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139 Cards in this Set

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  • Back
Which kind of muscle is voluntary?
Which kind of muscle lacks striations and looks like "salmon swimming upstream" or "wormy"?
Which kind of muscle has striations and peripherally located nuclei? Centrally?
skeletal; cardiac
Which kind of muscle contains intercalated disks?
Which kind of muscle is relatively weak and slow?
Which kind of muscle is quick and continuous? Quick and discontinuous?
cardiac; skeletal
What are the dark vertical lines in skeletal muscle called? Light vertical lines?
A bands; I bands
(hint: d'A'rk and l'I'ght)
Where does skeletal muscle of the body come from? Skeletal muscle of the head?
1. Somite->dermatome + myotome
2. neural crest
What is the term for when muscles do not form where they normally do?
muscle agenesis
How are the dorsal and ventral masses formed embryologically?
Myotome gives rise to mesoderm->this migrates into upper and lower limb buds
(hint: 3 M's: Myotome-Mesoderm-Migration)
Dorsal vs. ventral muscle masses: which will become flexors? Extensors?
1. Dorsal become extensors
2. Ventral become flexors
(hint: 'd' and 'e' are closer alphabetically)
How are nerves distributed embryologically?
muscle masses pull along motor axons behind them into limbs; sensory axons follow these to reach skin
(hint: when you string up Christmas lights, you use physical effort (motor); once they are up, you see them twinkle (sensory)
Where do limb bones come from embryologically?
lateral mesoderm
What 3 areas does the median n. innervate (motor)?
1. forearm flexors
2. thenar eminence
3. 1st 2 lumbricals
What bony structure do most forearm flexors originate from?
medial epicondyle
What areas does the median n. innervate (cutaneous)?
anterior palm and digits 1, 2, 3, and 1/2 of 4
What are the bones that are most prominent on the medial and lateral wrist?
ulnar and radial styloids, respectively
What nerve needs to be intact to demonstrate a strong grip?
median n.
What are the 2 tests for carpal tunnel syndrome?
phalen's (dorsal hand touching other dorsal hand) and tinel's sign (tapping carpal tunnel)
(hint: Tinel's-Tapping)
What 2 places might present with carpal tunnel-like pain?
1. pronator teres impinging upon the median nerve
2. thoracic outlet
What 3 things might cause thoracic outlet syndrome?
1. elevated 1st rib
2. clavicle compression
3. pectoralis minor pulls coracoid process inferiorly
What muscles does the ulnar n. provide motor to primarily? What are the other muscles?
1. intrinsic hand mm.
2. flexor carpi ulnaris and flexor digitorum profundus
What areas does the ulnar n. provide cutaneous innervation to?
anterior and posterior 1/2 of 4th digit and all of 5th digit
What compartment does the musculocutaneous n. provide motor to? Cutaneous innervation?
1. anterior arm compartment
2. lateral forearm
What bony feature allows for supination and pronation of forearm? What bony feature is the insertion point for the biceps tendon?
1. radial head
2. radial tuberosity
(hint: Tuberosity=Tendon)
The radial n. innervates which mm?
1. posterior arm mm.
The axillary n. innervates which mm? What is their function?
1. deltoid and teres minor
2. abduct, flex, and extend shoulder
All arm extensors (and supinator m.) are supplied by what nerve? From what bony feature do most of the forearm/wrist/hand extensors originate?
1. radial n.
2. lateral epicondyle
What mm. are supplied by the superior gluteal n.? What is their function?
1. gluteus medius and minimus, tensor fascia lata
2. abduct lower limb and resist pelvic tilt during gait
What m. is supplied by the inferior gluteal n.? What is its function?
1. gluteus maximus
2. extending hip (e.g. climbing stairs, rising from seated position)
What condition results from a dysfunctional superior gluteal n.?
trendelenburg gait
To which bony structure do most gluteal mm. insert? Hamstring mm.?
1. greater trochanter
2. ischial tuberosity
(hint: gluteal=greater; Hamstring and Ischial are close together alphabetically)
Sensory innervation from gluteal area is supplied by what nn?
cluneal nn.
Femoral n. supplies motor to which mm.? What is their function?
1. anterior thigh, psoas, and iliacus
2. flex the hip and extend the knee
What n. provides sensation to the medial thigh, leg, and heel? Lateral thigh?
1. saphenous n.
2. lateral cutaneous n. of the thigh
What n. is most commonly indicated in sensory losses along the anterior thigh and medial shin?
femoral nerve (anterior cutaneous branches)
Which n. provides motor to medial compartment of the thigh? What is the function of these mm?
1. obturator n.
2. adductors (uncommon) and hip stabilizer during gait
A small portion of medial thigh is cutaneously innervated by which n.?
obturator n.
What 2 nn. comprise the sciatic n.?
tibial and common fibular (peroneal) nn.
Tibial n. provides motor innervation to what compartment? What is their function?
1. hamstrings originating from ischial tuberosity (and part of adductor magnus)
2. extend the hip and flex the knee
What n. supplies motor innervation to the short head of the biceps femoris? What is the function of this m.?
1. common fibular (peroneal) n.
2. flexes knee
What n. provides sensory innervation to the posterior thigh compartment?
posterior cutaneous n. of the thigh
The tibial division of the sciatic n. also supplies motor to which other compartments aside from the posterior thigh compartment? What is their function?
1. deep/superficial posterior leg
2. plantar flexion and ankle inversion
Which n. cutaneously innervates posterior leg? This is a branch of what n.?
1. sural n.
2. tibial n.
Which nn. provide motor and sensory innervation to the plantar foot? What do these branch off of?
1. medial and lateral planter nn.
2. tibial n.
What compartment does the superficial fibular (peroneal) n. provide motor and sensory to? What is the function?
1. lateral leg and dorsal foot
2. ankle eversion
What compartment does the deep fibular (peroneal) n. provide motor and sensory to? What is the function?
1. anterior leg
2. ankle dorsiflexion
What bony structure is located near where the common fibular (peroneal) n. splits into the deep and superficial fibuar (peroneal) nn.?
fibular head
What m. should be checked to ensure that the deep fibular (peroneal) n. is working?
tibialis anterior
Patient with “foot drop” who can neither dorsiflex or evert his foot suffers from what nerve damage?
common fibular nerve (strong dorsiflexion is from deep fibular nerve; eversion of foot is superficial fibular nerve)
What bony feature may explain foot drop?
fibular head (ischial tuberosity could also be an explanation, but this is not as exact)
In patient with foot drop, if further testing revealed weakness in hamstring muscles, which nerve would be involved?
sciatic n.
Somites compose what tissues?
skeletal muscle, skin, vertebral bodies, and ribs
Which muscle fibers are slow-twitch, oxidative, and fatigue-resistant?
type I (red) fibers
(hint: Red=Resistant to fatigue; slow and steady wins the race= #1)
Which muscle fibers are fast-twitch, glycolytic, and fatigue quickly?
type II B (white) fibers
What structures control normal muscle tone?
muscle spindles
What structures provide information regarding degree of muscle tension and adjust tone to prevent injury?
muscle spindles
Muscle spindle fibers: extrafusal or intrafusal?
Briefly describe muscle spindle action:
1. muscle stretches
2. muscle spindle stretches
3. muscle spindle signals spinal cord to increase agonist tone to resist stretch
4. muscle spindle simultaneously signals spinal cord to decrease antagonist tone
Give two examples of muscle spindle action:
1. reflex hammer eliciting response
2. filling beer mug-arm increases tone but does not drop
What structures become activated only during intense stretching?
golgi tendon organs (GTO)
Which structures are located in the myo-tendinous areas and sense the amount of stretch being transmitted to the tendons?
Briefly describe the action of the GTO:
1. GTO senses stretch
2. signals spinal cord to decrease agonist tone and simultaneously increase antagonist tone
What structure is active during an intense stretch?
What do the ipsilateral extensors and flexors do when you step on a tack?
hamstrings contract and quadriceps relax
What do the contralateral extensors and flexors do when you step on a tack?
hamstrings relax and quadriceps contract
(hint: Contralateral=Quads=Contract)
In a biceps curl, what are GTOs telling the triceps to do?
biceps relax, triceps contract
What is a cheezy way to remember actions of GTOs vs. muscle spindles?
1. Gag reflex (Golgi-AGonist-relax)
2. Santa relaxes (Spindle-ANTAgonist-relax)
Describe the uppor motor neuron pathway:
precentral gyrus->PLIC->medullary pyramids->decussation->lateral corticospinal tract->ventral horn
Describe the lower motor neuron pathway:
ventral root->spinal nerve->ventral/dorsal rami->peripheral n.->muscle
UMN or LMN lesion: which shows flaccidity? Which shows rigidity?
1. lower=flaccid
2. upper=rigid
(hint: low key person=relaxed; uptight person=rigid)
UMN or LMN lesion: which shows facciculation? weakness?
1. LMN
2. both
Somatic mm. are innervated by what?
alpha-motor neurons; LMNs
Where are cell bodies located in somatic nn?
ventral gray horn
What is tonic effect of UMN on LMN?
The interface between a motor nerve axon & the muscle it innervates is the:
motor end plate
What is the chemical effect that causes contraction?
Ach released by axon terminal->Ach moves across synaptic cleft->binds to Ach receptors->AchE removes excess Ach
Which disease demonstrates an auto-antibody that binds Ach receptors, causing muscle weakness?
myasthenia gravis
What is the effect of curare poison?
binds Ach receptor-causes nearly-instant paralysis
What is a common clinical finding of myasthenia gravis?
eye drop
Which toxin causes "floppy baby syndrome?" Which toxin causes intense systemic muscle contraction?
1. botulin toxin (clostridium botulinum)
2. tetanospasmin toxin (clostridium tetani)
What are the invaginations of the muscle cell membrane that run alongside the SR?
transverse tubules
The gap between the t-tubules and SR is spanned by what proteins?
1. DHPR (in t-tubule)
2. RyR (in SR)
(hint: SoRRy)
DHPRs and RyRs: which are voltage gated and which are calcium channels?
DHPR is voltage gated and RyR is calcium channel
What is the functional unit of contraction?
Which band contains only actin filaments anchored to the Z line?
I band
(hint: IAZ-I band-actin-Z line)
Which band contains only myosin filaments anchored to the M line?
H band
(hint: HMM-H band-myosin-M line)
Which band contains myosin and actin filaments sliding across each other?
A band
(hint: AMA-A band-myosin & actin)
T-tubules are always located at what band junction in skeletal muscle?
A-I junction
What molecule consists of 2 identical heavy chains and 2 pairs of light chains and looks like golf clubs?
What is the elongated protein dimer that lies in grooves of the actin helix?
What are the 3 parts of the troponin complex?
Troponins T, I, and C
What are the functions of the 3 troponins?
1. Tn-T: binds Tn to tropomyosin
2. Tn-I: inhibits binding of actin and myosin
3. Tn-C: binds calcium, which uninhibits Tn-I
Briefly describe mechanism of contraction once the signal to contract has been propagated:
1. Troponin binds calcium
2. This moves troponins and tropomyosin out of the way so that myosin can bind to actin
3. The myosin head (golf club head) undergoes conformational shift and moves along the actin fialment
4. myosin head moves along actin filament towards Z line, causing contraction
The plasma membrane of a muscle fiber is also known as a:
What protein encircles the Z disc of each sarcomere and connects them to the sarcolemma?
Muscular Dystrophy is due to mutation of what protein?
dystrophin protein
What protein forms a link connecting muscle fibers to extracellular matrix and connective tissue?
Which proteins anchor muscle cells to the extracellular matrix?
What is the effect of dystrophin mutations?
muscle cells become leaky->leak out phospho-kinase->muscle satellite cells plug these gaps and cease mitosis
Describe Duchenne's MD:
1. no functional dystrophin gene is present in cells
2. early onset (pre-teen age 12-20)
3. severe progression to early death
Describe Becker's MD:
1. slightly functional dystrophin is made
2. later onset (usually occurs in early 20’s)
3. symptoms less severe but ultimately fatal
4. this is much more delayed than Duchenne's MD
Death in either MD is usually due to what?
failure of the diaphragm or heart
Follow the pull of contraction on tissues from inside to out:
contraction pulls on sarcolemma->endomycium->perimycium->epimycium->tendons->periosteum
Muscle cells are surrounded by a basal lamina & reticular fibers that is called what?
Muscle fiber bundles (fascicles) are surrounded by what?
(hint: PERI runs FASt)
Muscle tissue is surrounded by dense connective tissue called what?
What are the 4 compartments of the leg?
anterior, lateral, superficial posterior, deep posterior
Tendons and ligaments are normally composed of what tissue?
dense regular connective tissue
In dense regular connective tissue, which is correct:
fibers>nuclei or nuclei>fibers?
What are the 2 layers of periosteum?
outer, fibrous, dense collagenous layer and an osteogenic inner layer
What type I collagen structures connect periosteum to bone?
sharpey's fibers
What are the 2 main areas of mature bone?
compact bone (outer) and spongy bone (inner)
Compact bone is surrounded by tough fibrous material called what? (hint: this becomes bone)
Compact or spongy bone: which contains trabeculae?
Osteoblast vs. osteocyte: which has not yet surrounded itself with bone?
Flattened cells on inner layer of periosteum & cells lining marrow cavity that become osteoblasts are called what?
osteoprogenitor cells
Dense bone is made of concentric lamellae around a central what?
Haversian canal
How do osteocytes communicate with osteoblasts and other osteocytes?
canaliculi ending in gap junctions
What cell reabsorbs bone?
(hint: Clast=Calcium reabsorber)
Depression in bone created by osteoclast is called?
Howship's lacuna
Osteoclasts are derived from what other cell line?
What is the effect of PTH?
increase osteoclast activity->increases serum calcium
What is the effect of calcitonin?
decreases osteoclast activity->decreases serum calcium
What cells produce calcitonin?
thyroid c-cells
What are the basic steps of bone repair?
1. hematoma
2. periosteal callus
3. mesenchymal hyaline cartilage
4. woven (immature) bone
5. mature bone
Which is avascular: cartilage or bone? How are nutrients and waste passed back and forth?
cartilage; extracellular matrix
Where does cartilage reside in long bones until after maturation? Why?
epiphyses; allows for growth
Which cartilage is located in articular ends of long bones, walls of trachea & respiratory bronchi and the ventral ends of ribs?
Which cartilage is located in the ears, epiglottis, and trachea?
Which cartilage is located in the IV discs and pubic symphysis?
Fetal skeleton is composed of what?
hyaline cartilage
What are the steps in bone formation?
1. mesenchyme forms bone model
2. hyaline cartilage replaces mesenchyme
3. invasion of shaft by nutrient artery creates primary ossification centers
4. invasion of bone ends by nutrient arteries creates secondary ossification centers
5. bone replaces hyaline cartilage in ossification centers
6. chondrocytes at epiphyseal plates divide and produce new cartilage
7. caught between primary and secondary ossification centers, growth plate eventually ossifies
What is a cheezy way to remember segments of bone from middle to ends?
Develop My Epiphysis
What are the primary growth plates of the upper and lower limb?
shoulder and wrist; knee
What are fractures involving the growth plates before they fuse to the metaphysis?
salter-harris fractures
Articular surfaces are lined by this substance. It provides a smooth surface for bones to slide across each other.
hyaline cartilage (this kind doesn't ossify)
Synovial joints are surrounded by a 2-layered capsule. What are the layers of this capsule?
1. external (fibrous) capsular layer composed of dense connective tissue
2. internal (synovial) capsular layer lined by secretory cuboidal cells
What is proteus syndrome?
rare condition that the Elephant Man had