Anatomy chapter 11 Test

bipennate muscles

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multipennate muscles

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unipennate muscles

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the 2 ways actions can be described

1. Describes actions in terms of the bone or region affected. Thus, a muscle such as the biceps brachii muscle is said to perform "flexion of the forearm" 2. Identifies the joint (s) involved. In this approach, the action of the biceps brachii muscle would be "flexion at (or of) the elbow."

4 classifications of skeletal muscle

1. parallel muscles 2. convergent muscles 3. pennage muscles 4. circular muscles

how fascicle organization is used to name muscles

A muscle name may refer to the orientation of the muscle fascicles within a particular skeletal muscle. Rectus means "straight," and rectus muscles are parallel muscles whose fibers generally run along the long axis of the body. Because we have several rectus muscles, the name typically includes a second term that refers to a precise region of the body. For example, the rectus abdomens muscle is located on the abdomen, and the rectus femoris muscle on the thigh. Other common directional indicators include transverses and oblique, for muscles whose fibers run across or at an oblique angle to the longitudinal axis of the body, respectively

agonist

An agonist, or prime mover, is a muscle whose contraction is chiefly responsible for producing a particular movement. The biceps brachii muscle is an agonist that produces flexion at the elbow.

antagonist

An antagonist is an muscle whose action opposes that of a particular agonist. The triceps brachii muscle is an antagonist that extends the elbow. It is therefore an antagonist of the biceps brachii muscle, and the biceps brachii is an antagonist of the triceps brachia. Agonists and antagonists are functional opposites; if one produces flexion, the other will produce extension. When an agonist contracts to produce a particular movement, the corresponding antagonist will be stretched, but it will usually not relax completely. Instead, it will contract eccentrically, with just enough tension to control the speed of the movement and ensure its smoothness.

when a muscle contains both a aponeurosis and a tendon, where is the origin and insertion located?

If a muscle extends between a broad aponeurosis and a narrow tendon, the aponeurosis is the origin and the tendon is the insertion. If several tendons are at one end and just one is at the other, the muscle has multiple origins and a single insertion.

the attachment site for the origin and insertion of a muscle

In the body, the ends of a skeletal muscle are always attached to other structures that limit their movement. IN most cases one end is fixed in position, and during a contraction the other end moves tower the fixed end. The place where the fixed end attaches to a bone, cartilage, or connective tissue is called the origin of the muscle. The site where the movable end attaches to another structure is called the insertion of the muscle.

how origin and insertion is used to name muscles

Many muscle names include terms for body locales that tell you the specific origin and insertion of each muscle in such cases, the first part of the name indicates the origin, the second part of the insertion.

how relative position is used to name a muscle

Muscles visible at the body surface are often celled externs or superficials, where as deeper muscles are termed interns or profundus. Superficial muscles that stabilize an organ are called extrinsic. Muscles located entirely within an organ are intrinsic

how location in the body is used to name muscles

Regional terms are most common as modifiers that help identify individual muscles. In a few cases, a muscle is such as prominent feature of a body region that a name referring to the region alone will identify it.

how structural characteristics is used to name a muscle

Some muscles are name after distinctive structural features. Shape is sometimes an important clue to the name of a muscle. Many terms refer to muscle size.

typically, where is the origin in comparison to the insertion? distal or proximal?

The origin is typically proximal to the insertion. When a muscle contracts, it produces a specific action, or movement.

how action is used to name a muscle

There are many muscles name flexor, extensor, abductor, adductor, and so on these are such common actions that the names almost always include other clues as to the appearance or location of the muscle. A few muscles are named after the specific movement associated with special occupations or habits.

the names of muscles include what type of info?

They help you remember the names and identify the muscles. The descriptive info about its location in the body, origin and insertion,fascicle organization, relative position, structural characteristics, and action

circular muscles

also called sphincter, the fascicles are concentrically arranged around an opening or a recess. When the muscle contracts, the diameter of the opening decreases. Circular muscles guard entrances and exits of internal passageways such as the digestive and urinary tracts. An example is the orbicular is iris muscle of the mouth.

actions of skeletal muscle

flexion, extension, adduction, abduction, pronation, protraction, retraction, elevation, depression, rotation, circumduction, pronation, supination, inversion, eversion, lateral flexion, and opposition

convergens muscles

muscle fascicles extending over a broad area converge on a common attachment site. The muscle may pull on a tendon, an aponeurosis, or a slender band of collagen fibers known as the raphe. The muscle fibers typically spread out, like a fan or a broad triangle, with a tendon at the apex

synergist

provides additional pull near the insertion or may stabilize the point of origin. A time in which they help the most is when the antagonist is fully stretched.

parallel muscles

the fascicles are parallel to the long axis of the muscle. Most of the skeletal muscles in the body are parallel muscles. Some are flat bands with broad attachments (aponeuroses) at each end; others are plump and cylindrical, with tendons at one or both ends

pennate muscles

the fascicles form a common angle with the tendon. Because the muscle fibers pull at an angle, contraction pennate muscles do not move their tendons as far as parallel muscles do. But a pennate muscle contains more muscle fibers - and thus more fyofibrils - than does a parallel muscle of the same size and so produces more tension