Last Day Notes Flashcards
What forms the resting potential in muscles and nerves?
Sodium potassium exchanged
Na - K pump
Which Na or k out?
3 Na out
2 K in!
Why resting potential is mainly formed by K?
It has open K channels that are permeable while NA channels can’t leave the cell!
What counter the K concentration?
Negatively protein anions
- chloride anions
Why does Na plays a minor role in resting potential ?
Very little in the cell (0.9)
No Na permeability through membrane
To measure resting potential of an ion you need
Nernest equation in which it needs
Ideal gas constant
Faraday’s constant
Temperature in kelvin!
Properties of action potentials?
Uniform shapes
Made my short ion movements across membranes
Translate information by frequency modulation
Hyper polarization = refractory period is when?
Slow activation of the gate when +35 to -90 Mv
Conductance of Na is much more higher than
K!
Steps in excitation-coupling mechanism?
Ap spread through sarcoplasmic reteculim and T rubles causing Ca release by DHPRs = voltage gated channels in sarcolemma that opens Ca release channels called ryanodine receptors!
A voltage sensor of Ca in T tubles is
DHPRs ! Which is an L type
A motor unit is
A group of fibers innervated by a single lower motor neuron
Type 1 muscles are used in
Greater force shorter period activity like jumping, running
Characteristic of fast fibers?
Glycolytic enzyme Few mitochondria Less blood supply Great in strength Extensive sarcoplasmic reticulum
Function of titin
Connects actin and myofibrils together
A band is where
Actin and myosin overlap
I band is
Only actin!
H zone ?
Only myosin!
Z line is in the center of
I bands and it’s the start of a sarcomere
What’s constant and what shortens in a muscle contraction?
A band constant
I , H bands and sarcomeres shorten!
Load relation with velocity?
No load = rapid muscle contraction!
Heavier load= slower contraction
Clinical application of ncv
Detect neuropathy (demyelination )
Progression of injure have low ncv
Determine whether weaknes is due to muscle or nerve!
Joint pain must be distinguished from?
Other soft tissue or articulating bone pathologies
The joint pain is unlikely due to arthritis if?
The range of motion is preserved but their is tenderness on paplation!
