Week 5- Neuromuscular system Flashcards
What are the unique characteristics/properties of muscle tissue that help it with its function?
Stimulated/excitable
Generate action potential-conduct within itself-contracts/shortens
stretch and go back to original length
sarcolemma
Surrounding the cell
Cell membrane
sarcoplasmic reticulum
Stores calcium
T tubules
Allow action potential to travel deep into cell
Mitochondria
provides energy and atp
myofibrils
composed of thick and thin filaments
myofilaments
Actin-Thin
Myosin-Thick
Describe components of thick filament
Myosin
Appear thicker-have golf heads on ends
Describe components of thin filament
Actin
appear thinner
What is a sarcomere?
Length of Overlapping thick and thin filaments
Shorten sarcomere to contract
What does the term “innervation” refer to?
Requires a specific nerve to perform action
Describe the NMJ (neuromuscular junction)—what occurs there?
Where neuron and skeletal muscle meet
-Synaptic bulb on axon terminal releases ACH
-ACh travels inside of space called synaptic cleft
-Travels inside of cleft until it reaches nicotinic receptors- n.receptor then performs action
-After response is done, ACHE will break down ACH to get rid of it
What is a motor unit? How do motor units provide for muscle contraction?
Neuron(LMN) and all of skeletal muscle cells in one muscle that it can stimulate
Can recruit more motor units if needed-allows for rest of muscles to prevent fatigue
Small motor unit
smaller motor unit
fine degree of control
3-6 muscle cels per neuron
large motor unit
larger motor unit
has more strength then control
1000 muscle cells per neuron
many muscle fibers
excitation of muscle
-LMN will release ACH
-ACH will bind to nicotinic receptor on cell
-Stimulates action potential of skeletal muscle
-AP will go deep into t.tubleus-release calcium into cell
contraction of muscle
-Calcium will remove tt complex off of actin
-Myosin heads will bind to atp
-Myosin heads will attach to actin
Myosin heads will pull-release-pull etc.. on actin inward, which shortens length of sarcomere
relaxation of skeletal muscle
-Stop signal-get rid of ACH-Stops action potential
-calcium gets sucked back into sarcoplasmic reticulum
-Tt complex covers actin again
-myosin cant bind
-muscle cell goes back to original length
Why is ATP necessary for relaxation?
Calcium getting sucked back into SR
isotonic contraction
Same load/weight
moving of length of muscle
ex-lifting weight
isometric contraction
different amounts of load/weight
length of muscle doesnt move
ex-pushing on a wall
muscular atrophy
decrease in size and wasting of muscle tissue
muscular hypertrophy
increasing size of muscle cells
increasing load or stress on muscle will respond by creating more actin or myosin
What is the purpose of glycogen in skeletal muscle cells?
Can be broken down and used as glucose to generate ATP
Describe skeletal muscle metabolism to generate ATP
Glycolysis-generates 2 ATP-can go into rest of CR if needed-Generates lactic acid-no oxygen required
CP-quickly donates P to adp to make ATP-byproduct is creatine
Aerobic-glycolysis-formation of acetyl coa-krebs cycle-ETC
immediate metabolism
short- intense exercise
CP will supply phosphate to adp to make ATP
short term metabolism
Fermentation
yields small amounts of atp
used in minor situations
long term metabolism
Aerobic respiration-Glycolysis- acetyl coa-krebs-ETC
Produces 36 ATP
used for longer uses of metabolism
fast muscle cells
adapted for fast responses
adapted for fermentation to make ATP
pale appearance because no mitochondria or capillaries
slow muscle cells
adapted for aerobic respiration and fatigue resistance
relatively long twitch
Is NS required
Skeletal
cardiac
smooth
S-Yes
C-No
SM-No
Which ns will influence
Skeletal
cardiac
smooth
S-Somatic
C-Autonomic
SM-Autonomic
Name of contractile protein
Skeletal
cardiac
smooth
S-Actin+ myosin
C-Actin + myosin
SM-Actin + myosin
name of regulatory protein
Skeletal
cardiac
smooth
S- T-T
C-T-T
SM-Calmodulin and kinase
source of calcium
Skeletal
cardiac
smooth
S- Sarcoplasmic reticulum
C-Sarcoplasmic reticulum/ECF
SM-Extra cellular fluid
can it be autorythmic
Skeletal
cardiac
smooth
S-No
C-yes
SM-yes
can cells regenerate
Skeletal
cardiac
smooth
S-no-scar tissue
C-no-scar tissue
SM-yes
