The flashcards below were created by user
Anonymous
on FreezingBlue Flashcards.
-
Muscle originates from mesodermal cells called
Mysoblasts
-
This divides and elongates to become actin and myosin
Myoblasts
-
These are organized into myofilaments
Myoblasts=muscle cells = muscle fiber
-
This kind of muscle is very large and nulticucleate
Skeletal (striped aka striated)
-
Muscle cells are composed of two proteins
Actin and myosin
-
Thin filaments of muscle are
Actin
-
Thick filaments of muscle are
Myosin
-
How many myofibrils does each skeletal muscle FIBER contain
Hundreds to thousands
-
Myofibrils are made of smaller, repeating units called
Sarcomeres
-
Smalles unit of muscle fiber
Macromere
-
Why do myofibril have that striated appearance?
Combination of thin &thick filaments
-
When skeletal muscle contracts, this happens:
Hzone and I bands get smaller, zones overlap get larger, z moves closer, width of a band doesnt change. Cross bridges form
-
When do skeletal muscles contract?
When they receive a nerve impluse
-
What happens when action potential arrives at neuromuscular jnct?
Acetylcholine is released and it diffuses across to the synapse
-
______ at the motor end plate causes action potential that leads to contraction
Depolarization
-
Cell membrane of muscle
Sarcolemma
-
T-tubles cary action potential from ____ to _______ ________.
Sarcolemma; sarcoplasmic reticulum
-
Similar to cell endoplasmic reticulum; transports/releases CA when receives signal
SR (sarcoplasmic reticulum)
-
What has to happen in order for muscles to contract
Cross bridges must form between actin and myosin
-
Active sites are usually blocked by
Tropomyosin
-
When ______ from the SR bind to receptors on the troponin molecules, it changes config of troponin, which in turne causes what
Calcium ions, tropomyosin to move away from active sites.
-
These muscles are small with a single centrally placed nuc
Cardiac
-
This unites the individual cell with heart muscle
Intercalated disks
-
This is a functional syncytium
Heart
-
These muscles don't ever fatigue
Cardiac and smooth
-
Heart beat is ____; generated by muscle itself
Myogenic
-
This muscle has a single nuc around center of the cell
Smooth
-
This muscle has irregular arrangements of actin and myosin, resulting in no striations
Smooth muscle
-
Stretching can cause ______ in smooth muscles
Depolarization and action potentials.
-
All the muscle fibers conrolled by a single motor neuron
Motor unit
-
Tension depends on
# of motor units involved, freq at which motor units fire
-
Stimulation of a single muscle fiber cproduces a
Contraction-relaxation response.. (twitch)
-
A twich can last between
7-100 ms
-
A single contraction is a
Twitch
-
If the muscle is stimulated a second time after a twitch,
The new contraction will produce higher tansion than the previous; this is known as a treppe
-
Repeated contractions and no relaxation
Tetanus
-
What causes rigor mortis
Ca++ diffusing to sarcoplasm from extracellular fluid.
-
How long until rigor mortis stops
Until last enzymes break down proteins 15-24 hours later.
-
Slow conracting, low force sustained contraction
Muscle tone
-
Slow twitch muscle is red because
Of high myoglobin content
-
Slow twitch meat is good for
Aerobic/endurance
-
Slow twitch characteristics
Resistant to fatigue; energy from oxidative metab; high mitochondrial content; lots of blood vessels; lots of myoglobin (oxygen)
-
Fast twitch characteristics
Rapid movement of brief duration; fatigue quic; energy from glycolysis; low mitochon content; high glycogen; litle or no myoglobin; fewer blood vessels
-
3 ways to generate ATP for contraction
Immediate; glycolytic; oxidative
-
ATP and creatine phosphate . Short term
Intermediate
-
Metabolizes carbs to lactate and purivate. Less than minuts use
Glycolic
-
Metabolizes carbs completely to H20 and co2. fully activate after one minute. Slower to activate and replenish
Oxidative system
-
Act to anchor segments against substrate
Bristles
-
Skull, vertebral column, sternum, ribs
Axial skeleton
-
Pectoral and pelvic girdles, bones of arms, legs, hands and feet
Appendicular skeleton
-
Rigid calcium phosphate crystals
Bone
-
Bones are composed of
Osteocytes and laacunae
-
Extracellular matrix of bones mostly
Calcium phosphate
-
Ostoblasts build
New bone
-
Osteoclasts
Break down old bone
-
Whats good for bone health
Ca, Vitamin D, calcitonin, parathyroid hormone
-
Superficial skull bone, clavicle, scapula. Forms on top of collagen mat
Membrane bone (dermal bone)
-
Long bones; cartilage replacement bones
Endochondral bone
-
How do muscles attach
Skeletal element or tendon
-
Where they contact the bone, connective tissue extends to
Periosteum
|
|