10- Terms to Know!

Question 1

Fixators

Answer 1

When synergists immobilize a bone, or a muscles’s origin.

Question 2

Circular

Answer 2

fasicular pattern, fascicles are arranged in concentric rings.

Question 3

Convergent

Answer 3

broad origin, and its fascicles converge toward a single tendon of insertion.

Ex: triangular or fan shaped like the pectorals major muscle of the anterior thorax.

Question 4

Parallel

Answer 4

long axes of the fascicles run parallel to the long axis of the muscle.

Ex: straplike or spindle shaped with an expanded belly like the biceps brachii.

Question 5

Fusiform

Answer 5

spindle shaped muscles into a seperate class.

Question 6

Pennate

Answer 6

Fascicles are short and they attach obliquely to a central tendon that runs the length of the muscle.

Ex: Extensor digitorum muscle of the leg, the fascicles insert into only one side of the tendon, the muscle is unipennate.

Fascicles insert into the tendon from opposite sides, so that the muscles grain resembles a feather, the arrangement is bipennate.
The rectus femoris of the thigh is bipennate. A multipennate arrangement looks like many feathers situated side by side.

Question 7

Lever systems

Answer 7

operation of most skeletal muscles involves the use of leverage and lever systems. (partnerships between the muscular and skeletal systems).

Question 8

Lever

Answer 8

Rigid bar that moves on a fixed point.

Question 9

Fulcrum

Answer 9

when force is applied to it.

Question 10

Effort

Answer 10

applied force

Question 11

Load

Answer 11

used to move resistance

Question 12

Mechanical Advantage

Answer 12

Load is close to the fulcrum and the effort is applied far from the fulcrum, a small effort exerted over a relatively large distance can be used to move a large load over a small distance.

Commonly called a power lever.

Ex. Car Jack Pg. 327

Question 13

Mechanical Disadvantage

Answer 13

Commonly called speed lever. Levers are useful because they provide rapid contractions with a wide range of motion. Wielding a shovel is an example.

Pg. 328

Question 14

First Class Levers

Answer 14

Effort is applied at one end of the lever and the load is at the other, with the fulcrum somewhere between.

Ex. Seesaws, scissors, and lifting head off of chest.

Question 15

Second Class Levers

Answer 15

Effort is applied at one end of the lever and the fulcrum is located at the other, with the load between them.

Ex. Wheelbarrow, standing on your toes.

Question 16

Third Class Levers

Answer 16

Between the load and the fulcrum. Operate with great speed and always at a mechanical disadvantage. Tweezers or forceps provide this type of leverage. Most skeletal muscles of the body act in third class lever systems.

Ex. biceps muscle of the arm, lifting the distal forearm and anything carried in the hand. Permit a muscle to be inserted very close to the joint across which movement occurs. Little shortening of the muscle. Tend to be thicker and more powerful.