Chapter 10 objectives Flashcards
describe skeletal muscle tissue
long parallel, multinucleated, strands; striated
describe cardiac muscle
short, wide, branching, striated, intercalated disks, single to two nuclei
describe smooth muscle
thin smooth muscle cells, have single nucleus, usually have gap junctions
what are the 5 properties of muscle cells
contractility, excitability, conductivity, extensibility, elasticity
what is contractility
ability to contract
what is excitability
ability to respond to stimulus
what is conductivity
ability to conduct electrical changes across entire plasma membrane
what is extensibility
ability to stretch without rupturing
what is elasticity
ability to return to original length after stretching
define myocyte
a muscle cell
define sarcoplasm
a myocytes cytoplasm
define sarcolemma
a myocytes plasma membrane
define sarcoplasmic reticulum
modified endoplasmic reticulum for a muscle cell
define myofibril
the big sausage pieces in a muscle cell; allow for contraction; are 50%-80% of muscle cell
define transverse tubutles
a tunnel-like tube that surrounds the myofibrils
define Terminal cisternae
enlarged sections of SR;
flank each T-tubule
define triad
two terminal cisternae with a T-tubule
what are myofibrils made of?
myofilaments
what are the different kinds of proteins in a myofilament
contractile, regulatory, and structural proteins
define contractile protein
generates tension
define regulatory protein
dictates when a fiber may contract
define structural protein
maintains proper myofilament alignment and fiber stability
what are three types of myofilaments
thick, thins, elastic filaments
what is a myosin head
the small buds on a thick filament that attaches to the thin filament
what is tropomyosin
the long rope wrapping around the thin filament’s actin; covers active site
what is troponin
the small bundle of protein that holds the tropomyosin in place; dictates when contraction happens
how do striations relate to the muscle contraction model
striations are visible because of how the thick, thin, and elastic filaments overlap
define i band
the are where there are only thin filaments; light band
define A band
where the thick and thin filaments overlap; the dark band
define H zone
the middle of the A band where only thick filaments are
define Z disk
the middle of the I band that attaches the thin and the elastic filaments to each other
define the M line
the middle line that holds the thick filaments in place
what are the two glycolitic energy sources
glycolysis and anaerobic catabolism
describe glycolysis
provides energy for muscle contraction once immediate sources of energy are depleted; can supply ATP for
30–40 seconds of sustained contraction
what is a skeletal muscle fiber type I
slow; small diameter, has less power for longer
what is a skeletal muscle fiber type II
fast; large diameter, has more power for shorter time
