Muscles Flashcards
muscle fatigue
progressive weakness and loss of contractility from prolonged use of muscles
Factors in muscle fatigue: high-intensity/short time
- Potassium accumulation makes fiber less exciteable
- ADP accumulation - slows the cross bridge cycling of contraction
- P accumulation - inhibits Calcium release from SR and sensitivity of contractile mechinism
Factors in muscle fatigue: low-intensity, long-duration exercise
- fuel depletion - declining muscle glycogen and blood glucose leave less fuel for ATP synthesis (why runners eat high-carb before race to load muscles with extra glycogen)
- electrolyte loss - losing through sweat can decrease the muscle exciteability
- central fatigue - exercising generates ammonia which is absorbed by the brain and inhibits motor neurons
maximum oxygen uptake (Vo2max)
determines ability to maintain high-intensity for more than 4-5 minutes
is proportional to body size, larger in men, peaks at 20, and is greater in trained endurance atheletes
sedentary adult (35 milliliters/O2/min/kg of body weight) vs 70 ml/min in elite endurance atheletes
denervation atrophy
if a muscle nerve connection is severed or poisoned, muscle is paralyzed and atrophies
muscle endurance exercises
increased fatigue resistance - enhanced delivery and use of oxygen
jogging and swimming are good endurance exercise
slow-twitch fibers - grow more capillaries, mitochondria, glycogen as a result of conditioning
increased skeletal strength which increases RBC and oxygen transport capacity of the blood improves cardiovascular, respiratory, and nervous systems
deconditioning
if muscles not sufficiently active become weak and easily fatigued
Oxygen Debt / how to end it
post-exercise, heavy breathing
now called excess postexercise oxygen consumption
body needs Oxygen to regenerate ATP aerobically, regenerate creatine phospate, dispose of lactate, increased temp. uses more oxygen
remains elevated as long as 1 hr EPOC can be 6x typical consumption
Functions of Muscles
Movement (skeletal-locomotion, pumps heart, controls body openings/passageways, moves fluids)
Stability/posture
Stabilize joints - maintain tension on tendons
generate heat
control blood glucose
Purpose of all muscle
To convert ATP into the energy of motion (book)
muscle organ (components smallest to largest)
(see card)
tendons
attach muscles to bone at the origin and insertion
aponeuroses
tendon as a sheet - such as scalp, palmar aponeurosis
retinaculum
band of connective tissue “bracelet”
wrists/ankles
holds tendons in place
prime mover (agonist)
muscle producing most of the force of movement
synergist
muscle that is helping the prime mover
belly of muscle
largest/center of a fusiform muscle like the calf or biceps
intrinsic muscle
same region as use
Ex. hand muscle located in hand
extrinsic muscle
different region of origin
Ex. hand muscle origin in forearm
action
effect of muscle to produce or prevent a movement
fascicle
bundle of muscle fibers within a muscle
enclosed by perimysium
antagonist
muscle opposite the prime mover
antagonist pair
muscles around a joint - act together at times depending on movement (see class note)
fixator
holds a bone in place so another muscle can perform
Ex. rhomboids hold the scapula close to vertebral column while biceps contract, postural muscles hold bones steady
ensures bicep force moves radius rather than scapula
myofibril
myofibrils are bundles of myofilaments
long protein cords that fill up the majority of the sarcoplasm in muscle fibers
striated appearance because of overlapping myofilaments
each surrounded by sarcoplasmic reticulum
100s of sarcomeres end to end form
myofilament
The tiny filaments that make up myofibrils
thick - myosin
thin - actin
titin filaments
elastic proteins that ancor structures to z discs and M-line
helps stabalize the thick
prevents overstretching
recoils like a spring after the muscle is stretched
3 layers of collagenous connective tissue in skeletal muscle
endomysium
perimysium
epimysium
sarcomere
can be 100s in a muscle fiber
from z line to z line with the lighter Actin on the ends
gets shorter during muscle contraction
but fibers don’t change length/ they overlap
2 kinds of filaments
Myocin (thick)
Actin (thin)
Actin
thin myofilament
has a cover over the binding site by Tropomyacin
Troponin helps stabalize the cover
Myocin
thick myofilament
bundled with Actin
has glubular heads/cross bridges/extensions with binding sites for ATP, Actin, and ATPase
when muscle contracting, globular heads grab actin fibers and pull “power stroke”
Characteristics of a skeletal muscle fiber
long, single muscle cell
fast and strong contractions
striated - A bands and I bands
multi-nucleated along fiber edges, just under the sarcolemma
form the contours of the body
Smooth muscle fiber characteristics
visceral, non-striated, involuntary
slow and strong contractions
spindle shaped fibers
form the walls of hollow/visceral organs and tubes (stomach, bladder, respiratory tubes)
Cardiac Muscle Characteristics
synchronous contractions, involuntary
intercalcated discs, branching cells
only in heart
very light striations (microscopic)
Muscles comprise __-___% of total body weight and are the ________ machines of the body. Muscle presence in the human body includes over ____ muscle organs
Muscles comprise 40 – 50% of total body weight and are the movement machines of the body. Muscle presence in the human body includes over 650 muscle organs
In muscle cells:
cytoplasm is __________
plasma membrane is ____________
endoplasmic reticulum is _____________
cytoplasm is sarcoplasm
plasma membrane is sarcolemma
endoplasmic reticulum is sarcoplasmic reticulum
T-tubules
tubules in skeletal and cardiac muscle
finger like invaginations of the sarcolemma
Terminal cisternae
sac-like structures of sarcoplasmic reticulum on each side of a t-tubule
What makes triad for release are re-uptake of calcium in the sarcoplasm for contraction process
T-tubule invagination and adjacent terminal cisternae on either side
contractility
ability for muscle cells to shorten/produce tension within self when adequate stimulus is received
irritability
ability to receive/respond to stimulus
neuromuscular junction
association site of motor nerve and muscle (synaptic cleft - don’t touch)
interstitial fluid
fills the synaptic cleft between motor neuron axon buton and the muscle
excitability
muscle fibers stimulated by nerve impulses
extensibilty
muscle fiber ability to stretch beyond their relaxed, anatomical length
elasticity
muscle fibers ability to return to shape after stretch/contraction
isotonic contraction
“typical” skeletal muscle contraction where muscle shortens and movement occurs
Ex. bending knee, smiling, rotating arm
isometric contraction
“rare”
muscle engaged but not shortened (no contraction)
Ex. pushing a wall, muscle vs. immovable object
tetanic contraction
when muscle must sustain contraction because no chance to rest
Ex. carrying boxes down stairs
Tonus contraction
muscles that are in a constant state of partial contraction (muscle tone)
about 10% of fibers are contracted on a rotating basis
Ex. back muscles (even when sleeping), occipitalis (holds scalp down)
keeps muscles in an optimal length ready for action
involuntary
If the sarcomeres are less than 60% or more than 175% of their optimal length?
develop no tension in response to stimulus because there’s either too much overlap for movement or too little to grip
Treppe contractions
staircase looking contractions bk. initial contraction less than subsequent
(eventually reach a limit)
2 short term energy sources for muscles
Glycogen storage mechanism (storage from glucose and fatty acids for about 10 contractions)
Creatine Phosphate Pathway (CP+ADP = ATP+Creatine, about 100 contractions)
Cellular Respiration 2 kinds
Anaerobic Glycolosis when not enough oxygen, fast but inefficient (2 moles ATP), lactic acid byproduct
Aerobic Pathway - oxygen plus glucose is broken down by mitochondria - 36 moles of ATP, when oxygen debt, body shifts to anaerobic again
motor unit
1 motor neuron
plus all branches and fibers attached (few in fine motor, or 1000+ in gross motor)
average is about 200 fibers per motor neuron
fibers of motor unit are dispersed throughout a muscle (not clustered together)
describe process from nerve firing through muscle contraction and relaxing
see card
3 kinds of skeletal muscle fibers (general)
slow twitch/red fibers
fast twitch/white fibers
intermediate fibers
Muscle names based on 6 factors
direction (rectus = vertical, oblique = 45 degree angle)
relative size of the muscle (brevis/longus, maximus/minimus)
location (bones and markers)
number of origins (Ex. biceps brachii)
location of origins/insertions (sternumcleidomastoid)
shape (deltoid - ?triangle shape)
slow-twitch/red fibers
endurance muscle fibers
resist fatigue
aerobic respiration
thin fibers, many capillaries
high myoglobin makes red
Ex. back muscles, posture, erector spinae
fast twitch/white fibers
fast response
fatigue rapidly (writers cramp, bicep curls)
anaerobic glycolysis
no myoglobin
more stored glycogen/enzymes
thicker fibers
Ex. eye, hand, large muscles (biceps brachii, gastrocnemius)
Intermediate fibers
myoglobin
fast response
fatigue resistant
(characteristics of both slow and fast twitch)
RARE except some endurance atheletes
Ratio of muscle fiber types
genetic - accounts some for athletic achievement in different sports (training of genetic strengths)
Rigor Mortis
death of person = Sarcoplasmic reticulums release calcium as they deteriorate
causes permanent thin/thick bonding = post-mortum rigidity because no ATP to release bond
starts 3-4 hrs after death, peaks at 12 hours after
Acytylcholine
when a motor neuron is excited, the axon releases this neurotransmitter into the synaptic cleft
When sodium rushes into the cell it generates action _______________. Once started, a muscle contraction cannot be ________.
potential
]stopped
When sodium rushes into the cell it generates action _______________. Once started, a muscle contraction cannot be ________.
potential stopped
recovery stroke
recocking of the myosin head after contraction and ATP to release bond of the cross-bridge
The motor signal triggered by the motor neuron gets to the sarcoplasmic reticulum by way of the ___________. The S.R. then releases ________.
The motor signal triggered by the motor neuron gets to the sarcoplasmic reticulum by way of the (T-tubules). The S.R. then releases calcium.
When the sarcoplasmic reticulum releases calcium, ____________ releases ______________ and the _______ is exposed on the actin fiber for the ___________ __________ on the Myocin fibers to grab the actin and cause the muscle to ____________
When the sarcoplasmic reticulum releases calcium, (troponin) releases (tropomyacin) and the (actin) is exposed on the actin fiber for the (globular heads) on the Myocin fibers to grab the actin and cause the muscle to (contract)
“power stroke”
the moving of globular heads to “pull” the actin fiber with the help of ATP energy
In order for the Myocin filament to release the Actin filament following contraction, it needs a new _____ molecule to bind to it
In order for the Myocin filament to release the Actin filament following contraction, it needs a new ATP molecule to bind to it
graded responses
different degree of muscle shortening response based on stimulus
constant muscle contraction
tetanus
muscle force based on
number of fibers stimulated
muscle tension increases with _______ contracted fibers
more
muscles can contract as long as they have ______
energy
4 exercise effects on muscle
increases size
increases strength
increases efficiency
muscles more fatigue resistant
Frontalis muscle
- origin: cranial aponeurosis
- insertion: muscle/soft tissue at base of frontalis bone
- action: raise brows/ wringle forehead
Occipitalis muscle
- origin: posterior cranial aponeurosis
- insertion: occipital bone
- action: covers back of skull and pulls scalp down, tonis muscle
Orbicularis oculi
- origin: tissue at the center base of frontal bone, lacromial bone, around eye
- insertion: ??? same
- action: blink, wink, squint
- “oculi” means circular
Orbicularis oris
- origin: maxilla
- action: kissing
- lips are a part with additional tissues
Zygomaticus muscles
- origin: zygomatic bone
- action: smiling
- “major” - lower, longer, mouth upwards like laughing
- “minor” - upper, shorter, exposes upper teeth elevates upper lip
Buccinator
- origin: alveolar processes of mandible, maxilla
- insertion: into the fibers of the oris
- action:holds food between teeth, compresses cheeks (whistle, trumpet)
Masseter
- origin: zygomatic arch
- insertion: mandibular ramus/angle
- action: closes jaw by elevating mandible to maxilla
Temporalis
- origin: temporal bone
- insertion: goes over/under arch to connect to mandible
- action: also works with masseter to move mandible up
Platysma
- origin: manubrium, clavicles
- insertion: mandible, anteriorlateral x2
- action: I think it looks like a high collar, pulls jaw down, holds in stuff of neck
Sternocleidomastoid
- origin: mastoid process of the temporal bone
- insertion: 2 places: clavicle, and the sternum
- action:”prayer muscles” also lateral flexion, and cervical rotation
Pectoral major
- origin: sternum/8 ribs
- insertion: anterior humerus
- action:adduct/flex arm
Pectoral minor
- origin: ribs 3-5 travels supralaterally to scapula
- insertion: coracoid process of scapula
- action: synargist to pectoral major
trunk anterior
- not involved with head/appendages
- move vertebral column
- hold abdominal area
- 6/8 pack covered by abdominal apponeuroses
External Intercostals
- between ribs
- open to inhale
- run medial to lateral
Internal Intercostals
- deeper intercostals, between ribs
- depress to exhale
- laternal to medial
Rectus abdominus
origin: pubic symphysis xiphoid process
insertion: xiphoid process, costal cartilages 5-7
action: straight up and down muscle, flexes spine forward, push childbirth, pushes out excrement
External oblique
origin: external ribs 5-12, medial (low) to lateral, 45 degree angle
insertion: anterior iliac, superior margin of pubis
action: rotate spine, bend laterally, flex spine
Internal oblique
lateral (low) to medial, 45 degree angle
action:rotate spine, bend laterally, flex spine
Transverse abdominis
deepest abdominal
action:compress contents, horizontal fibers, opening with room for rectus abdominus
Trapezius
origin: posterior trunk
action: head up and back, scapula (elevate, depress, adduct); sternocleidomasctoid antagonist
Latissimus dorsi
action: muscle with largest surface area, posterior trunk, adducts humerus (power stroke swimming)
Erector spinae group
origin: posterior trunk
tonus muscles
spinalis, longissimus, iliocostalis
action:x3 extensors, hold up spine
Deltoid
action:arm abduction, triangle shape, holds scapula
Biceps brachii
origin: scapula
insertion: radial tuberosity
action: forearm flexion, supinate forearm, 2 heads
Brachialis
origin: upper limb, anterior, deep to bicep
insertion:
action: elbow flexion, synergist to biceps brachii
Brachioradialis
origin:synargist to biceps brachaii
insertion:
action: forearm pronation, weak
Triceps brachii
origin:
insertion: olecranon process
action: antagonist to bicep in elbow extension, punch muscle
Gluteus maximus/medius/minimus
origin: spine side
insertion: femur
maximus: hip extensor (largest muscle 350,000 cells)
medius/minimus - abduction of hip;shots in medius (max has siatic nerve)
Hamstring group order lateral to medial?
semimembranosus, biceps femoris, semitendinosus
semimenbranous, semitendinosus, biceps femoris
action: flex knee
Sartorius
oblique over quad
action: “tailor’s muscle” thigh flexor (weak)
Quadriceps group order medial to lateral and on top?
vastus medialis, vastus lateralis, rectus femoris, vastus intermedius?
vastus medialis, vastus intermedius, vastus lateralis, rectus femoris (crosses hip/knee,
action: extend the knee kick (gross movement)
Tibialis anterior
origin: lateral tibia
insertion: medial cuniform, 1st metatarsal
action: foot dorsiflexion, inversion
Fibularis muscles medial to lateral?
tertius, longus, brevis?
longus, brevis, tertius
reason why we can’t feel tibia (lateral side of lower limb)
plantar flexes, everts the foot
Gastrocnemius
- 2-bellied muscle that makes the calf
- insertion: into achilles, onto heel bone
- action: “toe dancer’s muscle”, foot plantar flexion (foot drags if achilles cut)
Soleus
deep to gastrocnemius (fish fillet, super thin)
also foot plantar flexion
Plantaris
- deep to Gastrocnemius and Soleus…
- skinny muscle under soleus, often missing, thin/weak, often fused into soleus)
Flexor carpi radialis
origin: anterior forearm (flexor surface)
insertion:
action:flexes the wrist, abducts the hand (away from midline)
both radialis abduct together, but antagonistic for flex/extension
Flexor carpi ulnaris
origin:anterior forearm (flexor surface)
insertion:
action:flexes the wrist, adducts the hand (towards midline)
both ulnaris adduct together but antagonistic for flex/extension
Flexor digitorium superficialis
origin:anterior forearm (flexor surface)
insertion:
action:flexes the wrist and fingers, sits under the retinaculum w/4 tendons going to phalanx bones
Extensor digitorum
origin:posterior forearm (entensor surface)
insertion:
action:extends the wrist and fingers 2,3,4 straight
Extensor carpi radialis
origin:posterior forearm (extensor surface)
insertion:2nd finger straight
action:extends wrist, abducts the hand (away from midline)
both radialis abduct together, but antagonistic for flex/extension
Extensor carpi ulnaris
origin:posterior forearm (extensor surface)
insertion:5th finger
action:extends wrist, adducts the hand (towards midline)
both ulnaris adduct together but antagonistic for flex/extension
Palmaris longus/brevis
origin:anterior forearm (flexor surface)
insertion:
action:flexes wrist and cups the palm of the hand
Thumb muscles:
Abductor Pollicis
Opponens pollicis
Adductor pollicis (brevis)
flexor pollicis brevis - on ? surface
extensor pollicis longus - on ? surface
Thumb muscles
- Abductor Pollicis (longus)
- Opponens pollicis (to meet pinky)
- Adductor pollicis (brevis)
- flexor pollicis brevis - on anterior surface
- extensor pollicis longus - on posterior surface
Palmar/plantar interosseous muscles
adduct (bring together) fingers, flex knuckles closest to the palm (bottom of proximal phalanges)
adduct (bring together toes)
Dorsal interosseous muscles
abduct (push apart) fingers, between metacarpals
abduct (push apart) toes, between metatarsals
3 shots locations
- deltoid - arm
- vastue lateralis (thigh side)/ rectus femorus (kids)
- gluteus medius (high hip)
Retinaculum
flexor (anterior wrist, back of ankle) or extensor (posterior wrist, front of ankle)
Opponens pollicis and digiti minimi
responsible for cupping palm (thumb to index)
flexor digiti minimi brevis
flexes pinky finger and toe
extensor digitorum vs. extensor digitorum brevis
brevis is the extender for the top of the foot - 4 toes
Lubricals
palmar side of hand/ plantar on foot - finger and toe flexion
big toe
- flexor hallucis longus tendon - plantar flexes big toe
- flexor hallucis brevis - flexes big toe
- abductor hallucis (medial foot) abducts big toe (out, which is towards
