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Jenesis Perez Per.2 Muscular System - Coggle Diagram
Jenesis Perez Per.2 Muscular System
Major functions of the muscular system
cause all types of movement
Actin- globular protein arranged in twisted filament that have myosin binding sites
Myosin- two twisted strands with globular heads projected outward along the strands
striations- bands in muscle
tropomyosin- protein
troponin- protein
Heat Production
Less than half of energy released in reactions of cellular respiration is used to form ATP, the rest becomes heat
maintain body temperature- heat is carried by the blood to other tissues
Muscle Fatigue
fatigue- muscle loses its ability to contract
may cause electrolyte imbalances and decreased ATP levels
decrease in pH due to lactic acid accumulation
muscle cramp- changes in the extracellular fluid around the muscle fibers
a sustained, painful, and involuntary contraction
uncontrolled muscle fiber stimulation by its motor neurons
Atrophy- decrease in muscle size and strength, due to disuse
Hypertrophy- enlargement of a muscle due to repeated exercise
synergists- Muscles that assist the prime mover
antagonists- Muscles that oppose an action
Action potential in a muscle fiber
signal to be transmitted quickly over long distances
the motor endplate potential is sufficient to raise the surrounding sarcolemmal potential above the threshold for activation of the voltage gated Na+ channels
special type of electrical signal that can travel along a cell membrane
occurs in surface of the muscle cell along the membrane of T tubules that penetrate into the cytosol of the cell
calcium ions diffuse from the sarcolemma into the sarcoplasm
the resting potential, threshold, the rising phase, the falling phase, and the recovery phase.
Names of all the skeletal muscles (including the facial muscles)
Anterior
rectus abdoninin
external oblique
serratus anterior
illiopsoas
pectoralis major
sartorius
gracilis
rectus femoris
vastus medialis
fibuians longus
soleus
palmoris longus
extensor digitorum longus
adductor longus
vastus lateral
Flexer carpi radialis
brachioradialis
gastrocremius
biceps brachii
deltoid
trapezius
sternocleidomastiod
tibialis anterior
Posterior
extensor digitorum
infraspinatus
extensor carpi radislis longus
teres major
tricep brachii
latissimas dorsi
rhomboid
gluteus maximus
biceps femoris
gostrocremios
soleus
semitendinosus
semimembranosus
trapezius
deltoid
sternocleidomastiod
fibuiaris longus
Facial
orbicularis-pucker
frontalis-raise eyebrow
zygomaticus-smile
orbicularic-blink
tempoalis-tense jaw
masseter-elevates jaw
platysma-tense neck
3 types of muscles & their functions
smooth
Walls of hollow viscera and blood vessels
Movement of viscera
Has no striations
Lacks transverse tubules
Contracts and relaxes slowly
cardiac
Wall of the heart
Pumping action of the heart
Striations present
Well-developed transverse tubule system
intercalated discs
separating adjacent cells
Involuntary
Network of cells contracts as a unit or rhythmic
skeletal
over 600 skeletal muscles in the body
Connective tissue coverings
fascia-Layers of dense connective tissue
aponeuroses -broad sheets of connective tissue
tendons
Skeletal muscle Fibers
respond to stimulation by contracting
muscle fiber- single, long, cylindrical muscle cell
sarcolemma- cell membrane of a muscle fiber
sarcoplasm- cytoplasm in muscle cell
parallel myofibrils- become active in muscle contraction
Thick filaments- myofibrils consist of the protein myosin
Thin filaments- myofibrils are mainly composed of the protein actin, troponinand, and tropomyosin
sarcoplasmic reticulum- Beneath the sarcolemma of the muscle fiber is a network of membranous channels
transverse tubules- invaginations of the sarcolemma
in between 2 cisternaeof the sarcoplasmic reticulum
the outside of the muscle fiber
activate the muscle contraction mechanism when the fiber is stimulated
Movement of bones at joints
Striations
voluntary
Contracts and relaxes rapidly
Neuromuscular junction
synapse- connected to the axon of a motor neuron
neurotransmitters- when released by synapse, neuron communicates with the muscle fiber by way of chemicals
Acetylcholine- neurotransmitter for skeletal muscle fiber contraction
produced in the motor neuron
stored in the synaptic vesicles
it's released into the synaptic cleft in response to an impulse in the motor neuron
sarcoplasmic reticulum releases its stored calcium to the cytosol
high concentration of calcium in the sarcoplasm interacts with the troponin and tropomyosin molecules
exposing the myosin binding sites on the actin filaments
Cross-bridges now form and pull on the actin filaments, using the energy of ATP
causes the sarcomere to shorten
relaxation- he nerve impulse stops
ATP breaks cross-bridge linkages between actin and myosin filaments without breakdown of the ATP
Breakdown of ATP cocks the myosin heads.
Calcium ions are transported back into the sarcoplasmic reticulum
Troponin and tropomyosin molecules block the interaction between myosin and actin filaments to start relaxing
The muscle fiber remains relaxed and will soon can be stimulated again.
Acetylcholinesterase decomposes acetylcholine, the muscle fiber membrane is no longer stimulated.
cellular respiration- generate ATP
ATP must be regenerated for contraction
motor neuron- Skeletal muscle fibers that can contract only when stimulated
a synapse between a motor neuron and a muscle fiber that it regulates
mitochondria- power house of the cell
motor end plate- muscle fiber membrane in a specialized region
contains specific receptors
synaptic vesicles- stores neurotransmitters
synaptic cleft- the gap between the membranes of the neuron and muscle fiber
neurotransmitters diffuse across the cleft, bind to the motor end plate, and stimulate the muscle fiber to contract
Sarcomere
sarcomeres- made up of many units
Z line- extends to sacromere
A bands- made up of overlapping thick and thin filaments
I bands- actin filaments, which are anchored to the Z lines
H zone- In the center of the A band and only has myosin
M line- in center of H and has proteins that hold the myosin filaments in place
Muscle coverings
epimysium-layer of connective tissue around each skeletal muscle
perimysium- inward from the epimysium
fascicles- surrounds bundles of skeletal muscle fibers
endomysium- covered by a connective tissue layer
Sliding filament theory of muscle contraction
it causes the head to bend, pulling on the actin filament, and moving it toward the center of the sarcomere
Then the head then releases, and attaches to the next binding site on the actin, pulling this site toward the center
it occurs again and again, the filaments increase their overlap, and the sarcomere shortens from both ends
a myosin head attaches to a binding site on the actin filament, forming a cross-bridge
many sarcomeres shorten at the same time, the muscle fiber shortens
ATPase- the enzyme provides it to cross-bridge
ATP breakdown causes the heads to return to a cocked position, ready to bind to another actin binding site