Download Muscle Location Action

Muscular System
How does a muscle contraction occur?
What action does muscle perform?
A. All movements require contraction of muscles.
B. 3 types of muscle skeletal, smooth, and cardiac
C. over 600 skeletal muscles in the body.
3 Types of Muscle Tissue
Skeletal muscle
 Cardiac muscle
 Smooth muscle

3 Types of Muscle Tissue

Skeletal muscle
 Tendons attach muscle to bone
 striations (light & dark bands) visible with
microscope
 voluntary control of contraction & relaxation
3 Types of Muscle Tissue

Cardiac muscle
 striations alternating dark and light bands
 involuntary control (no conscious
control)
 autorhythmic because of built in
pacemaker
3 Types of Muscle Tissue

Smooth muscle
 in walls of hollow organs -- blood vessels
& digestive organs (esophagus,stomach,
intestine)
 nonstriated in appearance
 involuntary

Muscles do 2 things
1. contract 2. relax
How? chemical energy
changed into
mechanical energy
 Movement produced

Functions of Muscle Tissue
Produce body movements
 Stabilize body positions
 Regulates organ volumes
 through smooth muscles called sphincters

Functions of Muscle Tissue
Movement of substances w/in body regulated by
muscles
 blood, lymph, urine, air, food and fluids
 Produces heat
 involuntary contractions of skeletal muscle
(shivering)

Directional Movements
Directional MovementsFlexion- decreasing the angle between 2 bones (ex. Bicep)
extension- increasing the angle between 2 bones (ex.Tricep)
Directional Movements-
Dorsiflexion- decrease angle between foot and shin (tibia)
Plantar flexion- foot towards floor (ex. Standing on toes)
Directional Movements
abduction- moving part away from midline
adduction- moving part toward midline
Directional Movements
Rotation- turning from side to side (Movement around axis)
Circumduction- end part follows a circle (cone shaped motion)
Directional Movements
Pronation- turning face down (palms down)
Supination- turning face up (palms up)
Directional Movements
Eversion- bottom of foot turned laterally
Inversion- bottom of foot turned medially
Directional Movements
Retraction- pulling part backward (chin back in)
Protraction- moving part forward (stick out chin)
Directional Movements
Elevation- raising part (ex. Shoulder shrug)
Depression- lowering a part
Directional Movements
Lateral Flexion- bending to your side
Lateral Extension- straighten back up
Directional Movements
describe movements
Origin and Insertion
Origin- the attachment of a muscle’s tendon to
a stationary bone usually proximal
Insertion- the attachment of a muscles tendon
to a movable bone usually distal
Origin- coracoid
process of scapula
Insertion- tuberosity
of radius
 Skeletal
Muscle made up of 3 tissues
A. a muscle is an organ, made of skeletal muscle tissue,
connective tissues, and nervous tissue.
Skeletal Muscle Organization
From big fibers to small fibers
Ex. Rope made up of string
Muscle  Fascicle  Muscle Fiber (cell)  Myofibrils  actin myosin
Connective Tissue Covers our Muscles
Fascia- layers of dense connective tissue surrounds and separate
each muscle. (looks and feels like leather)
Connective Tissue becomes Tendons
This connective tissue extends beyond the ends of the muscle and
gives rise to Tendons that are fused to the periosteum of bones.
Epimysium- connective tissue that surrounds entire
muscle (saran wrap)
Perimysium connective tissue that surrounds bundles of
muscle fibers (fascicles) [tear chicken]
Endomysium each individual muscle cell (fiber) is
covered by this connective tissue [endo=inside]
describe movements
8 - 31
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Muscle Fibers are cells
a muscle fiber is a single, long, cylindrical cell.
Muscle Fibers are specialized cells
The cell membrane of a muscle fiber is called the
Sarcolemma it contains:
Sarcoplasm, mitochondria, sarcoplasmic reticulum and
myofibrils
Skeletal Muscle Fiber (cell)
Sarcoplasm- liquid interior of the muscle cell
Mitochondria- helps produce ATP
Sarcoplasmic Reticulum- network of tubes that hold
Calcium- when released causes muscle contraction
Skeletal Muscle Fiber (cell)
Myofibrils- are made up of smaller myofilaments
One of the myofilaments is thick and other one is thin
Thick filaments are made up of the protein myosin.
Thin filaments are made up of the protein actin.
organization of filaments produces striations (stripes).
Sarcomere Basic unit contraction.
I bands (light bands) made up of only actin filaments
anchored to structure called “Z lines”
A bands (dark bands) are made up of overlapping
thick and thin filaments. (myosin and actin)
Sarcomere microscopic contraction.
In the center of A bands (dark band) is an H zone,
consisting of myosin filaments only.
The H zone is a region near center of sarcomere.
Sarcomere- Box that contracts
goes from Z line to Z line
Remember that by the word “ZarcomereZ”
sarcomere
I bands (lIght bands) made up of only actin filaments
anchored to Z lines.
Actin think “act thin”
A bands (dArk bands) overlapping thick and thin
filaments. (both myosin and actin filaments) that’s
why it’s dark [A band = length of Myosin]
Beneath the sarcolemma lies the sarcoplasmic
reticulum (holds calcium)
NMJ and the Sarcomere Drawing
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COLOR and LABEL the following
Motor Neuron and synapse = yellow
Acetylcholine = orange
Sarcolemma = blue
Sarcoplasmic reticulum = brown
For the test you must be able to
Calcium = pink
draw and label all the structures
Z line = black
of the NMJ and the Sarcomere
Actin = Purple
Troponin and tropomyosin = grey
Myosin = Red
IMPORTANT: Make sure to label all bands and zones
I band, A band, Z line, H zone
Neuromuscular Junction- NMJ
Site where Nerve (Neuron) and Muscle Fiber meet
more precisely where synapse of nerve connects with
sarcolemma of the muscle cell
NMJ- nerve talks to muscles using chemicals
motor neuron stores neurotransmitters (acetylcholine) in
synaptic vesicles- “bubbles that carry chemicals”
[neurotransmitters = chemical messengers] “chem messaging”
Magnified view
A Motor Unit controls a bundle of fibers
A motor neuron and the muscle fibers it controls make up a
motor unit; when stimulated to do so, the muscle fibers of
the motor unit contract all at once.
A Closer look at -- Myosin


Thick filaments are composed of myosin
 myosin resembles golf clubs twisted together
 myosin hands (cross bridges) extend toward actin
Held in place by M line proteins in center of sarcomere.
A closer look at -- Actin
Actin has a protein strand wrapped around it that
protects actins binding sites and blocks myosin from
connecting with actin.
 The protective protein strand is made up of 2
proteins called Troponin and Tropomyosin

When calcium is released from the sarcoplasmic
reticulum it binds to sites on tropomyosin and
troponin causing the protective strand to shift
which uncovers actin’s binding site
Myosin and Actin are now allowed to connect with
each other. Myosin reaches out his hand to Actin
and she readily takes hold of his hand and the two
slide pass each other.
Sliding Filament Mechanism Of Contraction





Myosin cross bridges
pull on thin filaments
Thin filaments slide
inward
Z Line come toward
each other
Sarcomeres shorten.The
muscle fiber shortens. The
muscle shortens
Notice :Thick & thin
filaments do not change in
length
Actin and Myosin a Love Story
Actin and Myosin are in love with each other and
desperately want to hold hands with each other
The problem:
Actins overprotective brothers (T and T) hate Myosin
and keep him far from their younger sister
Steps for a Muscle Contraction
1. A nerve impulse travels down motor neuron
releases
acetylcholine ACh from its synaptic
vesicles into the synaptic gap
(Cupid sends his love arrows ACh into muscle)
2.
Steps for a Muscle Contraction
ACh triggers a muscle impulse which travels to
sarcoplasmic reticulum.
{Ach- like cupids arrows- creates a wave of love
from the skin to heart}
Steps for a Muscle Contraction
3. After the muscle impulse has been generated,
acetylcholinesterase [ACherase] rapidly destroys Ach
(AChErases erases acetylcholine)
{Cupid arrows get destroyed but things are already set in
motion)
4.
The muscle impulse causes the sarcoplasmic
reticulum to releases its stored calcium.
{Actin knows her brothers T & T love milk so she
gets some milk from the refrigerator}
5. Calcium binds with troponin and tropomyosin
molecules on actin, which move aside, exposing
the myosin binding sites on the actin filaments.
{The T & T brothers drink the milk and forget about their job of
protecting the younger sister
outstreched arms and hands}
leaving her open to Myosin’s
6.
Myosin cross-bridges (hands) now bind and pull
on the actin filaments, the two filaments now
slide past one another causing the sarcomeres to
shorten. (requires ATP)
{Actin and Myosin get to hold hands and hug one another}
7.
Calcium returns to sarcoplasmic reticulum, this
causes troponin and tropomyosin to cover up and
protect the myosin binding sites on actin
{T and T get full of milk and then break up the love affair and throw out
Myosin and protect Actin once again.}
8.
Actin and Myosin are no longer able to bind to one
another and the muscle relaxes
{Actin and Myosin are no longer able to hold each other hands and must
once again wait for a love arrow from “Nerve Cupid” to start the
whole thing over again}
Relaxation
Contraction
Rigor Mortis
Body becomes stiff after death
"actin and myosin filaments of the muscle fibers
remain linked because ATP is no longer produced
{Actin and Myosin hold hands forever}
Draw the NMJ and the Sarcomere label all structures
Draw the NMJ and the Sarcomere label all structures
Draw the NMJ and the Sarcomere label all structures
Stimulus for Contraction
1.The motor neuron must release the neurotransmitter
acetylcholine from its synaptic vesicles into the synaptic
cleft in order to initiate a muscle contraction.
2. Protein receptors in the motor end plate detect the
neurotransmitters, and a muscle impulse spreads over the
surface of the sarcolemma and into the T tubules, where it
reaches the sarcoplasmic reticulum.
3. Upon receipt of the muscle impulse, the
sarcoplasmic reticulum releases its stored calcium
to the muscle fiber.
4. The calcium interacts with the troponin and
tropomyosin molecules on the actin, which move
aside, exposing the myosin binding sites on the
actin filaments.
5. Myosin cross-bridges (oars) now bind and pull on
actin filaments, causing the sarcomeres to shorten.
the
6. After the nervous impulse has been received,
acetylcholinesterase rapidly decomposes the acetylcholine.
7. Then, calcium is returned to the sarcoplasmic reticulum,
and the linkages between myosin and actin are broken.
The muscle then relaxes
Study Analogy: Think of a love story. The actin and
myosin are in love and would love to hold hands.
However, Actin is being guarded by Troponin and
Tropomysin (Actin’s older Twin brothers) Actin’s friend
Neuron wants Actin and Myosin to get together so she
calls (call=nerve impulse) for a pizza to be delivered to
Actin’s house to distract Troponin and Tropomysin.The
pizzaman(acetylcholine) deliveres the pizza (calcium)
and the pizza distracts the T&T brothers and gives
Myosin the chance to finally hold the hand of his
beautifully thin lover Actin.
While the T-T complex is so occupied, actin and
myosin are free to bind. Of course this takes a lot of
energy (who said love was easy?)
But the
messenger has only been paid for so long (destroyed
by acetylcholinesterase) and the pizza only last for
so long before its gone
(calcium returns to
sarcoplasmic reticulum). Thus the linkages are
broken and they cannot live happily every after. But
wait, another impulse may come along at any time!
D.
Energy Sources for Contraction
1.
Energy for contraction comes
from molecules of ATP. This
chemical is in limited supply and
so must often be regenerated
2.
Creatine phosphate, which stores
excess energy released by the
mitochondria, is present to
regenerate ATP from ADP and
phosphate.
3.
Whenever the supply of ATP is
sufficient, creatine phosphokinase
promotes the synthesis of creatine
phosphate.
4.
As ATP decomposes, the energy
from creatine phosphate can be
transferred to ADP molecules,
converting them back to ATP.
E. Oxygen Supply and Cellular Respiration
1.
The early phase of cellular respiration
yields few molecules of ATP, so muscle
has a high requirement for oxygen,
which enables the complete breakdown
of glucose in the mitochondria.
2.
Hemoglobin in red blood cells carries
oxygen to muscle.
3.
The pigment myoglobin stores oxygen
in muscle tissue.
F. Oxygen Debt
1.
During rest or moderate activity, there
is enough oxygen to support aerobic
respiration.
2.
Oxygen deficiency may develop during
strenuous exercise, and lactic acid
accumulates as an end product of
anaerobic respiration.
a.
Lactic acid diffuses out of muscle
cells and is carried in the
bloodstream to the liver.
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3.
Oxygen debt refers to the amount of
oxygen that liver cells require to convert
the accumulated lactic acid into glucose,
plus the amount that muscle cells need
to resynthesize ATP and creatine
phosphate to their original
concentrations.
4.
Repaying oxygen debt may take several
hours.
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G. Muscle Fatigue
1.
When a muscle loses its ability to
contract during strenuous exercise, it is
referred to as fatigue.
2.
Muscle fatigue usually arises from the
accumulation of lactic acid in the
muscle.
a.
A lowered pH as a result of
accumulated lactic acid prevents
the muscle from contracting.
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3.
A muscle cramp occurs due to a lack of
ATP required to return calcium ions
back to the sarcoplasmic reticulum so
muscle fibers can relax.
COOL information
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H. Heat Production
1.
Contraction of skeletal muscle
represents an important source of heat
for the body.
2.
Much of the energy produced through
the reactions of cellular respiration is
lost as heat (another source of heat for
the body).
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 Muscular Responses
A.
One method of studying muscle
function is to remove a single fiber and
connect it to a device that records its
responses to electrical stimulation.
B.
Threshold Stimulus
1.
A muscle fiber remains
unresponsive to stimulation
unless the stimulus is of a certain
strength, called the threshold
stimulus.
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C. All-or-None Response
1.
When a muscle fiber contracts, it
contracts to its full extent (all-or-none
response); it cannot contract partially.
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D. Recording a Muscular Contraction
1.
A myogram is the recording of an
electrically-stimulated muscle
contraction.
2.
A single, short contraction involving
only a few motor units is referred to as a
twitch.
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3.
The time delay between when the
stimulus is applied and when the muscle
contracts is called the latent period,
which is less than 0.01 second.
4.
The latent period is followed by a
period of contraction and a period of
relaxation.
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E. Summation
1.
A muscle fiber receiving a series of
stimuli of increasing frequency reaches
a point when it is unable to relax
completely and the force of individual
twitches combine by the process of
summation.
2.
If the sustained contraction lacks any
relaxation, it is called a tetanic
contraction.
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F. Recruitment of Motor Units
1.
An increase in the number of activated
motor units within a muscle at higher
intensities of stimulation is called
recruitment.
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G. Sustained Contractions
1.
Summation and recruitment together
can produce a sustained contraction of
increasing strength.
2.
Muscle tone is achieved by a continuous
state of sustained contraction of motor
units within a muscle.
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Smooth Muscles
A.
Smooth Muscle Fibers
1.
Smooth muscle cells are
elongated with tapered ends, lack
striations, and have a relatively
undeveloped sarcoplasmic
reticulum.
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2.
Multiunit smooth muscle and
visceral muscle are two types of
smooth muscles.
a.
In multiunit smooth muscle, such
as in the blood vessels and iris of
the eye, fibers occur separately
rather than as sheets.
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b.
Visceral smooth muscle occurs in
sheets and is found in the walls of
hollow organs; these fibers can
stimulate one another and display
rhythmicity, and are thus
responsible for peristalsis in
hollow organs and tubes.
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B.
Smooth Muscle Contraction
1.
The myosin-binding-to-actin
mechanism is the mostly same for
smooth muscles and skeletal
muscles.
2.
Both acetylcholine and
norepinephrine stimulate and
inhibit smooth muscle
contraction, depending on the
target muscle.
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3.
Hormones can also stimulate or inhibit
contraction.
4.
Smooth muscle is slower to contract
and relax than is skeletal muscle, but
can contract longer using the same
amount of ATP.
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Cardiac Muscle
A.
B.
The mechanism of contraction in
cardiac muscle is essentially the same as
that for skeletal and smooth muscle, but
with some differences.
Cardiac muscle has transverse tubules
that supply extra calcium, and can thus
contract for longer periods.
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C.
Complex membrane junctions, called
intercalated disks, join cells and
transmit the force of contraction from
one cell to the next, as well as aid in the
rapid transmission of impulses
throughout the heart.
D.
Cardiac muscle is self-exciting and
rhythmic, and the whole structure
contracts as a unit.
 Skeletal Muscle Actions
A.
Origin and Insertion
1.
The immovable end of a muscle
is the origin, while the movable
end is the insertion; contraction
pulls the insertion toward the
origin.
2.
Some muscles have more than
one insertion or origin.
B.
Interaction of Skeletal Muscles
1.
Of a group of muscles, the one
doing the majority of the work is
the prime mover.
2.
Helper muscles are called
synergists; opposing muscles are
called antagonists.
Major Skeletal Muscles
“I will pump you up
girly man”
Muscles named according to:
Size- Maximus versus minimus, longus and brevis
Shape- Deltoid = triangle, Trapezius = trapezoid
Location- Frontalis, zygomaticus, brachioradialis
Muscles named according to:
Action- Flexor digitorum, Pronator Teres
Number attachments- Bicep, Tricep
Direction of fibers- Rectus = straight , Oblique = angled
Muscle
Muscles of Facial Expression
Location
Frontalis
Orbicularis oculi
Zygomaticus
Orbicularis oris
Platysma
forehead
circle ms. around eye
cheek to corner mouth
circle ms. around mouth
lower jaw and front neck
Action
raises eye brow
closes eyes
smile
protrudes lips(kiss)
opens mouth
Muscles for chewing
Muscle
Location
Masseter
back of cheek
Temporalis
over temporal bone
Action
closes jaw
closes jaw
Muscles that Move the Head
Muscle
Location
Sternocleidomastoid side of neck
Splenius capitis back of neck
bandage
Action
flex neck
ext. or rotat.
8 - 108
Muscles of the Abdominal Wall
This group of muscles connects the ribcage and vertebral column to the
pelvic girdle.
Muscle
Location
Action
External oblique side stomach
like belt/girdle
Rectus Abdominus
front stomach
“6-pack”
flexes spine
Muscles used in back extension
Muscle
Location
Quadratus Lumborum Low back
Erector Spinae
Low back
Action
extends back
extends back
Muscles used in breathing
Muscle
Diaphragm
Location
inferior to lungs
External Intercostals
between ribs
Action
breathing
breathing
Muscle
Muscles that Move the Shoulder
Location
Trapezius
Levator Scapula
Rhomboid Major
Action
occiput to scapula to T12
shoulder shrug
C1-C6 to scapula
elevates scapula
T1-T6 to scapula
raises/adducts scapula
Muscle
Pectoralis Major
Latissimus Dorsi
Deltoid
Supraspinatus
Muscles that Move the Humerus
Location
Action
Chest
pulls arms forward
lower back to arm Adducts/extends arm
top shoulder
abducts arm
top scapula
abducts arm
Infraspinatus
top of scapula
Teres Major
scapula
rotates arm
extends arms
Muscle
Muscles that Move the Forearm
Location
Biceps
Brachioradialis
Brachialis
Triceps
ant. humerus (10)
ant. Inf. humerus (11)
lateral humerus (13)
posterior humerus
Action
flex forearm
flex forearm
flex forearm
extends forearm
Latissimus = Wide or broad
Muscles that Move the Forearm
Muscle
Pronator Teres
Supinator
Location
by elbow joint
by elbow joint
Action
pronates forearm
supinates forearm
Muscles that Move the Wrist, Hand, and Fingers
Muscle
Flexor digitorum
Extensor digitorum
Location
4-arm to fingers
post. 4-arm to fingers
Action
flex fingers
extends fingers
Muscles that Move the Thumb
Muscle
Location
Abductor Pollicus Longus
Adductor Pollicus
Action
abducts thumb
adducts thumb
Muscles that Move the Femur
Muscle
Location
Psoas Major
Lumbar-femur
Action
raise femur
Muscle
Muscles that move femur
Location
Action
gluteus maximus
gluteus medius
sacrum-femur
ilium-femur
extends femur
abducts femur
Muscles that Move the Ankle, Foot, and Toes
Muscle
Location
Tibialis anterior
tibia-tarsals
extensor digitorum tibia-phalanges
Action
dorsiflex foot
extends toes
Muscles that move foot
Muscle
Gastrocnemius
Soleus
Location
femur-calcaneus
tibia-calcaneus
Action
tippy toes
tippy toes
Muscle
Muscles that move femur
Location
gluteus medius
ilium-femur
tensor fasciae latae ilium-fascia thigh
Action
abducts femur
abducts femur
Muscles that move the femur
Muscle
Location
Action
Piriformis
sacrum to femur
adductor longus
pubic-femur
rotates femur
adducts femur
Muscles that Move lower leg- “Quadriceps”
Muscle
Location
Action
Rectus Femoris
ilium-patella
extends L.L.
Vastus Intermedius femur-patella
extends L.L.
Vastus Lateralis femur-patella
extends L.L.
Vastus Medialis femur-patella
extends L.L.
FILM
Vastus=GREAT
Muscles that Move the lower leg (Hamstrings)
Muscle
Location
Action
biceps femoris
ishium-tibia
flexes L.L
Semitendinosus
ishium-tibia
flexes L.L
semimembranosus
ishium-tibia
flexes L.L
Bi Semi
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1. Deltoid: scapula/clavicle to humerus- abducts arm
2. Levator scapulae: C-vertebrae to scapula- elevates scapula
3. Infraspinatus: lower scapular spine to humeral head- lateral rotation of humerus
4. Teres major: scapula to anterior humerus- medial rotation of humerus'
5. Teres Minor: scapula to posterior humerus- lateral rotaion of humerus
6. Supraspinatus: upper scapular spine to humeral head- abducts humerus
7. Trapezius- shoulder shrug
8. Rhomboidius: T-vertebrae to scapula- raise/adduct scapula
9. Latissimus Dorsi- adducts humerus
10. Biceps: scapula to radius- flex elbow
11. Tricep- extends forearm (radius)
12. Pronator: Medial humerus to radius- medial rotation of forearm (pronation)
13. Brachioradialis- flexes forearm
14. Flexor Digitorum: medial humerus/ulna to phalanges- flex fingers
15.
16. Extensor digitorum: lateral humerus to phalanges- extend fingers
17. Extensor carpi radialis: lateral humerus to 2nd/3rd metacarpal- extend/adduct hand
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