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Evelyn Santiago P2 - Muscular System - Coggle Diagram
Evelyn Santiago P2 - Muscular System
Major Functions
Stabilize joints
Maintain posture & body position
Produce Movement- all locomotion & manipulation
Generate heat as contract
Names of all Skeletal Muscles
Head, Face, Neck
Epicranius frontalis
Epicranius occipitalis
Orbicularis oris
Zygomaticus
Buccinator
Platysma
Orbicularis oris
Levator palpabrae
Masseter
Sternocleidomastoid
Splenius
Abdomen
Rectus Abdominis
External oblique
Internal oblique
Transversus abdominis
Breathing
Diaphragm
External intercostals
internal intercostals
Thorax and Back
Pectoralis major
Pectoralis minor
Serratus anterior
Deltoid
Trapezius
Latissimus dorsi
Infraspinatus
Teres Major
Teres Minor
Upperlimb
Biceps brachii
brachialis
triceps brachii
brachioradialis
pronator teres
flexor carpi radialis
palmaris longus
flexor carpi ulnaris
flexor digitorum superficialis
extensor carpi radialis
extensor digitorum
Extensor carpi ulnaris
abductor pollicis brevis
flexor pollicis brevis
Buttock & Lower Limb
Gluteus maximus
gluteus medius
rectus femoris
vastus lateralis
vastus medialis
gracilis
adductors
pectineus
illiopsoas
sartorius
tensor fasciae latae
biceps femoris
semitendinosus
semimembranosus
tibialis anterior
extensor digitorum longus
fibularis (peroneus) longus
gastrocnemius
soleus
AP in a muscle fiber
Depolarization
generation & propagation of AP
if end plate poten causes change in membrane voltage, Na+ channels open
large influx of Na+ thru channels into cell triggers AP that is unstoppable
Ap spreads across sarcolemma from one voltage-gated Na+ to next one
Repolarization
restoration of resting conditions
Na+ voltage-gated channels close and voltage-gated K+ channels open
K+ efflux out rapidly, leading to 1st resting mem. voltage
Refractory period: muscle fiber cannot be stimulated for a specific amount of time
end plate potential
ACh released from motor neuron binds to ACh receptors on sarcolemma
causes chem-gated ion channels to open
Na+ diffuses into muscle fiber, K+ diffuses outwork
interior of sarcolemma becomes less negative
results in local depolarization called end plate potential
Disorders/Diseases
Duchenne Muscular Dystrophy (DMD) - most common & serious
ages 2- 7, more common in males
sex-linked recessive diseases
caused by defective gene dystrophin
Myasthenia gravis
dropping upper eyelids, difficulty swallowing and talking, muscle weakness
Sarcomere
compose of 2 protein filaments
thin actin
thick myosin
basic unity of myocyte
3 types of Muscles and functions
Skeletal
attaches to bones or some facial muscles to skin
Smooth
in walls of hollow visceral organ
Cardiac
walls of heart
Sliding Filament Theory
skeletal muscle fibers - long cylindrical & many nuclei
Sarcolemma - muscle fiber plasma membrane
Sarcoplasm - muscle fiber cytoplasm
contains glycosomes and myoglobin
Modified organelles
Myofibrils
densly packed
features
Striations
stripes formed from repeating dark & light bands along myofibril
A bands : dark regions
H zone: lighter region in middle of A
M line: protein (myomesin) bisects H zone vertically
I bands: lighter regions
Z disc (line): coin shaped sheet of proteins on midline of I
Myofilaments
actin and myosin w/in sarcomere
Actin myofilaments : thin
extends across I band & partway in A band
Anchored to Z disc
tropomyson and troponin _ regulatory proteins bound to actin
Myosin : thick
extends length of A band
connected @ M line
Molecular Composition of myofilaments
Sarcoplasmic reticulum
network of smooth endo reticulum tubules
T tubules
tube formed by protrusion of sarcolemma deep into cell
"During contraction, thin filaments slide past thick filaments, causing action and myosin to overlap more"
Muscle coverings (connective tissue coverings)
each skeletal muscle and muscle fiber- covered
support cells and reinforce whole muscle
Sheaths (ex to in)
Endomysium 3
fine areolar connective tissue surrounding each muscle fiber
Perimysium 2
fibrous connective tissue surrounding fascicles :(groups of muscle fibers)
Epimysium 1
dense irregular connective tissue - may blend w/ fascia
Neuromuscular junction (NMJ)
AP arrives at axon terminal 1
Voltage-gated calcium channels open, calcium enters motor neuron 2
Calcium entry causes release of ACh neurotransmitter into synaptic cleft 3
ACh diffuses across to ACh receptors on sarcolemma 4
ACh binding to receptors, opens gates, allowed Na+ to enter resulting in end plate potential 5
Acetylcholinesterase degrades ACh 6