Chapter 48: Musculoskeletal Systems Flashcards
skeletal muscle
responsible for all voluntary movements, and many involuntary actions
cardiac muscle
responsible for the beating of the heart
smooth muscle
creates movement in many hollow internal organs
under the control of the autonomic nervous system
muscle fibers
skeletal muscle cells
large with many nuclei
actin
thin filament, used for muscle contraction
myosin
thick filament
myofibrils
bundles of thick myosin and thin actin arranged in an orderly fashion
sarcomeres
repeating units of overlapping filaments of actin and myosin.
titin
largest protein in the body
runs right through a myosin bundle(from z line to z line)
each sarcomere is bounded by
z line
centered in the sarcomere is the..
a band, which contains all the myosin filaments
H zone and I bands are..
regions where actin and myosin filaments do not overlap in the relaxed muscle
tropomyosin
twisting around the actin chains
troponin
attached to tropomyosin at intervals
motor unit
a motor neuron and all of the fibers with which it forms synapses with
sacroplasm
muscle fiber cytoplasm
T tubules
system of transverse tubules
twitch
the spread of an action potential through the muscle fiber’s T tubule system causes a minimum unit of contraction
the strength of a muscle contraction depends on…
- how many fibers are contracting
2. and at what rate
tetanus
continuous activation of the contractile machinery.
slow-twitch fibers
oxidative or red muscles
contain myoglobin
many mitochondria
well supplied with blood vessels
fast-twitch fibers
glycolytic or white muscles fewer mitochondria little to no myoglobin fewer blood vessels look pale in comparison to slow-twitch fibers
muscle ATP systems
immediate, glycolytic, and oxidative systems
immediate system
uses performed ATP and creatine phosphate
glycolytic system
metabolizes carbohydrates to lactate and pyruvate
oxidative system
metabolizes carbohydrates or fats alllll the way to water and carbon dioxide
hydrostatic skeletons
consists of a volume of fluid enclosed in body cavity surrounded by muscle
cartilage
extracellular matrix that is tough, rubbery mixture of polysaccharides and proteins(mainly collagen)
supportive tissue
bone
also contains collagen fibers
contains calcium phosphate crystals that give it rigidity and hardness
osteoblast
lay down new matrix material on bone surface
osteocyte
osteoblasts that get trapped by their own handiwork
osteoclasts
cells that reabsorb bones
membranous bone
forms on a scaffold of connective tissue membrane
cartilage bone
forms first as a cartilaginous structure resembling the future mature bone, then gradually hardens, or ossifies, to become bone
compact
solid and hard
cancellous
having numerous internal cavities that make it appear spongy, although it’s rigid)
Haversian systems
set of thin, concentric bony cylinders, between which are the osteocytes in their lacunae (small cavities)
narrow canal containing blood vessels and nerves running through the middle
joints
where two or more bones come together
flexor
the muscle that bends or flexes the joint
extensor
the muscle that straightens or extends the joint
ligaments
flexible bands of connective tissue
connect bones to bone
tendons
attache the muscle to bone
