Anatomy SB 3

From a functional and historical perspective, the _____ part of the muscle is its origin.

least movable

muscle naming rationale- abdominal

location

Identify the nerves that form the lumbosacral plexus. (Check all that apply.)

lumbar nerves coccygeal nerves sacral nerves

The _____ plexus supplies sensation and motor function to the lower trunk and the entire lower extremity and perineum.

lumbosacral

For most of the skeletal muscles, _____ is a very useful way to determine muscle action, but it is limited to superficial muscles.

palpation

_____ are the two major types of fiber arrangements that group all skeletal muscles.

pennate and parallel

Some agonist muscles that are able to contribute significantly more to a joint movement than other agonists are known as _____.

primary movers

In the context of muscle terminology, fascial tissue forms a(n) _____ to retain tendons close to the body.

retinaculum

Identify the nerves that form the lumbosacral plexus. (Check all that apply.)

sacral nerves coccygeal nerves lumbar nerves

The _____ or afferent nerves bring impulses from receptors in the skin, joints, muscles, and other peripheral aspects of the body to the central nervous system.

sensory

muscle naming rationale-hamstring

shape

Every muscle fiber is innervated by a _____, which, when an appropriate stimulus is provided, results in a muscle contraction.

somatic motor neuron

In the context of muscle terminology, _____ are tough yet flexible bands of fibrous connective tissue that connect muscles to bones and other structures.

tendons

In the context of muscle nomenclature, the name adductor magnus muscle is based on which distinctive characteristic?

Action and size (list of muscle nomenclature on pg.38)

Which of the following muscles contracts concentrically to cause joint motion through a specified plane of motion?

Agonist muscles

____________ are central or connecting neurons that conduct impulses from sensory neurons to motor neurons.

Interneurons

_____ transmit impulses away from the brain and spinal cord to muscle and glandular tissue.

Motor neurons

Identify the muscles that counteract the action of other muscles to prevent undesirable movements such as inappropriate muscle substitutions.

Neutralizer muscles

Which of the following muscles surrounds a joint or body part and contracts to fixate the area to enable another limb or body segment to exert force and move?

Stabilizers

Identify the parallel muscle based on the muscle features depicted in the image.

Strap muscle Radiate muscle Fusiform muscle Flat muscle

Which of the following types of muscles contracts to prevent an undesired joint action of the agonist and has no direct effect on the agonist action?

True synergists muscles

Action is the specific movement of a joint resulting from a _____ contraction of a muscle that crosses the joint.

concentric

Biceps brachii that has the action of flexion at the elbow is an example of _____ contraction.

concentric

One or more branching projection in a neuron is known as a(n) _____.

dendrite

In the context of muscles, _____ occur when two or more forces are pulling in different directions on an object, causing the object to rotate about its axis.

force couples

In the context of muscle terminology, the _____ is the central, fleshy portion of the muscle.

gaster (belly or body)

A muscle that assists another muscle move a joint in the desired manner and simultaneously prevents undesired actions is referred to as a(n) _____.

helping synergist muscle

In the context of muscle terminology, the contractile portion or the gaster generally _____ as the muscle contracts.

increases in diameter

Afferent nerves

Bring impulses from receptors to the central nervous system

Efferent nerves

Carry impulses to the outlying regions of the body

Extensibility (muscle tissue property)

Ability of muscle to be passively stretched beyond its normal resting length

Contractility (muscle tissue property)

Ability of muscle to contract and develop tension or internal force against resistance when stimulated

Synergist

-muscles that assist in the action of an agonist but are not necessarily prime movers for the action, known as guiding muscles, assist in refined movement and rule out undesired motion. -synergist muscles may be either helping synergists or true synergists. -Helping synergists -have an action in common but also have actions antagonistic to each other -help another muscle move the joint in the desired manner and simultaneously prevent undesired actions. --ex: involves the anterior and posterior deltoid -the anterior deltoid acts as an agonist in glenohumeral flexion, while the posterior . . deltoid acts as an extensor -helping each other, they work in synergy with . the middle deltoid to accomplish abduction READ -True synergists -contract to prevent an undesired joint action of the agonist and have no direct effect on the agonist action -the finger flexors are provided true synergy by the wrist extensors when one is grasping an object. The finger flexors originating on the forearm and humerus are agonists in both wrist flexion and finger flexion. The wrist extensors contract to prevent wrist flexion by the finger flexors. This allows the finger flexors to maintain more of their length and therefore utilize more of their force in flexing the fingers.

Elasticity (muscle tissue property)

Ability of muscle to return to its original resting length following stretching

Identify an example of intrinsic muscles

-The small muscles found entirely within the hand

Which of the following statements is true of stabilizers?

-They are essential in establishing a relatively firm base for the more distal joints to work from when carrying out movements. -They help another muscle move the joint in the desired manner and simultaneously prevent undesired actions. -They counteract or neutralize the action of other muscles to prevent undesirable movements such as inappropriate muscle substitutions. -They cause body parts to rotate about their axes resulting in more efficient movements

Fascia

-a sheet or band of fibrous connective tissue that envelopes, separates, or binds together parts of the body such as muscles, organs and other soft-tissue structures of the body -ex: around joints like the wrist and ankle, fascial tissue forms a retinaculum to retain tendons close to the body.

aponeurosis

-a tendinous expansion of dense fibrous connective tissue that is sheet- or ribbonlike in appearance and resembles a flattened tendon -serve as a fascia to bind muscles together or as a means of connecting muscle to bone -ex: the palmar aponeurosis for the palmaris longus

Agonist

-agonist muscles, when contracting concentrically, cause joint motion through a specified plane of motion. -any concentrically contracting muscle that causes the same joint motion is an agonist for the motion -some muscles, because of their relative location, size, length, or force generation capacity, are able to contribute significantly more to the joint movement than other agonists (primary movers or as muscles most involved) -agonist muscles that contribute significantly less to the joint motion are commonly referred to as assisters or assistant movers -consensus among all authorities regarding which muscles are primary movers and which are weak assistants does not exist in every case -ex: the hamstrings (semitendinosus, semimembranosus, biceps femoris), sartorius, gracilis, popliteus, plantaris and gastrocnemius are all agonists in knee flexion, but most kinesiologists regard only the hamstrings as the prime movers

Antagonist

-antagonist muscles have the opposite concentric action from agonists -referred to as contralateral muscles, antagonists are located on the opposite side of the joint from the agonist and work in cooperation with agonist muscles by relaxing and allowing movement -but when contracting concentrically, they perform the joint motion opposite to that of the agonist -ex: using the previous example, the quadriceps muscles are antagonists to the hamstrings in knee flexion.

Origin

-from a structural perspective, the proximal attachment of a muscle or the part that attaches closest to the midline or center of the body is usually considered to be the origin -from a functional and historical perspective, the least movable part or attachment of the muscle has generally been considered to be the origin.

Innervation

-occurs in the segment of the nervous system responsible for providing a stimulus to muscle fibers within a specific muscle or portion of a muscle -a particular muscle may be innervated by more than one nerve, and a particular nerve may innervate more than one muscle or portion of a muscle.

Extrinsic

-pertaining usually to muscles that arise or originate outside of (proximal to) the body part on which they act -example (of extrinsic muscles of the hand): the forearm muscles that attach proximally on the distal humerus and insert on the fingers (pg.42)

Intrinsic

-pertaining usually to muscles within or belonging solely to the body part on which they act -examples: the small intrinsic muscles found entirely within the hand (pg.42)

Insertion

-structurally, the distal attachment, or the part that attaches farthest from the midline or center of the body, is considered the insertion -functionally and historically, the most movable part is generally considered the insertion READ THROUGH THIS EXAMPLE As an example, in the biceps curl exercise, the biceps brachii muscle in the arm has its origin on the scapula (least movable bone) and its insertion on the radius (most movable bone). In some movements this process can be reversed. An example of this reversal can be seen in the pull-up, where the radius is relatively stable and the scapula moves up. Even though in this example the most movable bone is reversed, the proximal attachment of the biceps brachii is always on the scapula and is still considered to be the origin, and the insertion is still on the radius. The biceps brachii would be an extrinsic muscle of the elbow, whereas the brachialis would be intrinsic to the elbow. For each muscle studied, the origin and insertion are indicated.

Stabilizers

-surround the joint or body part and contract to fixate or stabilize the area to enable another limb or body segment to exert force and move -known as fixators, they are essential in establishing a relatively firm base for the more distal joints to work from when carrying out movements. READ THROUGH EXAMPLE In a biceps curling example, the muscles of the scapula and glenohumeral joint must contract in order to maintain the shoulder complex and humerus in a relatively static position so that the biceps brachii can more effectively perform the curls. The antagonists for each motion of the proximal joint co-contract or contract against each other to prevent motion. This is an example of proximal stabilization to enhance the effectiveness of distal joint motion, which occurs commonly with the upper extremity.

Gaster (belly or body)

-the central, fleshy portion of the muscle. -this contractile portion of the muscle generally increases in diameter as the muscle contracts -when a particular muscle contracts, it tends to pull both ends toward the gaster, or middle, of the muscle . -consequently, if neither of the bones to which a muscle is attached were stabilized, both bones would move toward each other upon contraction . -the more common case, however, is that one bone is more stabilized by a variety of factors, and as a result the less stabilized bone usually moves toward the more stabilized bone upon contraction

Action

-the specific movement of the joint resulting from a concentric contraction of a muscle that crosses the joint -example: biceps brachii, which has the action of flexion at the elbow -In most cases a particular action is caused by a group of muscles working together -Any of the muscles in the group can be said to cause the action, even though it is usually an effort of the entire group -A particular muscle may cause more than one action either at the same joint or at a different joint, depending upon the characteristics of the joints crossed by the muscle and the exact location of the muscle and its attachments in relation to the joint(s)

Tendon

-tough yet flexible bands of fibrous connective tissue -often cordlike in appearance -connect muscles to bones and other structures. -transmit the force generated by the contracting muscle to the bone through providing the connection -two muscles may share a common tendon -ex: achilles tendon of the gastrocnemius and soleus muscles -in other cases a muscle may have multiple tendons connecting it to one or more bones -ex:the three proximal attachments of the triceps brachii

Muscles are usually named because of one or more distinctive characteristics, such as their:

-visual appearance (shape and size) -anatomical location (2) -functionor action -Number of divisions -Direction of fibers -Points of attachment

Cervical nerves 5 through 8, along with thoracic nerve _____, form the brachial plexus.

1

Cervical nerves _____ form the cervical plexus.

1 through 4

In the context of parallel muscles, identify an example of fusiform muscle

Brachialis

Match the muscle names (in the left column) to the distinctive characteristics after which they are named. (in the right column).

Deltoid------------>shape Teres minor-------->size Triceps brachii----->number of divisions Rectus femoris----->location Supinator----------->action

True or false: A particular nerve innervates only one muscle or portion of a muscle.

False -Innervation occurs in the segment of the nervous system responsible for providing a stimulus to muscle fibers within a specific muscle or portion of a muscle -A particular muscle may be innervated by more than one nerve, and a particular nerve may innervate more than one muscle or portion of a muscle

True or false: Generally, pennate muscles produce a greater range of movement than similar-size muscles with a parallel arrangement.

False -Parallel (fibers arranged parallel to the length of the muscle): produces greater range of movement than similar-size pennate muscles; long excursion (contract over a great distance); good endurance

Bipennate muscles

Fibers run obliquely from a central tendon on both sides

Unipennate muscle

Fibers run obliquely from a tendon on one side only

_____ muscles are categorized on the basis of the exact arrangement between the fibers and the tendon.

Pennate

Irritability (muscle tissue property)

Sensitive or responsive to chemical, electrical, or mechanical stimuli

_____ transmit impulses to the spinal cord and brain from all parts of the body.

Sensory neurons

Multipennate muscles

Several tendons with fibers running diagonally between them

Identify the muscle groups that are named after their location in the body. (Check all that apply.)

Shoulder girdle Abdominal

In the context of muscle terminology, identify a case wherein two muscles share a common tendon.

The Achilles tendon of the gastrocnemius and soleus muscles

Which of the following statements is true of stabilizers?

They are essential in establishing a relatively firm base for the more distal joints to work from when carrying out movements.

True or false: All voluntary movement is a result of the muscular and the nervous systems working together.

True

True or false: There are over 600 skeletal muscles, which constitute approximately 40% to 50% of body weight.

True -These pairs of muscles usually work in cooperation with each other to perform opposite actions at the joints they cross

In the context of determination of muscle action, palpation is done by using the sense of touch to feel or examine _____.

a muscle as it contracts

muscle naming rationale- rotator cuff

action

Muscles working in a group rather than independently to achieve a given joint motion is known as _____.

aggregate muscle action

In the context of muscle terminology, fascial tissue form a retinaculum to retain tendons close to the body in certain places throughout the body, such as _____.

around joints like wrist and ankle

A(n) _____ is an elongated projection that transmits impulses away from neuron cell bodies.

axon

The _____ plexus supplies motor and sensory function to the upper extremity and most of the scapula.

brachial

In the context of neural control of voluntary movement, which of the following is the most specific level of control in the central nervous system?

cerebral cortex basal ganglia cerebellum (in order from most general to most specific) The spinal cord

The central nervous system (CNS) is divided into five levels of neural control of voluntary movement. List these levels from the most superiorly located level to the most inferiorly located level. (Place the most superiorly located level at the top.) Instructions

cerebral cortex basal ganglia cerebellum brain stem spinal cord

The _____ plexus is responsible for sensation from the upper part of the shoulders to the back of the head and front of the neck.

cervical

When only the supination action of the biceps brachii is desired, the triceps brachii contracts to counteract the flexion action of the biceps brachii. In the given action, the triceps brachii act as a(n) _____.

neutralizer

True synergist

no effect on agonist action prevents undesired actions

muscle naming rationale-quadriceps

number of division