Physiology 208 Muscles

tasnimjaisee's version from 2017-11-23 20:52

Lecture 1

Question Answer
The primary function of all muscle is to generate?force responding to physiological stimulus
Generation of force in muscles depends on conversion of ____ energychemical (ATP)
Skeletal Muscles have which type of nuclei (multi/single)Multinucleated
Skeletal Muscles are primarily voluntary by?somatic motor neurons
Between skeletal and cardiac muscles which cells are non-branched?Skeletal
Cardiac Muscle are primarily involuntary by?spontaneous electrical activity
Cardiac Muscle can be altered by? (2)Autonomic NS - Hormones
Smooth Muscle are primarily involuntary by? (5)spontaneous, hormones, autonomic control, paracrine/autocrines
Smooth Muscle provides mechanical control of which tracts? (3)Digestive - Urinary - Reproductive
Skeletal Muscle attached to bones by?Tendons
Skeletal Muscle: Originclosest to trunk or stationary bone
Skeletal Muscle: Insertionmore distal/mobile attachment
Skeletal Muscle: Antagonistic muscle groupsflexor - extensor pairs
Flexorbrings bones together
Extensormoves bones away
Skeletal Muscle is how much of the body's weight?40%
Skeletal Muscle is how much of daily energy expenditure?15-60%
Muscle terminology: Muscle cellMuscle fiber
Muscle terminology: Cell membraneSacolemma
Muscle terminology: CytoplasmSacoplasm
Muscle terminology: Modified ERSacoplasmic reticulum
Breakdown of Skeletal Muscle (4)Skeletal Muscle→ Muscle Fasicle→Muscle fiber→Myofibril→Sarcomere
Thick filamentMyosin
Thin filamentActin
Explain the structural form of F-Actin (3)Double-stranded alpha helical polymer of G-actin molecules
What is a binding site for thick filaments?F-Actin
What is the thin filament backbone?F-Actin
Explain the structural form of Tropomyosin2 identical coiled alpha helices
What does Tropomyosin regulate?Myosin to actin binding
troponin T (TnT)binds single tropomyosin
troponin C (Tnc)Ca2+ binding site
What are the parts of Troponin complex?heterotrimer consisting of TnT, Tnc, TnI
troponin I (TnI)In resting conditions bound to actin inhibiting contraction
Troponin complex is situated in every ___ actin molecules7
What does F-Actin belong in? (Thick/Thin)Thin filaments
What does Tropomyosin belong in? (Thick/Thin)Thin filaments
What does Myosin molecules belong in? (Thick/Thin)Thick filaments
Explain the structure of Myosin molecule and what it's followed by (2)2 heavy chains heads; 2 light chains each - Followed by alpha-helical rods wrapped around each other
What are the light chains called on each heavy chain head?MLC-1 (Essential) and MLC-2 (Regulatory)
MLC-1Essential light chain
MLC-2Regulatory light chain
What does regulatory light chain maintain?ATPase activity of myosin
What does essential light chain maintain?stabilizes myosin head
Titin (3)Protein from M to Z - elastic recoil - Stabilization
Nebulin (3)Wraps around thin filament - regulates length & structure
Z disk (2)zigzag - attachment site for thin filaments
Lightest band of sarcomereI band
Which sarcomere controls region occupied only by thin filamentsI band
Darkest band of sarcomereA Band
Which sarcomere encompasses entire length of the thick filament?A band
Which sarcomere includes very dark area where thin and thick filaments overlap?A Band
Which sarcomere is the central region of A band H-Zone
Which sarcomere consists only of thick filaments?H-zone
Which sarcomere forms the attachment site for the thick filaments?M line
Which sarcomere is equivalent to z disk for thin filaments, for thickM line
Glucose is stored as ____ within the sarcoplasmglycogen
In the sliding filament model, what does the actin & myosin do? slide past each other without length change
In the sliding filament model, what does the sacromere do?shortens during contraction
During muscle contractions: Explain H zone, I band and A band's actionsH zone and I band shorten; A band stays the same
Force generated by a contracting skeletal muscle is?Tension
Neuromuscular junctionsomatic motor neuron & muscle fibre synapse
Excitation-contraction coupling results?Action potential increasing Ca2+
Contraction-Relaxation cycle comes from which signal?Ca2+
Contraction-Relaxation cycle froms which reactions?Muscle twitch - Sliding filament theory
A single muscle fibre contains ____+ myofibrils1000
Where does Tropomyosin sit in?In 2 groves formed by actin strands

Lecture 2

Question Answer
Primary motor cortexpremotor cortex - Basal ganglia - Thalamus - Midbrain - Cerebellum
Corticospinal Tractdescending tract (ventral and interior lateral white matter)
Upper motor neuronbrain to spinal cord
Alpha (lower) motor neuronfrom spinal cord to muscle
Describe alpha-motor neurons (length, myelinated/unmyelinated(?), seconds)Large - Myelinated - 15-120m/s
Number muscle fibers/motor units for alpha-motor neurons delicate precise work<10
Number muscle fibers/motor units for alpha-motor neurons powerful less precise contractions>100
All the muscle fibres Alpha (lower) motor neuron innervates is known as?Motor units
Which compartment degeneration causes ALS?Upper and/or lower motor neurons
What is present in 25% cases of ALS due to a mutation in gene(s)?superoxide dismutase
Motor neuron vesicles contain which chemical?acetylcholine
Motor end platesarcolemma at the neuromuscular junction
____ ____ on sarcolemma increase surface areaJunctional folds
Muscle sarcolemma contains ____ ____ receptorsnicotinic acetylcholine
Opening of ACh receptor requires how many acetylcholine molecules?2
Net Na+ influx _____ muscle fibreDepolarizes
Na+ entry through nACh generates which type of potential?excitatory end-plate potential
What type of channel does the Nicotinic Acetylcholine Receptor open?Non-specific monovalent cation channel
What does an EPP spreading to adjacent voltage gated Na+ channels on the sarcolemma and initiate?Action potential
excitatory end-plate potential spreads to which channels on the sarcolemma?Na+
Once AP’s stop firing in the alpha motor neuron, what must be done to the acetylcholine in the synaptic cleft? (2)Removed and diffused - Broken down to acetate & choline by acetylcholinesterase
What does choline acetyltransferase do?Supplies Acetyl CoA to make acetylcholine
Which cell part is Acetyl CoA made from?mitochondria
For Myasthenia gravis, what occurs through from the autoimmune system?Antibodies bind to ACh receptors - Inactivates AChR - Postjunctional fold degeneration
Action potentials propagate from the sarcolemma to the interior of muscle fibres along the ____ ____ networkTransverse tubule
Sarcolemma penetrates into the muscle fibre in the form of?T-tubules wrapping myofibrils
Specialized Ca2+ storage organelles known as ____ ____ are strategically organized with the T-tublulessarcoplasmic reticulum
At how many points do T-tubules penetrate the muscle fibre and surround the myofibrils?2
Which bands do T-tubules penetrate the muscle fibre and surround the myofibrils?A and I band
Along its length the tubules are associated with two ___ to form a "triad"cisternae
What do sarcoplasmic reticulums store?Ca2+

Lecture 6

Nociceptor activates->Primary sensory neuron enters spinal cord and diverges->Collateral activates ascending pathways for sensation & postural adjustment->Withdrawl reflex pulls foot away->Crossed extensor reflex supports body as weight shifts away from pain
Question Answer
Describe cardiac myocytes (length, visual, nucleus#)Short - Branched - Single nucleus
Intercalated discsDesmosomes - Gap junctions
How are cardiac muscles and skeletal muscles similar?Stirated - Sarcomeres with arrays of thick and think filaments
how are cardiac muscles and skeletal muscles different?Less abundant but larger T-tubules - Less sarcoplasmic reticulum
Which cell part makes up 1/3 of cardiac muscle volume?Mitochondria
cardiac muscle cells may contract almost ___ times in an average life span without resting3 billion
Autorhythmic cellsPacemakers
Approximately what percent of myocardial cells are specialized non-contracting autorhythmic cells?1%