Term
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Definition
1) excitability- muscles have membrane potential
2) Contractility: stimulation of muscle leads to depolarization and contraction
3) Extensibility- muscle can lengthen in response to stretch
4) elasticity: ability to return to original resting length
5) Direction of fibers: rectus- straight or parallel to axis of body; oblique means at an angle to body axis
6) number of origins/bellies: biceps branchii M means 2 heads
7) Attachement site or origin: sternocephalicus M originates at sternum |
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Term
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Definition
1) movement: locomotion, posture changes, facial expressions, movement of blood, contraction of G.I., bladder to move contents
2) Posture: active process resulting from actions of signals generated from sensors in joints, tendons, & muscles
3) Stabilizing Joints
4) Generating heat |
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Term
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Definition
| striated; not under voluntary control, cardiocytes smaller in diameter and length than skeletal; one nucleus; b/t cardiocytes there are intercalated discs, which are specialized cell junctions that electrically connect cells. |
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Term
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Definition
non-striated; mononucleate and involuntary.
found in blood vessels, G.I. tract, urinary system, repro system. |
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Term
| 2 types of smooth muscles |
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Definition
1) Single unit smooth muscle aka visceral muscle- widely distributed. found in 2 layers (circular and longitudinal)
2) Multiunit smooth muscle- found in iris of eye, portions of male repro tract, walls of large arteries, and arrector pili muscles |
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Term
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Definition
makes up 40% of animals BW
striated appearance from arrangement of contractile proteins actin and myosin.
multinucleated |
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Term
| Components of individual skeletal muscles |
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Definition
Muscle fibers or cells
Connective tissue
Blood vessels and nerves |
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Term
Skeletal Muscle Connective tissue
epimysium:
perimysium
endomysium |
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Definition
Epimysium: outer covering of dense irregular connective tissue separating muscles. deep fascia of muscle
perimysium: surrounds each muscle fascicle or bundle of muscle fibers. contains collagen and elastic fibers.
endomysium: surrounds each muscle fiber w/in each fascicle containing capillaries, nerve fibers, and satellite or stem cells. |
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Term
Classifying Muscles by Shape
Parallel
Circular
Convergent
Pennate
Unipennate
Bipennate
Multipennate |
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Definition
Parallel- the fascicles are arranged in a straight line and have the greatest potential for overall shortening but are relatively weak.
Circular: fascicles in concentric rings (eyes, mouth)
Convergent: muscle origin is wide but narrows to a tendon.
Pennate: featherlike. Short and attach obliquely to a tendon. Increase power at expense of how far muscle can contract.
Unipennate: tendon runs along one side of muscle
Bipennate: muscle fascicles converge from 2 sides onto tendon
Mutlipennate: tendon branches three or more times w/in muscle |
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Term
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Definition
1) Location: temporalis M on temporal bone
2) Action of muscle: extensor carpi radialis extends the carpus
3) Size: major vs minor; longus vs brevis
4) Shape: deltoideus (delta shaped); trapezius (trapezoid shape) |
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Term
Attachment of muscles
origin
insertion |
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Definition
The origin of a muscle refers to a fixed attachement site which is usually proximal.
insertion: moveable end of the muscle and is distal.
ex: sternohyoideus muscle originates at first sternebra and first costal cartilage (distal) and inserts on the basihyoid bone (proximal) ?????? |
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Term
| Types of attachments to bone |
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Definition
Tendon: dense band or cord of regular connective tissue that attaches the muscle to periosteum of bone.
Aponeurosis: tendinous sheet usually associated w/ flat muscles. ex: aponeurosis of external abdominal oblique muscle
Fascia: this is a common type of attachment for superficial muscles like the tensor fasciae latae. |
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Term
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Definition
A lever is a rigid structure like a bone that moves around a fixed point, which is called a fulcrum.
Muscle contraction is the force that moves a load (bone) |
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Term
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Definition
First class lever- fulcrum is b/t the load and force applied. like a seesaw. ex: animal lifting head
Second Class Lever: force is applied at one end and the fulcrum is at the other end with the load in between. ex: wheelbarrow and muscles causing plantar flexion.
Third Class: fulcrum and load are at either end of the lever and force applied is b/t the two. Speed and distance traveled by the load are increased by this type but at the expense of effective force. Ex: biceps brachii M flexing the elbow. |
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Term
Agonist
Antagonist
Synergist |
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Definition
Agonist: muscle that is primarily responsible for producing a movement
Antagonist: muscle that opposes the action of the agonist.
Ex: biceps brachii M is an agonist for flexing the elbow and triceps brachii M is the antagonist
Synergist: muscle that helps the agonist work more efficiently by producing additional force to move a joint or stabilize a joint. |
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Term
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Definition
in the superficial fascia b/t the skin and the fascia covering deeper muscles.
allow for movement of the skin (twitching of horse skin in response to a fly)
Include: platysma of head, cutaneous colli muscle in neck, and cutaneous trunci muscle. |
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Term
Terms describing movement
flexion:
extension:
abduction:
adduction:
circumduction:
rotation:
supination:
pronation: |
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Definition
flexion: movement that decreases angle of a joint.
extension: movement that increases angle of a joint.
abduction: movement of a part away from median plane.
adduction: movement of a part toward the median plane.
Circumduction: circular movement
Rotation: movement of a part around its long axis.
Supination: lateral movement of appendage so that the palmar/plantar surface faces medially.
Pronation: medial movement of the appendage so that the palmar/plantar surface faces the ground. |
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Term
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Definition
a synovial sac that is located b/t 2 structures to cushion the area and reduce friction on the muscle tendon.
ex: bicipital bursa b/t the biceps brachii muscle and the proximal humerus. Atlantal bursa b/t the atlas and ligamentum nuchae. |
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Term
| Synovial or tendon sheath |
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Definition
modified bursa that serves to protect a larger area of contact and movement of a tendon against bone.
edges are reflected around tendon, encircling it.
mesotendon is where the edges meet and is the site of the passage of blood vessels and nerves.
synovial fluid lubricates tendon sheath.
tendons are poorly vascularized and slow to heal. |
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Term
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Definition
general term for the connective tissue that separates and surrounds important structures.
divided into superficial, middle and deep parts. |
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Term
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Definition
located deep to the skin as an areolar or loose tissue.
allows neighboring structures to move against each other and to change shape.
looseness is dependent on amount of fluid in it
site of storage for subcutaneous fat. |
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Term
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Definition
tougher tissue and continuous with superficial fascia. layer of deep fascia deep to the superficial fascia that is found over most of the body and attaches to bone.
sends out septa b/t muscles that wraps around individual muscles or groups of muscles.
prominent in the limbs in the antebrachium and crus.
since muscles are encased in this fascia, when muscles contract the blood and lymph vessels are compressed, aiding in circulation of the limbs. |
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Term
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Definition
| the swelling sen in the distal limbs of horses kept confined and inactive for a time. Once the horse is turned out to exercise, the swelling is readily resolved. |
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Term
| Fascia can be thickened locally to provide specific functions. |
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Definition
| Retinacula (retinaculum) and annular ligaments hold tendons in position |
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Term
Examples of retinacula
Extensor retinacula |
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Definition
Found in both thoracic and pelvic limbs.
In forearm, extensor retinaculum is a thickening of the carpal fascia that blends with joint capsule.
Thickened crural fascia forms extensor crural retinaculum.
tarsal retinaculum is a fibrous loop that extends from the calcaneus and wraps aroudn the long digital extensor tendon. |
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Term
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Definition
found in all limbs
on the carpus, flexor retinaculum is on plantar aspect.
flexor retinaculum of the tarsus
In the shoulder joint, theres a transverse humeral retinaculum that holds the tendon of origin of the biceps brachii in place in the intertubercular groove of the humerus; involved w/ stability of the shoulder joint. |
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Term
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Definition
these are thickenings of fascia on the flexor aspect of the digits.
The palmar annular ligament is a thick fibrous structure on the palmar/plantar aspect of the metacarpophalangeal (metatarsophalangeal) joint and holds the SDFT and DDFT firmly in place.
the proximal annular ligament is associated w/ the first phalange and holds DDFT and SDFT in place. supports the DDFT at second phalange. |
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