Ch.10 Muscles Flashcards
What are the muscle types
Skeletal, cardiac, smooth
Skeletal muscles
voluntary, striated, multinucleated and mainly attached to bones except for face
Muscle fiber
Skeletal muscle cell
Belly
Body of a muscle bundle
Tendons
connect belly to bone
Aponeurosis
sheet like tendon
organizational levels of skeletal muscle
Fascicle
Muscle fibers
Myofibrils
Thick and thin filaments
Fascia
Connective tissue that surrounds organs and muscles
epimysium
fibrous elastic tissue surrounding a muscle
Fascicle
Strands that contains the muscle fibers
Perimysium
connective tissue that surrounds Muscle Fibers
Endomysium
connective tissue that surrounds the muscle fibers
Sarcolemma
plasma membrane of a muscle fiber, sends T tubules into the cytosol
Sarcoplasmic reticulum
specialized endoplasmic reticulum that contain calcium and from triads with T tubules
Myoglobin
protein present in myocells, it binds to oxygen
T-tubules
extensions of the cell membrane that penetrate into the centre of skeletal and cardiac muscle cells
Contractile proteins
generate force during contraction. Like myosin and and actin
Regulatory proteins
helps switch the contraction process on and off. Like tropomyosin and troponin
Structural proteins
keep the thick and thin filaments together and give elasticity. Like titin, myomesin, nebulin, and dystrophin
What are myofibrils made of?
Thick filaments (myosin) and thin filaments (actin)
Thin filaments
composed of actin, troponin, and tropomyosin
active site
socket of the G-actin where myosin bonds into
Tropomyosin
binds to the active site in a state of relaxation
troponin
binds to calcium to move away the tropomyosin from the active site
Myosin
Have a tail and head, they attach to the active site when the troponin binds to calcium, moving away the tropomyosin
Sarcomere
arrangement of thin and thick filaments
Zband
boundaries of the sarcomere, has titin for elasticity and connects it to the thick thick filament
M line
midline of a myofibril and holds the contract proteins in place, it is formed by myomesin proteins
A band
is where thick and thin filaments overlap
H zone
here is no thin filaments and the heads of the myosin are missing
I band
where thick and thin filaments do not overlap
motor unit
Somatic motor neuron + muscle fibers
Neuromuscular junction
where the axon terminal/ synaptic knob meets the motor endplate of the sarcolemma
nuero transmitters of the axon terminal
acetylcholine
motor end plate
part of the sarcolemma that meets the axon terminal/synaptic knob
Describe how atp and movement is generated
Atp is generated when acetylcholine is released from the synaptic knob into the ach receptors in the motor end plate and that allows sodium cations to go through the sarcolemma. This makes the cell have a positive polarization (depolarization). Then calcium bonds to troponin that moves tropomyosin away from actin, and that allows the active site to bond with myosin can now attach to it through a cross bridge and through a power stroke slide the thin filament over it. detaches when new ATP goes to the head of the myosin
Myasthenia gravis
autoimmune disease where antibodies destroy the ach receptors, causing muscle weakness
Rigor mortis
movement after death because calcium is still in the body
Muscle Hypertrophy
increase of actin and myosin filaments
