Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
36 Cards in this Set
- Front
- Back
|
What kinds of movements does skeletal muscle provide?
What are they described as? |
Voluntary movements
Described as fibers Multinucleate syncytium |
|
|
What is the size and diameter of a skeletal muscle fiber?
|
10-100 micron diameter
1 mm-30 cm length |
|
|
What is the structural organization of Skeletal Muscle?
|
Epimysium
Perimysium Endomysium |
|
|
Where is the Epimysium located on a fiber?
|
CT surrrounds entire muscle
|
|
|
Where is the Perimysium located on a fiber?
|
CT separates muscle into fascicles
|
|
|
Where is the Endomysium located on a fiber?
|
CT separates fascicles into fibers
Highly vascularized |
|
|
What are the Satellite cells of the skeletal muscle fiber?
|
Located within basal lamina, can divide and contribute new muscle fiber in response to minor injury.
|
|
|
What is the connective tissue at the end of the muscle, that continues as a tendon (dense regular connective tissue)
|
(endomysium and perimysium)
|
|
|
What are Myofibrils?
|
Rod-shaped bundles of myofilaments
|
|
|
What is actin and myosin in the skeletal muscle fiber?
|
Actin - thin filament
Myosin - thick filament |
|
|
What is the Sarcomere?
|
Serially repeating segments on myofibrils
|
|
|
Name the A band, I Band, and Z Line
|
A band - dark
I band - light Z line - dark band bisecting I band |
|
|
What changes and what stays the same with respect to sliding filaments?
|
I bands decrease in width during contraction.
A band width does not change. |
|
|
What characterizes the Sarcoplasmic Reticulum?
|
- Smooth ER
- Depolarization from T tubules stimulates SR to release calcium |
|
|
What constitutes the triad?
|
T tubule + 2 terminal cisternae
|
|
|
Where are the T tubules aligned
|
At A-I junction
|
|
|
Depolarization of T-tubule membrane initiate release of _____ into the sarcoplasm.
|
calcium
|
|
|
What activates calcium-gated channels on sarcoplasmic reticulum?
|
Voltage sensor proteins in membrane of T-tubules
|
|
|
What makes up the Motor End Plate?
|
- Motor end plate: nerve axon expands - Synaptic vesicles -release acetylcholine into synaptic cleft
|
|
|
What is a motor unit?
|
A neuron and the muscle fibers it innervates
|
|
|
What happens with Myesthenia Gravis?
|
Antibodies block Ach receptors, causing muscle weakness
|
|
|
What are some characteristics of Cardiac Muscle?
|
- Striated muscle
-Myocardium of heart -Contracts rhythmically - May have limited capacity for mitosis. (no satellite cells) |
|
|
What provides cellular attachment and communication in cardiac muscle?
Junctional Complexes |
Intercalated Disks
|
|
|
What are some specific examples of Junctional Complexes?
|
Fascia adherens
Macula adherens Gap junctions |
|
|
How does the Cardiac muscle T-tubule system compare with the skeletal muscle system?
|
- Larger T-tubules.
- SR is poorly developed. - T-tubule associated with only one terminal cistern (dyad). - Dyads located at Z lines rather than A-I junctions. - Contain more and larger mitochondria |
|
|
Cardiac muscle cells have a _____ of contraction.
|
wave
|
|
|
What is the Propagation of a cardiac contraction?
|
SA node --> AV Node -->Purkinje fibers
|
|
|
How is Cardiac Muscle innervated?
|
- Contract spontaneously.
- Autonomic fibers terminate near the sinoatrial node to modify rate of contraction. - Stimulus for contraction delivered to cardiac cells via Purkinje fibers coming from the atrioventricular node |
|
|
What are Purkinje Fibers?
|
- Cardiac muscle cells modified for impulse conduction.
- Larger, pale-staining. - More gap junctions. - Contain more glycogen and fewer myofibrils |
|
|
What characterizes smooth muscle?
|
- Spindle-shaped (tapered ends)
- Centrally located nucleus - Thin actin filaments insert onto dense bodies |
|
|
How is contraction stimulated in Smooth Muscle?
|
- Contraction stimulated by endocytosis of calcium vesicles (and from SER)
- Calcium binds to calmodulin, which leads to myosin phosphorylation |
|
|
How do Smooth Muscle cells communicate with one another?
|
Communicate with neighboring fibers via gap junctions
|
|
|
What is a special function of Smooth muscle?
|
High regenerative capacity in response to injury (can undergo mitosis)
|
|
|
What are equivalent to Z-lines in smooth muscle?
|
Dense bodies (contain α–actinin)
|
|
|
Where are the dense bodies attached and what are they an attachment site to?
|
- Some are attached to plasma membrane
- Attachment site for actin filaments and intermediate filaments (desmin) |
|
|
What pulls on the dense bodies?
|
Actin (associated with myosin) pulls on dense bodies
“ruffling” of cell and formation of “corkscrew” nucleus |
