BL 8 Flashcards
(52 cards)
Whats myalgia?
Muscle Pain
Myoclonus?
Sudden spasm of the muscle
Explain the 3 muscle types morphology
Skel: Long parallel cyclinders
Card: Short branched cyclinders
Sm: Spindle shaped
Explain the 3 muscle types innervation/control
Skel: Somatic motor control
Card: Intrinsic, involuntary modification
Sm: Involuntary, autonomic intrinsic activity
Skeletal Muscle has 3 types of fibres? Which is the sprinters or marathon runner?
Red - Marathon runner
Intermediate
White - Sprinter
Explain the structure of a muscle from the actin-myosin fibres up
Muscle Fibre (Endomysium)
Fascicle (perimysium)
Muscle, bundle of fascicles (epimysium)
Muscle structure sheaths. 3 types
Endo
Peri
Epi
myseum
How would you identify skeletal muscle? Nuclei
Striations
Multi-nucleaic
Arranged in fascicles
Striated Muscle. What are the dark strands?
what are the light strands?
A bands = Dark
H band = light
How do you remember the sarcomere lines and zones
Z is the end of the alphabet and Z is the end of the sarcomere.
M is the middle of the alphabet and M is in the middle of the sarcomere.
Attached to the M line are your Mighty Myosin (Mighty = thick filaments)
“My tits” (Sorry for the vulgar language) is for remembering that myosin is attached by titin to the Z line.
Actin (acthin) is the thin filament attached to the Z line.
H is a thick letter so only thick filaments are found in the H band.
I is a thin letter so I band has only thin filaments!
Myosin doesn’t like to change and is very bossy. So it not only took the middle M letter for the M line, but also took the A alphabet to represent
What happens in hypertrophy?
Increase contractile proteins so increased fibre diameter
What does stretching do?
Adds sarcomeres
Whats the name of the curve associated with sliding filament mechanism. And use for heart output?
Frank-starling curve
What can a troponin Assay detect?
Cardiac Ischaemia (1hr-20hrs)
Creatin Kinase detection?
Ck can be used to diagnose MIs and the proportion of its conc indicates size of MI
What does tropomysosin do when IC calcium is increased?
Ca binds to TropC and tropomyosin confirmationally changes revealing actin bind sites
4 steps in sliding filament theory
1) Myosin head attaches to actin binding site
2) POWER STROKE (pulls actin and ADP+Pi dissociates)
3) ATP attaches to myosin head and it detaches
4) ATP split which cocks the myosin head
Explain the events leading to a skeletal muscle contraction. 9
- Initiation: nerve impulse along motor neuron
axon arrives at neuromuscular junction. - Impulse prompts release of acetylcholine
(Ach) into synaptic cleft causing local
depolarization of sarcolemma. - Voltage-gated Na+channels open; Na+
enters cell. - General depolarization spreads over
sarcolemma and into T tubules. - Voltage sensor proteins of T tubule
membrane change their conformation. - Gated Ca2+-release channels of adjacent
terminal cisternae are activated by 5.
7.Ca2+is rapidly released from the terminal
cisternae into the sarcoplasm. - Ca2+binds to the TnC subunit of troponin.
- The contraction cycle is initiated and Ca2+
is returned to the terminal cisternae of
sarcoplasmic reticulum.
Cardiac Muscle structural characteristics? 4
Striations
Centrally positioned Nuclei (1or2)
Intercalated discs
Branching
Whats hypertropy and hyperplasia?
cellular hypertrophy = increased cell size
cellular hyperplasia = increased cell number
Whats ANP?
Whens it released?
Whats its effect?
Atrial Naturetic Peptide
Released in atrium due to stretch
Decreased blood volume
Whats BNP?
Whens it released?
Whats its effect?
Brain natriuretic peptide
Ventricles (10X lower affinity but double half life compared to ANP)
Reduces BP by naturesis and decreases in systematic vascular resistance
How does ANP/BNP relate to RAASystem
natriuretic peptides serve as a counter-regulatory system for the renin-angiotensin-aldosterone system
Myopathy?
Any disease of the muscles
