Muscle Structure and Function Flashcards
What are the three types of muscles that we focused on?
-Skeletal
-Cardiac
-Smooth
Most skeletal muscles attach via _____
tendons
(At two sites - origin and insertion)
The entire muscle is attached to the shaft, ______, of a long bone with a strong rope-like tendon
diaphysis
Surrounding the entire muscle is a layer of dense irregular connective tissue termed the _____.
epimysium
The epimysium of some muscles may actually fuse with the _____ of the bone.
periosteum
Within the entire muscle, individual muscle cells are grouped into bundles termed ______.
fascicles
Each fascicle is wrapped with a layer of dense irregular connective tissues called the _____.
perimysium
Surrounding the individual muscle cells within each fascicle is a thin layer of areolar connective tissue termed the ______.
endomysium
The fascicles are made of individual ______ or _______
muscle cells; muscle fibers
Running within the length of the individual muscle cells are numerous groups or bundles of functional, contractile elements called ______.
myofibrils
The myofibrils contain the contractile units of skeletal muscles, the _____.
sarcomeres
The myofibrils are in turn composed of an orderly arrangement of thick and thin proteins ______ made of myosin and actin.
myofilaments
What are the major characteristics of skeletal muscle tissue?
-It contains striations
-It contains multinucleate cells
-Voluntary control
What are the major characteristics of cardiac muscle tissue?
-It has striations, but these are less obvious
-It contains uninucleate cells
-It contains intercalated cells
-It contains branched cells
-Involuntary control
What are the major characteristics of smooth muscle tissue?
-It contains uninucleate cells
-It contains spindle-shaped cells. (Tapered ends)
A graph of the muscle’s electrical activity
Electromyogram (EMG)
The muscles recruit additional ________ to contract and produce more tension.
motor units
What trends do you see in the voltage measurements as the subject gradually increased the force of muscle contraction?
The voltage measurement also gradually increased
What is the “source” of the signals (voltages) detected by the electrodes on the arm
Muscle action potentials –> collective electrical activity of all fibers because the electrode is on the skin. The movement produces current.
How does the term “motor unit recruitment” apply to this specific activity, that is, the relationship between clench strengths and voltages?
Activate motor units –> greater force produced
Greater change in electrical activity because more muscle fibers are depolarizing
The recording of muscle activity obtained by using electrodes on the skin
Electromyography
