Muscles Chapter Flashcards
circumduction is
ball and socket
circumduction is found in how many places
2
What motion can your axis and occipital condyles do
gliding
Muscles fibers/cells look like
twizzlers(licorice)
Strings of twizzlers, single one
muscle fiber or muscle cell
bundle muscle fibers/cells are covered by and called
covered by perimysium, bundle called fascicle
my, myo, myology, sarco means
muscle
A bunch of fascicles are wrapped up in the
epimysium
epimysium with many bundles of fascicles are
muscles
what is the extension of the muscle stuck to the bone
tendon
thin skin that covers whole muscle
epimysium
smallest functional unit of muscle
sarcomere
location differences between skeletal, smooth and cardiac muscle.
skeleton,
hallow organs/gi tract/blood vessels,
heart.
skeletal muscle apperance
striations
multinucliated
cardiac muscle appearance
striations, intercalated discs (vertical lines)
smooth muscle appearance
no striations
Involuntary muscles
smooth and cardiac
voluntary muscles
skeletal
functions of muscle tissue
motion, posture, stabilization, thermogenesis
Motion and muscle tissue
external (walking, running, talking and looking) and internal (heartbeat, blood pressure, digestion, elimination) body part movements
Thermogenesis and muscle tissue (creation of heat)
generating heat by normal contractions and by shivering
Muscles are always in a state of
partial contraction
Posture and muscle tissue
slight muscle contraction maintains body posture
Stabilization and musc
stabilize joints- muscles have tone even at rest
When contracting muscles you are always doing what as well
relaxing the opposing force
every single muscle in our body has an…
agonist and antagonist
an antagonist is there
to stabilize the agonist
movement is one of our and how does it have to do with muscle
necessary life functions…
Functional characteristics
Excitability Contractility Extensibility Elasticity Conductivity
Excitability/irritability
the ability to receive and respond to a stimulus (chemical signal molecules)
Contractility
ability of muscle tissue to shorten
Ability to work in muscle.
Excitability or irritability
Extensibility
the ability to be stretched without damage
most muscles are arranged in functionally opposing pairs – as one contracts, the other relaxes, which permits the relaxing muscle to be stretched back
Elasticity
the ability to return to its original shape
Conductivity (impulse transmission)
the ability to conduct excitation over length of muscle
Thin Filaments (Myofibrils – Sarcomeres -Myofilaments)
actin (plus some tropomyosin & troponin)
Thick Filaments (Myofibrils – Sarcomeres -Myofilaments)
Myosin
Elastic filaments (Myofibrils – Sarcomeres -Myofilaments)
titin (connectin) attaches myosin to the Z discs (very high mol. wt.)
Elasticity is only described with what muscles?
Smooth (blood vessels)
The ability of a muscle to return back to its shape
elasticity
Do you measure elasticity
yes
Conductivity relates to
the nervous system and its ability to conduct excitation
miogram
measures the conductivity of a muscle
ability to spread message across muscle fiber
conductivity
sarcomeres are made up of
a lot of protein components
Sarcomeres in visual are
overlapping of actin and myosin overlapping the z lines of a muscle fiber contraction
Tropomyosin is the what in the story
chasity belt
troponin is the what in the story
lock
Key to get into the lock
Calcium and Atp
The functional unit of striated muscle contraction
Sarcomere
The foundation of the muscle cell’s contractile organelle, myofibril
Sarcomere
The myofilaments between two adjacent Z discs
The regular geometric arrangement of the actin and myosin produces the visible banding pattern (striations)
Sarcomere
Rod-like tail with two heads
Tails point to the M line
Myosin
Each head contains ATPase and an actin-binding site; point to the Z line
Myosin
Splitting ATP releases energy which causes the head to “ratchet” and pull on actin fibers
Myosin
Each thick filament contains many myosin units woven together
Myosin
Two G actin strands are arranged into helical strands
Actin
Each G actin has a binding site for myosin
Actin
Two tropomyosin filaments spiral around the actin strands
Actin
Troponin regulatory proteins (“switch molecules”) may bind to actin and tropomyosin & have Ca2+ binding sites
Actin
what has actin binding sites
myosin
what has myosin binding site
actin
Triads
2 terminal cisternae + 1 T tubule
Sarcoplasmic reticulum (SER):
modified smooth ER, stores Ca2+ ions
Terminal cisternae
large flattened sacs of the SER
Transverse (T) tubules
: inward folding of the sarcolemma
where motor neurons communicate with the muscle fibers
The Neuromuscular Junction:
composed of an axon terminal, a synapse and a motor end plate
The Neuromuscular Junction:
the end of the motor neuron’s branches (axon)
axon terminal
the specialized region of the muscle cell plasma membrane adjacent to the axon terminal
motor end plate
Synapse:
point of communication is a small gap
Synaptic cleft
the space between axon terminal & motor end plate
Synaptic vesicles
membrane-enclosed sacs in the axon terminals containing the neurotransmitter
Neurotransmitter:
: the chemical signal molecule that diffuses across the synapse, i.e., acetylcholine, ACh)
Acetylcholine (ACh) receptors:
integral membrane proteins which bind ACh
Binding of the neurotransmitter (ACh) … in excitation
Binding of the neurotransmitter (ACh) causes the ligand-gated Na+ channels to open
Opening of the Na+ channels…. in excitation
Opening of the Na+ channels depolarizes the sarcolemma (cell membrane)
Initial depolarization causes
adjacent voltage-gated Na+ channels to open; Na+ ions flow in, beginning an action potential
Action potential
a large transient depolarization of the membrane potential
transmitted over the entire sarcolemma (and down the T tubules)
Repolarization
the return to polarization due to the closing voltage-gated Na+ channels and the opening of voltage gated K+ channels
when you hear troponin you think
calcium
Where does atp bind to
myosin
Refractory period
the time during membrane repolarization when the muscle fiber cannot respond to a new stimulus (a few milliseconds)
All-or-none response
once an action potential is initiated it results in a complete contraction of the muscle cell
Structure covering all of the muscular fibers
SER
Sarcoplasmic reticulum
What is the job of the SER sarcoplasmic reticulum
to be a storage center for calcium
Where does the calcium come from that is stored in SER
Diet
Parathyroid Horomone breaks down bone for calcium
What happens the minute we have an chemical or electrical signal sent to our sarcomere
we open up these gates that are attached to the SER called T (Transverse) Tubules
SR opens up the T tubules and sends calcium to
troponin for muscle contraction
Crossbridge
myosin/actin getting together
The actual binding of the myosin and actin sites is called
powerstroke
What two things do you need to have myosin and actin to couple
atp and calcium
Whats telling the sarcoplasmic reticulum to release that calcium
the nervous system
Acetylcholine
Is a specific neuromuscular joint that sends a signal to muscle to release calcium
When you see acetylcholine
Muscle contraction
Sarcolema
Membrane of the muscle that is in “contact” with axons of the neuromuscular contractions
The way that any cell in our body conducts impulses
is to change the ionic composition
The way to change the ionic composition and conduct impulses
3Na 2K pump
All acetylcholine doing on the muscle is
opening sodium channels
When we open sodium channels we…
are going against the concentration gradient and sending more 3 sodium out and bringing 2 potassium in
Depolarization
Send sodium out bringing potassium in
Sodium channels open causing
the disruption of whats at rest and that continues to send that impulse or spark all the way down that muscle fiber so it can activate the SER to open and release calcium through the T tubules, attaching to troponin, moving tropomyosin . Then myosin and actin can combine.
At rest inside the cell there is more
potassium
If the cell isnt at rest then we create an action potential that
goes all the way down to those t tubles
What is the neurotransmitter called that sends the message from the nuerons to the muscles?
acetylcholine
acetylcholine has do do with
sending nervous systems mesaage to the muscle side
Where does the neurotransmitter acetylcholine go?
across the synaptic cleft to its receptor on the muscle cell membrane (sarcolemma)
What happens as soon as acetylcholine reaches that recpetor
Opens sodium channels causing to open sodium channels on the muscle side and creates a spark
9 volt batteries are like our
cells
At rest our cells are at
-70 milivolts
Why are our cells at -70 milivolts at rest
because of the concentration of potassium ions on the inside of that cell
we have ionic distribution that is what in our cells at all times
uneven
At rest on the inside of the cell it is what charge
negative
circle K means
at rest K is more in the middle causing it to be negative
acetylcholine causes what?
that switch in K being predominant in a cell to Na being predominant
When we open up sodium channels with acetylcholine what happens
causes sodium to flow rapidly into the cell making the charge from positive to neg
Flipping of the charge in a cell from K- to Na+ is called what
action potential or spark.
Depolarization
The opening of sodium channels,, whole wave going through.
Repolarization
Going back to rest by opening up K channels,sending more K in. Causing the concentration to equalize
Impulse in a cell happens around the
entire membrane
All or none response
Charge goes all the way or not at all