Muscle Unit Flashcards
Types of Muscle Cells
- Skeletal (voluntary)
- Smooth
- Cardiac
Function of Muscles
- Produce movement
- Maintain posture
- Support soft tissues
- Protection
- Maintain body temperature
- Store nutrient reserves
Skeletal
Multinucleated with long large fibers
Cardiac
Branch shaped cells with intercalated disks (doesn’t need a nerve to activate)
What do muscle fascicles make up?
Skeletal Muscle
What do muscle fibers make up?
Muscle fascicle
What do myocytes make up?
muscle fibers
What do myofibrils make up?
myocytes
What makes up the myofibrils?
sacromers
What is the thick filament
Myosin
What holds myosin in place?
Titin
What is the thin filament? What does it do?
Actin ; it pulls myosin together
Tropmyosin
prevent the muscle from contracting at the wrong time
Troponin
promotes muscle contraction
A band
spans length of myosin fiber
I band
contains only actin fibers ; no myosin
H band
contains myosin fibers ; no actin
Z line
acts as anchor for actin fibers
M line
middle line (vertical medial line) to hold myosin in place
How does fiber shortening happen?
As sarcomeres shorten, muscle pulls together, producing tension
Which bands get smaller during muscle contraction?
I band
H band