Chapter 10 objectives

Question 1

describe skeletal muscle tissue

Answer 1

long parallel, multinucleated, strands; striated

Question 2

describe cardiac muscle

Answer 2

short, wide, branching, striated, intercalated disks, single to two nuclei

Question 3

describe smooth muscle

Answer 3

thin smooth muscle cells, have single nucleus, usually have gap junctions

Question 4

what are the 5 properties of muscle cells

Answer 4

contractility, excitability, conductivity, extensibility, elasticity

Question 5

what is contractility

Answer 5

ability to contract

Question 6

what is excitability

Answer 6

ability to respond to stimulus

Question 7

what is conductivity

Answer 7

ability to conduct electrical changes across entire plasma membrane

Question 8

what is extensibility

Answer 8

ability to stretch without rupturing

Question 9

what is elasticity

Answer 9

ability to return to original length after stretching

Question 10

define myocyte

Answer 10

a muscle cell

Question 11

define sarcoplasm

Answer 11

a myocytes cytoplasm

Question 12

define sarcolemma

Answer 12

a myocytes plasma membrane

Question 13

define sarcoplasmic reticulum

Answer 13

modified endoplasmic reticulum for a muscle cell

Question 14

define myofibril

Answer 14

the big sausage pieces in a muscle cell; allow for contraction; are 50%-80% of muscle cell

Question 15

define transverse tubutles

Answer 15

a tunnel-like tube that surrounds the myofibrils

Question 16

define Terminal cisternae

Answer 16

enlarged sections of SR;
flank each T-tubule

Question 17

define triad

Answer 17

two terminal cisternae with a T-tubule

Question 18

what are myofibrils made of?

Answer 18

myofilaments

Question 19

what are the different kinds of proteins in a myofilament

Answer 19

contractile, regulatory, and structural proteins

Question 20

define contractile protein

Answer 20

generates tension

Question 21

define regulatory protein

Answer 21

dictates when a fiber may contract

Question 22

define structural protein

Answer 22

maintains proper myofilament alignment and fiber stability

Question 23

what are three types of myofilaments

Answer 23

thick, thins, elastic filaments

Question 24

what is a myosin head

Answer 24

the small buds on a thick filament that attaches to the thin filament

Question 25

what is tropomyosin

Answer 25

the long rope wrapping around the thin filament’s actin; covers active site

Question 26

what is troponin

Answer 26

the small bundle of protein that holds the tropomyosin in place; dictates when contraction happens

Question 27

how do striations relate to the muscle contraction model

Answer 27

striations are visible because of how the thick, thin, and elastic filaments overlap

Question 28

define i band

Answer 28

the are where there are only thin filaments; light band

Question 29

define A band

Answer 29

where the thick and thin filaments overlap; the dark band

Question 30

define H zone

Answer 30

the middle of the A band where only thick filaments are

Question 31

define Z disk

Answer 31

the middle of the I band that attaches the thin and the elastic filaments to each other

Question 32

define the M line

Answer 32

the middle line that holds the thick filaments in place

Question 33

what are the two glycolitic energy sources

Answer 33

glycolysis and anaerobic catabolism

Question 34

describe glycolysis

Answer 34

provides energy for muscle contraction once immediate sources of energy are depleted; can supply ATP for
30–40 seconds of sustained contraction

Question 35

what is a skeletal muscle fiber type I

Answer 35

slow; small diameter, has less power for longer

Question 36

what is a skeletal muscle fiber type II

Answer 36

fast; large diameter, has more power for shorter time