Ch 3 Muscle Anatomy and the Sliding Filament Theory Flashcards
What is the saying we need to always remember
Specific Adaption to Imposed Demand
Hypertrophy
increase in size of existing muscle fibers
Hyperplasia
development of new muscle fibers
(requires high demand to get this to happen)
Atrophy
loss of muscle mass
Sarcopenia
age related atrophy
What are the 3 types of muscle tissue
Smooth Muscle
Striated Cardiac Muscle
Striated Skeletal Muscle
Smooth Muscle
Involuntary (controlled unconsciously)
Mononucleated
Striated Cardiac Muscle
Controls itself along with nervous endocrine system input
Mononucleated
Striated Skeletal Muscle
Voluntary (controlled consciously)
Multi-nucleated cells
Where would you find smooth muscle
blood vessel walls and internal organs
where do you find striated cardiac muscle
heart
why are muscles elastic
so they can stretch to help gain more power in a movement (ex. Lowing legs first before jumping)
strongest muscle pound per pound
masseter
hypnic jerk
brain misreading relaxing muscle signals as falling and fires all muscles in attempt to regain balance
anatomy of skeletal muscle from smallest to largest
myofibril
Muscle fiber (surrounded by endomysium)
Fasciculi (surrounded by perimysium)
Entire muscle (surrounded by epimysium)
Plasmalemma (cell membrane)
Fuses with tendon
Conducts action potential
Maintains pH, transports nutrients
Involved in muscle growth and development.
Aids response to injury, immobilization, training
Satellite Cells
Sarcoplasm
serves as cytoplasm of muscle cell.
Glycogen storage, myoblobin
Carry action potential deep into muscle fiber, serve as extensions of plasmalemma
Transverse Tubules (T-tubules)
Sarcoplasmic reticulum
Ca2+ storage
Basic Contractile element of skeletal muscle
End to end for full myofibril length
Sarcomeres
What is the smallest contractile unit
sarcomere
What is sliding filament theory
Actin (thin filaments) and myosin (thick filaments) pulling on each other and coming closer together
What does the I-band contain
actin filaments
what does the a-band contain
both actin and myosin filaments
what does the h-zone contain
myosin filaments
Globular heads
Located in myosin
Interact with actin filaments for contraction
Actin
contains myosin-binding site
Tropomyosin
covers active site at rest
Troponin
moves tropomyosin
Titan
stabilizes sarcoomeres and centers myosin
Prevents overstretching
Consists of a single a-motor neuron + all fibers it innervates
Motor unit
Serves as site of communication between neuron and muscle
Neuromuscular Junction
Muscle Fiber Contraction: Excitation-contraction coupling
- Action Potential starts in the brain
- Action Potential arrives at axon terminal, releases acetylcholine
3.Acetylcholine crosses synaps, binds to acetylcholine receptors on plasmalemma
4.Action potential travels down plasmalemma and T-tubules - Triggers Ca2+ release from sarcoplasmic reticulum
6.Ca2+ enables actin-myosin contraction
Role of Ca2+ in muscle fiber
Ca2+ binds to troponin on thin filament
Relaxed Muscle state
No actin-myosin interaction
Contracted Muscle State
Myosin head pulls active toward sarcomere center
What is necessary for muscle contraction
Adenosine Triphosphate (ATP)
