Please enable JavaScript.
Coggle requires JavaScript to display documents.
Muscular System Sariah Lozano Period 3 - Coggle Diagram
Muscular System Sariah Lozano Period 3
Major functions of the Muscular System
-
Generates heat
as it contracts
-Maintains
posture
and body position
-
Movement
; responsible for locomotion and manipulation
-
Stabilizes joints
Three Types of Muscles
Skeletal Muscle
Location:
Throughout the body
Function:
Attaches bone to skin, produces movement, maintains posture, stabilizes joints
Cardiac Muscle
Location:
Walls of the heart
Function:
Contract and relax involuntarily cardiac muscles to pump blood
Smooth Muscle
Location:
Walls of hollow organs
Function:
Involuntarily control organ
All the Skeletal Muscles
Lower Extermity:
-Lliopsas
-Tensor Fasciae latae
-Pectinus
-Adductor Longus
-Sartorius
-Gracilils
-Vastus Laterakus
-Rectus Femoris
-Vastus medialis
-Lliotibial tract
-Tibialis anterior
-Extensor Digitorum Longus
-Gastrocnemius
-Fibularis Longus
-Soleus
-Gluteus Maximus
-Adductor magnus
-Semitendinosus
-Bicep Femoris
-Semimembranosus
-Fibularis Llongus
Upper Extermity
-Deltoid
-Brachialis
-Biceps Brachii
-Pronator teres
=Brachioradialis
-Flexor Carpi Radialis
-Palmoris Longus
-Flexor Carpi Ulnaris
-Tricep brachii
-Flexor carpi radialis Longus
-Extensor Digitorum
-Extensor carpi radialis
-Extensor carpi ulnaris
-Flexor carpi ulnaris
Facial:
-Frontalis
-Orbicularis Oculi
-Zygomaticus
-Temporalis
-Masseter
-Orbicularis oris
-Occipitalis
Neck
-Sternohyoid
-Sternocleidomastoid
-Trapezius
Torso
-Pectoralis Major
-Serratus Anterior
-Rectus Abdominis
-External Oblique
Back
-Trapezius
-Infrapinatus
-Teres Minor/Major
-Rhomboid
-Latissimus dorsi
Sacromere
-Smallest functional unit of muscle fibers
-Contain I and A bands
-Function: Contract muscles by shortening
Neuromuscular Junction:
-Region where motor neuron connects with skeletal muscle
-Each muscle fiber has one
Events at Neuromuscular Junction:
AP (action potential) arrives at axon terminal
Voltage-gated calcium channels open, calcium enters motor neuron
Calcium entry causes release of ACh (acetylcholine) neurotransmitter into synpatic cleft
ACh diffuses across to ACh receptors (𝑁𝑎 + chemical gates) on sarcolemma
ACh binding to receptors, opens gates, allowing 𝑁𝑎 +(sodium) to enter resulting in end plate potential
Acetylcholinesterase degrades ACh
Sliding Filament Theory
Contraction:
the activation of cross bridges to generate force; end when cross bridges become inactive
During
contraction
, thin filaments slide and thick filaments overlap.
Cross bridges
are formed when
myosin heads
bind to
actin
muscle fibers are stimulated by the nervous system.
Cross bridges
attachments form and break several times which causes the shortening of a muscle.
-
Z discs
become closer and are pulled toward
M line
-
I bands
shorten
-
H zone
disappears
-
A band
s move closer to each other
Action Potential in a Muscle FIber
1. End Plate Potential
ACh (Acetylcholine) gets released from motor neuron binds to ACh receptors on sarcolemma. This causes
chemically gated ion channels
on the sarcolemma to open. Sodium diffuses into muscle fiber which makes the interior of the sarcolemma less negative/more positive. Results in local depolarization called end plate potential
2. Depolarzation
Depolarization is the generation and propagation of an
action potential (AP)
. If end plate potential causes enough change in membrane voltage to reach critical
level (called
threshold
) voltage-gated sodium channels in membrane will open. The influx of sodium triggers AP that leads to muscle fiber contraction. AP spreads across sarcolemma from one voltage-gated sodium channel to next one in nearby areas, causing that area to depolarize.
3. Repolarization
Repolarization is when the restoration of resting condition. Sodium voltage gated channels close and voltage gated potassium channels open. The efflux of potassium out of cells brings the cell back to reseting membrane voltage. Then there’s the
refractory period
when the muscle fiber can’t be stimulated for a specific amount of time until depolarization is complete.
Muscle Disorders
Muscular Dystrophy
Muscle weakness and
atropy
(decrease in muscle mass)
Causes:
-Genetic
-Duchene
-Becker
Symptoms:
-Mental retardation
-Muscle weakness
-Eyelid dropping
Treatments:
-None
-Physical therapy
-Medication
Fibromyalgia
Muscle pain
Causes:
-Unknown
-Physical Trauma
-Abnormal pain response
Symptoms:
-Muscle pain
-Tender points
-Joint pain
Treatments:
-Physical therapy
-Exercing regimen
-Massage
Myasthenia Gravis:
Neuromuscular disorder that blocks neurotransmitters
Causes:
-Autoimmune
-Possible tumor of the thymus
-age
Symptoms:
-Muscle weakness
-Shortening of breathe
-Difficulty swallowing and chewing
Treatments:
-None
-Medications
-Thymectomy
Cerebral Palsy
Spastic paralysis causing muscle weakness
Causes:
-Brain injury/abnormality
-Premature birth
-Brain infection
Symptoms:
-Delayed development
-Muscle tightness
-Abnormal gait
Treatment
-None
-Medication for symptoms
-Physical therapy
Myositis
Inflammation of muscle
Causes
-Autoimmune
-Infection
-medication induced
Symptoms
-Muscle weakness
-Swelling
-Tenderness
Treatment
-Medication
-Antibiotics
-Reduced inflammation
Muscle Coverings
From external to internal
-
Epimysium:
dense irregular connective tissue that surrounds an entire muscle
-
Perimysium:
fibrous connective tissue surrounding
fascicles
(groups of muscle fibers)
-
Endomysium:
areolar connective tissue surrounding each muscle fiber