Anatomy: MSK 2

extrinsic ligaments

supporting bands

electrical excitability

the ability to respond to a stimulus and convert it into an action potential

types of cartilaginous joints

synchondrosis, symphysis

aponeurosis

A broad, flat tendon

pivot joints

C1-C2, rotation

extensibility

ability to be stretched

bursa

a fibrous sac between certain tendons and bones that is lined with a synovial membrane that secretes synovial fluid

ball-and socket joint

shoulder and hip, all actions

myofibrils

contractile elements of muscle fiber

elasticity

ability to return to original length after contraction

contractability

ability to shorten

contractile myofilaments

actin (thin) and myosin (thick)

epimysium

connective tissue surrounding entire muscle

sarcomere

contractile unit of a myofibril

types of myofilaments

contractile, regulatory, structural

sarcoplasm

cytoplasm of a muscle cell

terminal cisterns

dilated end sacs of the sarcoplasmic reticulum

articular disc

discs of fibrocartilage that divides synovial cavity

hinge joint

elbow and knee, flexion and extension

Properties of Muscular Tissue

electrical excitability, contractility, extensibility, elasticity

labrum

fibrocartilaginous lip, ball-and-socket joints

diathrosis

freely movable

plane joints

hand bones, flat/sliding/gliding

troponin

holds tropomyosin in place

articular cartilage

hyaline cartilage that covers ends of bones in synovial joints, NOT binding

meniscus

incomplete, fibrocartilaginous disc in the knee

hypertrophy

increase in muscle size; increase production of myofibrils

transverse (T) tubules

invaginations of sarcolemma; allow electrical impulses to travel deep into the cell

sarcoplasmic reticulum (SR)

membranous sacs that encircle each myofibril; stores Ca2+

isometric contraction

muscle tenses but does not shorten

synergist

muscle that aids a prime mover in a movement and helps prevent rotation

antagonist

muscle that opposes the prime mover

fixator

muscle that prevents a bone from moving

prime mover (agonist)

muscle that produces most of force during a joint action

isotonic contraction

muscles contract and shorten

gomphoses

peg-in-socket, teeth, periodontal ligament

crystal arthritis (gout)

sodium crystals deposited in joints

skeletal muscle

striated and voluntary

types of fibrous joints

sutures, syndesmoses, gomphoses

syndochondrosis

bones joined by hyaline cartilage; epiphyseal growth plates

fibrous joints

bones joined by solid mass of dense irregular CT

fibrous and cartilaginous joints

bones joined by solid masses of CT

ligaments

Connect bone to bone

tendons

Connect muscle to bone

perimysium

Connective tissue surrounding a fascicle

endomysium

Connective tissue surrounding a muscle fiber

sarcolemma

muscle plasma membrane

extension

Straightening of a joint, sagittal plan

insertion

attachment of tendon to moveable bone; distal/inferior

origin

attachment of tendon to stationary bone; proximal/superior

rheumatoid arthritis (RA)

autoimmune, attacks own joint lining/synovial membrane

abduction

away from the midline

flexion

bending a joint, sagittal plane

tropomyosin

blocks myosin head from binding to actin in relaxed muscle

rotation

bone revolves around its own longitudinal axis, internal or external

synovial joints

bones joined by a CT capsule surrounding a lubricated cavity

symphysis

bones joined by fibrocartilage; intervertebral discs

Osteoarthritis (OA)

breakdown of articular cartilage

fascia

dense irregular CT, wraps around groups of muscles or structures

syndesmosis

more substantial and longer fibrous connections, between forearms bones and leg bones

adduction

movement toward the midline

eccentric contraction

muscle lengthens

sutures

seams between bones of the skull

synovial membrane

secretes synovial fluid which reduces friction and absorbs shock

circumduction

the circular movement at the far end of a limb, all four movements

intrinsic ligament

the ligament that is binding the bones

synovial capsule

the outermost layer of dense irregular CT that resembles a sleeve as it surrounds the joint

saddle joint

thumb, everything except rotation

Ca2+ when released into sarcoplasm

triggers muscle contraction

regulatory myofilaments

troponin and tropomyosin

condyloid joint

wrist, everything except rotating