Anatomy exam 3

Agonist

prime mover, major responsibility specific movement

fixator

synergist that immobilizes bone or muscle origin

synergist

helps prime movers, adds extra force to same movement or stabilizes joint

Functional groups

agonist, antagonist, synergist, fixators

antagonist

opposes movement of agonist, controls motion, muscles can only pull

direct connection

epimysium fused to attachment site

3 types of fibrous joints

gomphoses, syndesmoses, sutures

fibrous joints

bones joined by dense irregular connective tissue, little to no movement

osteogenesis imperfecta

group of genetic disorders, bone deformities, brittle bone disease

Annulus fibrous

tough outer ring of intervertebral disc

Perimysium

fibrous connective tissue sheath, blood vessels and nerves

how does the signal reach the interior quickly

transverse tubules= T tubules, tubes of sacrolemma projecting into sacroplasm

osteopenia

BMD, aging, osteoporosis (severe loss of BMD)

A band

dArk band, thick and thin together, M line

I band

light band, only thin fil + titin, Z line or disc

cranial bones thru life

fontanelle to sutures to synostoses

2 types of cartilaginous joints

synchondrosis, symphysis

cartilaginous joints

bones connected by disc or plate of cartilage, more movement than fibrous

synovial joints 6 features: 6 rich supply of

sensory nerve fibers, blood capillaries

synovial joints 6 features: 5 reinforcing ligaments

hold joint together

Synovial joints 6 features: 4 articular capsule

encloses joint cavity, fibrous outer layer, synovial membrane

Synovial joints 6 features: 3 synovial fluid

viscous (thick), weight bearing, lubricates

Synovial joints 6 features: 2 joint cavity

filled with synovial fluid

Synovial joints 6 features: 1 articular cartilage

smooth surface, absorbs shock , remains of endochondral ossification, smaller than 1mm

synarthrosis

very little to no movement, bony+ fibrous+ cartilaginous

Amphiarthrosis

some movement, syndesmosis, symphysis, fibrous cartilaginous

Diathrosis

alot of movement, synovial joints

Triads

t-tubules tightly bound to cisternae by transmembrane protein (separate compartments)

contraction

all sacromeres in a myofibril shorten together, entire muscle fibers shortens, filaments slide past eachother

in contraction what do z lines do

get closer

in contraction what do i bands do

narrow

in contraction what do H bands do

narrow

in contraction what do A bands do

stay the same

tropomyosin

thin protein strand, controls acess to myosin binding site

Thick filaments

myosin, binds actin, motor molecule, has ATPase activity

troponin

binds Ca2+, controls tropomyosin

intervertebral discs

between vertebrae bodies, cushioning, flexability

2 things in intervertebral discs

nucleus pulposus, annulus fibrosis

terminal cisterna

enlarged cha,ber of SR, where SR meets t tubules

triad=

2 terminal cisternae + 1 t tubule

connections

myofibrils anchored to eachother, to sacrolemma, all at 2 discs

Titin

Largest protein, extends from Z disc to M line, forms core of thick filaments

NMJ

where neuron meets muscle, axon terminals, motor neuron release acetylcholine

A-band subdivisions

H band, no thin filaments, m- line, zone of overlap

Thin filaments

actin = double helix strand and myosin binding site

thin filaments regulatory proteins

tropomyosin, troponin

elastic filaments

spring back after stretching, made of titin

sacromeres

repeating highly organized functional units of myofibrils

costameres

connect z discs to the sarcolemma, multi protein complexes

skeletal muscle structural hierarchy

muscle to fascicles to muscle fiber to myofibril to sarcomere to myofilaments (thin and thick)

myofilaments

they make up myofibrils, parallel protein fibers, myosin and actin

sarcoplasmic reticulum (SR)

specialized smooth ER for muscle cells, stores and releases calcium

myofibrils

it’s as long as a muscle fiber, where the action is at, uses ATP, actively shorten + contraction

vertebral compression fractures

most common fracture in patients with osteoporosis, can be caused by sneezing and stepping out of shower

Nucleus pulposus

squishy inside, gel-like, in the intervertebral disc

herniated disc

Nucleus pulposus sticks out

acetabular labrum

labrum= lip, protects rim

Arthritis

joint inflammation

types of arthritis

osteoarthritis, Rheumatoid (RA)

Osteoarthritis

most common type, degeneration of joints, aging, pain, stiffness, inflammation

Rheumatoid arthritis

autoimmune disorder, chronic and relapsing

Non-synovial effects of Rheumatoid arthritis

Rash, rheumatoid lung disease, pericarditis, osteoporosis

Coxal joint

ball + socket, motion somewhat limited by deep socket, hip socket = acetabulum

Coxal joint, round ligament

aka ligamentum teres, connects the fovea capitis to edge of the acetabulum

plane joint examples

intercarpal joints, intertarsal joints, facet joints, costovertebral joints

6 types of synovial joints

plane (gliding), hinge, pivot, condylar, saddle, ball +socket

Mitochondria

Just under sacrolemma between myofibrils, lots of ATP needed

muscle fiber terms

sacroplasm= muscle cell cytoplasm , sacrolemma = muscle cell plasma membrane

motor endplate

shallow depression in muscle fiber, ACh receptors, junctional folds

ligand- gated ion channels

transmembrane receptors with “gates”, not GPCR

ligand

= signaling molecule, like a key for the gates

Pre synaptic membrane

sends signal, releases nuerotransmitter

postsynaptic membrane

receives signal, receptor proteins

chemical synapses

cells do not touch, space= synaptic cleft

chemical synapses examples

presynaptic membrane, postsynaptic membrane

NMJ mircoanatomy

motor neuron = nerve cell that controls muscles, axon branches to several muscle fibers