Smooth Muscle (Non-striated, Involuntary)
Slower but able to sustain contraction longer than striated muscle?
Calmodulin
What is the binding protein that is used by smooth muscle during contraction?
Calmodulin
maintains constant state of weak, partial contraction called tonus (does not relax completely under normal conditions)?
Tonic
Has one nerve to large numbers of fibers.Fibers respond to hormones, and stretch as well as nerve?
Unitary (Visceral) smooth muscle
What type of smooth muscle is the most; occurs in sheets and walls of hollow tubes & organs (ie. GI tract, blood vessels, uterus, ureters, etc.)?
Unitary (Visceral) smooth muscle
What is the common shape of smooth muscle cells?
spindle shape, taper at the ends
What is the structure that releases neurotransmitters in a unitary smooth muscle cell?
varicosities
During contractions, what is being pulled on of neighboring smooth muscle cells?
basil lamina
What enters into the caveolae of the smooth muscle cells?
Calcium
What is the ratio of actin/ myosin in smooth muscles?
12/1
What is the ANS regulation of smooth muscle contraction?
Ach and Ne
What are dense bodies made up of?
Alpha-actinin
What type of muscle has no capacity for regeneration, replaced with connective tissue scar?
Cardiac muscle
What are the little dips on the outside membrane of smooth muscle cells?
Caveolae
What do thin/thick filaments attach to and shorten during contraction?
Dense bodies
What are the two types of smooth muscle?
Multi-unit and Unitary (Visceral)
Smooth muscle type that is rare, needs innervation to function properly and has a motor unit (nerve/muscle ratio) approaching = 1.0?
Multi-unit smooth muscle
Does the sarcoplasmic reticulum (SER) of smooth muscle store a lot of calcium like skeletal muscle?
No, does not store as much
What is an example of a multi-unit smooth muscle?
Pupillary muscles of eye
contracts periodically in waves ie. peristalsis?
Rhythmic
What are the two types of unitary smooth muscle?
Rhythmic and tonic
What kind of tissue doesn't conduct electricity?
Scar tissue
What type of muscle has a poor capacity to regenerate new muscle. Comes from satellite cells that can act as myoblasts. Extremely limited?
Skeletal muscle
What type of muscle regenerates well, has great potential for renewal and repair?
Smooth muscle
occurs singly or in groups (sheets and bundles) with ct. (elastic, & retic) surrounding cells?
Smooth muscle cells
What does the structure of smooth muscle lack? Instead, what do they have?
T-system and intercalated discs Subsacrolemmal caveolae
Does smooth muscle cell use Ca++ for contraction like skeletal muscle?
Yes
Does smooth muscle have actin and myosin? Does smooth muscle have sarcomeres?
Yes No
What are dense bodies similar to?
Z-lines
When a smooth muscle contracts, what kind of nucleus do we have?
a pleated, corkscrew nucleus
What kind of cytoplasm is within a smooth muscle cell? What kind of nucleus?
eosinophilic cytoplasm basophilic, ovoid nucleus
Actin and myosin filaments are in what kind of bundles in smooth muscles?
longitudinal and parallel bands