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

Naming Muscles

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

How the muscles are namedExample –

Transverse abdominus

How the muscles are namedExample –

Extensor carpi ulnaris

Muscular System

Types of Muscle Tissue

Skeletal focus of the chapter

Cardiac

Smooth

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

Tendon “Issues”

Bursitis Inflamed bursae

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)

Disorders

Polio Viral infection

Affects nerves that control skeletal muscle

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)

Cardiac Muscle

Heart only

Striated cells join end to end

Actin and myosin

Intercalated disks

myofibril attachment

transmit rapidly (self-exciting)

all or none response