Please enable JavaScript.
Coggle requires JavaScript to display documents.
Aleeah Garcia P.1 Muscular System - Coggle Diagram
Aleeah Garcia P.1 Muscular System
Functions
Produce movement : responsible for locomotion and manipulations
Maintain posture/position
Stabilize joints
Generate heat as mucsles contract
Types of Muscle
Cardiac - help to pump blood circulation in the heart
Smooth - help waste travel through intestines
Skeletal - produce movement, maintain body posture, stabilize joints, and regulate body temperature
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
Muscular Diseases
Cerebral Palsy - spastic paralysis causing muscle weakness
Myositis - Infalmmation of the muscle
Myasthenia Gravis - neuromuscular disorder blocking neurotransmitters
Muscle Fatigue - physiological inability to contract muscles
Muscular Dystrophy - muscle weakness and atrophy
Fibromyalgia - muscle pain
Neuromuscular Junction
Step 4 - ACh diffuses across to ACh receptors or sarcolemma
Step 2 - voltage - gated calcium channels open, calcium enters motor neuron
Step 5 - ACh binding to receptors, opens gates, allowing Na to enter resulting in end plate potential
Step 1 - AP arrives at axon terminal
Step 6 - Acetycholinesterase degrades ACh
Step 3 - calcium entry causes release of ACh neurrotransmitter into synaptic cleft
Sliding Filament Theory
During contraction, actin slides past myosin and overlap more
Muscle fiber gets stimulated, so myosin heads bind to actin to form cross bridges, and sliding contraction begins
When relaxed, actin and myosin overlap at the ends of A band
Cross bridge attachments form and break multiple times, which pulls actin towards the center of sarcomere
Contraction ends when cross bridge is inactive
Shortening occurs when tension generated by cross bridge on thin filaments exceeds forces
Z discs are pulled towards M line, I bands shorten, Z discs become closer, H zones disappear, A bands move closer to one another
Contraction activates the cross bridge which generates force
Sarcomere
Each level contains A bands with half an I band
Smallest contractile/functional unit of the muscle fiber
Align end to end along myofibril
Action Potential
Step 1 - generation of end plate potential
Sodium diffuses into the muscle fiber
Interior of sarcolemma becomes more positive
Causes ligands on sarcolemma to open
leads to depolarization
ACh released from motor neuron binds to ACh receptors on sarcolemma
Step 2 - Depolarization
generation and propagation of an action potential
If end plate potential causes enough change in membrane voltage to reach threshold, voltage-gated sodium channels in membrane will open
Large influx of sodium through channels into cell triggers AP that is unstoppable and will lead to muscle fiber contraction
AP spreads across sarcolemma from one voltage-gated sodium channel to next one in adjacent areas, causing that area to depolarize
Step 3 - Repolarization
Calcium voltage-gated channels close, and voltage-gated potassium channels open
Potassium efflux out of cell rapidly brings cell back to initial resting membrane voltage
restoration of resting conditions
Refractory period - muscle fiber cannot be stimulated until repolarization is complete
Ionic conditions of resting state are restored by 𝑁𝑎 + −𝐾 + pump
Skeletal Muscles
Bicep brachii
Brachialis
Brachioradialis
Deltoid
External obliques
Flexor carpi radialis
Flexor carpi ulnaris
Frontalis (Epicranius frontal belly)
Iliopsoas
Masseter
Orbicularis oris
Orbicularis oculi
Palmaris longus
Pectinus
Pectoralis major
Pronator teres
Rectus abdominis
Serratus anterior
Sternocleidomastoid
Sternohyoid
Temporalis
Tensor fasciae latae
Trapezius
Tricep brachii
Zygomaticus
Adductor longus
Fibularis longus
Extensor digitorum longus
Gastrocnemius
Gracilis
Iliotibial tract
Rectus femoris
Sartorius
Soleus
Tibialis anterior
Vastus lateralis
Vastus medialis