Muscle Structure and Function

Question 1

What are the three types of muscles that we focused on?

Answer 1

-Skeletal
-Cardiac
-Smooth

Question 2

Most skeletal muscles attach via _____

Answer 2

tendons

(At two sites - origin and insertion)

Question 3

The entire muscle is attached to the shaft, ______, of a long bone with a strong rope-like tendon

Answer 3

diaphysis

Question 4

Surrounding the entire muscle is a layer of dense irregular connective tissue termed the _____.

Answer 4

epimysium

Question 5

The epimysium of some muscles may actually fuse with the _____ of the bone.

Answer 5

periosteum

Question 6

Within the entire muscle, individual muscle cells are grouped into bundles termed ______.

Answer 6

fascicles

Question 7

Each fascicle is wrapped with a layer of dense irregular connective tissues called the _____.

Answer 7

perimysium

Question 8

Surrounding the individual muscle cells within each fascicle is a thin layer of areolar connective tissue termed the ______.

Answer 8

endomysium

Question 9

The fascicles are made of individual ______ or _______

Answer 9

muscle cells; muscle fibers

Question 10

Running within the length of the individual muscle cells are numerous groups or bundles of functional, contractile elements called ______.

Answer 10

myofibrils

Question 11

The myofibrils contain the contractile units of skeletal muscles, the _____.

Answer 11

sarcomeres

Question 12

The myofibrils are in turn composed of an orderly arrangement of thick and thin proteins ______ made of myosin and actin.

Answer 12

myofilaments

Question 13

What are the major characteristics of skeletal muscle tissue?

Answer 13

-It contains striations
-It contains multinucleate cells
-Voluntary control

Question 14

What are the major characteristics of cardiac muscle tissue?

Answer 14

-It has striations, but these are less obvious
-It contains uninucleate cells
-It contains intercalated cells
-It contains branched cells
-Involuntary control

Question 15

What are the major characteristics of smooth muscle tissue?

Answer 15

-It contains uninucleate cells
-It contains spindle-shaped cells. (Tapered ends)

Question 16

A graph of the muscle’s electrical activity

Answer 16

Electromyogram (EMG)

Question 17

The muscles recruit additional ________ to contract and produce more tension.

Answer 17

motor units

Question 18

What trends do you see in the voltage measurements as the subject gradually increased the force of muscle contraction?

Answer 18

The voltage measurement also gradually increased

Question 19

What is the “source” of the signals (voltages) detected by the electrodes on the arm

Answer 19

Muscle action potentials –> collective electrical activity of all fibers because the electrode is on the skin. The movement produces current.

Question 20

How does the term “motor unit recruitment” apply to this specific activity, that is, the relationship between clench strengths and voltages?

Answer 20

Activate motor units –> greater force produced
Greater change in electrical activity because more muscle fibers are depolarizing

Question 21

The recording of muscle activity obtained by using electrodes on the skin

Answer 21

Electromyography