Please enable JavaScript.
Coggle requires JavaScript to display documents.
Andrea Hernandez Period 3 Muscular System - Coggle Diagram
Andrea Hernandez Period 3 Muscular System
NeuromuscularJunction
AP arrives at axon terminal
voltage-gated calcium channels open, calcium enters motor neuron
calcium entry causes release of ACh neurotransmitter into synpatic cleft
ACh diffuses across to ACh receptors on sarcolemma
ACh binding to receptors, opens gates, allowing ๐๐ + to enter resulting in end plate
potential
Acetylcholinesterase degrades ACh
axons travel from central nervoussystem to skeletal muscle
axon branches end on muscle fiber, forming neuromuscular junction
axon terminal (end of axon) and muscle fiber are separated by synaptic cleft
stored within axon terminals are membrane-bound synaptic vesicles
infoldings of sarcolemma (junctional fold) contain millions of ACh receptors
Major Functuons
produce movement: responsible for all locomotion and manipulation
stabilize joints
maintain posture and body position
generate heat as they contract
Muscle Coverings
perimysium: fibrous connective tissue surrounding fascicles
endomysium: fine areolar connective tissue surrounding each muscle fiber
epimysium: dense irregular connective tissue surrounding entire muscle; may
blend with fascia
Name of All Skeletal Muscles
flexor carpi radialis: flexes and abducts wrist
flexor carpi ulnaris: flexes and adducts wrist
pronator teres: pronates forearm
palmaris longus: flexes wrist
extensor carpi radialis: extends and abducts wrist
extensor carpi ulnaris: extends and adducts wrist
extensor digitorum: extends fingers
gluteus maximus: extends hip
brachioradialis: assists in elbow flexion
triceps brachii: extends elbow
gluteus medius: abducts and stabilizes hip
ensor fasciae latae: stabilizes and abducts thigh
iliopsoas:flexes hip
adductor longus/magnus/brevis: adduct thigh
sartorius: rotates thigh
rectus femoris, vastus lateralis, vastus medialis, vastus intermedius: extend knee, flex hip
biceps femoris, semitendinosus, semimembranosus: flex knee, extend hip
gracilis: adducts thigh
tibialis anterior:dorsiflexes foot
brachialis: flexes elbow
biceps brachii: flexes elbow
infraspinatus: rotates arm laterally
teres major: assists in arm extension and rotation
latissimus dorsi: extends, adducts, and rotates arm inwards
external oblique: compresses abdomenv
rectus abdominis: flexes vertebral column
serratus anterior: moves scapula forward
pectoralis: flexes, adducts, and medially rotates arm & pulls scapula forward and downward
deltoid: abducts, flexes, and extends shoulder
trapezius: moves scapula
sternocleidomastoid: flexes neck, rotates head
temporalis: elevates and retracts mandible
gastrocnemius: plantar flexes foot
masseter: elevates mandible
fibularis longus: everts and plantar flexes foot
orbicularis oris: closes and puckers lips
extensor digitorum longus:extends toes
zygomaticus: raises corners of mouth & elevates upper lip
lexor digitorum longus: flexes toes
orbicularis oculi: closes eyelids
soleus:assists in plantar flexion
frontalis: raises eyebrows, wrinkles forehead
Disorders
Duchenne Muscular Dystrophy (DMD): common and serious form of muscular dystrophies, muscle-destroying diseases that generally appear during childhood
Myasthenia gravis: disease characterized by drooping upper eyelids,difficulty swallowing and talking, and generalized muscle weakness
Rigor Mortis: 3โ4 hours after death, muscles begin to stiffen, intracellular calcium levels increase because ATP is no longer being synthesized, muscles stay contracted until muscle proteins break down, making myosin to
release
Three Types of Muscles & Functions
cardiac muscle: contracts involuntarily to pump blood through the heart
smooth muscle: moves substances involuntarily through organs like the stomach and blood vessels
skeletal muscle: moves the body voluntarily and maintains posture
Sarcomere
smallest contractile unit of muscle fiber
contains A band with half of an I band at each end
individual sarcomeres align end to end along myofibril, like boxcars of train
Action Potential in Muscle Fiber
refractory period: muscle fiber cannot be stimulated for a specific amount of
time, until repolarization is complete
depolarization: generation and propagation of an action potential & AP spreads across sarcolemma from one voltage-gated ๐๐ + channel to next one in adjacent areas, causing that area to depolarize
end plate potential: Ch released from motor neuron binds to ACh receptors on sarcolemma & causes ion channels on sarcolemma to open, ๐๐ + diffuses in, interior of sarcolemma becomes less negative
action potential is caused by changes in electrical changes
repolarization: restoration of resting conditions & ๐๐ + voltage-gated channels close, and voltage-gated ๐พ + channels open
Sliding Filament Theory of Muscle Contraction
cross bridges: myosin heads are allowed to bind to
actin
Zones/Bands/Discs
Z discs are pulled toward M lines
I bands shorten
Z discs become closer
H zones disappear
A bands move closer to each other
sliding filament model of contraction: states that during contraction, thin filaments slide past thick filaments, causing actin and myosin to overlap more
shortening occurs when tension generated by cross bridges on thin filaments exceeds forces opposing shortening
contraction: the activation of cross bridges to generate force