muscle contracts (there is change in force) but does not change in length
What is the site where an axon and a muscle fiber meet?
the neurmuscular junction (NMJ) (or myoneural junction)
What are the two types of proteins in muscle fibers?
protein (thick filament) and actin (thin filament)
I bands are made of what?
they are composed of thin actin (protein) filaments…(held by direct attachments to structures called Z lines, which appear in the center of the I bands)
What is the origin and insertion of the levator scapulae?
origin: cervical vertebrae / insertion: scapula
Why do birds that migrate long distances have dark flesh?
because they have abundant dark, slow-twitch muscles...
A twitch has a brief delay between the time of stimulation and the time of contraction, what is the name of the delay?
the latent period
What is a fascicle?
a small bundle of muscle fibers
What muscle helps you smile?
zygomaticus
Acetylcholine (ACh) is synthesized where?
synthesized in the cytoplasm of the motor neuron
What happens when calcium is removed from the cytoplasm?
the muscle relaxes...
Creatine phospate stores energy that quickly converts what?
quickly converts ADP to ATP
The aerobic phase occurs where?
it occurs in the mitochondria (the complete breakdown of glucose)
What is the refractory period?
a short period after a nerve or muscle cell fires during which the cell cannot respond to additional stimulation (can be stimulated but won't respond)
Where would you find the extensor digitorum?
in the forearm...
The names of muscles often describe them, what a name indicate?
the muscle's size, shape, location, action, number of attachments, or direction of fibers...
What are the four components of levers?
(1) rigid bar - bones (2) fulcrum - parts on which bar moves; joint (3) object - moved against resistance; weight (4) force - supplies energy for movement; muscles
Toss-up question from last class!
A layer of connective tissue that surrounds a skeletal muscle is what?
epimysium
What is it called when you increase the number of activated motor units?
recruitment
What is the origin and insertion of the trapezius?
What are the two muscles used to raise your eyebrows?
epicranius frontalis and occipitalis
Define peristalsis?
a wavelike motion; consists of alternate contractions and relaxations of the longitudinal and circular muscles; helping to force the contents of a tube along its length
What is the recording of muscle contraction called?
a myogram
The irises of the eyes are an example of what?
a multi-unit smooth muscle
What causes rigor mortis to happen?
results in an increase in membrane permeability to calcium ions, which promotes cross-bridge attachment, and a decrease in availability of ATP in the muscle fibers, which prevents cross-bridge release from actin…thus, the actin and myosin filaments of the muscle fibers remains linked until the muscles begin to decompose
What three (3) muscles extend the leg at the knee?
rectus femoris, vastus lateralis, vastus medialis
Neurons release what chemicals in order to communicate with the cells that they control?
neurotransmitters
Drugs called what are used to treat irregular heart rhythms?
calcium channel blockers
do it by blocking ion channels that admit extracellular calcium into cardiac muscle cells
What is a sarcomere?
the structural and functional unit of a myofibril
What do liver cells turn lactic acid into?
glucose
What is a connective tissue covering that is associated with muscle forming and is broad, shaped like fibrous sheet, that attaches muscles to other muscles called?
aponeuroses
What is the origin and insertion of the Teres minor?
origin: scapula / insertion: humerus
What is the type of contraction that results in shortening of a muscle?
concentric, shortening contraction / an isotonic contraction
What is the cell membrane of a muscle cell called?
sarcolemma
What is the difference between the origin and the insertion?
the origin is the unmovable end and the insertion is the movable end
What are two things that cause smooth muscle to contract?
acetylcholine (ACh) & norepinephrine (NE)
What is cordlike part that attaches a muscle to a bone?
tendon
What does lactic acid accumulation result in?
it results in oxygen debt
What is the enzyme that removes acetylcholine (ACh) from the synapse?
acetylcholinesterase…(rapidly decomposes ACh in the synapse; this enzyme present in the synapse and on
the membrane of the motor end plate, prevent a single nerve impulse from continuously stimulating a muscle fiber)
Toss up question!
When a person walk with a constant waddle it called what?
gluteal gait…(when the gluteus medius and minimus are paralyzed)
What is the action of the buccinator?
compresses cheeks (blowing)
What are the two major types of smooth muscle fibers?
visceral smooth muscle and multi-unit smooth muscle
Smooth muscle fibers lack troponin, what protein do they have?
calmodulin…(binds to calcium ions released when its fibers are stimulated, activating contraction)
The assistant to the prime mover is called what?
synergist
True or False: Troponin is a muscle protein who's
chemical activity cause the contraction of muscle fibers?
False: Troponin is a protein which acts to block the contraction of the sarcomere
What is one of the first sign of Parkinson's disease?
shaky hands
What muscle am I contracting when I put my chin to my chest?
sternocleidomastoid
What is the function of intercalated discs?
help cells join, helping transmit the force of contraction from cell to cell; also allow ions to diffuse between cells, allowing muscle impulse to travel rapidly from cell to cell
True or False: Fascicles, Muscles, Thick and thin filaments, Muscle fibers (cells), Myofibrils. Is this the correct order?
