what are the three types of muscle tissue?
- skeletal muscle tissue
- cardiac muscle tissue
- smooth muscle tissue
describe the traits and function of skeletal muscle tissue
- cells are long, clindrical, striated (parallel), and multi-nucleate
- combined with connective tissues and neural tissue in skeletal muscles
- moves or stabilizes the position of the skeleton; guards entrances and exits to the digestive, respiratory tracts; generates heat; protects internal organs
function and traits of cardiac muscle tissue
- cells are short, branched, and striated, usually with a single nucleus, celler are interconnected by intercalated discs
- located in the heart
- circulates blood, maintains blood (hydrostatic) pressure
smooth muscle tissue characteristics
- cells are short, spindleoshaped, and nonstriated with single nucleus
- all of blood vessels and digestive, respiratory organs
- moves food, urine, and reproductive tract secretions, regulates diameter of blood vessels
what are the five skeletal muscle functions
- produce movement of the skeleton
- maintain body position and posture
- support soft tissues
- guard entrances and exits
- maintain body temperature
what is the organization of skeletal muscle tissue called?
organs that contains connective tissue, blood vessels, nerves, skeletal muscle tissue
what is the purpose of extensive network of blood vessels in skeletal muscle provide?
nutrients and oxygen; skeletal muscles have high metabolic needs
is skeletal muscle tissue under voluntary or involuntray control?
voluntary; must be stimulated by central nervous system
how are muscle fibers (myocyte) formed?
from specialized stem cells called myoblasts into one long multinucleated muscle fiber
what does the graph of muscle fiber tell us about its development?
you were born wil all your muscle cells
what are the implications of the decline in myoblast proliferation?
less able to repiar muscle cells
how do tendons form?
where the ends of all three layers of connective tissue come togethe and attach the muscle to a bone
what is scarcolemma
muscle fiber plasma membrane has opneing acorss the surface that lead to a network of t-tubles (which allow signals to be effectively communicated to all)
what are myofribrils?
bundles of thick and think myofilaments (contractile proteins)
what does the sarcoplsmic reticulum contain?
high level of calcium ions
how are the Z and M line related to thick and thin filaments
M line has the thick filaments while the Z line had the thin filaments
what is the relationship between actin and myosin?
actin is a thin twisted protein, with specific active sites for myosin binding
what is tropomyosin?
protein that are held in position by troponin (green line) in the active sites
what are the A, I and H bands for?
- A is all the thick filaments including thin
- I is just the thin filaments
- H is only thick
which of the bands or zones would not change as muscle is contracted?
what is nebulin
- an actin binding protein localized to the thin filament of the sarcomeres in skeletal muscle
- acts as a thin filament "ruler" and regulates thin filament length during sarcomere assembly
- stabilize actin, keep it straight so myosin can bind
what is titin
giant protein that functions as a molecular spring which is responsible for the passive elasticity of muscle