Chapter 10 Muscle Phisiology Flashcards
Muscle cells (fibers) are
-contractile- get shorter
-extensible- get longer
-elastic- return to normal shape after getting shorter/longer
-excitable-can create and carry electrochemical signais
(Sliding filament Theory)
Endomysium
Surrounds muscle cell
Transverse (T) -tubule is
inward Projections of cell membrane (sarcol emma) that go through in a transverse direction through cell
Sarcoplasmic reticulum
stores a releases ca+ ions (specialized ER)
Myofibrils are
Little fiber inside muscle cell
Triad is
Terminal cisternae on each side of the T-tubule
Order of muscle cell
Myofilaments are inside myofibrils→ inside muscle fibers (cells) → inside the muscle fascicles → inside muscle (organ)
Thick filament is
Myosin (head)
Thin filaments are
-consists of
Actins
-tropomyosin
-troponin
Tropomyosin is
(Rope) Strings along actin and covers the active sites
Troponin is
Proteins scattered across tropomyosin
(Moves protein)
Sarcomere
functional unit of skeletal muscle contraction
•When we establish a RMP
-90 mv) we say the cm is
Polarized
when the Na+ is rushing in the cmis
Depolarized
Myographs
Generates recordings of a muscle twitch
•muscle twitch (single twitch)
response of muscle fiber to a single action Potential in a motor neuron
(Spits out 1 ACh)
•unfused tetanus
muscle fiber Not allowed to relax complety between stimuli
(spits out mult. Ach fast; like 30-50 times per min)
Fused tetanus
muscle fibers NoT allowed to relax between stimuli
-tension remains constant at maximal level
-Spits Ach out about 40-60 times/min
TENSION HIGHEST HERE
when Ach is no longer being spat out what happens
Muscle relaxes
If skeletal muscle cells follow the “All or Nothing Principle”.
…How do we create varying
amounts of force?
we decide how many cells to use to create force we need
Motor unit
1 motor neuron and the muscle fibers it’s controls ( spits out)
-some motor units are as small as 2to 3 muscle fibers
AVERAGE SIZE IN HUMANS- 150 muscle cells per motor unit
Differential recruitment
usin different numbers of motor units for Particular actions
-small effort =fewer motor units
- recruiting all motor units =greatest force generated
Isotonic contraction is
Tension- constant
Length -changes
Isometric contraction
Length is constant (no change)
Tension changes
Isotonic CONCENTRIC contraction
Muscle shortens (regular contraction)
Isotonic ECCENTRIC contraction
Muscle gets longer while contracting
Where do cells get ATP
They make it
2molecules that help (a little bit) with ATP. Production
1: myoglobin
2: creatine PhosPhate
Myoglobin
Provides little more 02 (for more aerobic metabolism) (Red)
creatine PhosPhate
can provide extra Phosphates for ATP Production for about 10-15 secs.
To get muscles larger & Stronger - you have to
Increase diameter of muscle fibers
(Makes cells we have bigger doesn’t create new cells)
Oxygen debt is
the 02 needed to restore pre-work conditions to a muscle
If ATP’S run out in a muscle what happens?
The muscle stays how it was when the ATP ran out because the myosin heads can’t release because their is no more ATP
-this causes rigor morris
smooth muscle fibers binds different than skeletal muscle in that
Calcium Ca+ - binds too calmodulin (not troponin)
-calmodulin actives enzyme —> myasin light chain kinase ( allows myosin to attach to actins)
Smooth muscles still
BUT do what differently than skeletal muscles
Contract and move
Have myosin’s and actins
Have different arrangement of myofilaments
•atrophy means
decrease in size of cell due to lose of myofibrils
hypertrophy means
increase in cell size, increase number of myofibrils and diameter of muscle cells
Lactic acid is
Muscles and red blood cells produce lactic acid when body breaks down glucose and there isn’t enough oxygen to create its normal energy
Myasthenia Gravis
Weakness and rapid fatigue of muscles under voluntary control
Tendinitis is
Inflammation of a tendon from injury or overuse of
Duchenne muscuar dystrophy is
Inherited disorder of progressive muscular weakness
-typically in boys
Duchenne muscuar dystrophy is
Inherited disorder of progressive muscular weakness
-typically in boys
aponeurosis means
a thin sheath of connective tissue that helps connect your muscles to your bones.
fixator means
a muscle that stabilizes or fixes a part of the body to which a muscle in the process of moving another part is attached.
