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Natalie Valdivia Period: 3 Muscular System - Coggle Diagram
Natalie Valdivia
Period: 3
Muscular System
Muscle covering (connective tissue coverings)
Each of the muscle cell (fiber) are covered by a connective tissue layer
called endomysium
The
perimysium
extends inward from the epimysium and surrounds the bundles of skeletal muscle fibers called fascicles within each
muscle
Epimysium
is the layer of the connective tissue
around each skeletal muscle
Action potential in a muscle fiber
Muscle Fiber Relaxation Steps:
ATP breaks cross-bridge linkages between actin and
myosin filaments without breakdown of the ATP itself
Breakdown of ATP “cocks” the myosin heads
Calcium ions are actively transported into the
sarcoplasmic reticulum
Troponin and tropomyosin molecules block the
interaction between myosin and actin filaments
Acetylcholinesterase decomposes acetylcholine, and
the muscle fiber membrane is no longer stimulated
The muscle fiber remains relaxed, yet ready, until
stimulated again
Muscle Fiber Contraction Steps:
The impulse reaches the sarcoplasmic reticulum, and
calcium channels open
Calcium ions diffuse from the sarcoplasmic reticulum
into the cytosol and bind to troponin molecules
The sarcolemma is stimulated. An implulse travels over the surface of the muscle fiber and deep into the fiber through the transverse tubules
Tropomyosin molecules move and expose specific sites
on actin where myosin heads can bind
ACh binds to ACh receptors in the muscle fiber
membrane
Cross-bridges form, linking thin and thick filaments
The motor neuron releases the neurotransmitter
acetylcholine (ACh)
Thin filaments are pulled toward the center of the
sarcomere by pulling of the cross-bridges.
An impulse travels down a motor neuron axon
10.The muscle fiber exerts a pulling force on its
attachments as a contraction occurs
Major functions of the muscular system
The skeletal muscle is the movement of the bones at joints, maintenance of posture
The cardiac muscle is the pumping action of the heart
The smooth muscle is the movement of the viscera, peristalsis, and vasoconstriction
Disorders associated with the Muscular system
Cerebral Palsy
The
causes
or
risks
are:
-brain injury or abnormality
Symptoms
include: (mild and severe) (dELAYED DEVELOPMENT) (JOINT CONTRACTIRE)
spastic paralysis causing muscle weakness
Treatment options
are:
-No Cure -PhsyICAL ThERAPY AND MEDICATION FOR SYMTOPs
Myositis
The
causes
or
risks
are:
-medication induced -infection -autoimmune
Symptoms
include:
-swealing
-rash
-tenderness
inflammation of the muscle
Treatment options
are:
-medications
-antibiotics
-reduce inflammation
Myasthenia Gravis
The
causes
or
risks
are:
-autoimmune
possible tumor of the tymus
-age
Symptoms
include:
-muscle weakness
-shortness of breath
-drooping eyelids
Neuromuscular disorder that blocks neurontransmitters
Treatment options
are:
-no know cure
-medications
-eye patch for double vision
Fibromyalgia
The
causes
or
risks
are:
-more common in women
-physical trauma
-infection
Symptoms
include:
-fatigue
-muscle pain
-tendor points
is muscle pain
Treatment options
are:
-physical therapy
-exercise regimen
Muscular Dystrophy
The
causes
or
risks
are:
-genetic
-myotonic
-fascioscapulohumeral
Symptoms
include:
-mentalretardation
-muscle weakness
-delayed motor skills
is a muscle weakness and atrophy
Treatment
options
are:
-no known cure
-surgery to improve function
-medication
Sarcomere
Sarcomeres are joined end-to-
end
Extends from one Z line to the next
Sarcomeres
are myofibrils that are made up of many units
I bands (light bands)
are made up of actin filaments, which are anchored to the Z lines
H zone
are in the center and they consists of myosin
filaments only
A bands (dark bands)
are made up of overlapping thick and thin filaments
The
M line
is in the center of the H zone and it consists of proteins that hold the myosin filaments in place
Muscle contraction involves several events that result in the shortening of sarcomeres
Names of all the skeletal muscles
(
Front
) Anterior/Inferior View Muscles:
Iliotibial tract
Rectus femoris
Gracilis
Sartorius
Gastrocnemius
Soleus
Extensor digitorum longus
Tibialis anterior
Fibularis longus
Vastus lateralis
Adductor longus
Vastus medialis
(
Back
) Posterior/Superior View Muscles:
Gluteus medius
Infraspinatus
Gluteus maximus
Latissimus dorsi
Flexor carpi ulnaris
Occipitalis (Epicranius occipital belly)
Extensor carpi ulnaris
Rhomboid major
Extensor carpi radialis
Sternocleidomastoid
Deltoid
Teres major
Brachioradialis
Trapezius
Tricep brachii
(
Front
) Anterior/Superior View Muscles:
Palmaris longus
Pectinus
Orbicularis oculi
Pectoralis major
Orbicularis oris
Pronator teres
Masseter
Rectus abdominis
Iliopsoas
Serratus anterior
Frontalis (Epicranius frontal belly)
Sternocleidomastoid
Flexor carpi ulnaris
Sternohyoid
Flexor carpi radialis
External obliques
Deltoid
Brachioradialis
Temporalis
Tensor fasciae latae
Trapezius
Tricep brachii
Brachialis
Zygomaticus
Bicep brachii
(
Back
) Posterior/Inferior View Muscle:
Gracilis
Soleus
Fibularis longus
Semitendinosus
Semimembranosus
Gastrocnemius
Adductor magnus
Bicep femoris
Sliding filament theory of muscle contraction
The energu of ATP will cause the sarcomere to shorten
Acetylcholine is the neurotransmitter for skeletal muscle fiber and contraction at the neuronmuscular fiber
This binding will cause the head to bend, pulling on the actin filament, and moving
it toward the center of the sarcomere
A myosin head attaches to a binding site on the actiin filament and forms a cross-bridge
Three types of muscles and their functions
Cardiac Muscle
Is self-exciting (involuntary)
Complex membrane junctions, called intercalated discs, join cells and transmit the force of contraction from one cell to the next
Is found in the wall of the heart
Consists of branching, striated cells that interconnect in
three-dimensional networks
Is only found in the heart
Skeletal Muscle
Muscle contraction pulls the insertion toward the origin
Some muscles have more than one insertion or origin
Insertion: the more movable end of a skeletal muscle
Origin: the less movable end of a skeletal muscle
Smooth Muscle
are elongated with tapered ends, lack striationsand, have a relatively undeveloped sarcoplasmic reticulum
Contains thick and thin filaments
involves reaction between actin and myosin
Neuromuscular Junction
Neuromuscular junction
: is the synapse between a motor neuron and the muscle fiber that it regulates
The cytoplasm of the distal end of the motor neuron contains numerous
mitochondria
and s
ynaptic vesicles
storing neurotransmitters
Neurotransmitters
is the way that neurons communicate with muscle fibers through chemicals
The
motor end plate
is in a muscle fiber membrane is a special region
The cell is functionally not physically connected to the axon of a motor neuron, creating a
synapse
The synaptic vesicles release neurotransmitter into the
synaptic cleft
, the gap between the membranes of the neuron and muscle fiber
Skeletal muscle fibers contract only when stimulated by a
motor neuron
The neurotransmitters diffuse across the cleft, bind to the motor end plate, and stimulate the muscle fiber to contract