Exam 1 Flashcards
The middle protective sheath of connective tissue in a muscle is called
Perimysium
Which of the following muscle structures does not shorten when a muscle contracts?
Myofilament
Which of the following is true concerning Ca++ in muscle structure and muscle contraction?
Present in lateral sacs when muscle is relaxed, attaches to troponin to start contraction
Muscles apply force by…
Pulling
Which of the following is included in a motor unit?
Motor neuron and the muscle fibers activated by that motor neuron
Which statement is correct regarding muscle fiber arrangement?
Parallel fibers are less densely packed and are most efficient on being stretched just beyond their normal length
Which of the following organs is responsible for protection of the muscle against active tensions?
Golgi Tendon Organs
The stretch reflex or myotatic reflex is provoked by activation of which in a rapidly lengthening muscle?
Muscle Spindles
Active insufficiency is the…
inability of a multi-jointed muscle to maximally move all crossed joints through their full ROM
Passive insufficiency is the…
inability of a multi-jointed muscle to stretch enough to allow all crossed joints to move through their full ROM
The main functions of joint receptors are to…
anticipation of force to be encountered AND the amount of actual force encountered
Which of the following nerve signal conditions would bring about the highest force production within a muscle?
High intensity nerve signal with moderate signal frequency
Concerning the Force-Velocity curve, which is the correct statement?
The higher the velocity of a concentric contraction the lower the force produced
Which statement correctly states the four major properties present when an external force acts upon an object to cause motion?
Point of application, line of action, direction, magnitude
Compression
forces that press structures together
Tension
forces that act in opposite direction causing a pulling action
Shear
parallel forces acting in opposite directions
Torsion
rotation forces that oppose each other in the direction they act
Combined Loading
the simultaneous action of multiple forces on a structure
Eccentric forces
a force applied outside an object’s center of gravity
Law of Inertia
a body will maintain a state of motion unless acted on by an external force
Law of Acceleration
A force applied to a body causes a rate of change in velocity of that body proportional to the magnitude of the force
Law of Reaction
When one body exerts a force on a second, the second body exerts a force that is equal in magnitude and opposite in direction of the first force
Center of Gravity
The point where all a body’s mass appears to be concentrated
Power
Force times distance over time (F)(d/t)
Torque
the turning effect of an eccentric force that produces angular motion
Impulse
The change in momentum of an object from time 1 to time 2
Momentum
mass times the velocity of that mass
provide mechanical levers and structural support
Long Bones
provide elasticity, flexibility, and shock absorption
Short Bones
provide protection and anchor/attachment points for musculature
Flat Bones
provide protection and anchor/attachment points for musculature, and flexibility and shock absorption
Irregular Bones
Complete ROM
Enarthroidal Joints
Hinge; action primarily in one plane
Ginglymus joint
Gliding; one plane with little movement
arthroidial joint
Biaxial; two planes
condyloidal joint
Saddle; thumb
Sellar joint
Pivot, rotation around the long axis
trochoidal joint
Concentric Contraction
shortening of a muscle while producing force, muscle force exceeds resistance, i.e. lifting dumbbell toward body
Eccentric Contraction
engthening of a muscle while producing force, resistance overcomes muscle, i.e. lowering dumbbell, resisting weight
Isometric Contraction
production of force with no change in fiber length
Shock Absorption
time up, force down
maximum acceleration
time up, force up
abrupt change in direction
time down, force up
6 Mechanical Components of a Lever
- Axis/Fulcrum:
- Rod:
- Motive Force: in concentric = muscle, eccentric = external force
- Resistance Force: in eccentric = muscle
- Force Arm: distance from fulcrum to force
- Resistance Arm: distance from fulcrum to resistance
Work
force times distance (F)(d)
