myology- animal anatomy

define myology

the study of muscle

What is a muscle

a specialized connective tissue that, when stimulated by a nerve or hormone, can contract and produce movement of the body or its parts or contents.

what are the three classification of muscles ?

striated or non-striated, involuntary or voluntary, the type of muscle.

What are the three types of muscles

Smooth muscle, cardiac muscle, skeletal muscle

What type of nuclei does the cardiac muscle have ?

central

What are intercalated discs?

the discs that connect the cardiac muscle cells

How do action potentials work across cells that don’t use nerve or chemical transmission?

they use intercalated discs to spread action potentials from one cardiac muscle cell to another without the need for nerve or chemical transmission.

What are the cell junction ( intercalated discs?) in cardiac muscles?

gap junctions, desmosomes, and fascia adherens

Does cardiac muscle regenerate?

no

is cardiac muscle striated or non-striated?

striated

Which muscle type is non-striated

smooth muscle

Name the 6 characteristics of the smooth muscle

They have spindle shaped cells, central nucleus, non-striated, dense bodies, gap junctions, and they can regenerate

What type of nuclei does skeletal muscle have

peripheral

Is skeletal muscle striated or non-striated

striated

Which type of muscle is voluntary

skeletal

What are the 6 different ways you can name skeletal muscles

By attachments, shape, function, location/ position, number of heads, number of bellies

How many heads does the triceps have

4

What does cleido mean/ refer to

clavical

what does Brach/brachium mean/ refer to

arm

What are the 4 types of muscle attachments

tendon, aponeurosis, fascia, periosteum

What is the aponeurosis

a broad, flat, tendonous structure- like a sheet

what does periosteum mean

( a membranous tissue that covers the surface of your bones) periosteal of fleshy muscle attachment via the perimysium of muscle.

what is the perimysium

a loose connective tissue

What are 4 accessory structures

sesamoid bones, bursae, tendon sheaths, fascia

what does a sesamoid bone do and what is an example

they grow within the tendon to provide extra support and an example is the patella( knee cap)

What is a bursae

a fluid filled sac that provides cushion and support and keeps down inflammation

What are tendon sheaths

they are similar to the bursae, but they wrap around a tendon (synovial living on tendons)

what is fascia

a sheet or band of fibrous connective tissue that attaches skin to the underlying structures and invest in muscle.

what is the origin of muscle and where is it found on a limb

the movable attachment of the muscle found at the proximal part of the limb

What is the insertion of the muscle and where is it found on a limb

the more mobile movement of muscle and is found more distal on the limb

What is muscle contraction

the shortening of a muscle that causes a change in the alignment of bones around a joint

What is muscle function

the movement of the parts of the body

What are the three types of muscles used for movement

agonist, antagonist, and synergist

What is the agonist muscle

this is the prime mover muscle that flexes

What is the antagonist muscle

the muscle that extends; does the opposite movement of the agonist

What is the synergist muscle

the muscle that helps/ assists the agonist

what is extrinsic muscle

muscle that attaches to the thoracic limb and some other part of the body ( like the head or the trunk)- the axial skeleton

What is the intrinsic muscle

muscle having both attachments on the thoracic limb bones

what does the serratus Ventralis do

supports the trunk

What does the rhomboideus and trapezius do

elevate the limbs

What are examples of protractor extrinsic muscles

omotransversarius and brachiocephalius

What are examples of retractors of extrinsic muscles

deep pectoral and latissimus dorsi

What is an example of an extrinsic muscle that has multiple actions

superficial pectoral

what do protractors do

they extend away from the body

what do retractors do

pull trunk cranially

what does the superficial pectoral do

adduct the limb when not weight bearing and prevents abduction

what does adduction mean

towards the body

what does abduction mean

away from the body

What 3 intrinsic muscles extend the shoulder

(ISS) Supraspinatus, subscapularis, and infraspinatus

what intrinsic muscles flex the shoulder

(DTT) Teres major, teres minor, deltoideus

What are the muscles that flex the elbow

(BCB) Brachialis, Coracobrachialis, and biceps bracii

what are the muscles that extend the elbow

( ATT) Triceps brachii, tensor fascia antebrachii, anconeus

What muscles extend the carpus

(EU) extensor carpi radialis and ulnaris lateralis

What muscles flex the carpus

(FF) flexor carpi radialis and flexor carpi ulnaris

What are the 5 muscles in the forearm that involve the digits

common digital extensor, lateral digital extensor, superficial digital flexor, deep digital flexor, and abductor pollicis longus

what does the common digital extensor do

extends the all 5 digits and carpus

what does the lateral digital extensor do

extends digits 3-5 and carpus

what does the superficial digital flexor do

flexes digits 2-5 and the carpus

what does the deep digital flexor do

flexes all the digits and carpus

What does the abductor pollicis longus do

abduct the 1st digit

what are the three minor forearm muscles

(SPP) supinator, pronator teres, pronator quadratus

What are the 7 muscle categories for hindlimb myology

caudal thigh, medial thigh, cranial thigh, lateral pelvis, caudal hip, craniolateral leg, caudal leg

What are the three muscles in the caudal thigh

(BSS) biceps femoris, semitendinosus, semimembranosus

what are the 4 muscles in the medial thigh

(GPAS) Gracillus, Pectineus, Adductor, Satorius

What are the 4 muscles in the lateral pelvis

(SMDT) superficial gluteal, middle gluteal, deep gluteal, and tensor fasciae latae

what are the 4 muscles in the caudal hip

internal obturator, gemelli, quadratus femoris, external obturator

What are the 2 muscles on the cranial thigh

Quadriceps femoris, iliopsoas

what are the 3 muscles in the craniolateral leg

cranial tibial, long digital extensor, peroneus longus

what are the 4 muscles in the caudal leg

Gastrocnemius, superficial digital flexor, deep digital flexors, popliteus

what is the gastrocnemius muscle like in the caudal leg; a agonist, synergist or antagonist

an synergist

what are muscle bellies made up of

a differing number or muscle cells ( muscle fibers)

what are muscle fibers made up of

thousands of myofibrils

what are myofibrils made up of

A series of repeating sarcomeres

What is the basic contractile unit of the muscle fiber

sarcomeres

FITB: The sarcomere has a disk at each end called the _______

Z-disk

What does the z-disc extend from

Z-line to Z-line

what are the numerous thin protein filaments attached to the Z- disks called

actin

What do actin filaments consist of

two strands of tropomyosin

What are the globular proteins that run along tropomyosin called

troponin

what ion does troponin have an affinity for

Ca2+

what type of filaments are suspended between the actin filaments

myosin

What results when myosin filaments react with actin filaments

the sacromere shortens

What are the structures parallel to the myofibrils

numerous ling endoplasmic reticula called sarcoplasmic reticula

What does the sarcoplasmic reticula hold in relaxed muscles

calcium ions

What are the 5 bands/ lines in the sarcomere

I band, A band, H band, M line, Z line

What does the I band consist of

Portions of the thin filaments that do not overlap with the thick filaments

What does the A band consist of

mainly thick filaments in addition to portions of overlapping thin filaments

What does the H band consist of

rod like portion of the myosin molecule

What does the M line consist of/ is

a region where lateral connections are made between adjacent thick filaments

what does the z line do

bisects each I band

what is the first step in contraction

the nerves innervate the muscle cell

what is the site of innervation called

Motor end plate/ myoneural junction

What is a single nerve branching and innervating hundreds of muscle fibers called

a motor unit

what is between the axon and the muscle

the synaptic cleft

what happens when an action potential invades the motor end-plate

acetylcholine ( neurotransmitter) is released from the axon terminal

What does the acetylcholine do after being released from the axon terminal

it binds to the acetylcholine receptor in the sarcolemma

what does the binding of the acetylcholine to the acetylcholine receptor do

sends a signal to the sarcoplasmic reticulum and causes the release of the Ca2+ which initiates the contraction

What occurs once the contraction is complete

the ca2+ goes back to the sarcoplasmic reticulum and the muscle relaxes

What does the Huxley’s sliding filament theory of muscle contraction state

that the contacted states of a myofibril showing sliding of the actin filaments into the spaces between the myosin filaments

What is the first step of the Huxley’s sliding filament theory of muscle contraction

the ca ions become available to the sarcomere