Muscles and Muscle Tissue
Chapters 9 & 10
1
Joint Movements
•
•
•
•
•
•
Extension
– A movement that increases the angle at a joint
• Straightening the elbow or knee
Dorsiflexion
– Flexion of the foot so the toe is moving back towards the shin
Plantar flexion
– Flexion of the foot so the toe pointing down
Abduction
– Moving body part away from the midline
• Lifting arm out, away from the body
Adduction
– Moving body part towards the midline
• Arms down at the side of the body
Circumduction
– Moving a limb in a circular motion
• Swing the arms
2
Joint Movement
Rotation
Turning a bone around a single axis
Head side to side
Supination
Turning the hand palm forward
Pronation
Turning the hand palm facing posteriorly
Inversion
Turning the foot so the sole faces medially
Eversion
Turning the foot so the sole faces laterally
Protraction
Jutting out the jaw
Retraction
Returning the jaw back to normal
Elevation
Lifting the body part superiorly (closing the jaw)
Depression
Lowering the body part (open the jaw)
3
Facial/ Cranial muscles
1st rib (cut)
Anterior scalene
Auriculotemporal nerve
Brachial plexus nerves
Brachiocephalic vein
Buccinator
Depressor anguli oris
Depressor labii
inferioris
Digastric
External jugular vein
Facial nerve branches
Frontalis
Greater auricular nerve
Hyoid bone
Internal carotid artery
Levator labii sup.
Levator scapulae
Masseter
Mentalis
Middle scalene
Mylohyoid
Nasalis
4
Facial Cranial
Omohyoid
Orbicularis oculi
Oribicularis oris
Parotid duct
Parotid gland
Posterior scalene
Risorius
Scalenes
Splenius capitus
Sternocleidomastoid
Sternohyoid
Stylohyoid
Subclavian artery
Subclavian vein
Submandibular gland
Supraclavicular nerves
Temporal arteries
Temporoparietialis
Thyroidhyoid
Transverse facial nerve
Trapezius
Zygomaticus
Zygomaticus major
Zygomaticus minor
5
Posterior shoulder
Acromion of scapula
Biceps brachii
Brachialis
Brachioradialis
Clavicle
Deltoid
Extensor carpi radialis longus
Infraspinatus
Misc. Radial n. branches
Spine of scapula
Supraspinatus
Triceps brachii, lateral head
Triceps brachii, long head
Teres major
Teres minor
6
Anterior Shoulder
Axillary artery
Axillary nerve
Biceps brachii
Brachial artery
Brachialis
Brachial plexus
Brachioradialis
Clavicle
Coracobrachialis
Deltoid
Forearm muscle group
Latissimus dorsi (insertion)
Median nerve
Musculocutaneous nerve
Subclavius
Subscapularis
Sup. ulnar collateral artery
Supraspinatus
Teres major
Triceps brachii, long head
Triceps brachii, medial head
Thoracodorsal nerve
Ulnar nerve
7
Posterior Forearm
Abductor pollicis longus
Anconeus (cubitalis rolani)
Brachioradialis
Extensor carpi radialis brevis
Extensor carpi radialis longus
Extensor carpi ulnaris
Extensor digiti minimi
Extensor digitorum
Extensor pollicis brevis
Extensor retinaculum
Flexor carpi ulnaris
8
Anterior Forearm
Biceps brachii
Brachialis
Brachioradialis
Flexor carpi radialis
Flexor carpi ulnaris
Flexor digitorum superficialis
Flexor retinaculum
Median nerve
Palmar arch arteries
Palmaris longus
Pronator teres
9
Temporalis
Masseter
Platysma
Triceps brachii
Biceps brachii
Brachialis
Brachioradialis
Flexor carpi radialis
Palmaris longus
iliopsoas
Frontalis
Orbicularis oculi
Zygomaticus
Orbicularis oris
Sternohyoid
Sternocleidomastoid
Deltoid
Pectoralis Major
Intercostals
Rectus abdominis
External Oblique
Internal Oblique
Transversus abdominis
Pectineus
Rectus femoris
Vastus lateralis
Vastus medialis
Fibularis longus
Extensor digitorum longus
Tibialis anterior
Sartorius
Adductor longus
Gracilis
Gastrocnemius
Soleus
10
Triceps Brachii
Brachialis
Brachioradialis
Extensor carpi radialis longus
Flexor carpi ulnaris
Extensor carpi ulnaris
Extensor digitorum
Occipitalis
Sternocleidomastoid
Trapezius
Deltoid
Infraspinatus
Teres major
Rhomboid major
Latissimus dorsi
Gluteus medius
Gluteus maximus
Iliotibial tract
Adductor magnus
Biceps femoris
Semitendinosus
Gastrocnemius
Semimembranosus
Soleus
Fibularis longus
Calcaneal
Achilles tendon
11
•
Head
– SCM – sternocleidomastoid
– Trapezius (extender)
•
Muscle Relations & Actions
Shoulder
– Adductor
• Pectoralis girdle
• Trapezius
• rhomboid
– Elevator
• Levator scapulae
• serratus anterior
• pectoralis minor
•
Upper arm
– Flexors
• Pectoralis major
• coracobrachialis
• deltoid extenders
– Extenders
•
•
•
Latissimus dorsi
teres major
deltoid
– Abduct
•
•
•
•
•
•
•
Pec major
coracobrachialis
latissimus dorsi
teres major
subscapularis
deltoid
supraspinatus
12
•
Upper arm (cont)
– Medially rotate
Muscle Relations & Actions
• Latissimus dorsi, pec
major, coracobrachialis,
teres major, subscapularis
– Lateral rotation
• Supraspinatus,
infraspinatus, teres major
•
Lower arm
– B flexors
• Biceps brachii, brachialis,
brachioradialis
– Extension
• Triceps brachii
•
Hand
– Flexors
• Anterior muscles
– Extenders
• Posterior
•
Trunk
– Flexors
• Rectus abdominus,
iliopsoas
– Extender
Erector spinae
13
•Sarcolemma
–Plasma membrane of striated
muscle
Muscular Terms
•Intercalated disc
–Gap junction connecting muscle
cells of myocardium
•Sarcoplasm
–Cytoplasm of striated muscle
•Fascicle
–Bundle of nerve, muscle fibers
bound by connective tissue
•Striations
–Striped, mark of fatty deposit on
heart muscle
•Myofiliments
–Threadlike bundles of striated
muscle fiber
•T-tubules
–Pathways for electrical excitation
of muscle
14
Function of Muscle
•
•
•
•
Movement
Maintain posture
Stabilize joints
Heat generation
15
Characteristics of Muscle tissue
• What are the special functional properties of muscle?
– Excitability or irritability: What is this?
• Ability to perceive and respond to stimulus
– What is usually the stimulus in muscle?
• Chemical. Neurotransmitter released by nerve cell or change in pH
– Contractility: What it this?
• Ability to shorten forcefully
– Extensibility: What is this?
• Stretch or extend
– Elasticity: What is this?
• Ability to recoil, resume resting length after stretched
16
•What are the 2 sets of intracellular
tubules in skeletal muscle?
–Sarcoplasmic ret
–T tubules
•What is the major role of the SR?
Sarcoplamic reticulum
T - tubules
–Regulate intracellular levels of ionic
calcium
•What does calcium provide for muscle?
–The final “go” for contraction
•Where are the T tubules located on
cell?
–At each A and I band junctions
•What is a triad?
–Grouping of 3 membranous structures:
•Terminal cisterna
•T tubule
•Terminal cisterna
•What are the T tubules function?
–Taking nerve impulses that travel from
the sarcolemma deep into the muscle
fiber and to every sarcomere
•What do these impulses signal?
–The release of calcium from the terminal
cisternae
•What is the result of these T tubule
actions?
–Every myofibril contracts virtually at the
same time
17
Sarcoplasm reticulum
18
Role of ionic calcium
• A: Tropomyosin blocks actin binding sites preventing cross
bridges enforcing relaxed state
• B: Higher Ca2+ concentrations, additional calcium binds to (TnC)
or troponin
• C: Calcium activated troponin undergoes change, moves
tropomyosin away from actins binding sites
• D: displacement allows myosin heads to bind and cycle, and
contraction begins
19
•What is this process?
–Sequence of events by which
transmission of an action potential along
the sarcolemma leads to the sliding of
myofilaments
Excitation/Contraction
Coupling
•When does this occur?
–During the latent period; between
action potential and mechanical activity
•What causes filament sliding?
–A rise in calcium ion concentration
•Steps:
–Action potential along sarcolemma
–Transmission past triads; calcium
released into sarcoplasm becomes
available to myofilaments
–Calcium binds to troponin which
changes shape, stops blocking action of
tropomyosin
–Calcium about 10-5M, myosin heads
attach and pull thin filaments toward
center of sarcomere
–Ca2+ signal ends (30ms after AP), fall in
Ca2+begins calcium pumps action moving
Ca2+ back into SR to be stored again
–Ca2+drop too low for contraction,
tropomyosin block reestablished. Cross
bridge ends
•When is this repeated?
–When another impulse arrives from
neuromuscular junction
20
3 Types of Muscle Tissue
• Skeletal. Name Characteristics:
–
–
–
–
–
–
Voluntary, striated
Causes movement of the body
Long, cylindrical
Multinucleated cells
Banded, striated in appearance
Contracts rapidly, tires easily
• Cardiac. Name Characteristics
– Found in walls of heart
– Involuntary
– Striated
– One centrally located nucleus (uninucleate)
– Branched fibers
– Intercalated discs
Contractions of cardiac initiated by special cardiac muscle cells
21
3 Types of Muscle Tissue (cont)
• Smooth muscle.
Characteristics
–
–
–
–
–
Spindle shaped cells
No striations
Uninucleate
Walls of organs
Slow sustained
contractions
22
•What surrounds muscle tissue?
Skeletal Muscle Structure
–Connective tissue called fascia
•How many layers of connective
tissue found in skeletal muscle
and what are they?
–3
–Epimysium
•Around entire muscle
–Perimysium
•Wraps around bundles of
muscle fibers called fascicles
–Endomysium
•Surrounds each individual
muscle fiber or cell
23
Muscle Action
• Muscle Action
– The body movement caused by a muscle when it contracts
• How does movement occur when muscles contract?
– The stationary bone remains stationary while the other bone it is
attached to moves
• What is the non-moving point called?
– Origin
• What it the point where movement occurs called?
– Insertion
• What are synergists?
– Group of muscles working together to do the same action
• What is the prime mover?
– The one muscle that does the most work
• What are antagonists?
– Muscles that work opposite of each other
24
Skeletal
Nerve and blood supply
• How many nerves, arteries, and veins to each muscle?
– At least 1 nerve, artery and 1 or more veins
• What controls the activity of each skeletal muscle?
– Nerve ending
• How much energy does contracting muscle use?
– Huge amounts (continuous supply of oxygen and nutrients)
• How do the large amounts of metabolic waste leave muscle cells?
– Through veins
• What characteristics define muscle capillaries?
–
–
–
–
Long, winding
Numerous cross links
Straighten when muscle stretched
Contort when contracted
25
Structure of muscle
26
•What is a muscle fiber composed of?
–Thousands of stacked, cylindrical,
contractile structures called myofibrils
•What are the smaller contractile units
of myofibrils?
Structure of skeletal
muscle fiber
–Sarcomeres
•What are the rod-like protein filaments
each sarcomere contains?
–Actin, myosin
•What gives skeletal muscle its striated
appearance?
–The arrangement of actin and myosin
filaments
•What is the sarcoplasm?
–Like the cytoplasm of typical cell but
contains myoglobin
•What is myoglobin?
–Red pigment that stores oxygen in
muscle cells
•What is the sarcolemma?
–Plasma membrane of muscle fiber
–Forms hollow T-tubules that conduct
impulses deep into muscle fiber
27
Structure of skeletal muscle fiber (cont)
• What is the sarcoplasmic reticulum?
– An interconnecting system of endoplasmic reticulum that surrounds
each myofibril
– In muscle cell it stores calcium ions that are needed for muscle
contraction
• What does the sarcoplasmic reticulum do at each end of the
sarcomere?
– Widens into larger channels called terminal cisternae
• What is the terminal cisternae’s function?
– Release calcium when striated muscle is activated
– Surround each T tubule
28
Structure of a Sarcomere
•
What is a sarcomere?
– The smallest contractile unit of a muscle fiber
•
Are myosin filaments thin or thick?
– Thick
– Each have a rod-like tail that terminates in a globular head
•
What are the 6 thin filaments surrounding each myosin filament?
– Actin filaments
•
How are the myosin and actin filaments arranged?
– They are stacked in such a way that they overlap each other in some areas
but in other areas there are just one or the other
•
What gives its striated appearance?
– The pattern of myosin and actin overlapping
•
What is a “Z” line?
– Where a sheet of protein anchors the actin filaments and attaches each
myofibril to the next
•
Where do sarcomere extend to?
– One “Z” line to the next
29
•
What is the H zone?
Sarcomere Regions
– A light area in the center of the sarcomere with no actin filaments
•
What runs down the center of the H zone?
– A dark M line
•
What is the A band?
– The darkened area containing both actin and myosin filaments
•
What is the I band?
– The light area at both ends of the sarcomere where only actin filaments are
present (no myosin)
•
What runs down the center of the I band?
– The Z line
30
•How is skeletal muscle innervated?
The Neuromuscular Junction
–By motor neurons
–Axon from motor neurons travel in
bundles called nerves to the
muscles they serve
•How many nerves serve each
muscle?
–At least one motor nerve composed
of many motor neurons
•What do axons form when they
branch into smaller endings?
–Neuromuscular junction
•Does the axon ending touch the
muscle fiber?
–No. It sits very close but does not
touch it
•What is the small space between
the neuron axon and muscle fiber?
–Synaptic cleft
31
•Where do motor neurons reside?
–In the brain, spinal cord
Neuromuscular junction
•What are their long threadlike
extensions called?
–Axons
•What is the synaptic cleft and what
is it filled with?
–Space at attachment site of muscle
–Filled with gel-like substance rich
in glycoproteins
•How is Ach released into the cleft?
–Exocytosis
32
•The Axon Terminal:
•What is the axon terminal?
Neuromuscular Junction
–The small branch of the axon that forms
the neuromuscular junction with the
muscle fiber
•What are small membrane bound sacs
found in the axon terminal that contain
acetylcholine?
–Synaptic vesicles
•What is the neurotransmitter secreted
by the neuron axon that binds to
receptor sites on the muscle fiber
initiating an impulse in the sarcolemma?
–Acetylcholine
•What happens when a nerve impulse
reaches the axon terminal?
–Calcium channels in its cell membrane
open
•When open, what do the channels allow
to enter?
–Large amounts of calcium ions
•What is the function of the calcium?
–It causes the Ach to be released into the
synaptic cleft by exocytosis
33
Neuromuscular Junction
• An indented trough-like area on the muscle fiber where the Ach is
released by the axon terminal of the motor neuron is?
– Motor end plate
• Where are numerous Ach receptors present?
– On the motor end of the sarcolemma
• One neuron may supply as few as 4 or as many as several
hundred what?
– Muscle fibers
• What is a motor unit?
– A motor neuron and all the muscle fibers it supplies
34
Action Potential and Sarcolemma
•
1.
The difference between the charge
inside and outside the membrane is
called the?
– Resting Membrane potential
•
Polarized sarcolemma: The
outside face is positive, inside
negative. Predominate
extracellular ion is sodium;
intracellular is potassium.
Sarcolemma impermeable to
both ions
Inside the sarcolemma, more negative
4. Immediately after
or positive?
waveatpasses,
2.depolarization
End plate potential
motor end
causes adjacent
areasagain:
of
sarcolemma
changes
Na+
sarcolemma
toKbecome
permeable
+ channels
channels
close,
• What diffuses out of the fiber?
to sodium
(voltage gated sodium
+ diffuses
open,
K
from cell.
channels open). Sodium
ionsThis
• K+ ions
restores
potential.
diffuseresting
rapidly into
the cell, resting
–+ What is the sodium pumps function
in
potential decreases
– in same
Repolarization
occurs
↑ Na Stimulus
this process?
depolarization.
If stimulus is
direction
as depolarization
and
strong
enough
action
potential
is
• Restores ionic conditions to restore
a occurcharge
3. Positive
inside
initial
must
again
before
muscle
initiated
patch
of sarcolemma changes the
negative resting membrane potential
stimulated
again. Ionic
permeablility of an adjacent patch,
• Action potential generation:
concentrations
resting
opening voltage of
gated
Na+
potential
restored
by sodium
channels there.
Membrane
potential inpump.
that region decreases
potassium
– Negative
and depolarization occurs there
also. Action potential travels
rapidly over entire sarcolemma
35
Steps of the Action Potential
• Depolarization
• Propagation
• Repolarization
• What happens once acetylcholine is released and bound to
receptors?
– It is destroyed by acetylcholinesterase (AChE)
• What does this breakdown assure?
– That the muscle won’t continually contract
• What resumes contraction?
– Further nerve stimulation
• What is the, “all or none response?”
– Once the action potential triggers the muscle contraction, it will
completely contract or not contract at all.
– There is no partial contraction
36
•
What is a quick
contraction/relaxation of a muscle
due to a single, brief stimulus?
–
•
Muscle Contraction
Muscle twitch
What does the strength of a muscle
twitch depend on?
–
How many motor units are involved
• Name the 3 phases of a twitch:
1. The latent period –
•
•
Initiation of the action potential to
beginning of the shortening of the
muscle fiber
Usually a few milliseconds
2. Period of contraction –
•
•
Onset of shortening to the peak of
the pull
10-100 milliseconds
3. Period of relaxation –
•
•
•
•
Ca++ reenters the sarcoplasmic
reticulum.
Muscle tension decreases to zero.
Returns to normal length
Cell will not respond to further
stimulation until the repolarization is
complete – “absolute refractory
period”
37
Graded muscle response
• Muscle contractions don’t usually occur as single twitches. How
do they usually occur?
– As long smooth contractions
• Do they vary in strength?
– Yes
• What are these variations called?
– Graded responses
• Name the 2 ways to grade responses:
– Change of stimulation speed (frequency)
– Change of number of motor proteins involved (strength)
38
Wave summation
• What happens if 2 electrical stimuli are delivered to a muscle in
rapid succession?
– The second will be stronger than the first
• Why?
– There is more shortening of the second because the muscle is already
partially contracted when the second one begins (they are added
together making the second bigger)
• What is the exception to this rule?
– When the second stimulus occurs before the refractory period is over
39
Tetanus
• What is tetanus?
– Smooth, sustained contraction
• What causes it?
– Increasing the rate of the stimulus to the point that relaxation time
between twitches becomes shorter and shorter and the degree of
summation becomes greater
• What eventually occurs due to this?
– All evidence of muscle relaxation disappears and contractions fuse
into a sustained contraction
• What will prolonged tetanus result in?
– Muscle fatigue
• Unfused/incomplete tetanus
– if stimulate at 20-30 times/second, there will be only partial
relaxation between stimuli
• Fused/complete tetanus
– if stimulate at 80-100 times/second, a sustained contraction with no
relaxation between stimuli will result
40
Multiple Motor Unit Summation
• What is another name for this process?
– Recruitment
• Describe it.
– Delivering shocks of increasing voltage to make more muscle fibers
respond to the stimulus
• What is the stimulus at which the first noticeable contraction
occurs?
– Threshold stimulus
• As the stimulus increases and more motor units respond causing
more vigorous contraction, what is ultimately reached?
– Maximal stimulus
• What is the maximal stimulus?
– The point at which all motor units are responding and and increase in
stimulus intensity will no longer increase the strength of the
contraction
41
Motor Unit
• What is a motor unit?
– A motor neuron and all the muscle fibers it supplies
• What happens when a motor neuron fires?
– All the muscles it innervates contract
• How many muscle fibers per motor unit?
– From several hundred to 4
• Which muscles have small motor units?
– Muscles with fine control (eyes, fingers)
• Which have large?
– Weight bearing muscles (hip)
• What type of contraction occurs when only a single motor unit is
stimulated and why?
– Weak contraction
– Muscle fibers are not clustered they are spread out so a single motor
unit does not affect enough of the muscle
42
Treppe/Muscle Tone
• What is another name for Treppe?
– The staircase effect
• Explain this process.
– If a stimulus of the same strength is repeated several times,
contraction strength increases with each successive stimulus
• What is the reason for this?
– Increased efficiency of the muscle’s enzymes after it warms up and
the increased availability of calcium
• Muscle Tone:
• What is it?
– State of slight but constant contraction in skeletal muscle
• What is the result of this?
– Joint stability and posture maintenance
• Does it result in movement?
– No
43
Isotonic/Isometric Contractions
• What is an isotonic contraction?
– Muscle contracts
– Changes in length
– Causes movement of the load put on it
• What are the 2 flavors of isotonic contractions?
– Concentric – muscle shortens and does work
– Eccentric – muscle contracts as it lengthens
• What is an isometric contraction?
– Muscle contracts
– Tension increases
– Length of muscle doesn’t change (does not shorten or lengthen)
44
•How many myofibrils are in a
single muscle fiber?
–100’s to 1000’s
Anatomy of skeletal
muscle fiber
•How much of a cells volume
are myofibrils?
–About 80%
•What are the dark and light
bands on each myofibril?
–A and I bands
•What is the name of the
region between Z discs?
–Sarcomere
•What are the functional units
of skeletal muscle?
–Sarcomeres aligned end to
end
•What is squeezed in between
the myofibrils and sarcoplasm?
–mitochondria
45
•What is the tail of myosin
composed of?
Myofilament composition
–Heavy polypeptide chains
•What are the business ends of
myosin?
–Globular heads
•What do the heads link
together during contraction?
–Thick and thin filaments
(cross bridges)
•What other binding sites
beside actin sites are found on
the myosin heads?
–ATP and ATPase enzymes
•Where do myosin heads
attach during contraction?
–G actin (globular)
•The G actin monomers are
polymerized into what?
– long actin filaments called F
actin (fibrous)
46
•What is the backbone of of thin
filament formed by?
–Actin filament that coils back on
itself, forms helical, double strand
of pearls
Myofilament comp (cont)
•What are the regulatory proteins
found in thin filament?
–2 strands of tropomyosin (stiffens)
–Troponin
•What is tropomyosin’s function?
–In relaxed muscle it blocks actin’s
active sites, preventing myosin
from binding
•What is troponin’s function?
–3 polypeptide complex
• (TnI) inhibitory, binds to actin
•(TnT) binds to tropomyosin,
positions it on actin
•(TnC) binds calcium ions
•What do both of these regulatory
proteins help control?
–Myosin/actin interactions during
contraction
•What is the newly discovered muscle
filament?
–Elastic filament
•What are its functions? What is it made
of?
–Holds thick filaments in place
–Helps muscle spring back into shape
–Titin
47
Sliding filament Mechanism for Muscle fiber
contraction
• What occurs when a muscle contracts?
– Each individual sarcomere shortens
– Overall length of muscle cell decreases
• What is the position of actin filaments in a relaxed state?
– Barely overlapping each other
• What is their position during contraction?
– Pulled inward
– Overlap to a major extent
• What happens to the distance between Z lines?
– They are reduced, and the overall length of the sarcomere is
shortened
• What are major role players in the “Sliding Filament
Mechanism?”
– The structure of myosin and actin
48
•Once actin binding sites are
exposed what are the events
of contraction?
Muscle fiber
Contraction
–Cross bridge: myosin heads
strongly attracted to
exposed sites
–Power stroke: As binding
occurs, head of myosin
pivots (70o) to bent low
energy shape; pulls on thin
filament, sliding toward
center or sarcomere
–Cross bridge detachment:
ATP bind to myosin head,
loosens hold on actin; cross
bridge detaches
–Cocking of myosin head:
ATPase in myosin head
hydrolyzes ATP to ADP and
Pi; returns myosin head to
pre-stroke, high-energy,
position. Ready for next
sequence.
49
•What is the structure of thick filament?
–Head of each thick filament is extended
on a flexible arm
–Head attracted to active sites on the
actin molecule
–Myosin can cleave to ATP to form ADP
and release energy (ATPase enzyme)
Sliding filament (cont)
•What is the structure of thin filament?
–Two actin strands coiled with a
tropomyosin strand
–Tropomyosin strand covers the binding
sites that myosin heads are attracted to
•What is troponin?
–Protein molecule that is bound to both
the tropomyosin strand and actin
–Binds calcium ions
50
Steps in Sliding Filament Mechanism
Step 1.
• What is the position of actin filaments when relaxed?
– Slightly overlapping
•
When ATP binds to myosin head what is it cleaved into?
– ADP
•
What is the result of this process?
– Energy released is stored
– Myosin head is in cocked position (perpendicular to actin and myosin
strands)
Step 2.
• What travels down the sarcolemma of the muscle cell?
– An action potential
•
What carries the impulse deep into the myofibrils?
– T tubules
•
What does it trigger?
– The release of Ca++ from the sarcoplasmic reticulum
51
Steps of Sliding Mechanism (cont)
• What flows into the sarcoplasm surrounding the myofibrils?
– Calcium ions
Step 3.
• What occurs from the Ca++ binding to troponin?
– Troponin and tropomyosin becomes buried deeper into the actin
filaments
• What happens to the active binding sites for the myosin heads?
– They uncover
Step 4.
• What do the myosin heads do at this stage?
– Bind to the uncovered active sites on the actin strands
• What is the result of this binding?
– Stored energy form the cleavage of the ATP is used to tilt the head
inward
52
Steps of Sliding Mechanism (cont)
Step 5.
• As the myosin head tilts inward, what becomes of the actin
strand?
– It is pulled with it
• What is this inward pulling of the actin strand called?
– Power stroke
Step 6.
• Once tilted, what does the myosin head do?
– Releases ADP
• What binds to the head after this?
– A new ATP molecule
• What is the result of this?
– Head detaches from the actin
Step 7.
• What becomes of the new ATP molecule?
– It is cleaved into ADP, head is cocked again
– ready to reattach to a new active site
53
Anaerobic Glycolysis and Lactic Acid Formation
• What is the first step of aerobic or anaerobic respiration?
– Glycolysis
• Where does this occur?
– In the cytoplasm (no oxygen required)
• What is glycolysis?
– Glucose molecule is split into 2 pyruvic acid molecules
• What is released when the glucose is split?
– Energy to form some ATP
• How much ATP is obtained from each glucose molecule that is
split?
– A net gain of 2 ATP’s
• What happens to the pyruvic acids in the mitochondria if oxygen
is available?
– They will be broken down by aerobic respiration
• What happens when no oxygen is available for this process?
– Pyruvic acids are converted into lactic acid
• What is this conversion process called?
– Anaerobic glycolysis
54
Creatine Phosphate
•Excess ATP within resting muscle used to form creatine phosphate
•Creatine phosphate 3-6
times more plentiful
than ATP within muscle
•Its quick breakdown
provides energy for
creation of ATP
•Sustains maximal contraction for 15 sec (used for 100 meter dash).
•Athletes tried creatine supplementation
–gain muscle mass but shut down bodies own synthesis (safety?)
55
Aerobic
Cellular
Respiration
•ATP for any activity lasting over 30 seconds
–if sufficient oxygen is available, pyruvic acid enters the mitochondria to
generate ATP, water and heat
–fatty acids and amino acids can also be used by the mitochondria
•Provides 90% of ATP energy if activity lasts more than 10 minutes
•Where does aerobic respiration occur?
•In mitochondria
•What does it require?
•Oxygen
•What does it involve?
•Sequence of chemical reactions in which bonds of fuel molecules are broken
and energy released is used to make ATP
•What is broken down and what is the final product of ACR?
•Glucose
•Final product is: water, carbon dioxide and large amounts of ATP
56
Anaerobic Cellular Respiration
•ATP produced from glucose breakdown
into pyruvic acid during glycolysis
–if no O2 present
•pyruvic converted to lactic acid which diffuses
into the blood
•Glycolysis can continue anaerobically to
provide ATP for 30 to 40 seconds of
maximal activity (200 meter race)
57
Anaerobic Glycolysis and Lactic Acid Formation
• Is anaerobic glycolysis an efficient source of energy?
– No
• Why?
– Large amounts of glucose are needed and small amounts of ATP are
generated
• What can lactic acid build up in muscle cause?
– Muscle fatigue
– Muscle soreness
58
Use of Energy Systems
• When are ATP and creatine phosphate reserves used?
– Activities requiring short power surges
– Weight lifting, sprinting, diving
• When is anaerobic glycolysis used?
– More sustained activity
– Tennis, soccer, swimming
• When is aerobic respiration used?
– Very prolonged activities
– Marathons, jogging, bicycling
• What kicks in when an activity becomes prolonged or strenuous
and the aerobic mechanism can’t keep up with ATP production?
– The anaerobic mechanism
59
Muscle Fatigue
• What occurs when ATP production cant keep up with ATP usage?
– Muscle contractions become less effective until eventually the
muscle activity ceases completely
• What occurs is no ATP is available?
– Contractures
• What are contractures?
– The state of continuous contraction
• Why does this occur?
– Because myosin heads cannot detach
60
Oxygen debt
• What is required following exercise?
– Large amounts of oxygen
• Why?
– In order to complete and restore all the oxygen requiring activities
that were put on hold or slowed down during exercise
• What is an oxygen debt?
– The extra amount of oxygen that must be taken in by the body to
perform these restorative processes following exercise
• What must be restored?
– ATP
– Creatine phosphate reserves
– Muscle oxygen reserves must be replenished
61
Heat Production
• How much energy released during a muscle contraction is
actually used for work?
– 20 to 25%
• Where does the rest go?
– Into heat
• How does the body respond to this?
– By dilating blood vessels in the skin and sweating to release some of
the heat
• What does the body do when it is too cold?
– Stimulates rapid muscle contractions to produce heat
62
Force, Velocity and Duration of Muscle Contraction
•
What affects the force or strength of a muscle contraction?
1. Number of muscle fibers contracting
The more motor units recruited, stronger the contraction
2. The relative size of the muscle –
Greater bulk = Greater strength
Strength increases from exercise – hypertrophy
3. Series – Elastic elements –
Non-contracting components of muscle
Transfer tension to load being worked on
More rapid stimulation = more force exerts
4. The degree of muscle twitch
Optimal operational length of skeletal muscle = 80-120%
of resting length
Muscles maintain this length by the way they are attached to bone
63
Velocity and Duration of Muscle Contraction
• What is a load?
– The resistance the contracting muscle is up against
• What happens if the force of contraction is greater than the load?
– Movement occurs
• What if the load exceeds the force of contraction?
– Muscle length does not change and the contraction is isometric (no
movement)
64
Fiber types
Red (slow twitch) fibers –
– These thin muscle cells contract slowly and are rich in?
• Myoglobin
– They have abundant supply of ____________?
• Oxygen
– What do they use for ATP production?
• Aerobic pathway
•
They are fatigue resistant. What does this mean?
– They can contract for long periods of time
•
Because they are thin, they don’t generate much?
– Power
White (fast twitch) Fiber –
– Large, light colored fibers with little?
• Myoglobin
– Contract rapidly
– Depend on aerobic pathway for ATP generation
– Powerful contractions but fatigue easily
Intermediate (fast twitch) fibers –
– Reddish pink
– Intermediate size, quick contractions
– Fatigue resistant (but less than slow twitch fibers)
65
Fibers
• What kind of fibers do most muscles contain?
– A mixture of:
– Red fibers – slow twitch, fatigue resistant
– White fibers – fast twitch, easily fatigued
– Intermediate fibers – fast twitch, fatigue resistant (less than slow
twitch)
• What determines the percentage of each fiber type?
– Genetics
• Do athletes in endurance events have higher % of slow or fast
twitch fibers?
– Slow twitch
• Athletes in sprint events. Higher % of slow or fast twitch fibers?
– Fast twitch
66
Effects of Exercise on Muscle
•
What effects does aerobic exercise have on muscle?
1.
2.
3.
4.
5.
•
Increased capillaries surrounding skeletal muscle
Mitochondria in each skeletal muscle increases
Skeletal muscles synthesize more myoglobin
Improved delivery of nutrients and oxygen to body tissues
Heart develops greater stroke volume
What becomes of muscle that isn’t used?
– Atrophy
– Degeneration
– Loss of muscle mass
67
Skeletal Muscle Characteristics
•Elaborate sarcoplasm
–Yes
•Gap junctions
–No
•Neuromuscular junctions
–Yes
•Regulation of contraction
–Voluntary via axonal endings of somatic
•Source of Ca++
•Location
–Attached to bone or skin
•Appearance
–Single, long, , cylindrical, multinucleate,
striated
•Connective Tissue components
–Epimysium, perimysium, endomysium
•Myofibrils composed of sarcomeres
–Yes
•T tubules, site invagination
–Yes; 2 in each sarcomere
–At A-I junctions
–SR
•Site of calcium regulation
–Troponin on actin thin filaments
•Pacemakers
–No
•Speed of contraction
–Slow to fast
•Rhythmic contraction
–No
•Response to stretch
–Contractile strength increases with
degree of stretch
•Respiration
–Aerobic and anaerobic
68
Cardiac Characteristics
•Location
–Walls of heart
•Appearance
–Branching chains of cells,
uni/binucleate; striations
•Connective Tissue components
–Endomysium, attached to fibrous
skeleton of heart
•Myofibrils composed of sarcomeres
–Yes. But myo’s irregular thickness
•T tubules, site invagination
–Yes. One in each sarcomere at Z
disc
–Larger than skeletal
•Elaborate sarcoplasmic ret.
–Less than skeletal. 1-8% of cell
volume; scant terminal cisternae
•Gap junctions
–Yes. At intercalated discs
•Neuromuscular junctions
–No
•Regulation of contraction
–Involuntary
•Source of Ca++
–SR, extracellular fluid
•Site of calcium regulation
–Troponin on actin thin filaments
•Pacemakers
–Yes
•Speed of contraction
–Slow
•Rhythmic contraction
–Yes
•Response to stretch
–Contractile strength increases with
degree of stretch
•Respiration
–Aerobic
69
Smooth Muscle Characteristics
•Neuromuscular junctions
•Location
–Walls of hollow organs( - Heart)
•Appearance
–Uninucleate, fusiform, no striations
•Connective Tissue components
–Endomysium
•Myofibrils composed of sarcomeres
–No. Actin/myo throughout
–Dense bodies anchor actin filament
•T tubules, site invagination
–No. Only caveoli
•Elaborate sarcoplasm
–Equivalent to cardiac
–Some SR contacts the sarcolemma
•Gap junctions
–No in single unit
–Yes in multi
•Regulation of contraction
–Involuntary
•Source of Ca++
–SR, extracellular fluid
•Site of calcium regulation
–Calmodulin in the sarcoplasm
•Pacemakers
–Yes (single only)
•Speed of contraction
–Very slow
•Rhythmic contraction
–Yes (single unit only)
•Response to stretch
–Stress-relaxation response
•Respiration
–Mainly aerobic
70
Neck Muscles (Cat)
1.
2.
3.
4.
5.
6.
7.
Digastricus
Mylohyoideus
Geniohyoid
Sternohyoideus
Sternomastoid
Clavotrapezius
External Jugular
Vein
71
Thoracic superficial (cat)
1. Pectoantebrachialis
2. Pectoralis Major
3. Pectoralis Minor
4. Xiphihumeralis
5. Linea Albea
6. Epitrochlearis
7. Triceps (Long Head)
8. Teres Major
9. Subscapularis
10.Serratus Anterior
11.Latissimus Dorsi
72
Thoracic – deep (cat)
1. x
2. Rectus Abdominis
3a. Scalenus Anterior
3b. Scalenus Medius
3c. Scalenus Posterior
4. Serratus Anterior
5. Subscapularis
6. Teres Major
7. Coracobrachialis
8. Latissimus Dorsi
73
Shoulder & Upper Back - superficial
1.
2.
3.
4.
5.
Latissimus Dorsi
Spinotrapezius
Acromiotrapezius
Clavotrapezius
Levator Scapulae
Ventralis
6. Spinodeltoid
7. Acromiodeltoid
8. Clavodeltoid
9. Triceps Lateral Head
10. Triceps Long Head
74
Shoulder and Upper Back - deep
1. Trapezius
(Reflected)
2. Acromiotrapezius
3. Supraspinatus
4. Infraspinatus
5. Triceps (Long Head)
6. Triceps (Lateral
Head)
7. Acromiodeltoid
8. Clavodeltoid
9. x
10.x
11.Rhomboideus Minor
12.Rhomboideus Major
13.Trapezius
14.Latissimus Dorsi
15.x
75
Deep Back – view 2
76
Upper Arm - lateral
1.
2.
3.
4.
5.
6.
7.
8.
9.
Trapezius
Levator Scapulae
Teres Major
Triceps Lateral Head
(Reflected)
Triceps Long Head
Triceps Medial Head
Brachialis
Clavodeltoid
x
77
Upper Arm - Medial
1.
2.
3.
4.
Clavodeltoid
Biceps Brachii
Triceps Medial Head
Epitrochlearis (Cat
Muscle)
5. Triceps Long Head
78
Forearm - lateral
1. Long Head of Triceps
2. Lateral Head of Triceps
3. Brachialis
4. Brachioradialis
5. Extensor Carpi Radialis Longus
6. Extensor Carpi Radialis Brevis
7. Extensor Digitorum Communis
8. Extensor Digitorum Lateralis
9. Extensor Carpi Ulnaris
10. Flexor Carpi Ulnaris
11. X
79
Forearm - medial
1. Brachioradialis
2.
3.
4.
5.
6.
7.
Extensor Carpi Radialis Longus
Extensor Carpi Radialis Brevis
Pronator Teres
Flexor Carpi Radialis
Palmaris Longus
Flexor Carpi Ulnaris
8. Clavodeltoid
9. Biceps Brachii
10. x
11. Long Head of Triceps
12. Medial Head of Triceps
13. Flexor Digitorum Superficialis
80
Abdominal & Lower Back
1.
2.
3.
4.
5.
Aponeurosa
Rectus Abdominus
Transversus Abdominus
External Oblique
Internal Oblique
81
Lower Back
1.
2.
3.
4.
5.
6.
Multifidus
Erector Spinae
External Oblique
Latissimus Dorsi
Spinotrapezius
Thoracolumbar Fascia (Cut)
82
Upper Leg – lateral, superficial
1.
2.
3.
4.
5.
6.
7.
Semitendinosus
Biceps Femoris
Caudofemoralis
Gluteus Maximus
Gluteus Medius
Tensor Fascia Lata
Sartorius
83
Upper Leg – lateral, deep
1.
2.
3.
4.
5.
6.
7.
8.
9.
Biceps Femoris (Reflected)
Caudofemoralis (Reflected)
Gluteus Maximus (Reflected)
Gluteus Medius
Tensor Fascia Lata (Reflected)
Semitendinosus
Semimembranosus
Adductor Femoris
Sciatic Nerve
10.
11.
12.
13.
14.
15.
16.
17.
Vastus Lateralis
Sartorius
Tibialis Anterior
Extensor Digitorum Longus
Peroneus Complex
Soleus
Gastrocnemius
Skippy's Tail
84
Upper Leg - medial, superficial
1.
2.
3.
4.
5.
6.
7.
Sartorius
Gracilis
Skippy's Scrotum
Semitendinosus
Gastrocnemius
Plantaris
Soleus
85
Upper Leg – medial, deep
1.
2.
3.
4.
5.
6.
Sartorius
Vastus Lateralis
Rectus Femoris
Vastus Medialis
Iliopsoas Complex
Pectineus
7. Adductor Longus
8. Adductor Femoris (2 Heads)
9. Semimembranosus
10. Semitendinosus
11. Gastrocnemius
86
Lower Leg - lateral
1.
2.
3.
4.
5.
6.
7.
Tibialis Anterior
Extensor Digitorm Longus
Peroneus Longus
Peroneus Brevis
Peroneus Tertius
Soleus
Gastrocnemius
8. Biceps Femoris
9. Semitendinosus
10. Semimembranosus
11. Adductor Femoris
12. Vastus Lateralis
87
Lower Leg - Medial
88
Frontalis
Corrugator supercilli
Orbicularis oculi
Levatator labil superioris
Zygomatic Minor/Major
Galea
aponeurotica
Temporalis
Epicranius
Occipitalis
Buccinator
Risorius
Orbicularis oris
Mentalis
Depressor labil inferioris
Depressor
Anguli oris
Platysma
Masseter
Sternocleidomastoid
Splenius capitis
Trapezius
89
•Epicranius/ occipitalfrontalis
•Desc
Muscles of scalp
–Bipartite
–Frontalis/occipitalis connected by
cranial aponeuroses
•Actions
–Pull scalp back and forward
•Frontalis
•Desc
–Covers forehead and dome of skull
–No bony attachments
•Origin/Insertion?
–O: Galea aponeurotica
–I: Skin of eyebrows and root of
nose
•Action
–Raise eyes, wrinkles forehead
horizontally
•Nerve
–Cranial VII
90
•Occipitalis
•Desc
Muscles of Scalp
–Overlies posterior occiput
–Fixes origin of frontalis
•O/I
– O: Occipital, temporal
– I: Galea aponeurotica
•Action
–Fixes aponeurosis
–Pulls scalp posteriorly
•Nerve
–Facial
91
•Corrugator supercilii
•Desc
–Small muscle associated with ocularis
oculi
Muscles of the face
Expression
•O/I
– O: Arch of frontal above nasal
– I: Skin of eyebrow
•Action
–Draws eyebrows together
–Wrinkles forehead skin vertically
(frown)
•Facial nerve
•Orbicularis oculi
•Desc
–Thin, tripartite sphincter of eyelid
–Surround rim of orbit
•O/I
– O: Frontal, maxillary, ligs around orbit
– I: Tissue of eyelid
•Action
–Protect from light/injury
–Blink, squint, eyebrows inferiorly
•Nerve
–Facial
92
•Zygomaticus
•Desc
–Pair of muscles diagonal from
cheek to corner of mouth
Face muscles
Expression
•O/I
–Zygomatic
–Skin and muscle at corner of
mouth
•Action
–Raises corner of mouth upward
(smile)
•Nerve
–Facial
•Risorius
•Desc
–Slender, inferior and lateral to
zygo
•O/I
–Lateral fascia – masseter
–Skin at angle of mouth
•Action
–Draws corner of lip laterally;
tenses lips; synergist of
zygomaticus
93
•Levator labil superioris
•Desc
–Thin muscle between orbicularis
oris and inferior eye margin
Facial muscles
Expression
•O/I
–Zygomatic bone, infraorbital
margin of maxilla
–Skin and muscle of upper lip
•Action
–Open lips; raises and furrows the
upper lip
•Depressor labil inferioris
•Desc
–Small muscle running from
mandible to lower lip
•O/I
–Body of mandible lateral to its
midline
–Skin and muscle of lower lip
•Action
–Draws lower lip inferiorly (pout)
94
•Depressor anguli oris
•Desc
–Small muscle lateral to depressor
labii inferioris
Facial muscles
Expression
•O/I
–Body of mandible below incisors
–Skin and muscle at angle of mouth
below insertion of zygo
•Action
–Draws corner of mouth downward
and lateral (tragedy mask grimace)
•Obicularis oris
•Desc
–Complicated, multi-layered, fibers
in many directions, most circular
•O/I
–Arises indirectly from maxilla and
mandible; associated with lips
–Encircles mouth; inserts into
muscle and skin at angles of mouth
•Action
–Closes lips, purses and protrudes
lips (kissing, whistling)
95
•Mentalis
•Desc
–One of pair forming V-shaped
muscle of chin
Facial muscles
Expression
•O/I
–Mandible below incisors
–Skin of chin
•Action
–Protrude lower lip
–Wrinkles chin
•Buccinator
•Desc
–Thin, horizontal cheek muscle,
deep to masseter
•O/I
–Molar region of maxilla and
mandible
–Orbicularis oris
•Action
–Draws corner of mouth laterally
–Holds food during chewing
–Whistling, sucking
96
Facial muscles
Expression
•Platysma
•Desc
–Unpaired, thin, sheet-like
superficial neck muscle
•O/I
–Fascia of chest (over pec and delt)
–Lower margin of mandible and skin
and muscle at corner of mouth
•Action
–Depress mandible
–Pull lower lip back and down
–Downward sag of mouth
–Tensed skin of neck (shaving)
97
•Masseter
•Desc
–Powerful muscle at lateral aspect
of mandible
Mastication and tongue
Chewing
•O/I
–Zygomatic arch and maxilla
–Angle and ramus of mandible
•Action
–Prime mover of jaw closure;
elevates mandible
•Nerve
–Trigeminal (cranial V)
•Temporalis
•Desc
–Fan shaped
–Covers temporal, frontal and
parietal bones
•O/I
–Temporal fossa
–Coronoid process of mandible via
tendon deep to zygomatic arch
98
•Medial pterygoid
•Desc
–Deep 2 headed muscle runs along
internal surface of mandible
–Largely concealed by bone
Mastication and tongue
Chewing
•O/I
–Medial surface of lateral pterygoid plate,
maxilla, palatine
–Medial surface of mandible, near angle
•Action
–Elevate mandible
–Side to side (grinding teeth)
–Protrude mandible
•Lateral pterygoid
•Desc
–Deep 2 headed, superior to medial
pterygoid
•O/I
–Greater wing, pterygoid plate
–Mandible condyle, capsule of
temporomandibular joint
•Action
–Protrude mandible anteriorly
–Forward, side to side grind of lower
teeth
99
•Buccinator
•Desc
–Thin, horizontal cheek muscle,
deep to masseter
Mastication and tongue
Chewing
•O/I
–Molar region of maxilla and
mandible
–Orbicularis oris
•Action
–Draws corner of mouth laterally
–Holds food during chewing
–Whistling, sucking
100
•Genioglossus
–Fan shaped muscle forms
bulk of inferior tongue
–Prevents tongue from falling
backward obstructing
respiration
Mastication and tongue
Chewing
•O/I
–Internal mandible near
symphysis
–Inferior tongue, body of
hyoid bone
•Action
–Protrudes tongue
–Can depress, or with other
muscles retract tongue
•Nerve
–Hypoglossal (cranial XII)
101
•Hypoglossus
•Flat quadrilateral muscle
•O/I
–Body, greater horn of hyoid
–Inferolateral tongue
Mastication and tongue
Chewing
•Action
–Depress tongue, draw its sides
downward
•Nerve
–Hypoglossal nerve
•Styloglossal
•Slender, runs superior, right
angles hypoglossus
•O/I
–Styloid process of temporal
bone
–Inferolateral tongue
•Action
–Retract, elevate tongue
•Nerve
–Hypoglossal nerve
102
Indentify muscles
103
•Digastric
•Two bellies united by inter
tendon, V shape under chin
•O/I
Suprahyoid Muscles
Swallow
–Lower margin of mandible
(anterior belly), mastoid
process (posterior belly)
–Connective tissue loop to
hyoid bone
•Action
–In concert, elevate hyoid
–Steady for swallowing, speech
–Open mouth, depress
mandible
•Nerve
–Cranial V (anterior)
–Cranial VII (posterior)
104
•Stylohyoid
Suprahyoid muscles - swallow
–Slender, below jaw angle
–O-styloid process
–I- hyoid, median raphe
–Action: elevate, retract hyoid, elongate
mouth floor during swallow
–Facial nerve
•Mylohoid
–Flat, triangular, deep to digi, pair forms
sling, floor of anterior mouth
–O: medial mandible
–I: hyoid, raphe
–Action: elevate hyoid, floor of mouth;
tongue back, up, force food into pharynx
–Mandible trigeminal nerve
•Geniohyoid
–Narrow, partner medially, chin to hyoid
–O: inner mandible surface
–I: Hyoid bone
–Action: pull hyoid superiorly, anteriorly;
widen pharynx to receive food
–Cranial XII
105
•Sternohyoid
Infrahyoid Muscles - swallow
–Most medial of neck, thin,
superficial (-neck), covered by SCM
–O: manubrium, medial clavicle
–I: Lower hyoid
–Action: Depress larynx, hyoid
(mandible fixed), flex skull
–C1-C3 thru ansa cervicals
•Sternothyroid
–Lateral, deep to sternohyoid
–O: posterior manubrium
–I:thyroid cartilage
–Action: Pull thyroid cartilage,
larynx, hyoid inferiorly
–Same as sterno
•Omohyoid
–Strap like, 2 bellies, lateral to
sternohyoid
–O: superior scapula
–I: hyoid, lower border
–Action: Depress, retract hyoid
–Same as sterno
106
•Thyrohyoid
Infrahyoid muscles - swallow
–Superior continuation of
sternothyroid
–O:thyroid cartilage
–I: hyoid bone
–Action: depress hyoid, elevate
larynx if hyoid fixed
–1st cervical nerve vie hypoglossal
•Pharyngeal constrictor
–3 paired, fibers run circularly in
pharynx wall, superior – innermost,
inferior – outer
–O: anteriorly to mandible, medial
pterygoid plate, hyoid, laryngeal
cartilages
–I: posterior median raphe of
pharynx
–Action: as group, in sequence,
constrict pharynx during
swallowing, peristalsis
107
Identify throat muscles
108
Identify muscles
109
Identify muscles
110
•Sternocleidomastoid
Anterolateral Neck
–2 headed, deep to platysma,
anterolateral neck, key
muscle in neck
–O: manubrium, medial
clavicle
–I: mastoid process, superior
nuchal line
–Action: Prime head mover,
neck flexion,
•Alone: rotate head toward
shoulder, tilt head side to
side
–Cranial XI, Cervical spinal
2-4
•Scalenes
–More lateral than anterior;
deep to Platysma and SCM
–O: transverse process of
Cervical Vert
–I: anterolateral 1st 2 ribs
–Action: elevate 1st 2 ribs
(breathing), flex, rotate neck
111
Intrinsic back
Head and trunk movement
Splenius
–Broad bipartite superficial, upper
thoracic to skull, bandage muscle
–O: ligamente nuchae, spinous
process C7-T6
–I: mastoid, occipital (capitis),
transverse processes C2-C4
–Action: group – extend/
hyperextend head, splenius on one
side – rotate head, bent toward
same side
–Cervical spinal nerves
112
•Erector spinae
–Prime mover of back extension
–3 columns:
Intrinsic back
head and trunk movement
•Iliocostalis
•Longissimus
•Spinalis
–Bending at waist, return to erect
position
–Full flexion (touch toes) – relaxed
–Reversal (come up) – inactive.
Hamstrings, gluteus max
responsible for straightening (back
injury)
•Iliocostalis
–Most lateral group of ES; from
pelvis to neck
–O: iliac crests, inferior 6 ribs; 3 to 6
cervicals
–I: angles of ribs, transverse of C6C4
–Action: extend vertebral column;
maintain erect posture; one side –
bend vertebral to same side
–Spinal nerves
113
•Longissimus
–Intermediate tripartite of ES;
lumbar to skull; between transverse
processes of vert
–O: transverse of lumbar through
cervical
–I: transverse of thoracic or
cervical, ribs superior to origin
name; capitis into mastoid
–Action: thoracis and cervicis
extend vert column; one side – bend
laterally; capitis – extend head, turn
face same side
–Spinal nerve
Intrinsic back
Head and trunk movement
•Spinalis
–Most medial column of ES, cervicis
rudimentary, poor
–O: spines of upper lumbar, lower
thoracic
–I: spines of upper thoracic, cervical
–Action: extends vertebral column
–Spinal nerves
114
•Semispinalis
–Deep layer of intrinsic back;
thoracic to head
–O: transverse of C7 –T12
–I: occipital (capitis), spinous
process of cervicis and T1-T4
–Action: extend vertebral and head,
rotate to opposite side;
synergistically with SCM
–Spinal nerves
Intrinsic back
head and trunk movement
•Quadratus lumborum
–Fleshy muscles, part of posterior
abdominal wall
–O: iliac crest, lumbar fascia
–I: transverse of upper lumbar,
lower margin of rib 12
–Action: flexes vertebral laterally
(alone), maintains upright, assists
inspiration
–T12 and upper lumbar nerves
115
Identify back muscles
116
•External intercostals
–11 pairs, between ribs; run
obliquely from rib to rib below; in
lower, fibers continuous with
external oblique forming part of
abdominal
–O: inferior border of rib above
–I: superior border of rib below
–Action: With 1st ribs fixed by
scalenes, pull ribs toward each
other to elevate rib cage;
inspiration
–Intercostal nerves
Thorax
Breathing
•Internal intercostals
–11 pairs between ribs; deep and at
angles to externals; lower
continuous with internal oblique,
abdominal wall
–O: superior border of rib below
–I: costal groove of rib above
–Action: 12th ribs fixed by quadratus
lumb, posterior abdominal and
obliques – draw ribs together,
depress rib cage; forced expiration
–Intercostal nerves
117
•Diaphragm
–Broad muscle
pierced by aorta,
inferior vena cava,
esophagus; floor of
thoracic cavity;
dome shaped;
fibers converge
from margins of
thoracic to central
tendon
–O: inferior,
internal surface of
rib cage, sternum,
costal cartilage of
last 6 ribs and
lumbar vert
–I: central tendon
–Action: prime
inspiration
–Phrenic nerves
Thorax
Breathing
118
Identify the parts of diaphragm
119
•Rectus abdominis
–Medial, superficial, pair;
pubis to rib cage; 3 segments
–O: pubic crest, symphysis
–I: xiphoid process, costals of
ribs 5-7
–Flex, rotate lumbar region;
fix, depress ribs; stabilize
pelvis during walking
–Intercostal nerves
Anterior, lateral abdomen
•External oblique
–Largest, most superficial of 3
lateral muscles; fibers – down,
medial;
–O: fleshy strips outer surface
of 8 ribs
–I: anteriorly via aponeurosis
into linea alba; pubic crest,
tubercle, iliac crest
–Flex vert column, compress
ab wall, aid back and trunk
rotation
–Intercostal nerves
120
•Internal oblique
Abdomen
–Fibers upward, medial; muscle fans
inferior run downward medial
–O: lumbar fascia, iliac crest,
inguinal lig
–I: linea alba, pubic crest, last 3-4
ribs, costal margin
–Action: same as external
–Intercostal nerves
•Transversus abdominis
–Deepest abdominal muscle, fiber –
horizontal
–O: inguinal lig, lumbar fascia,
cartilage of last 6 ribs, iliac crest
–I: linea alba, pubic crest
–Compresses abdominal wall
–Intercostal nerves
121
Identify muscles
122
Abdomen
123
•Levator ani
Pelvic Diaphragm
–Broad thin, tripartite
(pubococcygeus,
puborectalis, iliococcygeus);
fibers extend inferomedially
–O: pelvis from pubis to
ischial spine
–I: inner coccyx, levator ani
of opposite side
–Support, maintain pelvic
viscera, resists thrusts
(coughing, vomit); forms
sphincters; lifts anal canal
–S4, inferior rectal nerve
•Coccygeus
–Small, triangular, posterior
to ani,
–O: ischial spine
–I: sacrum, coccyx
–Support pelvic viscera,
coccyx; pulls forward
(defecation, childbirth)
–S4-S5
124
Identify pelvic muscles
125
•Deep transverse perineus
Urogenital diaphragm
–Pair spans distance of
ischial rami; females –
posterior to vagina
–O: ischial rami
–I: midline central tendon,
some into vagina wall
–Supports pelvic organs;
steadies central tendon
–Pudendal nerve
•Sphincter urethrae
–Muscle incircling urethra
and vagina
–O: ischiopubic rami
–I: midline raphi
–Constricts urethra; support
pelvis
–Pudendal nerve
126
Identify urogenital
127
•Ischiocavernosus
Superficial genital
–Pelvis to base of penis or
clitoris
–O: ischial tuberosities
–I: crus of corpus cavernosa or
male penis, female clit
–Empties male urethra;
erection of penis and clitoris
–Pudendal nerve
•Bulbospongiosus
–Encloses base of penis, deep
to labia (female)
–O: central tendon, midline
raphe
–I: anteriorly into corpus
cavernosa of penis, clit
–Stabilize, strengthen midline
tendon
–Pudendal nerve
128
Identify genital muscles
129
•Pectoralis minor
–Flat, thin muscle beneath
pec major
–O: anterior surface of ribs
3-5
–I: coracoid process
–Ribs fixed: draw scap
forward/downward; scap
fixed: draw ribs superiorly
–Pectoral nerves
Anterior Thorax
•Serratus anterior
–Deep to scap; beneath,
inferior to pecs on lateral rib
cage; medial wall of axilla;
serrated origins;
–O: muscle slips – ribs 1-8
–I: entire anterior scapula
–Prime mover to hold scap
against chest; rotate scap
lateral/up; raise shoulder;
abduct/raise arm;
–Long thoracic nerve
130
•Subclavius
Anterior thorax
–Small cylindrical; from rib 1
to clavicle
–O: costal of rib 1
–I: groove, inferior clavicle
–Stabilize pec girdle
–Subclavius nerve
131
Identify anterior thorax
132
•Trapezius
–Most superficial of post thorax;
flat, triangular
–O: occipital, nuchae, spines of C7,
all of thoracic
–I: continuous along acromion,
spine of scap, lat 3rd of clavicle
–Stabilize, rotate, retract, raise
scapula;
–Cranial XI
Posterior thorax
•Levator scapulae
–Back/side of neck; deep to traps,
thick, strap like
–O: transverse of C1-C4
–I: medial border of scap
–Elevates/adducts scap; tilts
glenoid down;
–Cervical/spinal nerves
•Rhomboid
–2 rectangular; deep to trap
–O: spinous of C7 – T1
–I: medial scap border
–Square shoulders
–C4-C5 nerves
133
Identify posterior thorax
muscles
134
•Pectoralis major
Arm movement
–O: sternal end of clavicle
–I: fibers converge into
intertubercular groove of
humerus
–Action: prime mover of arm;
rotates medially; adducts; pulls
rib cage
•Latissimus dorsi
–O: indirect via lumbodorsal
fascia into lower 6 thoracic
vert; lower 3-4 ribs; iliac crest
–I: spirals around teres major
into intertubercular groove of
humerus
–Action: prime arm extender;
adduct; rotate at shoulder;
depress scap
•Deltoid
–O: trapezius; lateral 1/3 of
clavicle; acromion/spine
scapula
–I: deltoid tuberosity of
humerus
–Action: prime abduction;
adduct; rotate medially; extend
135
•Subscapularis
–O: subscap fossa
–I: lesser tubercle of humerus
–Action: chief rotator of humerus; holds
humerus head in glenoid
Arm movement
•Supraspinatus
–O: supraspinous fossa
–I: superior greater tubercle
–Action: stabilize shoulder; prevent
downward dislocation
•Infraspinatus
–O: infraspinous fossa
–I: greater tubercle to supraspinatus
–Action: hold head of humerus in glenoid;
rotates humerus laterally
•Teres minor
–O:lateral,dorsal scapula
–I: greater tubercle to infraspinatus
insertion
•Teres major
–O: posterior scapula (inferior angle)
–I: intertubercular groove; latissimus
dorsi
–Action: posteromedially extends,
medially rotates; adducts humerus
136
•Triceps
–O: long head:infraglenoid tubercle;
Lateral head: posterior shaft of
humerus; medial: humerus shaft;
–I: tendon into olecranon process
–Action: extend forearm; flex
forearm;
Arm
Posterior Muscles
•Anconeus
–O: lateral epicondyle
–I: lateral olecranon process of ulna
–Action: abduct ulna; elbow
extension
137
•Biceps brachii
–O: short head: coracoid
process; long head: tubercle
above glenoid; groove of
humerus
–I: radial tuberosity
–Flexes elbow joint; supinate
forearm
Arm
Anterior Muscles
•Brachialis
–O: front of distal humerus;
deltoid muscle
–I: coronoid process of ulna
–Major forearm flexor
•Brachioradialis
–O:lateral supracondyle ridge
at distal humerus
–I: styloid process of radius
–Forearm flexion; stabilize
elbow
138
Identify anterior shoulder
muscles
139
Identify posterior
shoulder
muscles
140
•Pronator teres
–O: medial epicondyle; coronoid
process of ulna
–I: common tendon into lateral
radius
–Pronate forearm
Forearm anterior - superficial
hand, wrist, finger movement
•Flexor carpi radialis
–O: medial epicondyle
–I: base of 2nd and 3rd
metacarpals;
–Wrist flexor
•Palmaris longus
–O: medial epicondyle
–I: palmar aponeurosis; skin
and fascia of palm
–Weak wrist flexor; tense skin
and fascia of palm;
•Flexor carpi ulnaris
–O: medial epicondyle;
olecranon process, posterior
ulna
–I: pisiform, hamate; base of
5th metacarpal
–Flexor of wrist; adducts hand
with extensor carpi ulnaris;
stabilize wrist
141
•Flexor digitorum superficialis
Forearm anterior - superficial
–2 head; deeply placed
(intermediate); overlain, but visible
at distal forearm
–O: Medial epicondyle of humerus;
coronoid of ulna; shaft of radius
–I: 4 tendons into middle phalanges
2-5
–Flex wrist and middle phalanges 25; important finger flexor
–Median nerve
142
Identify anterior
superficial
143
•Flexor pollicis longus
Forearm anterior - deep
–O: anterior surface of
radius and interosseous
membrane
–I: distal phalanx of thumb
–Flexes distal phalanx of
thumb
–Median nerve
•Flexor digitorum
profundus
–O: coronoid process,
anteromedial ulna;
interosseous membrane
–I: 4 tendons into distal
phalanges 2-5
–Slow flexing of any or all
fingers; flex wrist; only
muscle that can flex distal
interphalangeal joints
–Ulnar nerve; median
nerve
144
•Pronator quadratus
Forearm anterior - deep
–O: distal anterior ulnar
shaft
–I: distal anterior radius
–Prime mover of forearm
pronation; helps hold
radius and ulna together
–Median nerve
145
Identify anterior
forearm deep
146
•Extensor carpi radialis
longus
–O: lateral supracondylar
ridge of humerus
–I: base of 2nd meta
–Extend, abduct wrist
–Radial nerve
Forearm – posterior
superficial
•Extensor carpi radialis
brevis
–O: lateral epicondyle
–I: base of 3rd meta
–Extend, abduct wrist;
steady wrist
–Deep radial nerve
•Extensor digitorum
–O: lateral epicondyle
–I: 4 tendons into extensor
expansions, distal
phalanges 2-5
–Prime mover of finger
extensions; extend wrist;
abduct fingers (flare)
147
•Extensor carpi ulnaris
Posterior forearm - superficial
–O: lateral epicondyle,
posterior border of ulna
–I: base of 5th meta
–Extends wrist (+carpi
radialis); adducts wrist
(+carpi ulnaris)
–Posterior interosseous nerve
148
Identify forearm
posterior superficial
149
•Supinator
–O: lateral epicondyle; proximal ulna
–I: proximal radius
–Assists biceps brachii to supinate
forearm; slow supination;
–Posterior interosseous nerve
Posterior forearm - deep
•Abductor pollicis longus
–O: posterior radius and ulna;
interosseous membrane
–I: base of 1st meta, trapezium
–Adducts, extend thumb; abducts wrist
–Posterior interosseous nerve
•Extensor pollicis brevis/longus
–O: dorsal shaft of radius/ulna;
interosseous membrane
–I: base of proximal and distal phalanx of
thumb
–Extends thumb
–Posterior interosseous nerve
•Extensor indicis
–O: posterior ulna; interosseous
membrane
–I: extensor expansion of index finger;
joins tendon of digitorum
–Extends index finger; wrist extension
–Posterior interosseous nerve
150
Identify forearm
muscles deep
151
Muscles acting on the arm
•
Name the muscles that act on the arm.
1. Pectoralis
2. Latissimus dorsi
3. Deltoid
4. Subscapularis
5. Supraspinatus
6. Infraspinatus
7. Teres major/minor
8. Coracobrachialis
9. Biceps brachii
10.Triceps brachii
152
Muscles acting on forearm
•
Name the muscles acting on forearm.
1.
2.
3.
4.
5.
6.
7.
8.
Biceps brachii
Triceps
Anconeus
Brachialis
Brachioradialis
Pronator teres
Pronator quadratus
supinator
153
Muscles acting on wrist./fingers
•
Anterior
1.
2.
3.
4.
5.
6.
•
Flexor carpi radialis
Palmaris longus
Flexor carpi ulnaris
Flexor digitorum superficialis
Flexor pollicis longus
Flexor digitorum profundus
Posterior
1.
2.
3.
4.
5.
6.
Extensor carpi radialis longus/brevis
Extensor digitorum
Extensor carpi ulnaris
Abductor pollicis longus
Extensor pollicis longus
Extensor indicis
154
•Abductor pollicis brevis
Hand – Thenar ball of thumb
–O: flexor retinaculum, nearby
carpals
–I: lateral base of thumb’s
proximal phalanx
–Abducts thumb
–Median nerve
•Flexor pollicis brevis
–O: flexor retinaculum,
trapezium
–I: lateral side of base of
proximal thumb
–Flex thumb
–Median (occasionally ulnar)
•Adductor pollicis
–O: capitate bone and bases of
meta’s 2-4, front of meta 3
–I: medial side of base of
proximal phalanx of thumb
155
•Abductor digiti minimi
–O: pisiform
–I: medial side of proximal
phalanx of little finger
–Abducts little finger
–Ulnar nerve
Hypothenar muscles
in ball of little finger
•Flexor digiti minimi brevis
–O: hamate, flexor
retinaculum
–I: same as abductor minimi
–Flexes little finger
–Ulnar nerve
•Opponens digiti minimi
–O: same as flexor
–I: most of length of meta 5
–Brings meta 5 toward thumb
to cup hand
156
•Palmar interossei
–4 long cone shaped
between meta’s
–O: side of each meta that
faces midaxis of hand
–I: extensor expansion on
1st phalanx of each finger (3)
–Adduct fingers; pull
fingers in; extend fingers
–Ulnar nerve
Midpalmar muscles
•Dorsal interossei
–4 bipennate; fill space
between meta’s; deepest
palm muscles
–O: sides of meta
–I: extensor expansion over
1st phalanx of fingers 2-4
–Abduct fingers; extend
fingers; flex fingers
–Ulnar nerve
157
Midpalmar muscles
•Lumbricals
–O: lateral side of each
tendon of flexor
digitorum profundus
–I: lateral edge of
extensor expansion of
first phalanx of 2-5
–Flex fingers at meta
joints; extend at
interphalangeal
–Median nerve
158
Identify hand muscles
159
•Iliopsoas
–Iliacus/psoas major
–Pass under inguinal lig to insert
via tendon on femur
Thigh and leg
Origin on pelvis
•Iliacus
–O: iliac fossa/crest; lateral sacrum
–I: femur on below lesser
trochanter
–Prime mover for flexing thigh;
trunk during bow
–Femoral nerve
•Psoas major
–O: fleshy slips from transverse
processes, bodies, discs of lumbar
and T12
–I: lesser trochanter of femur
–Same as iliacus; also, lateral
flexion of vert column; posture
–Ventral rami
•Sartorius
–O: anterior superior iliac spine
–I: winds around medial aspect of
knee; inserts into medial, proximal
tibia
–Flexes, abducts, lateral rotation of
thigh; flex knee; tailor’s muscle
–Femoral nerve
160
•Adductor magnus
–O: ishchial and pubic rami and
ischial tuberosity
–I: linea aspera, adductor tubercle of
femur
–Adduct, medially rotate and flex
thigh; hamstring extension
–Obturator nerve
Medial thigh
•Adductor longus
–O: pubis near symphysis
–I: linea aspera
–Adduct, flex, rotate thigh
–Anterior obturator nerve
•Adductor brevis
–O: body and inferior ramus of pubis
–I: linea aspera above adductor
longus
– adducts, medially rotate thigh
–Femoral nerve
•Pectineus
–O: pectineal line of pubis, superior ramus
–I: inferior from lesser trochanter to linea
aspera
–Same as longus
–Femoral, obturator
•Gracilis
–O: inferior ramus, body of pubis, ischial
ramus
–I: medial surface of tibia
–Adduct thigh, flex, medially rotate thigh
161
•Quadriceps femoris
– 4 separate heads, front and side
of thigh, common insertion into
patella and tibial tuberosity
Anterior thigh
•Rectus femoris
–O: anterior inferior iliac spine,
superior margin of acetabulum
–I: patella and tibial tuberosity via
patellar ligament
–Extend knee; flex thigh at hip
–Femoral nerve
•Vastus lateralis
–O: greater trochanter,
interotrochanteric line, linea
aspera
–I: same as femoris
–Extend, stabilize knee
–Femoral nerve
•Vastus medialis
–O: linea aspera,
interotrochanteric line
–I: same as femoris
–Extends knee, stabilize patella
–Femoral nerve
162
•Vastus intermedius
–O: anterior, lateral proximal femur
shaft
–I: same as rectus femoris
–Extend knee
–Femoral nerve
Anterior thigh
•Tensor fasciae latae
–O: anterior iliac crest; anterior,
superior iliac spine
–I: iliotibial tract
– flexes and abducts thigh of the
iliopsoas and gluteus medius and
minimus; rotate thigh medially;
steady the knee and trunk
163
•Gluteus maximus
–Largest, most superficial gluteal
–Bulk of buttocks
–O: dorsal ilium, sacrum, and coccyx
–I: gluteal tuberosity of femur;
iliotibial tract
–Major extensor of thigh;
–Inferior gluteal nerve
Gluteal muscles
•Gluteus medius
–Covered by glut max
–O: between anterior and posterior
gluteal lines – lateral ilium
–I: short tendon lateral aspect of
greater trochanter
–Same as max
–Superior gluteal
•Gluteus minimus
–Smallest, deepest glut
–O: between ant/inf gluteal lines on
ilium
–I: ant bord of greater trochanter of
femur
164
•Piriformis
–Pyramidal muscle posterior hip
–O: anterolateral sacrum
–I: superior border of greater
trochanter femur
–Rotates thigh laterally; abduct
thigh
–S1-S2 – L5
Lateral Rotators
•Obturator externus
–Flat, triangular; deep upper
medial thigh
–O: outer obturator membrane;
pubis; ischium
–I: trochanter fossa of femur
–Same as piriform
–Obturator nerve
•Obturator internus
–O: inner surface of obturator;
greater schiatic; obturator
foramen
–I: greater trochanter
–Same as piri
•Gemellus
–O: ischial spine; ischial tuberosity
–I:greater trochanter
•Quadratus femoris
–O: ischial tuberosity
–I: trochanteric crest
–Rotates thigh laterally
165
Anterior thigh
166
Posterior thigh
167
Deep gluteal muscles
168