Msk Final Flashcards
Autoimmune disorder attaching schwann cells causing demyelination in the peripheral nervous system
Guillian barre
hypaxial/ Extrinsic back muscles are innervated by who
CN11 and brachial plexus branches
epaxial/ intrinsic back muscles are innervated by who
dorsal rami of spinal nerves
what muscles make up the erector spinae group of intrinsic back muscles? They extend and laterally flex vertebral column.
spinalis, longissimus, iliocostalis
what muscles make up the transversospinalis group of intrinsic back muslces
rotatores, multifidus, semispinalis
what modalities are carried by dorsal root fibers
sensory
what modalities are carried by dorsal ramus of spinal nerve
sensory and motor
what modalities are carried by ventral root fibers
motor
what modalities are carried by ventral ramus of spinal nerve
sensory and motor
insertion, action, and innervation of splenius cervicis (originates at nuchal ligament)
transverse process of C-3
extend head/ neck, lateral flexion and rotation of neck
dorsal rami of spinal nerves
insertion, action, and innervation of splenius capitis
lateral part of mastoid process
extend head/ neck, lateral flexion and rotation of neck
dorsal rami of spinal nerves
action, blood supply, and innervation of iliocostalis (runs from iliac crest to lumbar, thoracic, and cervical transverse processes)
extend and laterally flex vertebral column
posterior intercostal and lumbar aa.
dorsal rami of spinal nerves
action, blood supply, and innervation of longissimus
extend/ lateral flex vertebral column
posterior intercostal aa. for thoracis and cervicis portions
occipital a. for capitis portion
nerve: dorsal rami
action, blood supply, and innervation of spinalis m. (thoracis, cervicis, capitis portions)
extend and lateral flex vertebral column
posterior intercostal aa.
dorsal rami
blood supply and innervation for semispinalis
cervicis and capitis: deep cervical a.
thoracis: posterior intercostal aa.
all are innervated by dorsal rami
muscle running from transverse process of one vertebra to spinous process of the vertebra superiorly
multifidus (attach to tip of spinous process)
rotatores (2 bellies attach at base of spinous process)
blood supply, innervation, and action of multifidus
posterior lumbar arteries
dorsal rami
stabilize vertebra during localized movement
blood supply, innervation, and action of rotatores
posterior intercostal arteries
dorsal rami
extend head and spine and rotate contralaterally
what is the only intrinsic back muscle that receives BOTH ventral and dorsal contribution from spinal nerves
intertransversari m.
blood supply to interspinales
vertebra, occipital, posterior intercostal aa.
blood supply to intertransversari
deep cervical, vertebral, posterior intercostal aa.
blood supply to legator costarum
posterior intercostal a.
which ligament surrounds the dens holding it in place
transverse ligament of the atlas
ligament holding atlas and axis together posteriorly
deep: cruciate ligament
superficial: tectorial membrane
the mm. of the sub occipital region are all innervated by dorsal rami of which spinal nerve?
C1: sub occipital nerve
rectus capitis posterior major and minor, obliquus capitis superior and inferior are postural muscles that aid extension and rotation at which joint
atlantoaxial joint (they are sub occipital muslces)
what are the borders and contents of sub occipital triangle
boarders: obliquus capités superior and inferior and rectus capitis major
contents: suboccipital n. and vertebral a.
which vertebrae have foramina in their transverse process
cervical
which vertebrae have bifid spinous process
cervical
which vertebrae have facets for ribs
thoracic
which vertebrae have greatest ROM
cervical
which vertebrae have greatest strain
lumbar (dispace energy to pelvis)
where does ligamentum flavum run
just anteriorly to the spinous process of vertebra
what structure surrounds nucleus pulpous to help maintain intervertebral joints
annulus fibrosus
what supplies blood to the vertebra
cervical- vertebral/ cervical aa
thoracic- posterior intercostal as
lumbar- subcostal and lumbar aa
sacral- iliolumbar/ sacral aa
what are the 2 enlargements of the spinal cord
cervical, lumbar
what is the outermost meningeal covering of the spinal cord
dura mater
which layer of spinal cord meningeal covering contains circulating CSF
arachnoid mater (middle layer)
what is the innermost layer of meningeal covering for the spinal cord and what connects it to the spinal cord
pia mater
denticulate ligaments
spinal nerve roots are partially covered by which meningeal layer
dura mater
which ribs are considered false ribs since they articulate with the sternum via cartilage rather than bone
8-10
which ribs are considered floating since they do not have their own cartilaginous or bony attachment to the sternum
11 and 12
what are the 3 components of the sternum
manubrium, body, xiphoid
which rib inserts to the xiphosternal joint?
7th
which rib inserts to the manubrosternal joint
2
mammary glands are classified as what
modified sweat glands
the breast rests on what superficial structure
pectoral fascia
name the potential space between breast and pectoral fascia
retromammary space
breast is innervated by what
intercostal nn 4-6
mammary gland lobules condense and drain into what structure before converging on the nipple
lactiferous ducts then sinuses
mammary gland lobules are separated by what named structure that also attaches to dermis of overlaying skin
suspensory ligament (Cooper’s ligament)
arterial supply to breast tissue comes from where
axillary a. (via mammary branches)
internal thoracic a.
what causes rapid metastasis of breast cancer
lots of lymph drainage to axillary nodes
lymph from nipple, aerola, and lactiferous lobules drains to what
subareolar lymph nodes
75% of breast lymph drains to what
axillary nodes (pectoral, central, apical)
what innervates breast tissue
supraclavicular nn.
intercostal nn 4-6 (mammary branches)
deltopectoral (clavipectoral) triangle borders
deltoid, pec major, middle 1/3 of clavicle
deltopectoral (clavipectoral) triangle contents
cephalic vein
deltopectoral lymph nodes
deltoid branch of thoracoacromial a. (from axillary a)
what kind of fascia encloses the pec major
pectoral fascia
what kind of fascia encloses the subclavius and pec minor
clavipectoral fascia
contents of clavipectoral triangle pierce which layer of fascia
clavipectoral fascia
the clavipectoral fascia becomes what inferior to the pec minor
suspensory ligament of the axilla
innervation and blood supply to pec major
pectoral branch of thoracoacromial arterial trunk
lateral and medial pectoral nn. (C5-T1)
innervation and blood supply to pec minor
pectoral branch of thoracoacromial arterial trunk
medial pectoral n (C8-T1)… this also pierces the muscle
innervation and blood supply to subclavius
clavicular branches of thoracoacromial trunk
nerve to subclavius (C5-6)
innervation and blood supply to serratus anterior
lateral thoracic a
long thoracic n. (C5,6,7)
peau d’orange (skin resembling orange peel) of the breast indicates what
blockage of cutaneous lymph vessels
breast elevates when woman places hands on hips and lesses elbows foreword indicates what is happening
invasion of pec major by the cancer
finger sized dimple in superiolateral quadrant of breast indicates what condition
shortening of suspensory ligaments by cancer in axillary tail of breast
action of pec major
adduct, medial rotate, flex, extend humerus
anterior and inferior movement of scapula
action of pec minor
stabilize scapula
action of subclavius
depress and anchor scapula
action of serratus anterior
protraction and upward rotation of scapula
thoracoacromial trunk of axillary artery has what branches
acromial, deltoid, pectoral
what muscle is responsible for splitting the axillary artery into its 3 major regions in the clavipectoral region
pec minor
what major branch is given off of the axillary artery in part 1 (proximal to p minor)
superior thoracic a
what major branch is given off of the axillary artery in part 2 (posterior to p minor)
thoracoacromial trunk
what major branch is given off of the axillary artery in part 3 (distal to p minor)
subscapular a (circumflex scapular and thoracodorsal branches)
anterior circumflex humeral
posterior circumflex humoral
what are the anastomosing arterial branches of the scapula
suprascapular, dorsal scapular, posterior intercostal aa, circumflex scapular, thoracodorsal a
what are the 2 superficial venous contributions to axillary vein in the pectoral region
cephalic v
basilic v
what are the boundaries of axilla
anterior: pec major and minor
posterior: scapula and subscapularis
lateral: humerus (intertubercular sulcus and biceps tendon)
what all is contained in the axillary sheath
axillary v
axillary a
brachial plexus
shoulder joints are held together by which ligaments
coracoclavicular (trapezoid and conoid)
coracoacromial
glenohumeral (superior, middle, inferior)
what are the rotator cuff muscles of the shoulder
subscapularis
supraspinatus
infraspinatus
teres minor
long thoracic n (C5, 6, 7) innervates which muscle
serratus anterior
blood supply and innervation to deltoid
deltoid branch of thoracoacromial arterial trunk
axillary n
blood supply and innervation to trees major
circumflex scapular a
lower sub scapular n
the transverse ligament of the humerus wraps around what holding it in the inter tubercular groove of the humerus
biceps tendon
what articulates with the greater tubercle of the humerus
supraspinatus, infraspinatus, teres minor
what articulates with the lesser tubercle of the humerus
subscapularis
blood supply and innervation to supraspinatus
suprascapular a
suprascapular n
blood supply and innervation to subscapularis
subscapular a
upper and lower subscapular nn
largest and strongest rotator cuff muscle
subscapularis
injuries to which rotator cuff muscle can lead to occipital tendon instability and biceps tendonitis
subscapularis
blood supply and innervation to infraspinatus
suprascapular a suprascapular n (C5-6)
blood supply and innervation to trees minor
circumflex scapular a
axillary n
what arterial branches come from the subclavian artery medial to the anterior scalene m
internal thoracic a
vertebral a
thyrocervical arterial trunk
what are the 4 branches of the thyrocervical arterial trunk
transverse cervical a
inferior thyroid a
ascending cervical a
suprascapular a
what arterial branches come from the subclavian artery posterior to the anterior scalene m
costocervical arterial trunk (supreme intercostal and deep cervical artery)
this special artery can arise from subclavian artery or from the transverse cervical artery (30% of the time)
dorsal scapular a (always runs along vertebral border of scapula
the most superficial “space” of the posterior shoulder
triangle of auscultation
trees major, trees minor, and the long and lateral heads of triceps brachii all converge at the posterior shoulder to make what 3 spaces
triangular space (circumflex scapular a) quadrangular space (axillary n, post circumflex humeral a) triangular interval (deep brachial a, radial n)
first long bone to completely ossify (can present as congenital pseudoarthrosis or poorly healed fracture if ossification fails)
clavicle
what muscles abduct humerus
deltoid
supraspinatus
what muscles adduct humerus
teres major
what muscles flex humerus
deltoid
what muscles extend humerus
deltoid
what muscles lateral rotate humerus
infraspinatus, teres minor, deltoid
what muscles medial rotate humerus
trees major, subscapularis, deltoid
what muscles protract scapula
serratus anterior
what muscles depress scapula
serratus anterior
what muscles upward rotate scapula
serratus anterior
impingement syndrome in the shoulder can involve what two structures
subacromial bursitis
supraspintaus tendonitis
which tendon likely tears in a “rotator cuff tear”
supraspinatus tendon
size of quadrangular space is reduced compressing what structure
axillary n (or posterior circumflex humeral artery)
what nerve supplies the skin over the forearm
lateral and medial antebrachial cutaneous n
the main arterial supply for the superficial palmar arch comes from what a
ulnar a
the main arterial supply for the deep palmar arch comes from what a
radial a
superficial muscles of the forearm (lateral to medial)
pronator teres
flexor carpi radialis
palmaris longus
flexor carpi ulnaris
intermediate (layer 2) muscles of the forearm (lateral to medial)
flexor digitorum superficialis
deep muscles of the forearm (lateral to medial)
flexor pollicis longus, flexor digitorum profundus, pronator quadratus
blood supply and innervation for pronator teres
anterior ulnar recurrent a
median n
blood supply and innervation for flexor carpi radialis
ulnar a
median n
blood supply and innervation for palmaris longus
ulnar a
median n
blood supply and innervation for flexor carpi ulnaris
ulnar a
ulnar n
blood supply and innervation for flexor digitorum superficialis
ulnar a
median n
blood supply and innervation for flexor digitorum profundus
anterior interosseous a
median and ulnar nn
blood supply and innervation for flexor pollicis longus
anterior interosseous a
median n via anterior interosseous n
blood supply and innervation for pronator quadratus
anterior interosseous a
median n via anterior interosseous n
which nerve runs just superficial to the medial epicondyle of the humerus before supplying intrinsic hand mm
ulnar nerve
the median n pierces which forearm m
pronator teres
which nerve runs through the carpal tunnel making it susceptible to compression during carpal tunnel syndrome
median n
the anterior interosseous n and a run just deep to what muscle
pronator quadratus
What cutaneous innervations of the dorsum of the hand contain?
Ulnar nerve- lateral 2.5 fingers and lateral metatarsals/carpals
Radial nerve- thumb, index, and half. Of middle finger and skin proximal to those fingers
Median nerve- index and middle fingers distal to PIP joint
What muscles make up the radialis group
Brachioradialis
Extensor carpi radialis longus
Extensor carpi radialis brevis
Which muscles make up the superficial layer of the posterior forearm
extensor carpi ulnaris
Extensor digiti minimi
Extensor digitorum
Which muscles make up the deep layer of the posterior forearm
Extensor indicus Extensor pollicis longus Extensor pollicis brevis Adductor pollicis longus Supinator
What is the common extensor origin of the forearm
Lateral epicondyle of humerus
All muscles of the posterior forearm are innervated by who
Radial nerve (deep branch or posterior interosseous n)
Superficial branch of the radial nerve does what
Cutaneous innervation in lateral hand
Blood supply and innervation to brachioradialis
Radial collateral and recurrent radial aa
Radial n
What is the action of brachioradialis
Flex forearm when pronated
Blood supply and innervation to extensor carpi radialis longus
Radial collateral, radial recurrent, radial interosseous aa
Radial n
Blood supply and innervation to extensor carpi radialis brevis
Radial collateral, radial recurrent, recurrent interosseous aa
Deep branch of radial n
Blood supply and innervation to extensor digitorum
Posterior interosseous, recurrent interosseous, perforating branches aa
Posterior interosseous n
Blood supply and innervation to extensor digiti minimi
Posterior interosseous, recurrent interosseous, perforating branches aa
Posterior interosseous n
When extensor digitorum contracts it. Pulls what structure causing IP joints to extend?
Extensor expansion (extensor hood mechanism)
Blood supply and innervation to extensor carpi ulnaris
Radial collateral, radial recurrent, recurrent interosseous aa
Posterior interosseous n
Blood supply and innervation to supinator
Radial, posterior interosseous, radial recurrent aa
Deep branch of radial n
Blood supply and innervation to extensor indicus
Posterior interosseous and perforating branch aa
Posterior interosseous n
Blood supply and innervation to adductor pollicis longus
Posterior interosseous a
Posterior interosseous n
Blood supply and innervation to extensor pollicis brevis
Posterior interosseous and perforating branch aa
Posterior interosseous n
Blood supply and innervation to extensor pollicis longus
Posterior interosseous a
Posterior interosseous n
What is the anastomosis in the hand
Radial artery contributes to both deep palmar arch and dorsal carpal arch
The deep branch of the radial nerve continues as the posterior interosseous nerve. After passing through what structure
Supinator m
Which artery and bone lie deep to the anatomical snuff box
Radial a
Scaphoid bone
Which structures are ruptured in a shoulder separation but not a shoulder dislocation
Acromioclavicular ligament (and sometimes other shoulder ligaments as well)
What nerve is most commonly injured with shoulder dislocation
Axillary n
When do upper limbs form? Lower limbs?
Day 26- arms
Day 27/28- Legs
What layer gives rise to limbs
Somatic layer of lateral plate mesoderm
Mesenchyme thickens at the surface to direct limb bud formation at what named structure
Apical ectodermal ridge
What signal causes mesenchyme to migrate and proliferate?
FGF8
What genes direct limb bud formation proximal to distal? What takes over as they get farther from the axial skeleton?
HOX genes until
RA takes over (tells mesenchyme which bones to form from proximal)
FGF8 signals at distal end
First cells to be exposed to RA become humerus and femur and are called what
Stylopod
cells that when exposed to RA become radius/ulna or tibia/fibula and are called what
Zeugopod
Last cells to be exposed to RA become carpels, metacarpals, tarsals, metatarsals, digits and are called what
Autopod
When do hand and foot plates appear along with chondrification centers appear in developing embryo?
Week 5
When do digital rays of hands appear in developing embryo? (Entire limb skeleton is cartilage)
Week 6
What occurs that removes webbing between our digits? When does this occur in developing embryo?
Apoptosis
Week 8
When do digital rays of feet form in developing embryo (and osteogenesis of long bones begins along with limb rotation)
Week 7
Limb musculature is derived from what
Dorsolateral cells of somites
During week 7, upper limbs rotate 90 degrees in which direction
Lateral rotation
During week 7, lower limbs rotate 90 degrees in which direction
Medial rotation
Cranial surface (preaxial/anterior) surface of the upper limb includes what features
Thumb and radius
Caudal surface (postaxial/posterior) surface of the upper limb includes what features
Ulna and little finger
Motor axons from spinal cord enter limb buds when during development
Week 5
What generates first motor or sensory axons?
Motor
Neural crest cells are doing what with the PNS during week 5 of development
Making sensory axons and schwann cells (myelination)
In the developing embryo what is the main blood. Supply. To the lower limb (before it gets taken over. By femoral a)
Deep femoral a (profunda femoris a)
Most common musculoskeletal defect: sole of foot turned medially and foot is inverted (more common in males) fixed usually by casting
Club foot
Musculoskeletal defect occurs more in females and involves under development of acetabulum of hip bone and joint laxity
Developmental hip dysplasia
Patterning and positioning of limbs along craniocaudal axis is regulated by what genes
HOX (also control type and shape of the bones in limbs)
Proximodistal growth and patterning of limbs occurs at what area and requires what type of signalling
Apical ectodermal ridge, FGF signalling
Dorso-ventral patterning helps us form flexor and extensor surfaces of limbs. The ventral surface is maintained by ___ signaling and dorsal is maintained by ___ signaling. These signals set up the apical ectodermal ridge
BMPS (ventral)
Wnt7 (dorsal)
Anterior posterior patterning of the limb is controlled by establishing what zone on posterior side of limb? What signal signals this posterior region?
Zone of polarizing activity
Shh and RA
Loss of ZPA (zone of polarizing activity) results in what
Loss of posterior elements (digits 3-5 or ulna) and you WILL have a thumb
Upregulation of ZPA (zone of polarizing activity) results in what
Polydactyly (extra digits) and you WILL have a thumb
Duplication of ZPA (zone of polarizing activity) results in what
Polydactyly::: Duplication of posterior elements (digits 3-5 mirrored on both sides of the “thumb” but may not have fingers with only 2 phalanges)
Which elements form first: posterior (little finger/ ulna) or anterior elements (thumb/ radius)
Posterior forms first!
Thus disruption of anteroposterior patterning= loss of anterior elements
Congenital joint contractures of 1 or more joints possibly caused by neurologic defect, muscular abnormalities, fetal crowding
Arthrogryposis
Vascuature remodeling occurs in the forearm and most people lose this artery but it canremain in some people
Median a
Abnormal short digits due to week 6 malfunction
Bradydactyly
Fusion of digits because apoptosis fails in week 8
Syndactyly
Development of limbs close to the body is called __ and can occur after mama bear takes what med?
Phocomelia , Thalidomide
MOA for phocomelia
FGF does not signal AER correctly causing the short limbs
Absence of limbs
Amelia (wk 4 upper limbs, wk 5 lower)
Absence of part of limb and the two sub types
Meromelia (hemimelia is missing a bone like ulna, phocomelia is limb develop close to body)
Which stage of limb development is most affected in hemimelia
Zeugopod
what are the steps involved in neurotransmission at the neuromuscular junction
ACh synthesis, storage, release, destruction leads to muscle contraction
enzyme that combines acetyl coA and choline to form ACh
choline acetyltransferase (ChAT)
alzheimer patients have reduced cerebral production of what ACh forming enzyme?
ChAT
by what mechanism is ACh shuttled into storage vesicles after synthesis
ACh vesicular transporter + ATP
upon depolarization, what kind of voltage gated channels open?
Ca++ channels open and calcium flows in
what is the role of calcium in NMJ transmission
promotes vesicle fusion to the presynaptic membrane
what are the vesicular and plasma membrane proteins that initiate vesicle plasma membrane fusion to release ACh
VAMP and SNAP (they are SNAREs)
what is known to block the snare complex thus inhibiting release of ACh from the presynaptic neuron
botulinum toxin (BOTOX)
enzyme that cleaves ACh into cholineand acetate so that choline can go back to motor neuron for reuse
acetylcholinesterase
sodium potassium pumps in the presynaptic membrane of the NMJ create a sodium gradient that is used to bring what into the cell for recycling in making neurotransmitter
choline
what is the effect of an acetylcholinesterase inhibitors
increase ACh
what type of ACh receptor do you find in skeletal muscle
nicotinic
where do we often find muscarinic ACh-R’s
smooth muscle mostly but also cardiac muscle
what type of channel is a nicotinic ACh-R?
ligand gated na+ channel
what type of channel is a muscarinic ACh-R?
GPCR
what lines the pore of the nicotinic ACh-R?
negatively charged AA side chains (Asp, Glu)
what are the 3 types of nAChRs?
skeletal, peripheral neuronal, central neuronal
what agonists bind to muscular nicotinic ACh receptors
nicotine
ACh
succinyl choline
what antagonists bind to muscular nicotinic ACh receptors
atracurium
vecuronium
d-tubocurarine
pancuronium
how can drugs target only one subtype of nicotinic ACh receptors
each subtype is made up of different subunits and these are the target for drugs that allow us to target only one subtype
how many molecules of ACh have to bind in order to activate a nAChR and allow Na+, K+ or Ca++ to pass through down their concentration gradient
2
while the motor end plate cannot perform this action itself, if enough Na+ comes in the adjacent muscle membrane can do what
depolarize (gotta reach threshold)
the presence of an action potential in the neuron at the NMJ causes the opening of what type of channel
voltage gated Ca++ (the calcium helps with vesicle fusion)
Tetrodotoxin (puffer fish) can cause weakness, dizzy, paresthesia, reflex loss, hypotension, paralysis by what MOA?
inhibiting voltage gated Na+ channels thus blocking axonal conduction
Local anesthetics like lidocaine, bupivacaine, procaine are used to control pain during procedures by what MOA?
inhibiting Na+ channels to inhibit axonal conduction
especially sensory neurons
batrachotoxin (poison dart frog) is potent and causes paralysis by what MOA?
increased Na+ permeability (persistent depolarization)
Botulinum toxin causes flaccid paralysis by what MOA
cleave SNARE components so neuron cannot release ACh
tetanus toxin causes muscle spasms and rigid paralysis by what MOA
cleave SNARE components to block vesicle fusion and travel up the spinal cord (retrograde movement)
curare alkaloids (like d-tubocurarine) are used during anesthesia to relax muscles (flaccid paralysis) by inhibiting Ach binding to receptor. whats the MOA
compete with Ach for the receptor
this Ach agonist is used as an induction agent for anesthesia and acts by binding nAChRs causing first depolarization which continues until receptor blockade and paralysis
succinylcholine
which of the Ach agonists is a depolarizing blocker?
which of the Ach agonists is a nondepolarizing blocker?
succinylcholine Curare alkaloids (non)
whats the function of cholinesterase inhibitors and when do we use them?
they increase ACh at the NMJ
parkinson, alzheimer, myasthenia gravis, nerve gas, reverse neuromuscular blockade during anesthesia
what drug inhibits ryanodine receptors in SR blocking release of ca++? when do we use it?
dantrolene
malignant hypothermia, upper motor nerve disorders
Property of muscles : Capacity to respond to stimulus
Excitability
Property of muscles : ability to shorten and generate pulling force
Contratility
Property of muscles : can strech back to original length
Extensibility
Property of muscles : can recoil to original resting length after stretched
Elasticity
Muscle fibers are surrounded by what structures that deliver oxygen and nutrients
Capillary beds
Each skeletal muscle Fiber contains several nuclei. As well as what to maintain energy required for contraction
Lots of mitochondria, myoglobin
How and when does the troponin-tropomyosin complex move to expose actins myosin binding site?
When calcium binds to troponin C, it causes the troponin-tropomyosin complex to release from the myosin binding site
Which myofilament has ATPase activity
Myosin (thick filament)
If the. Power stroke. Generated by actin/myosin interaction is strong enough to move the load what type of muscle contraction results?
Isotonic (muscle shortens)
If the. Power stroke. Generated by actin/myosin interaction is NOT strong enough to move the load what type of muscle contraction results?
Isometric (no shortening of muscle)
What type of Ach receptors. Do you. Find at the. Neuromuscular junction
Nicotinic
Where. Does an action potential propagate to in a muscle cell
Through sarcolemma and down t tubules
Voltage gated ca++ channels allow calcium out of the sarcoplasmic Reticulum and open in response to binding of what molecules
Ryanodine, DHPP
Renal failure, blood. Clotting, and cardiac arrhythmias can result from leakage of ca++, K+, phosphate, urate, myoglobin, or lactate dehydrogenase into circulation as a result of what condition
Rhabdomyolysis (unaccustomed physical excersize)
When bound to actin, myosin heads pull causing sarcomere to shorten. What “bands disappear” as the thin filament moves toward the center
H and I
Which “band” in the sarcomere remains the same length during contraction
A band (myosin)
During contraction myosin forms a bond with an actin molecule. What do we call this bond
Crossbridge
Once a cross bridge is formed, myosin head bends and pulls itself along the actin filament. What is this motion called
Power stroke
What happens when ATP binds to myosin during power stroke
It releases from the actin
How do we. Restore calcium. Levels. After contraction
Active transport in the SR
After you die the cytosolic concentration of calcium rises because the muscle membrane is no longer active. calcium leaks out and moves troponin complex aside letting actin and myosin form cross bridges. Since no ATP is being generated, they cannot detach so dead muscles remain stiff. What do we call this?
Rigor Mortis
What mechanisms control strength of a muscle contraction
- Motor unit recruitment
2. Individual fiber contractility manipulation (frequency of stimulation)
What makes up a motor unit
1 neuron + all muscle fibers it supplies
What happens if two action potentials reach one muscle fiber at the same time
Summation - tension of the two is added (more time is needed for ca++ to leave after and muscle to relax)
What do you call it when repeated stimulation to muscle results in a plateau of tension and the muscle stays there
Tetanus
A decline in muscles ability to maintain a constant force of crontraction in the face of long term repetitive stimulation
Fatigue
Type of periodic paralysis caused by decreased blood K+ during paralytic episodes
Hypokalemic periodic paralysis
Type of periodic paralysis caused by normal or increased blood K+ during paralytic episodes
Hyperkalemic periodic paralysis
Which skeletal muscle type is comprised for slow twitch fibers (high blood flow, lots of mitochondria, fatigue resistant)
Type I
Which skeletal muscle type is comprised for fast twitch fibers that receive HIGH blood flow and HIGH mitochondrial content (relatively fatigue resistant)
Type IIa
Which skeletal muscle type is comprised for fast twitch fibers that receive LOW blood flow and LOW mitochondrial content (fatigue rapidly)
Type IIb
Disorder where patient creates autoantibodies against nicotinic acetylcholine receptors creating muscle weakness mostly in eyelids and mouth region is called what? What do we use to treat it?
Myasthenia gravis
Treat with acetylcholinesterase inhibitor
how are mtDNA inherited differently from nuclear DNA
we got it from our MAMA (also we have multiple copies per cell)
most common mitochondrial disease: subacute loss of vision in young adults (mostly men) due to mutation in gene encoding for complex I subunits
Leber’s Hereditary Optic Neuropathy (LHON)
this disease can be caused by mutations in nuclear or mitochondrial DNA that code for complex I or IV presenting as developmental delay, respiratory abnormality, recurrent vomiting, nystagmus, ataxia, dystonia, early death
Leigh’s Syndrome…. 90% of mtDNA contains mutation
multisystem mitochondrial disorder where brain, muscle, endocrine are involved leading to death in young adulthood. symptoms include stroke like episodes (infarct in temporal and occipital lobes). this is an angiopathy. Treat with L-arginine to decrease stokes.
mitochondrial encephalomyopathy, lactic acidosis, and stroke like episodes (MELAS)
mitochondrial disorder where mutations occur in tRNA for lysine. symptoms: cervical lipomas, myoclonus, epilepsy, COX negative
Myoclonus epilepsy and ragged red fibres (MERRF)
what are canonical features of mitochondrial OXPHOS disorders?
recessive inheritance, reduction in cellular oxygen consumption and ATP synthesis, increased resting lactic acid, overproduction of ROS, sometimes induce autoimmune response
all mtDNA is encoded to create what
OXPHOS system
who carrie sub threshold levels of potentially harmful mtDNA mutations
normal humans like you and me - we get more as we age
what type of mutation auses MELAS
A to G in gene for tRNA for leucine
what type of mutation auses MERRF
A to G in gene for tRNA Lys
what tissues are most likely to accumulate mtDNA mutations
postmitotic tissue (brain, heart, muscle)
what important cancer causing gene also regulates respiratory chain function and glycolysis via regulating transcription and making SCO2 (loss of this gene stimulates glycolysis and TCA cycle)
p53
whats the crabtree effect
p53 mutation causes cancer cells to prefer glycolysis and TCA cycle and suppress OXPHOS
Warburg hypothesis states that mutation in nDNA encoding which two TCA cycle intermediates can lead to cancer
succinate dehydrogenase, fumarase
a defect in the gene product of MELAS patients
tRNA for leucine or ND1
a defect in the gene product of MERRF patients
tRNA for lysine
a defect in the gene product of LHON patients
NADH ubiquinone oxidoreductase (N1)
how are transmitochondiral lines created for studying mitochondrial disease and mutation load of mitochondrial mutations
making cybrids: injecting mtDNA of sick pt into empty mitochondria
what is the phenotypic threshold value for mtDNA deletions? for mtDMA mutations?
60% for deletions
90% for mutations
different tissues have different thresholds for phenotype of mtDNA mutations. which has a higher threshold: brain or heart tissue?
heart!
What medication do we give in emergent situation of malignant hypothermia?
Dantrolene (blocks Ryanodine receptor)
cox positive mt disease
melas
cox negative mt disease
merrf
mt disease that has the red ragged fibers
merrf
mt disease with strokes due to angiopathy
melas
complex I mutation mt disease leads to blindness
lhon
