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Muscular System- Kaylyn Ganiron P.5 - Coggle Diagram
Muscular System- Kaylyn Ganiron P.5
Major functions of the muscular system
mobility (ex. walking/ speaking)
stability (ex. lifting weights)
posture ( ex. straight back)
circulation (ex. heart pumping)
respiration (ex. breathing from the diaphragm muscle)
digestion (ex. stomach breaking down food)
urination (ex. bladder)
childbirth ( ex. dilation, pushing)
vision (ex. track moving objects)
organ protection (ex. absorbing shock)
body temperature regulation (ex. shivering)
Cardiac Muscle
consists of branching, striated cells that interconnect in three-dimensional networks
involuntary
complex membrane junctions = intercalated discs
ONLY FOUND IN THE HEART
major function: pumping action of the heart
single nucleus
Skeletal Muscle
insertion: the more movable end of a skeletal muscle, contraction pulls the insertion toward the origin, some muscles have more than
1 insertion or origin = biceps brachii in the arm
voluntary
many nuclei
insertion is the radical tuberosity of the radius beneath the neck of the radius
striations
major function: movement of bones at joints, maintenance of posture
Smooth Muscle
involuntary
elongated w/ tapered ends, lack striations
contains thick and thin filaments (actin and myosin)
slower to contract and relax
maintains a contraction longer (w/ the same amount of ATP)
can change length w/o change in tautness (stretched or striated)
hormones can stimulate or inhibit contraction
single nucleus
major function: movement of viscera, peristalsis, vasconstriction
Muscles
Facial Muscles
occipitofrontalis muscle
Temporoparietalis muscle
Corrugator supercilii muscle
Depressor supercilii muscle
Orbicularis oculi muscle
Auricular muscles (anterior, superior and posterior)
Depressor septi nasi muscle
Orbicularis oris muscle
Nasalis muscle
Procerus muscle
Depressor anguli oris muscle
Risorius
Zygomaticus major muscle
Zygomaticus minor muscle
Levator labii superioris
Levator labii superioris alaeque nasi muscle
Depressor labii inferioris muscle
Levator anguli oris
Buccinator muscle
Mentalis
Major Skeletal
upper limb: deltoid, biceps brachii, triceps brachii
lower limb: gluteus maximus, sartorius, quadriceps group, hamstrings group, tibialis anterior, gastrocnemius,
trunk-anterior: pectoralis, rectus abdominus, external oblique
trunk-posterior: trapezius and latissimus dorsi
over 600 skeletal muscles
Sarcomere
major function: unit controlling changes in muscle length
functional unit of a muscle fiber
2 types of myofilaments: thick and thin
contains: mitochondria, SR, muscle fiber, transverse tubules, myofilaments, z-discs, I-band, and A-band
myosin = thick filaments
actin = thin filaments
Neuromuscular junction
skeletal muscle fibers contract only when stimulated by a motor neuron
neurotransmitters = neuron communicating with muscle fiber by chemicals
a synapse between a motor neuron and a muscle fiber that it regulates
the muscle fiber in this area contains a specialized region = motor end plate... which the sarcolemma is tightly folded
each skeletal muscle fiber (cell) is functionally (not physically) connected to the axon of a motor neuron, creating synapse
synaptic cleft: the space between neurons at a nerve synapse across which a nerve impulse is transmitted by a neurotransmitter
Sliding filament theory of muscle contraction
a myosin head attaches to a binding site on the actin filament, forming a cross-bridge
filaments increase their overlap
when many sarcomeres shorten at the same time, the muscle fiber shortens
energy from the conversion of ATP to ADP is provided to the cross-bridges by the enzyme ATPase; ATP breakdown causes the heads to return to the "cooked" position, ready to bind another actin binding site
Action potential in a muscle fiber
electrical signal
travel along a cell membrane as a wave
depolarizing
hyperpolarizing
resting potential
flexion: decrease in the angle between bones at a joint
extension: increase in the angle between bones at a joint
Muscle coverings
layers of connective tissue = fascia
fascia = surrounded and separate each muscle
fascia extends beyond the ends of the muscle and gives rise to tendons that are fused to the periosteum of bones
bundles of skeletal muscle fibers = fascicles
sometimes muscles connect to each other by broad sheets of connective tissue = aponeuroses
fascia blends with the epimysium
each muscle cell (fiber) is covered by a connective tissue called endomysium