Histo Lab: Muscle and Nervous Tissue Flashcards
smooth muscle contains what two filaments?
Contains actin and myosin filaments- but they are not organized in sarcomeres
is smooth muscle organized in a sarcomere?
no!
smooth muscle contains dense bodies which are similar to what in striated muscle sarcomere?
dense bodies are similar to Z-DISCS
smooth muscle cells do not contain troponin but do contain____?
tropomyosin (binds to and stabilizes actin filaments)
calmodulin
binds to Ca2+ in cytosol
activates myosin light-chain kinase
*smooth muscle
myosin light-chain kinase is responsible for…
responsible for the Ca2+ sensitivity of the contractile fibers in smooth muscle
Do Ca2+ ions that initiate contraction derive from outside the cell OR from the sarcoplasmic reticulum?
outside the cell
steps in smooth muscle contraction
myosin light chain kinase: control of smooth muscle contraction occurs principally on the ____
thick filament
smooth muscle contraction occurs via _____
dense bodies
during contraction of smooth muscle, filaments pull on ___ causing shortening of fiber
dense bodies
cardiac muscle contracts to…
reduce the volume of heart chambers
propel the blood
smooth muscle contracts to…
-propel food along the gut tube
-reduce the diameter of blood vessels and airways
-propel urine from the kidneys to the bladder
-give you goosebumps
skeletal muscle contracts to move…
skeleton
larynx and tongue for speech
facial features for nonverbal communication
upper esophagus for swallowing
thoracic diaphragm for breathing
most muscle tissues are derived from the____
mesoderm
comparison of muscle tissues appearance
skeletal muscle characteristics
striated
very large cells
multinucleated
peripheral nuclei
smooth muscle characteristics:
not striated
spindle-shaped cells
smallest cells
single, central nucleus
cardiac muscle characteristics:
typically branched
linked together via intercalated disks
1-2 centrally located nuclei
size of muscle cells ranked
skeletal > cardiac > smooth
compare cardiac and smooth muscle
skeletal muscle epimysium
- a dense connective tissue sheath that surrounds the entire muscle
- lots of collagen I
- thickens and merges with the tendons at the ends of the muscle
skeletal muscle perimysium
- skeletal muscle is divided into fascicles (bundles of fibers)
- comprised of dense connective tissue, but with collagen III > collagen I
skeletal muscle endomysium
- surrounds each myofiber
- myofibrils appear as small pink dots filling the entire muscle cell
- occcasional connective tissue nuclei and capillaries visible
skeletal muscle fiber (myofiber, muscle cell)
skeletal muscle fascicle
skeletal muscle is divided into fascicles (bundles of fibers)
myofibrils are composed of ___ , ___ , & ___
Myofibrils are composed of actin (thin filaments), myosin (thick filaments), and support proteins
sarcomere organization
identify
nucleus myofiber
myofiber
endomysium
perimysium
cardiac muscle intercalated disks
- specialized junctions that are characteristic of cardiac muscle
—– consist of adherens junctions, desmosomes and gap junctions
—– mutations in components of those junctions result in heart arrhythmias - visible as dark lines running perpendicular to the cell’s long axis, marking where two cells join end-to-end
- might also run parallel when connecting branches
cardiac muscle myocytes
branched
striations are sometimes seen
smooth muscle enteric ganglion (plexus)
middle “?”
smooth muscle neuronal cell bodies
?
golgi stain
precipitation of silver salts in cells
Randomly fills some cells entirely, turning them black so they can be seen clearly against the background of other cells in which no precipitation occurs
nissl stain
- basic stain for DNA in nuclei and to RNA in ribosomes (RER)
- useful for seeing shapes of neuronal cell bodies (abundant RER)
- strongest stain close to cell body
- in some cases, stains dendrites and the initial segment of axon
glial cells
comprise most cell bodies in the white matter, as well as many of the small cell bodies in the gray matter (oligodendrocytes and astrocytes)
what does white/grey matter look like under microscope?
what matter is left “?” and right “?”
Left “?”: grey matter
Right “?”: white matter
Purkinje neuronss
lie in the middle layer, with theor large, complex dendritic fans extending through the upper molecular layer to the surface of the cerebellum
what doe astrocytes look like?
