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What is a myogram?
A graph which represents the physical movement made by the skeletal muscle when stimulated
If a cell is stimulated at any level below the threshold level and the cell does not respond what is the stimulus said to be?
subthreshold stimulus or subliminal stimulus
If the cell is stimulated at any level equal to or above the threshold level and the cell contracts (with all contractile elements responding to their best ability), what is the stimulus said to be?
threshold stimulus or liminal stimulus
What principle do skeletal muscle cells respond according t?
all-or-none principal...the cell contracts to its fullest extent or id does not contract at all
Each muscle cell has an all or none principle, but a different threshold level
Which period of simple twitch has the shortest elapsed time?
The latent period-which begins at stimulation and lasts about 2ms.
The muscle fiber does not produce tension because the contraction cycle has yet to begin.
Which period of the simple twitch has the longest elapsed time?
The relaxation phase-which lasts about 25ms.
During the period Ca2+ levels are falling, active sites are being covered by tropomyosin, and the number of active cross bridges is declining as they detach.
The contraction phase lasts roughly 15ms, what is occuring during this time?
- 1.Tension rises to a peak.
- 2. (As the tension rises) calcium ions are binding to troponin
- 3.active sites on thin filaments are being exposed
- 4.cross-bridge interactions are occuring
What does Graded Response mean?
An increase in response that then flattens out
What does Treppe mean?
After a muscle contracts once, it will do it easier and better the next time
most skeletal muscles don't undergo treppe
What does a Length Tension Relationship explain?
More work is needed because its being lifted further
more lift = more work
What does it mean to be Antagonistic Pairs?
One side flexes, the other extends
in the body the muscle is usually in a stretched position
The muscle does not get to relax totally
the muscle is stimulated so fast that is doesn't have a chance to relax
Increased contraction from using the muscle
fatigue in the muscle
- using up Ca2+ & ATP
- build up of lactic acid = pain
- Z line
- M line
- A band
- I band
- Zone Overlap
- H Zone
- Thick Myolfilaments myosin
- Thin Myofilaments actin
- Sarcoplasmic Reticulum
- muscle cell
- neuromuscular junction
what do these muscles do?
- orbicularis oris
- zygomaticus major
- orbicularis oculi
- occipitofrontalis (frontal portion)
- occipitaofrontalis (occipital portion)
- buccinator - compresses cheeks
- mentalis - elevates and protruedes lower lip
- orbicularis oris - compresses, purses lips
- zygomaticus major - retracts and elevates corner of mouth
- orbicular oculi - closes eye
- occipitofrontalis (frontal portion) - raises eyebrows, wrinkles forehead
- occipitofrontalis (occipital portion) - tenses and retracts scalp
- platysma - tenses skin of neck, depresses mandible