Download muscles shorten

The
Muscular
System
1. How did the term
“MUSCLE” come into
being?
Because flexing
muscle look like mice
scurrying beneath
the skin, some
scientist dubbed them
“muscles” – Latin for
“little mouse”.
2. What is the
essential function of
muscle?
Muscle will
contract or
shorten.
As a result of this,
muscle is
responsible for all
movement.
How are all
muscle tissue
alike?
3.
3
-1 All
muscle
cells are
elongated , thus
called MUSCLE
FIBERS.
All muscles
will contract!
-2
-3 Similar
terminology!
Myo- or Mys = Muscle
Sarco = flesh
Question # 4 is a
duplicate question!
Delete.
List three
different
types of
muscle tissue:
5.
-1 SKELETAL
-2 SMOOTH
-3 CARDIAC
6. Explain
what is meant
by “striated”
muscle:
The muscle fibers
appear to be striped.
7. Answer the
following
questions
regarding
skeletal muscle.
Body Location
Attached to
bones.
Cell shape and appearance:
Single, very long,
multinucleate cells
with obvious striation.
Regulation of contractions.
Voluntary; via
nervous system
control.
Speed of contraction
Slow to fast
Rhythmic Contraction?
NO
Sketch of Skeletal muscle fiber.
8. Since Muscle tissue
is extremely delicate,
what keeps it from
snapping into as it
exerts such
tremendous force?
Thousands of their
fibers are bundled
together by
connective tissue,
which provides
strength and support
to the muscle as a
whole.
9. What is a
fascile?
A
bundle
of
muscle
fibers
10. Explain the
various connective
tissue wrappings of
skeletal muscle:
ENDOMYSIUM
A delicate
connective
sheath that is
wrapped
around each
individual
muscle fiber.
Perimysium:
Coarse
fibrous
membrane
wrapped
around a
fascile.
Epimysium
Tough
overcoat of
connective
tissue
surrounding
the entire
muscle.
Tendon
BONE
11. Compare
and contrast
tendons and
the
aponeuroses:
Compare:
Both attach
muscle to
bone
Contrast:
Tendon is a strong
cord, the
aponeuroses are
sheet like tissue.
12. List the three
ways that muscle
fibers may be
arranged:
-1 Spindle shaped.
-2 Fan pattern
-3 A circle
13. Answer the
following
questions
regarding
Smooth muscle.
Body Location
Typically in
walls of
hollow
visceral
organs.
Cell shape and appearance:
Single, fusiform, one
nucleus; no striations
Regulation of contractions.
Involuntary; nervous
system controls;
hormones, chemicals,
stretch.
Speed of contraction
Very slow, but
consistant!
Rhythmic Contraction?
Yes, in
some
Sketch of Smooth muscle fiber.
nucleus
14a. Explain the
“two-layer”
arrangement of
smooth muscle.
1 circular
layer of muscle
+
1 longitudinal
layer
14b. Explain how
the body used
this “two-layer”
arrangement of
smooth muscle:
As the two layers
alternately
contract and relax,
they change the size
and shape of the
organ.
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Slow and steady!
Alternate
contractions push food
through the digestive
tract, urine through
urinary system, and
blood through veins.
15. Compare the
muscular
contractions of the
smooth muscle to the
contractions of the
skeletal muscle:
Skeletal muscle is
like a speedy windup
car that quickly runs
down; but smooth
muscle is like a heavyduty engine that
runs SLOW BUT
STEADY.
16. Answer the
following questions
regarding Cardiac
Muscle.
Body Location
Walls
of the
heart.
Cell shape and appearance:
Branching chains of
cells; one nucleus;
complex striations.
Regulation of contractions.
Involuntary; the
heart has a
pacemaker; also
nervous system
controls; hormones
Speed of contraction
Slow!
Rhythmic Contraction?
yes
Sketch of Cardiac muscle fiber.
16. How are
the muscle
fibers
arranged
that make up
the heart?
Cardiac
muscle
bundles are
wrapped in a
spiral
arrangement
for added
strength.
17. Explain
how muscles
are involved
in producing
movement.
-1 Skeletal muscles
contract and pull
the bones.
-2 Smooth muscles
contract and force
items through the
smooth muscles.
.-3 Muscles work in
Antagonistic pairs!
One muscle contracts
and pulls the bone one
way, then its partner
will contract and pull
the bone the opposite
way.
18. Explain how the
muscles are involved
in maintaining
posture:
The skeletal muscles
function almost
continuously, making
one tiny adjustment
after another so that
we can maintain an
erect posture despite
the never-ending pull
of gravity.
19. Explain how
the muscles are
involved in
stabilizing joints:
As the skeletal
muscles pull on
bones to cause
movement, they
stabilize the joints of
the skeleton.
20. Explain how
the muscles are
involved in
generating body
heat:
When muscles
contract, ¾ of its
energy escapes as
heat. This heat is
vital in maintaining
normal body
temperature.
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21. What is a
sarcomere?
A single
contraction unit
in muscle.
22. What is a
myofibril>
A muscle
fiber
23. Differentiate
the two kinds of
filaments that make
up a myofibril:
is a thin
filament composed
ob two beaded
strains twisted
together.
is thick
with a bulbous head
and a tail.
24. Explain the
sliding – filament
model of muscle
contraction:
a) Each sarcomere
consist of two sets of
actin filaments that
are attached at each
end of the sarcomere.
b) In between the
attached actin
filaments is a single
unattached myocin
filament.
c) Fiber tow-chains
called “Cross
bridges” shoot out
from the myosin and
anchor on to the
actin filaments.
d) As the myosin
contracts, it tows
along the actin
which shortens the
muscle fiber. After
contraction, the
cross bridges
release.
25. Discuss the
control pathway of
muscular
contraction:
The nervous system
sends a signal to the
muscle.
At the
neuromuscular
junction,
acetylcholine
Causes the release
of calcium ions
which causes an
action potential in
the muscle.
26. Explain the
control mechanism
of muscular
contraction:
a) When the muscle is
at rest, the actin
binding sites are
blocked and myosin
cannot form cross
bridges with them.
b) The release of
calcium ions clears
the binding sites – so
the contraction
proceeds;
c) Afterwards,
calcium ions are
actively
transported back
into the membrane
storage system.
27. Where does the
energy come from for
contraction?
a)Short Intense
contraction:
Creatine phosphate used
to recreate ATP from
ADP.
b) Moderate contraction:
ATP created from
electron transport
phosphorylation.
c) Intense, Prolonged
Contraction:
Anaerobic fermentation
occurs. Small amounts
of ATP released. SORE
muscles result from
LACTIC ACID buildup.
28. What is the
relationship between
muscle tension and
contraction?
a) The cross-bridges tht
form during contraction
exert muscle tension.
b) When muscle tension is
greater than the force
opposing it – contraction
occurs. (muscles shorten)
When the opposing force is
greater – muscles lengthen
and contraction stops.
29. List three things that
determine muscle
strength:
A.
MUSCLE
SIZE
B.
Number of
muscle cells
contracting.
c.
The speed at
which the nervous
system is
stimulating the
muscle cells.
30. What is meant by
a motor unit?
A motor
neuron and
the muscle
cells under its
control.
31.
Differentiate
a TWITCH
and
TETANUS:
A BRIEF contraction
caused by a single
brief stimulus is a
muscle TWITCH.
Rapid, Continuous,
repeated stimulation
that will NOT let go is
TETANUS.
32. What causes
Muscle Fatique?
“Continuous high
frequency
stimulation”
33. Discuss the
differences in
recovery time
necessary from
muscle fatigue:
a. BRIEF INTENSE
EXERCISE:
RECOVER QUICKLY!
b. Prolonged,
moderate exercise
Recovery much more
slowly.
33. List the 5 Golden
Rules of skeletal
muscle activity:
1.All muscles cross at
least one joint.
2.Typically, the bulk of
the muscle lies
proximal to the joint
crossed.
3. All muscles have
at least two
attachments: The
origin and the
insertion.
4. Muscles can only
pull; they never push.
5. During contraction,
the muscle insertion
moves toward the
origin.
33.
Differentiate
the muscular
POINT OF
ORIGIN and
the POINT OF
INSERTION.
Point of origin
=
Attachment
to immovable
bone.
Insertion:
Attachment
to bone that
will move!
34. Identify the
following common
body movements
DELETE
35. Define the
following types of
muscle:
Prime Mover
The one muscle within
a group of muscles that
does most of the work
during a common
movement.
Synergist
Muscles that either
pull with the prime
mover, or reduces
unnecessary
movement
Fixator
They hold a bone
still or stabilize the
origin for a prime
mover.
36. Explain how
muscles are
named:
a)Direction of
the muscle
fiber:
Rectus = muscle
is straight up and
down.
Oblique = slanted
muscle
b)Size of the
muscle:
Maximus = largest
Minimus = smallest
Longus = long
c) Location of
the muscle:
Some muscles are
named for the bones
they are associated
with.
d)Number of
Origins
Biceps = two points of
origin!
Triceps = three points
of origin
Quadriceps?
Four points of
origin!
e)
Location of the
muscle’s origin and
insertion:
Occasionally,
muscles are named
after both their
attachment sites.
sternocleidomastoid
Origin
Sternum
Clavicle
Insertion:
Mastoid
process of
the
temporal
bone
f) Shape of the
muscle:
Some muscles have a
distinctive shape!
Ex. Deltoid =
triangular
g) Action of the
muscle
When muscles are
named for their
action, their name
refers to the type of
movement they cause.
“Straightens
forearm at elbow.”
“Draws the arm
forward and in
toward body”
“Draws shoulder
blade forward,
helps riase arm,
assist in pushes”
“Compresses the
Abdomen, permits
lateral rotation”
“Depresses the
chest cavity,
compresses the
abdomen, and bends
the backbone”
“Bends the thigh at
hip and bends lower
leg at knee; rotates
the thigh in
outward direction”
“Flexes, laterally
rotates, and draws
thigh toward body”
“Flexes the thigh at
the hip; extends the
leg at knee”
“Flexes the foot
toward the shin”
“Bends the forearm
at the elbow”
“Raises the Arm”
“Lifts the shoulder
blade and braces
the shoulder;
draws the head
back”
“Rotates, and
draws arm
backward and
toward body”
“Extends and
rotates thigh
outward when
walking, running,
and climbing.”
“(hamstring) draws
the thigh backward
or bends the knee”
“Bends lower leg at
the knee when
walking; extends
the foot when
jumping.