Muscle and nerve tissue - Olinger Flashcards
skeletal muscle attributes
striated strong quick voluntary can fatigue multinucleated (peripheral) very large cells (myotube)
cardiac muscle attributes
striated, strong, quick INvoluntary must NEVER fatigue uninucleated (central) branched cells (more efficient pumping) separated by intercalated discs
smooth muscle attributes
not striated, weaker slow and often rhythmic INvoluntary uninucleated (long, central) fusiform cell shape very different arrangement of contractile elements
cardiac muscle fibers
involuntary
spiral arrangment
insert into fibrous CARDIAC SKELETON (dense, regular CT)
where are gap junctions in cardiac muscle located ? whats their purpose?
- longitudinal portion of intercalated discs
- small ion channels pumping many ions throuh at once leading to fast propulsion of signal and synchronous muscle contraction [need nerves to accomplish this in ventricles coz they much thicker than atria]
smooth muscle microstructure
- slow/ involuntary
- lining the walls of hollow organs
controls how wide or narrow their lumens become - short, spindle-shaped cells (“fibers”)
- central “cigar-shaped” nucleus
a transverse cut of through smooth muscle may show
multiple mitochondria
caveolae (at the edge of cell)
caveolae?
“little caves”
- under plasma membranes of 2 adjacent smooth muscle cells
- act as sarcoplasmic reticulum!
contractile elements in smooth muscle
- mostly under cell membrane, tighten to contract cell itself (like a net around a blob)
- contain contractile fibers (actin and myosin)
- and supporting fibers containing intermediate filaments
another name for cell body of neuron
perikaryon
whats visible in the cell body of a neuron using light microscopy? why is it important?
nissl substance!
allows us to see where axon is! - wherever you don’thave nissl substance is where axon hillock is
additional non neuronal cells in the nervous system are called
glia
axon terminating on muscle tissue called
motor end plate
gaps in between myelinated axons
Nodes of Ranvier
type of golgi
Golgi Type I - has long singular axon (few dendrites)
Golgi Type II - short to no axon (giant dendritic tree)
[Long singular axon like drawing a 1 !!]
