Modifying A & P ch 10

What is the major factor controlling how levers work?

the difference in the positioning of the effort, load, and fulcrum

Second class lever

FLE (Fulcrum, Load, Effort)

Tibia - Calcaneus joint

FLE (Fulcrum, Load, Effort)

Which of the following joint muscles is correctly matched with its lever type? biceps brachii at the elbow; third-class lever triceps brachii at the elbow; third-class lever gastrocnemius tendon at the ankle: first-class lever trapezius action on the atlanto-occipital joint; second-class lever

biceps brachii at the elbow; third-class lever. In this case, the force is applied by the biceps brachii between the fulcrum, the elbow joint, and the load, which is the forearm.

The sternocleidomastoid muscle inserts on the ________.

mastoid process of the temporal bone

Which description of a muscle action is NOT correct? Fixators hold joints in place, so movement does not occur. Agonists are the prime movers for an action. Synergists help agonists. Antagonists counter the action of a prime mover.

Fixators hold joints in place, so movement does not occur.; Fixators do hold a bone in place; however, they provide a stable base for a prime mover to create movement.

Humerus - Ulna joint

LEF (Load, Effort, Fulcrum)

third class lever/ The action of lifting a shovel of snow?

LEF (load, effort, fulcrum)

Atlanto-occipital joint

LFE (Load, Fulcrum, Effort)

First class lever

LFE (Load, Fulcrum, Effort)

Which of the following muscles is named for its size? sternocleidomastoid deltoid gluteus maximus trapezius

The term maximus indicates the size of this muscle; gluteus maximus is the largest of the gluteus muscles. Additionally, gluteal is the name of the region where the muscle is located.

T or F Muscles are only able to pull, they never push.

True

T or F Muscles that help maintain upright posture are fixators.

True

A muscle that opposes, or reverses, a particular movement is a(n) ________.

antagonist

Which of the following are correctly matched? pennate arrangement of fascicles; spindle-shaped muscle convergent arrangement of fascicles; fan-shaped muscle circular arrangement of fascicles; describes the deltoid muscle parallel arrangement of fascicles; characteristic of sphincter muscles

convergent arrangement of fascicles; fan-shaped muscle A convergent muscle has a broad origin, and its fascicles converge toward a single tendon of insertion. Such a muscle is triangular or fan shaped like the pectoralis major muscle of the anterior thorax.

t or f ; Although all skeletal muscles have different shapes, the fascicle arrangement of each muscle is exactly the same.

false

Muscle that stabilizes the origin of another muscle.

fixator

Muscle that aids another by promoting the same movement. // What type of muscle assists an agonist by causing a like movement or by stabilizing a joint over which an agonist acts?

syngergist