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Crash Course BR
1. Notes• Download both
sets of notes2. Begin “lab”
• Turn in before bell rings
3. HW – Ch. 8 (15-19) due Tuesday
https://www.youtube.com/watch?v=jqy0i1KXUO4
How the muscles are namedSix criteria used in naming individual skeletal muscles:•location of the muscle •shape of the muscle
•Trapezius, deltoid, rhomboid•relative size of the muscle •direction/orientation of the muscle fibers/cells •number of origins •location of the attachments •action of the muscle
•Adductor, extensor
How the muscles
are named
Six criteria used in naming individual skeletal muscles:•Direction or orientation of the muscle fibers/cells
How the muscles are namedBasic naming conventions:
Deltoid
• Triangle shaped
Orbicularis
• Orbit
• Circular muscle
Major/Minor
• Large
• Small
How the muscles are namedBasic naming conventions:
Size
• Vastus (large)
• Maximus (large)
• Magnus (big)
Medialis/Lateralus
• Medial (toward the middle)
• Lateral (toward the outside)
How the muscles are namedBasic naming conventions:
Dorsi or dorsal
• backside
Infra/Supra
• Lower
• Upper
Longis/Brevis
• Long
• Short (brief)
How the muscles are namedBasic naming conventions:
• Named for the region in which they are found
• Named for the bone to which they are attached
• Example – Tibialis anterior
How the muscles are namedExample – Biceps femoris
• Two headed muscle
• Attached to the femur
Example – Extensor carpi radialis longus
• Long muscle
• Runs the length of the radius to the carpals
• Extends the fingers
Skeletal MuscleOrgan of the muscular
system
Composed of…
skeletal muscle tissue
nervous tissue
blood
connective tissue
Functions
Movement
Posture
Heat production
Connective Tissue CoveringsFascia Layers of fibrous connective
tissue
Separates an individual muscle from adjacent muscles
Holds it in place
Tendon Cordlike projection beyond
each muscle
Attaches to periosteum
Tendinitis & tenosynovitis
Bursitis
Tendon “Issues”
Tendinitis Fascia inflamed and swollen
Injury or repeated stress
Tenosynovitis Carpal tunnel syndrome
Skeletal Muscle Fibers Represents single cell of
a muscle
Responds to stimulation
contracts when
stimulated
Stimulation ends
relaxation
Contain many
mitochondria
Skeletal Fibers
Myofibrils
Fundamental role in
contractions
Actin (thin protein
filaments)
Myosin (thick protein
filaments)
Striations (alternations
between actin and myosin)
Muscle Strains
Mild strain few fibers are damaged
fascia remains intact
little loss of function
Severe strain muscle fibers and fascia tear
function may be completely
lost
painful, swelling,
discoloration
Begin Muscle Lab
Turn in before bell rings
Tomorrow – continue working on the lab - mainly the ID and coloring
HW – Ch. 8 (15-19)
ID BR
1. Finish notes
2. Finish lab
3. Review bones
4. HW – xword due Th.
Ch. 8 Quiz –Th.
Bone practical tomorrow
Ch. 7-8 Unit Exam –
Tues 3/19
Communication pathway for a
muscle contraction
Brain nerve
motor neuron
release of a
neurotransmitter
neurotransmitter
travels across
the synaptic gap
stimulates
muscle fiber to
contract
Neuromuscular JunctionConnection between neuron & muscle
fiber
Motor neuron
nerve cell that “connects” to
a fiber
Neurotransmitters
stored chemicals in the end of the
nerve fiber
Released when the impulse reaches
the end of the motor neuron
Motor Unit
One single motor
neuron end plate,
but they are densely
branched
One motor neuron
and the many
muscle fibers it
contracts
Skeletal Muscle Contraction
Answer the questions below while watching the video clip:
http://www.youtube.com/watch?v=mejCXr7p37U
What are the 3 types of muscle?
What does a tendon attach?
What is a sarcomere?
What are the 2 chemicals inside a sarcomere?
What does myosin need to “grab on to” actin?
What is the job of tropomyosin?
Why is calcium needed?
What does myosin do if calcium and ATP is present?
Skeletal Muscle Contraction
Role of actin & myosin
myosin contains cross bridges
actin contains binding sites
Sliding filament theory
myosin and actin bind together pulling the fibers to create the contraction (myofibrils shorten)
energy released from ATP by ATPase creating ADP
Skeletal Muscle ContractionAcetylcholine
neurotransmitter that stimulates a contraction
continues as long as Ca+ is present
ATP
energy supply
only enough for muscle to contract for a
short time
Cholinesterase
enzyme that rapidly decomposes acetylcholine
prevents continuous stimulation
Energy SourcesCreatine Phosphate
helps to regenerate ATP
stored if ATP is in sufficient supply
4-6 times more plentiful in cells but depleted rapidly
can’t directly supply the energy transfers energy to ADP
BotulismClostridium botulinum
bacteria that produces botulinus toxin
Inhibits release of acetylcholine
Food poisoning and temporary paralysis
Botox
Oxygen SupplyHemoglobin
carries the oxygen to cells for cellular respiration
iron has a high affinity for oxygen
Myoglobin (muscle cells only)
causes reddish brown color
can carry oxygen
reduces need for continuous blood
supply
Anemia
Oxygen Debt
Occurs if skeletal muscles are
used strenuously for even a
minute or two
Lacking oxygen
Convert to anaerobic
respiration
Pyruvic acid Lactic Acid
Must be repaid
may take hours
equals the amount of O2
needed to convert the lactic
acid back into glucose
Muscle fatigueInability to contract
Interruption in blood supply
Lack of acetylcholine
Accumulation of lactic acid which lowers ph and fibers no longer respond
Cramps
Sustained involuntary contraction
Lack of ATP but Ca+ is still present so contraction is sustained
Rigor Mortis
Partial contraction that fixes the joints
Increase in calcium b/c membrane is more permeable
Decrease in ATP
Actin and myosin remain contracted -cannot relax
Muscle decomposition appears as relaxation
Muscle Responses
Threshold stimulus
minimal strength required to
cause a contraction
Latent period
delay between time stimulus is
applied and the time the muscle
responds
followed by a period of
contraction then relaxation
Muscle ResponsesAll-or-None Response
muscle completely contracts when
exposed to a stimulus of threshold
strength or above
normally doesn’t partially contract
Recruitment
increase in # of motor units
activated
Muscle ResponsesTetanic contraction
forceful and lacks even partial relaxation
Sustained contraction
muscle tone
Tonic contraction
holds organs in place
counteracts gravity
Athletics and Muscle Contraction Although all muscle fibers
metabolize both aerobically & anaerobically, some muscle fibers utilize one method more than the other.
Slow-twitch fibers produce most of their energy aerobically & tire only when their fuel supply is gone.
Fast-twitch fibers tend to be anaerobic & seem to be designed for strength as their motor units contain many fibers.
Can develop greater, and more rapid, maximum tension than slow-twitch fibers.
Skeletal Muscle Actions
Joints
determine type of
movement
Origin
immovable attachment
Insertion
movable attachment
Insertion pulled to origin
Interaction of Skeletal
Muscles
Prime Mover
main muscle
Synergist
contract and assist the
prime mover
Antagonist
resist a prime mover’s action
Example
Flexion of biceps
brachii:
Bicep -
Brachialis -
Triceps brachii -
What about when the
arm is extended?
Disorders
Duchenne Muscular Dystrophy
X-linked Never presents in females
Boys inherit the disease from Mom
Dystrophin protein is not made
Atrophy of muscle masked by excessive replacement of muscle by fat and fibrous tissue
Respiratory and cardiac weakness leads to death (~21)
DisordersContusion
Muscle bruise
Local internal bleeding and inflammation
Moebius Syndrome
Rare congenital neurological disorder which is characterized by facial paralysis (normally complete paralysis)
No facial expressions
Inability to move the eyes from side to side and cannot close them
Normal intelligence
Smooth Muscles Thin and randomly arranged fibers
Lack striations
Rhythmicity (pattern or repeated contractions)
Peristalsis (wavelike motion)
Hollow organs
Multiunit
Less organized
Contracts only in response to stimulation by a
motor neuron or hormones
Acetylcholine and norepinephrine
Iris, blood vessels
Actin and myosin
Slower to contract and relax (peristalsis)