscle?

Answer 7

• excitability
• contractility
• extensibility
• elasticity

Question 8

the capacity of muscle to respond to a stimulus

Answer 8

excitability

Question 9

the ability of muscle to shorten and generate pulling force or tension

Answer 9

contractility

Question 10

the ability of a muscle to stretch or extend

Answer 10

extensibility

Question 11

the ability of muscle to recoil to original resting length after stretched

Answer 11

elasticity

Question 12

• production of force for movement and breathing
• production of force for postural support
• heat production while cold
  these are all functions of:

Answer 12

skeletal muscle

Question 13

true or false: skeletal muscles push and pull on bones to generate movement

Answer 13

false, muscles can only pull on bones, no pushing

Question 14

a protein containing heme, which carries and stores oxygen in muscle cells

Answer 14

myoglobin

Question 15

when do skeletal muscles release myoglobin?

Answer 15

when the cells are damaged

Question 16

myoglobin in the urine indicates:

Answer 16

muscle damage

Question 17

how are muscle fibers formed?

Answer 17

myoblasts fuse together to form a skeletal muscle fuber

Question 18

why do skeletal muscle cells need multiple nuclei?

Answer 18

to keep up with the high protein demands of the cell

Question 19

type of connective tissue which surround the entire muscle, separating it from the surrounding tissues/organs, and connected to the deep fascia

Answer 19

epimysium

Question 20

a type of connective tissue made of collagen and elastic fibers which surround a group of muscle fibers (fascicles)

Answer 20

perimysium

Question 21

a sheath of connective tissue that covers each individual muscle fiber

Answer 21

endomysium

Question 22

true or false: muscle fibers and muscle cells are the same thing

Answer 22

true

Question 23

any of the longitudinal parallel contractile elements of a muscle cell

Answer 23

myofibril

Question 24

what are the two types of myofilaments found in muscle cells?

Answer 24

actin and myosin

Question 25

attaches muscles to bones

Answer 25

tendons

Question 26

small bundles of muscle fibers wrapped in a connective tissue sheath

Answer 26

fascicles

Question 27

where are satellite cells found?

Answer 27

between the endomysium and other connective tissue

Question 28

the plasma membrane of muscle fibers

Answer 28

sarcolemma

Question 29

what is the structure of the sarcolemma?

Answer 29

a series of shallow folds when fiber is contracted or in the resting state; folds disappear when muscle is stretched

Question 30

junctional folds in the sarcolemma at the motoer end plate aid in:

Answer 30

transmission of action potentials

Question 31

the sarcolemma helps transport ______ from capillary blood into the muscle fiber

Answer 31

metabolites

Question 32

true or false: each muscle cell receives stimulation from only one motor neuron

Answer 32

true

Question 33

a gelatin-like substance that fills spaces within and between myofibrils; the cytoplasm of the muscle fiber

Answer 33

sarcoplasm

Question 34

the sarcoplasm contains stored:

Answer 34

glycogen, fat, enzymes, and myoglobin

Question 35

a duct system the synchronizes the release of Ca++ from the terminal cisternae of the sarcoplasmic reticulum

Answer 35

transverse tubules

Question 36

transverse tubules are extensions of:

Answer 36

the sarcolemma/surface membrane

Question 37

what is the function of the transverse tubules?

Answer 37

- they carry ions (Ca++), nutrients, and action potentials deep into the cell - rapid transmission of nerve impulses to individual myofibrils

Question 38

a modified smooth ER which forms a network of tubules and acts as a storage site for Ca++

Answer 38

sarcoplasmic reticulum

Question 39

how does the sarcoplasmic reticulum impact the rate of contraction?

Answer 39

speeds up contraction in skeletal muscle because Ca++ has shorter distances to diffuse

Question 40

refers to the arrangement of the t-tubules and terminal cisternae

Answer 40

triad

Question 41

an enlarged area of sarcoplasmic reticulum surrounding the t-tubules, and the compartment from which Ca++ is released following an action potential

Answer 41

terminal cisternae

Question 42

couples excitation to contraction and follows a pattern of terminal cisternae - t-tubule - terminal cisternae

Answer 42

triad

Question 43

interacts with myofilaments to stimulate contractions

Answer 43

Ca++

Question 44

cells which can self-replicate or can fuse to damaged muscle cells for repair and growth

Answer 44

satellite cells

Question 45

what happens to cell volume when muscle hypertrophy increeases?

Answer 45

cell volume increases

Question 46

satellite cells merge with the muscle fiber and add:

Answer 46

new nuclei for that fiber (allowing for greater protein synthesis)

Question 47

the basic contractile unit of muscle which gives a muscle fiber its striped appearance

Answer 47

sarcomere

Question 48

because sarcomeres are joined end to end throughout an entire muscle fiber, their simulaneous contraction:

Answer 48

shortens the entire muscle

Question 49

a dark band with a slightly lighter region in the center; contains thick and thin filaments

Answer 49

A-band

Question 50

a light region in the middle of the A-band that contains only thick filaments

Answer 50

H-zone

Question 51

a transverse line in the middle of the H-zone; composed of proteins that serve as the attachment site of the thick filaments and stabilizes the structure of the sarcomere; the myosin anchor site

Answer 51

M-line

Question 52

the light regions of the sarcomere which contains thin filaments but no thick filaments

Answer 52

I-bands

Question 53

a narrow dark line in the middle of the I-band; the site of attachment for titin to thin filaments

Answer 53

Z-line (disc)

Question 54

the distance from Z-line to Z-line is a:

Answer 54

sarcomere (2-3 um)

Question 55

all sarcomeres in a muscle fiber are:

Answer 55

identical

Question 56

an anchoring protein for actin; has a regulatory role in actin and myosin interactions

Answer 56

nebulin

Question 57

thin filaments contain active sites to bind:

Answer 57

myosin heads

Question 58

actin is composed of globular proteins called _____ which are found in 2 helical strands called _____

Answer 58

G-actin, F-actin

Question 59

a tubular protein of two identical alpha helices which shadows the actin double helix

Answer 59

tropomyosin

Question 60

troponin is a:

Answer 60

heterotrimer

Question 61

a component of troponin which binds to tropomyosin

Answer 61

TnT

Question 62

a component of troponin which binds to Ca++

Answer 62

TnC

Question 63

a component of troponin that binds to the actin monomer

Answer 63

TnI

Question 64

the thick filaments are polymers of:

Answer 64

myosin II

Question 65

each myosin molecule is a double trimer consisting of:

Answer 65

- two intertwined heavy chains - two regulatory light chains - two alkali (essential) light chains

Question 66

the two heavy myosin chains have three regions:

Answer 66

rod (tail), hinge, and head

Question 67

the rods of the myosin heavy chains are:

Answer 67

alpha helices

Question 68

the hinge regions of the myosin heavy chains flare into:

Answer 68

two globular heads

Question 69

the heavy myosin chain heads are:

Answer 69

- cross bridges - contain binding sites for actin - contain sites for binding and hydrolyzing ATP (ATPase activity)

Question 70

a large elastic protein which anchors the thick filament to the Z-disc, preventing over-stretching and providing elastic recoil

Answer 70

titin