Lecture 10- Muscle Flashcards
Skeletal muscle
connected to bones, voluntary control, striated, and multi-nucleated with nuclei often found in the periphery of the cells
Cardiac muscle
involuntary control, striated, centrally located mono-nucleated, branching, lots of mitochondria
Smooth muscle
in hollow organs, involuntary control, spindle shaped, non-striated, and mono-nucleated
Muscle tissues develops from what?
myoblasts. It is the fusion of mononucleated embryonic myoblasts
Purpose of satellite cells in skeletal muscle
help with regeneration.
Skeletal growth plasticity
atrophy and hypertrophy
Plasticity
ability to change in size but not number
Sacromere
the basic unit of a striated muscle tissue. Between two Z lines
When calcium is present in a muscle
Myosin is able to bind to actin when the binding sites on actin are exposed because of calcium binding
Z line
Where actin molecules (think filaments) are anchored. Found in the I band.
I band
zone of thin filaments only (actin)
A band
contains the entire length of a single thick filament
H zone
Within the A band. Only thick filaments (myosin)
M line
within the H one. Where the myosin is anchored.
3 CT layers of skeletal muscle
Epimysium, perimysium, and endomysium
Dystrophin
establishes contact with actin, transmembrane glycoproteins, and lamins of the extracellular matrix.
Titins
act as springs to help reshape after muscles are stretched.
T tubules
invaginations of the sarcolemma.
Triad
at the I-A junction. When cisterane (SR) sandwiches the T tubules.
Importance of triad
nerve induced muscle impulse causes calcium from SR into the sarcoplasm causing contraction of the myofilaments.
Number of actin to myosin in the A band
6 actin per myosin.
Tropomyosin
filamentous type of protein
Troponin’s 3 subunits
TnT: binds tropomyosin
TnC: binds calcium and causes a conformational change
TnI: inhibits the binding of all the proteins around
ATP’s role in muscle contraction
ATP binds to troponin but only is productive when calcium is present. ATPase hydrolyzes allowing for the binding of myosin and actin.
T or F: a neuron may innervate more than one fiber
True
Neurotransmitter found in neuromusclar junction and enzyme to break down
acetylcholine and cholinesterase
What causes relaxation of muscle?
ATP attached to the myosin head.
White muscle fibers
Type II, fast muscle fibers (ATP pool, phosphocreatine, glycogen). Little myoglobin, glycolytic respiration, abundant glycogen
Red muscle fibers
Type I, slow muscle fibers.(oxidative phosphorylation). Lots of myoglobin, mitochondria, small diameter
Propioceptors
relaying info to the brain to keep it informed.
Muscle spindle
relaying info to the CNS about the condition of the muscle via pseudounipolar neurons. contain intrafusal fivers. (example of golgi tendon organ)
Intrafusal vs extrafusal fibers
Intrafusal: sensory feedback (nuclear chain and bag fibers)
Extrafusal: majority, provides force (Type I&II, intermediate fibers)
Can cardiac muscle regrow?
No.
Layer of the heart that cardiac muscle is seen in?
Myocardium
Intercalated disks
disks seen between cardiac muscle cells
Natriuretic peptides
ANP and BNP. decreases blood pressure
3 ways BP is decreased from natriuretic peptides
promote kidney diuresis and natriuresis; cause vasodilation; inhibit central sympathetic outflow
Dense bodies in smooth muscle
distributed along the sarcolemma and are the actin and intermediate filament anchoring sites
Caveolae
tiny caves on smooth muscle cell surface that may be involved in sequestering calcium
Multi-unit smooth muscle
richly innervated for rapid, precise, graded contractions
Visceral smooth muscle
poorly innervated with slow contractions; excitations are transmitted from cell to cell by numerous gap junctions
Varicosities in muscles
accumulate neurotransmitters and will release the signal
Dense bodies that are phosphorylated
in the active state
Diad in cardiac muscle
Found at the Z line of cardiac muscle. No triads are present in cardiac muscles.
