Week 2 Flashcards
Myoblast
-muscle mesenchymal cells
Myotubule
- composed of
- will become
- made from myoblasts fusing together to make multinucleated tubes
- eventually become myofilaments once they make enough proteins and nuclei are displaced against sarcolemma
Myofilaments
- what do they make
- classes
- make myofibrils
- classes: actin (I band) and myosin (A band)
Sarcomere
- what forms it
- where does it extend from and to
- function
- formed by I and A bands,
- boundaries are between two z lines
- contractile unit of muscle cell
Sarcolemma
-what is it
-muscle cell membrane, encases multiple myofibril, contains sarcoplasmic reticulum
What lies outside of sarcolemma?
endomysium-fascia
Transverse-tubule
- what is it?
- function?
- Invaginations of the sarcolemma that penetrate deeply into the muscle fiber around all myofibrils
- allows action potential to propagate
Sarcoplasmic reticulum
-modified smooth ER of sarcolemma, holds Ca
Skeletal muscle triad
- made of
- function
- t-tubule and two terminal cisternae of SR
- allows depolarization of the sarcolemma in a T-tubule to affect the sarcoplasmic reticulum and trigger release of Ca2+ ions into cytoplasm around the thick and thin filaments, which initiates contraction of sarcomeres
H-band
-contains myosin and creatine kinase (will transfer phosphate groups from phosphocreatine to ADP to create ATP for muscle contraction)
M line
-in middle of H zone, contains myomesin which holds thick filaments in place
F-actin
-two actin monomers forming an actin filament
Troponin complex
-what is it made of? their functions?
- Tropnin I, C,, T
- T: binds troponin to tropomyosin
- I: inhibits binding of actin to myosin
- C: binds Ca (only in striated muscle)
Tropomyosin
- extends length of 7 actin monomers and binds to troponin
- blocks myosin-binding sites preventing crossbridges from forming
Myosin II head
driving force of movement when bound to ctin
Nebulin
- holds actin in place laterally
- anchors them to alpha actinin
Titin
-maintains position of myosin in sarcomere by generating passive tension
Costamere
- function
- disruption
- located on sarcolemm and connects sarcomere to sarcolemma
- dystrophin is one of main binding proteins and when mutated can cause disruption of costamere, alllowing for separation between sarcomere and sarcolemma
Satellite cells
- reserve myoblasts that are activated with injury and proliferate to form new skeletal fibers
- stored in sarolemma
Neuromuscular spindle
- function
- structure
- innervation
- primarily detect changes in the length of the muscle–provide information about contraction and relaxation
- composed of 2 to 14 muscle fibers wrapped with connective tissue in belly of muscle (intrafusal fibers)
- Sensory fibres (type Ia and type II) spiral around the intrafusal muscle fibres, ending near the middle of each fibre.
- Motor neuron: gamma
Types of skeletal muscle
Type I: slow
Type 2a/b: fast
Type I
- twitch
- metabolism
- myoglobin
- diameter
- fatigue
- used for
- slow twitch
- aerobic metabolism-use very little glycogen, mostly fat
- high myoglobin (appear red)
- small fiber diameter
- high resistance to fatigue
- used for prolonged aerobic exercise (marathon)
Type II A
- twitch
- metabolism
- myoglobin
- diameter
- fatigue
- intermediate twitch
- fast oxidative-glycolytic fibers (intermediate glycogen level)
- high myoglobin (red)
- intermediate fiber diameter
- intermediate resistance to fatigue
Type II B
- twitch
- metabolism
- myoglobin
- diameter
- fatigue
- used for
- fast twitch
- high glycogen (glycogenolysis), very little oxidative activity
- low myoglobin (white)
- large diameter
- sensitive to fatigue
- sprinting
Spaces in meninges (3)
1: epidural- space between wall of vertebral canal and duramater; fat, venous plexuses
2: subdural- potential space but not filled with anything usually as arachnoid mater is firm up against duramater
3: subarachnoid- between pia and arachnoid; CSF, arteries, veins
Spinal pathways
- Efferent: motor–sympathetic (organs; nicotonic (ACH) and adrenergic (EPI); thoracic and lumbar), parasympathetic (organs; nicotonic (ACH) and muscarinic (ACH); cranial and sacral), somatic (body wall; nicotinic ACH)
- Afferent: sensory
Nerve plexus
- formed by
- distribution
- formed from anterior primary rami
- peripheral distribution: not in dermatomes
Somite
-split into sclerotome and dermamyotome
Sclerotome
medial part of somite- will form vertebrae
- anterior portion: form body of vertebrae
- posterior portion: form vertebral arch
Dermamyotome
lateral part of somite-form skin and skeletal muscles
- anterior portion give rise to axial muscles of trunk and limbs and associated dermis
- posterior portion give rise to intrinsic muscles and overlying dermis of back
Referred pain
-somato sensory nerves run to same spinal segment and enter same spinal nerve as the sensory visceral nerves, so sometimes the sensation will get confused and the pain sensation will be perceived on body wall instead of on organ
Ondontoid view
-can see cervical spine through open mouth
Fyettes principals (3)
1: Neutral, side bending and rotation opposite
2: Flexed/extended, side bending and rotation same side
3: When initiating movement in any plane of motion on a segment, the segment will also move in the other planes of motion; therefore if someone is ESrRr, side bending them will also create motion in rotation and extension
