chapter 12

Question 1

what are the three types of muscle

Answer 1

-skeletal muscle: striated, somatic NS
-cardiac muscle: striated, ANS
-smooth muscle: no striations, ANS; constricts hollow organs

Question 2

skeletal muscle brief description

Answer 2

-skeletal and cardiac muscle are made in a similar way, account for striations due to development.
-work in antagonistic pairs: contract and relax around joints
-only excitable
-contract in a linear patter: one flexes (shortens), while the other relaxes (lengthens)

Question 3

muscle cell terminology

Answer 3

muscle fiber

Question 4

modified ER terminology

Answer 4

sarcoplasmic reticulum

Question 5

cytoplasm

Answer 5

sarcoplasm

Question 6

cell membrane

Answer 6

sarcolemma

Question 7

skeletal muscles are important for

Answer 7

interacting with environment

Question 8

how much weight does striated muscle account for in the adult body

Answer 8

40-50 percent

Question 9

how much do muscles consume at rest

Answer 9

25 percent of oxygen

Question 10

skeletal muscle

Answer 10

group of fascicles, muscle fiber cells are multinucleated

Question 11

fascicle

Answer 11

bundle of muscle fibers, made of myofibril

Question 12

1. endomyosin

Answer 12

CT around a muscle fiber

Question 13

2. perimysium

Answer 13

CT around a fascicle

Question 14

3. epimysium

Answer 14

CT around a bundle of fascicles= makes muscle, also has blood supply and nerves

Question 15

t tubules

Answer 15

transverse tubules
-created when the sarcolemma invaginates

Question 16

lateral sacs

Answer 16

terminal cristae
-swelling of sarcoplasmic reticulum in close proximity to t-tubule. stores calcium

Question 17

sarcomere

Answer 17

contractile unit of skeletal muscle, made z line to z line
-proteins: thick and thin filaments are found within and partially overlap each other

Question 18

myofribril

Answer 18

grouping of proteins, sarcomeres lined together, forms a small part of entire muscle cell.

Question 19

ultrastructure of muscle

Answer 19

molecular anatomy of a muscle cell, close examination of a sarcomere. has two contractile proteins: actin and myosin that represent thick and thin filaments

Question 20

contractile proteins
myosin

Answer 20

part of thick filament
-approx 250 join to form a thick filament
-quarternary structure: has 4 subunits; 2 heavy chains= tail, 2 light chains= head
-every head has a site for actin binding and another active site for ATPase

Question 21

contractile proteins
actin

Answer 21

makes thin filaments
-double helix of g-protein (globular) molecules
-each g-actin has a binding site for myosin
-strands of g-actin= called f-actin (fibrous)

Question 22

what are the regulatory proteins found on the thin filaments?

Answer 22

1. tropomysosin: regulatory protein that covers the binding site on f-actin
2. troponin: regulatory protein bound to tropomyosin and has a binding site for calcium.