Lab 7: PowerLab 1

the ____ converts a signal of interest into analog voltage

transducer

the voltage carried is amplified and filtered

signal conditioning

signal conditioning can also include this process to remove an unwanted, steady offset

zeroing

number of occurrences of a repeating event per unit time

Frequency

the height of the wave from baseline to crest

amplitude

is the shape and form of a signal

waveform

is the length from the crest of one peak to the crest of the next peak

wavelength

three types of muscle tissues

cardiac, skeletal, smooth

common prefixes for muscle related

myo, mys, sacro

what kind of cells make up 40% of the cell mass

skeletal muscle cells

skeletal muscle function

work locomotion and support of the body

muscle fibers

muscle cells

muscle fibers are organized in bundles caled

fascicles

muscles used the chemical energy stored in ____ to produce mechanical energy

ATP

a type of neuron damage due to stroke

upper motor neuron lesions

skeletal muscle control is

voluntary

skeletal muscle is ____, but ____ rapidly

powerful; tires

all muscle cell membranes have an electric charged differential which can be changed upon stimulation to ultimately produce an intracellular muscle response

excitability

muscle cells will shorten when stimulated

contractility

all muscle cells can be stretched, sometimes more than their resting length

extensibility

muscle cells that can recoil to their original length after being stretched are called

elasticity

muscles also have

nerves, blood vessels, and connective tissues

muscle tissue that connects to bone

tendons

tendons help the muscle move the ___

bone

the bone that moves is called the

insertion

the bone that doesnt move

origin

if the periosteum or perimysium is fused to the muscle’s epimysium this is called

direct attachments

a tendon, or aponeurosis for example is a type of

indirect attachment

muscles usually work antagonistically meaning

when one muscle contracts and shortens, the other relaxes and elongates

skeletal cells are

multinucleated

plasma membrane of the cell is called

sarcolemma

cytoplasm of the cell

sarcoplasm

part of the muscle cell that stores oxygen

myoglobin

granules of glycogen that can be broken down to supply ATP

glycosomes

repeating structures of sarcomeres are called

myofibrils

are the smallest atomic “contractile” units of skeletal muscle fibers

sarcomeres

the reason muscle cells are striated

dark A bands and light I bands

each a band has a middle region that is slightly lighter. this is called the

h band

the i band has a dark midline region termed the

z line

the sarcomere runs from the

z line to z line

another name for thick filament

myosin

myosin proteins contain

protruding globular heads

the m band connects

thick filaments in the middle of the sarcomere

the myosin bands only have globular heads where they overlap with

actin or thin filaments

when a muscle contracts, myosin heads link the thin and thick filaments together, which are called

cross bridges

cross bridges swivel as motors to do what to the sarcomere?

shortens

each thick filament can have up to how many myosin molecules

300

tropomyosin

blocks actin’s myosin-binding

troponin

composed of 3 globular polypeptides, each having a different function. One binds to tropomyosin, one binds to actin, and the last binds to calcium

elastic filaments are made of the protein

titin

elastic filaments

run from the z line to the thick filaments to hold them in place and allow for recoil in the muscle cells

when titin reaches it’s normal extension

it stiffens and resists further over stretching of the muscle

smooth ER equivalent in the muscle cells

sarcoplasmic reticulum

at the a band and i band junction, the sarcoplasmic reticulum forms large perpendicular cross channels called

terminal cisterns

mitochondria and glycogen granules are highly abundant where?

near the sarcoplasmic reticulum

terminal cisterns are always found in?

pairs

sarcoplasmic reticulum controls?

calcium levels, and releases calcium to control muscle contraction

at the a band and i band junction, elongated tubular extensions of the sarcolemma dive deep into the cell and are called

t tubules

t tubule plus terminal cisterns on either side are called

triads

electrical signal travels down where

sarcolemmas, and can be carried through the t tubules, since they’re extensions of sarcolemmas

the electrical signal stimulates the release of ____ from terminal cisterns

calcium

integral proteins of create gated channels for the RELEASE of ____

CALCIUM

sarcolemma carries a resting charge, polarization, where the inside of the cell is more _____ relative to the outside

negative

how many steps are there to the propogation of a muscle action potential

3

what is step one of the muscle action potential

acetylcholine binds to its receptor → opens the voltage gate for sodium → makes the inner surface of sarcolemma negatively charged (depolarization). happens at the end of the plate and is termed the end plate potential

step two of muscle action potential

voltage gated sodium channels respond to the charge change andopen, allowing sodium ions to rush into the cell, further depolarizing the membrane → called the muscle action potential

step three of muscle action potential

once the voltage gate is positive enough, the potassium gates open → allowing potassium to exit the cell, resulting in repolarization of the membrane.

gradient differences are restores by this pump

ATPase pump

while repolarization is occuring, this period is marked by the inability to contract for about a millisecond

refractory period

events to the contraction of the muscle are collectively referred to as

excitation-contraction coupling

when calcium is low, this protein blocks myosin receptors

tropomyosin

the force exerted by a contracting muscle on an object

muscle tension

the opposing force applied on teh muscle by the mass of the object being moved

load

the motor neuron, along with all the individual muscle fibers that get innervated are called

motor units

motor units vary in ____ & ____

size and function

the smaller the motor unit, the more ____ the muscle is controlled

finely

specific motor units only have how many neurons?

1