Chapter 1 Flashcards
What is a motor unit?
A single nerve(/neuron) and the collection of muscle fibers it innervates
What is a fascicle?
A group of muscle fibers that are bundled together by fiber type. (e.g. Type 1 slow twitch, type 2a/2x fast twitch).
What type of tissue is the perimysium and what does it surround?
It is a thin layer (middle layer) of connective tissue that surrounds the fascicle aka groups of muscle fibers.
What is the Epimysium?
The outer most layer of connective tissue/fascia that engulfs the entire muscle & extends beyond the muscle to connect our tendons to bone.
What is the Endomysium?
The (i)nner most connective tissue that surrounds each individual muscle fiber.
Strains apply to what?
Muscle
Sprains are associated with what?
Liagments
What bones make up the axial skeleton?
Skull, rib cage, sternum, and vertebrae
What bones make up the appendicular skeleton?
Scapula, Arm, Wrist, and Hand Bones, Leg, Ankle, and Feet Bones, Hips (Illium (large fan shape), Ischium (posteriorinferior portion), and Pubisn (anteromedial portion), Sacrum, and Cocyx.
What are muscle cells/fibers made up of? And what do they contain?
Muscle fibers are made of myofibrils and they contain sacromeres - the smallest contractile unit of muscle.\ which is made up of actin ^ myosin.
Between the Z-disc, I-band, H-zone, and A-band (of a sarcomere) which can shorten and which stays the same and never changes in length?
The Z-disc, I-band (which connects to actin), and H-Zone can shorten/contract, but the A-band, which is the length of the mysoin never changes in length.
When myosin pulls on actin like a row boat to shorten the muscle for contraction this action is referred to as what? How is this contraction relinquished or reset?
Power Stroke
Through ATP Hydrolysis
(Combined the process is what allows us to produce force)
When an action potential is sent from the brain and down the nerve to the neuromuscular junction, what is released?
Hint: This neurotransmitter causes excitation of the sarcolemma and hence causes muscle contraction.
Acetylcholine (ACH)
What 7 Steps are involved in Activating a Muscle Fiber?
- The creation of an action potential
- The AP moving down the nerve to the neuromuscular junction
- The consequent release and crossing of acetylcholine thru the neuromuscular junction which excites the sarcolemma
- This signal continues down the t-tubles and causes calcium to be released FROM the sarcoplasmic
reticulum (where it is stored) - Ca+ then binds with troponin which binds to tropomyosin (the “rope” around actin”) which allows that binding site of actin to be exposed.
- Myosin then binds to actin to allow crossbridging at the gubular head.
- The Sliding Filament Theory can now occur - i.e. continuous power strokes and crossbridging. This will last as long as Ca++ is available to bind with troponin OR until relaxation occurs.
Are type 2a muscle fibers, fast twitch, slow twitch, or mixed?
Explain why?
Type IIa are mixed and often referred to as “fast oxidative glycolytic fibers” because they have both oxidative (i.e. aerobic) and glycolytic (i.e. CHO reliant) properties.
(They are also surrounded by more capillaries hence, the greater capacity for aerobic metabolism)
What muscle fiber type is naturally oxidative and prominent in aerobic-style training?
Slow twitch aka Type I muscle fibers
What muscle fiber type possess the greatest twitch speed?
Type IIx (aka fast glycolytic fibers)
Hence why they have the greatest force and power production, and are most fatiguable.
What is the role of the Golgi Tendon Organ (GTO)
To detect and protect.
It senses when a TENDON is stretched hard thru a muscle contraction and causes the inhibition of too much muscle force by telling the muscle to relax. (It’s a protective mechanism against injury)
What is a role of muscle spindles?
“MS sense MS” – Muscle spindles sense muscle stretch.
Muscle spindles causes antagonist muscles to contract (it’s like an automatic reflex that helps prevent the muscle from stretching to far)
What is the process of blood flow through the heart?
(Deoxygenated) blood travels through the inferior vena cava (or superior vena cava if coming form the brain) then travels thru the right atrium – tricuspid valve – right ventricle – pulmonary artery–lungs–pulmonary vein00left atrium–mitral valve–left ventricle (i.e. the biggest chamber of the heart) – thru the Arota (aka the exit)
Arteries take blood ______ from the heart while veins _______ the heart.
Away
suppy/take blood TO the heart
What is the process of blood flow TO the muscles?
Arteries carry the deoxygenated blood thru the arteriole then capillaries (for gas exchange), venules then veins
NOTE: capillaries run thru muscles and are thin enough to allow for gas exchange.
What is the pathway of a heart beat?
SA node sends the eletrical signal, the AV sets the needed pace of the heart, the AV bundle sends the singal to the ventricles, and the purkinje fibers further divides the signal to the ventricles (which pumps the blood out to the arota for distribution throughout the body)
When looking at an ECG, what does the P wave, QRS complex, and T wave represent?,
P wave - atria depolarization (contraction)
QRS complex - vent depolarization and atria repolarization
T wave - vent. repolarization/”refilling”
Depolarization is ___________ of the heart, while repolarization is when the heart ________.
Contracts
Relaxes/”refills”
What is the passageway of air once inhaled?
Inhaled thru the trachea, then bronchus (singular)/bronchi (plural), and dispearsed thru the bronchiole then alevoli (for gas exchange)
