Muscle Tissue

smooth muscle can contract over a wider range of resting lengths than skeletal muscle can. Why?

actin and myosin filament arrangement is less organized in smooth muscle

fast fibers

anaerobic glycolysis

a band

anywhere there is thick filaments

speed and load

are inversely related

fascicle

bundle of fibers which are never activated all at one time

the a band comprises which of the following subunits

m line, h band, and zone of overlap

why are cardiac and smooth muscle contractions more affected by changes in extracellular Ca +2 than skeletal

most of the calcium for contractions comes from the extrecellular fluid

a motor unit is/are_____. You would need a small motor unit to control movement of the fingers______.

muscle fibers controlled by a single motor neuron; because you need precise control

isometric contraction

muscle remains the same length

concentric contraction

muscle shortening

perimysium

surrounds muscle fiber bundles(fascicles)

big motor unit

used for walking

how would a drug that blocks ACH from the axon terminal affect muscle contraction

contraction would be prevented

what would happen to muscles if a pesticide that inhibits ACHase were present at the motor end plate

contraction would be unable to happen

z lines have nothing to do with myosin

do not line up

myoblasts

fuse to form individual multinucleate skeletal muscle fibers...each nucleus in a skeletal muscle fiber reflects the contribution of a single myoblast. The unfused ones in adults become myosatellite cells to repair tissues

what feature of cardiac muscle tissue allow the heart to act as functional syncytium(cells working together)

gap junctions

mechanism primarily responsible for ATP production at peak levels

glycolysis in the cytoplasm

why is skeletal muscle striated

z lines and myosin filaments align within a muscle fiber

in what ways does the appearance of a sarcomere change during contraction of a skeletal muscle fiber

z lines move closer together; I bands and A bands both get smaller

what statements are false in regard to the contraction of skeletal muscle

a given muscle always uses the same number of motor units no matter what the muscle is trying to accomplish

with excitation-contraction coupling

both the nervous and muscular system! motor neuron releases ACh which allows an electrical event to be transferred to the muscular system

actinin

protein in z line

basic functional unit of the muscle

sarcomeres

myofibrils are organized into repeating sub units called

sarcomeres(the basic functional unit)

______ predominate in the large leg muscles of someone who excels at endurance activities, such as cycling. This is because _______

slow fibers; they have extensive capillary networks and much myoglobin

describe the characteristics of slow muscle fibers

small diameter, rich in myoglobin(makes them red and stores oxygen), and very vascular(brings in extra glucose as you use it up)

two cardiologists talk about functional characteristics of cardiac muscle tissue

special gap junctions, intrinsic conduction system allows contraction without neural stimulation

describe a neuromuscular junction (structure)

special intercellular connection between axon branches and a skeletal muscle fiber

why would a sprinter has muscle fatigue sooner than a marathon runner

sprinting involves anaerobic endurance

what anchors thin filaments of smooth muscle

dense bodies(desmin)

only layer with myosatellite cells

endomysium

does not have capillaries and nerves

epimysium because you need the connection with muscle fibers

epimysium

exterior collagen layer, connected to deep fascia, separates muscle from surrounding tissue ENTIRE MUSCLE

why does a muscle that has been overstretched produce less tension

few cross bridges form, causing weak contraction

what would you expect to happen to a resting skeletal muscle if the sarcolemma suddenly became very permeable to CA+2

increased strength of contraction and decreased ability to relax

which activity is more likely to create an oxygen debt: swimming laps or lifting weights

lifting weights

which of the following is not a major function of skeletal muscle

lining hollow organs

responsible for skeletal muscle contraction

myofibrils

z line anchors thin filaments in cardiac and skeletal muscle

yes

where would you expect the greatest concentrations of Ca+2 in resting

cisternae

severing the tendon attached to a muscle affect the muscle's ability to move a body part

no movement is possible without the muscle to bone connection

nonvascular fibers

no such thing

epimysium, perimysium, and endomysium are interrelated because

they are connective tissues and blend with tendons to provide firm attachments to bone