What are the 7 functions of muscle
Body Movement
Maintain Posture
Respiration
Produce body heat
Communication
Construction of organs and vessels
Heart Beat
not that important to remember
What are the 4 properties of muscles
Contractility, Excitability, Extensibility and Elasticity
Remember using CEEE
What is contractility?
ability to shorten when an adequate stimulus is received
What is excitability?
ability to receive and respond to a stimulus
what is extensibility?
ability to lengthen when an adequate stimulus is received
what is elasticity?
ability to return to standard shape
What are the 3 muscle types?
Skeletal Muscles, Cardiac muscles and Smooth muscles
Skeletal Muscles location, function, nuclei type and appearance
Attached to bone
Body movement
Voluntary Control
Striated
Multinucleate
Cardiac Muscle’s location, function, nuclei type, and appearance
Found in Heart
Involuntary Contraction
Single Nuclei
Intercalated disks
Circulate blood
Smooth Muscle’s location, function, nuclei type, and appearance
Found in blood vessels, glands, etc
Spindle Shaped
Single Nuclei
Involuntary contraction
No striations
Muscles can only ___(push/pull) and donot ___(push/pull)
pull; push. Just remember Muscles cannot push thats it
What are the 5 muscle components?
Muscle, Fascicle, Muscle Fiber, Myofibril and Myofilament
Remember: (m, f, mf, m, mm)
write the correct order from largest to smallest
muscle, fascicle, muscle fiber, myofibril, myofilament
(m, f , mf , m , m)
What is Action Potential?
rapid sequence of changes in the voltage across a membrane
What is resting state?
Cytosol (inside part of cell) has slightly negative charge.
Remember: Salty Banana (Na+ outside and K+ inside)
What is depolarization?
Influx of Na+ ions into neuron
What is repolarization?
attempt to restore. (K+ moves out, trying to balance contents inside cell)
What is Na+/ K+ pump?
Transports Na+ and K+ ions. Requires energy
Explain how Ach gets into synaptic cleft in Neuromuscular Junction
Action potential is sent along a neuron to axon terminal
The AP causes Ca2+ channels to open and thus allowing calcium in
Ca2+ causes vesicles containing the neurotransmitter Ach to fuse with the membrane of axon terminal and release Ach into synaptic cleft
Explain what happens after Ach reaches synaptic cleft in Neuromuscular Junction
Ach drifts through the synaptic cleft and binds with Na+ channels cuasing channels to open and allow Na+ to flow into cell and continue action potential
what does Achase does at Neuromuscular Junction
Once the Ap has continued the enzyme Achase will begin to breakdown excess Ach into components: acetic acid and choline
Acetic acid is waste while choline is moved back into axon terminal where it combines with new acetic acid forming Ach. This new Ach will get stored in vescile
What is myofibrils composed of?
overlapping myofilaments called actin and myosin.
They slide over each other to contract the muscle fiber
What does sliding filament theory state?
Actin and myosin pull the z-line closer the M-line, shortening the length of the sarcomere
Explain Z-lines, I bands, Hzone and A bands?
Z-lines: ends of sarcomere
I bands: only contain thin filament (actin)
H zone: only thick filament (mysoin)
A band: center of sarcomere where think (myosin) and thin (actin) filaments overlap
Analogy to remember Sliding filament theory
Actin strands contain:
Troponin (Juliet’s dad, Lord capulet)
Tropomyosin (the door)
Active sites (Juliet)
Myosin strands contain:
myosin heads (Romeo)
Cacium Ca2+ (the donut)
Romeo gives donut to the door and then door leaves, allowing Romeo to meet Juliet in Lord capulet’s castle
First 4 steps of Sliding Filament Theory (No need to memorize, just know Romeo’s Analogy)
Action potential along the sarcolemma travels through the T tubules causing the release of Ca2+ from sarcoplasmic reticulum
Increase in calcium causes it to bind to troponin cuasing a conformational change (shape changes)
This change is shape causes tropomyosin to move away from the active sites on actin exposing them
The myosin head will bond with the active site on actin, forming a cross bridge and push the actin forward
Last 8 steps of Sliding Filament Theory (No need to memorize, just know Romeo’s Analogy)
As ATP binds to myosin head, the head detaches from the actin
The myosin head splits the ATP into ADP+P becomes re-energized and reorients
Myosin head attaches to actin
Myosin head rotates to the center of the sarcomere and pulls/pushes the actin to the center
When the action potential ends, Ca2+ is reabsorbed via active transportation into the sarcoplasmic reticulum.
As Ca2+ moves out of the sarcomere, it unbinds with troponin
Without Ca2+, troponin moves the tropomyosin back into active sites
Myosin moves back to starting position.
What is a muscle twitch?
a single contraction of a single muscle fiber in response to a single action potential. Can last 10 to 100ms
What are the three parts of muscle twitch?
Latent period (lag phase)
Contraction phase
Relaxation phase
What is latent period?
A short delay from the time AP reaches the muscle until the tension in the muscle.
What is the contraction phase?
cycling of cross-bridges (myosin and actin contractions)
What is relaxation phase?
Muscle return to normal length
What is Threshold stimulus?
Stimuli must meet a minimum threshold to produce a response
What is submaximal stimuli?
As stimulus continues (gets stronger) the more motor units that will be respond
What is motor unit?
Single motor neuron and all attached muscle fibers.
Remember:
Small = more coordinated but less power. Ex: hands
large = less coordinated but more power. Ex: legs
What is maximal threshold?
Maximum tension that can be achieved
What are supramaximal stimuli?
the continued stimulus at maximum tension will continue to have all motor units responding
Example: the sudden bursts of energy where you can push a car to protect something
What is the difference between incomplete tetanus and complete tetanus?
muscles take time to relax in between stimuli.
incomplete tetanus means muscles fibers may only partially relax
cmplete tetanus means signal reaching high frequency and making muscle fibers not relax at all
What are the 2 types of contractions?
Isometric and Isotonic.
Isotonic is further divided into Concentric and Eccentric
What is Isometric?
Same length but muscle tension changes.
Example: holding barbell, wall sits and planks
What is Isotonic?
Same muscle tone but muscle length changes.
What is concentric?
Muscle tension is generated as muscles shorten.
What is Eccentric?
Muscle tension is generated as muscle length
What are the 3 types of energy sources?
Creatine phosphate
Glycolysis (Anaerobic)
Cellular Respiration (Aerobic)
What is Creatine phosphate?
ADP reacting with creatine phosphate to produce ATP.
Occurs very quickly but can only provide energy about 10 seconds
What is Glycolysis (Anaerobic)?
Doesn’t require oxygen. Produces 2 ATP and 2 Lactic acid for every glucose.
Quick but only sustains for 1-3 minutes
What is Cellular Respiration (Aerobic)?
Requires oxygen. Most efficient with 38 ATP for 1 glucose.
Sustains longer (but slower) muscle contraction activity
What is Type I Fibers
Slow Twitch
Lots of Mitochondria
Depend of Cellular respiration for ATP
Resistant to Fatigue
Rich in myoglobin (red color, dark meat of turkey)
Activated by slow conduction, small diameter motor neurons
Dominant in muscles used for endurance and tonus. Ex: posture
Marathon / Cross Country runner’s
What is Type II Fibers
Fast twitch
Few Mitochondria
Rich in glycogen
Depend on creatine phosphate & glycongen for ATP
Fatigue easily with production of lactic acid
Low in myoglobin (white meat of turkey)
Activated by fast - conducting, large diameter motor neurons
Dominant in muscles used for rapid movement. Example: Eyes
Sprinters.
Congratulations, that’s the end of all terms.
make sure to practice using cfu’s and near pods.