What are three types of muscle tissue types?
- Skeletal
- Cardiac
- Smooth
What is a Muscle Fiber?
- An individual muscle fiber is a bundle of myofibrils
What are 6 components of muscle structure?
- A-bands
- Sarcomere
- z-line
- I-band
- H-zone
- M-line
What is an A-band?
- Anisotrophic band
- an-without, iso-same, trophic-property
- appearance is dependent on its orientation
What is a Sarcomere?
- A contractile unit of Muscle
- contains arranged myofibrils
- thin
- thick
What is a Z-line?
The disk/line inbetween the I bands. Appears as a seires of dark lines.
What is an I-band?
- Zone of thin filaments that is not superimposed by thick filaments.
- Looks the same in every direction
What is the H-zone?
- “brighter”
- lighter appearance under microscope
- sone of thick filaments , not superimposed by thin filaments.
What are characteristics of Cardiac Muscle, where is it found?
- Branched
- has intercalated fibers
- striated
- involuntary
- Found in most of wall of the heart
What are characteristics of skeletal muscle, where is it found?
- striated
- voluntary
- mostly attached to bones
What are characteristic of smooth muscle, where is it found?
- nonstriated
- involuntary
- located in viscera
Name 6 types of fascicle arrangement of muscle.
- Unipennate
- Bipennate
- Multipennate
- Spiral
- Triangular
- Circular
List Muscle structure from innermost to outermost.
- Muscle cell/ Myofibril
- muscle fiber
- bundle of myofibril
- Endomysium
- fascicle
- bundle of muscle fiber
- paramysium
- skeletal muscle
- bundle of fascicles
- Epimysium
- fascia
- tendon
- bone
What are thin filaments of myofibril?
- Composed of Actin, tropomyosin, and troponin.
- have globular protein active sites that bind myosin heads
What are thick filaments of myofibril?
Consist of myosin tails and heads
What are the role of tropomyosin and troponin? Where are they found?
- FOund in thin filament
- Regulatory proteins.
How does Muscle Contraction happen?
Uses Tropomyosin and troponin, regulatory proteins.
Troponin binds to Ca and causes tropomyosin to change shape and expose the actin binding sites. thick filament head ataches at actin binding site and a “power stroke (row)” happens.
What are Type 1 muscle fibers?
- presence of oxygen binding protein, myoglobin.
- appear red
- suited for endurance
- small diameter
- slow to fatigue because they use oxidative metabolism to generate ATP
- “slow twitch muscle”
What are Type 2 Muscle Fibers?
- Absence of Myoglobin and reliance on glycolytic enzymes.
- Efficient for short bursts of speed and power
- Use both oxidative metabolism and anaeobic metabolism
- “fast twitch”
- quick to fatigue
