Exam 1 Study Guide Chamberlain
College.
ependymal cells
✔✔- line internal cavities of the brain
- secrete & circulate CSF
microglia
✔✔- macrophages
- develop from WBC (monocytes) & become
concentrated in areas of damage
astrocytes
✔✔- most abundant in CNS
- create supportive framework
- form blood-brain barrier
graded potential
✔✔1. stim does not reach threshold level
2. stim causes local change in membrane potential (ie:
-70 to -60mv)
3. it dies down over short distance
4. can be summated
5. does not obey all or non law
action potential
✔✔1. stim reaches threshold level therefore causes
AP
2. stim causes depolarization to threshold level
3. it is propagated
4. cannot be summated
5. obeys all or none law
,voltage-gated channels
✔✔controlled by membrane potential
ligand-gated channels
✔✔controlled by binding of a ligand to a membrane
protein (either on outside or inside)
mechanical-gated channels
✔✔controlled by mechanical force on cell
do skeletal muscles always pull
✔✔yes
H pattern
✔✔physical exam to test extrinsic eye muscles
1st step of contraction cycle
✔✔myosin head hydrolyzes ATP & become
energized & oriented
2nd step of contraction cycle
✔✔myosin head binds to actin, forming a cross-
bridge
3rd step of contraction cycle
✔✔myosin head pivots, pulling the thin filament past
the thick filament toward center of sarcomere (power
stroke)
4th step of contraction cycle
✔✔as myosin head binds ATP, cross-bridge detaches
, from actin
how are skeletal muscles names
✔✔direction of fascicles, size, shape, action, # of
origins, location of muscle, sites of origins & insertion
of the muscles
skeletal muscle
✔✔- long, thin, cylindrical in shape
- multinucleated
- attached to bone & skin
- voluntary
- striated
cardiac muscle
✔✔- short, fat, branched
- uninucleated
- in heart
- attached to intercalated discs
- involuntary
- striated
smooth muscle
✔✔- in hollow organs
- ininucleated
- involuntary
- lack striations
excitability
✔✔responsiveness to chemical signals, stretch, and
electrical changes across the plasma membrane
conductivity