Sarcomere stuff

Question 1

Sarcomere

Answer 1

the basic unit of contraction of skeletal muscles

Question 2

Thin filaments (actin)

Answer 2

extend from z disc toward the center of the sarcomere

Question 3

Thick filaments (myosin)

Answer 3

located in the center of the sarcomere (overlap the inner ends of the thin filaments)

Question 4

Elastic filaments (titan)

Answer 4

located between the myosin filament and end of sarcomere.
-function to hold the myosin in place in the center of the sarcomere

Question 5

Z disc

Answer 5

boundaries of each sarcomere

Question 6

A bands

Answer 6

full length of the thick filament (red)

Question 7

H zone

Answer 7

center part of A band where no thin filaments occur

Question 8

M line

Answer 8

center of the H-zone
-contains tiny rods that hold thick filaments together

Question 9

I band

Answer 9

region with only thin filaments
-lies within two adjacent sarcomeres (white)

Question 10

Sarcoplasmic reticulum

Answer 10

an elaborate smooth endoplasmic reticulum made of interconnecting tubules
=surround each myofibril
-contains calcium ions released when muscle is contracted
-trigger sliding filament

Question 11

Terminal Cisternae

Answer 11

larger cross-channels between the A and I bands
-occur in pairs on either side of a t tubule

Question 12

muscle contraction

Answer 12

1. signal travels down the sarcolemma on outside of the fiber and goes deep into the fiber by the T-tubules
   (deep invagination of the sarcolemma)

Question 13

sliding filament mechanism

Answer 13

myosin heads attach to actin in the thin filaments (cross bridges)
-then pivot to pull thin filaments inward toward the center of the sarcomere