Please enable JavaScript.
Coggle requires JavaScript to display documents.
Muscular System Mariah Mancinas P:1 - Coggle Diagram
Muscular System Mariah Mancinas P:1
Major functions of the Muscular System:
Produce Movement: Major function of the muscle system is to produce movement like walking.
Hold body postiton and posture
Stabilize the bodies joints
As they contract, generate heat.
3 Types of Muscles and their function:
Skeletal: Muscle that is attached to bones, allows movement.
Smooth: In internal structures in the digestive tract.
Cardiac: Cardiac is located in the walls of the heart and is specific to the heart.
Skeletal Muscles
Upper Half: Trapezius, Sternocleidomastoid, Deltoid , pectoralis major, serratus anterior, bicep brachii , tricep brachii, Brachioradialis , Flexor carpi radialis
Upper Half: rectus abdominis, external oblique, infraspinatus, teres major, latissimus dorsi , extensor carpi radialis, flexor carpi ulnaris , extensor digitorum
Lower Half: iliopsoas, adductor longus, sartorius, gracilis, rectus femoris, vastus lateralis, vastus medialis , bicep femoris, semitendinosus, semimembranosus
Lower Half: tibialis anterior , extensor digitorum longus, fibularis longus, gastrocnemius, soleus
Facial Muscles: Epicranial Aponeurosis, temporalis, Orbicularis oculi, zygomaticus, Buccinator, Orbicularis oris, Platysma, Masseter, Sternocleidomastoid, Trapezius, Frontalis, occipitalis.
Sarcomere
Sarcomere is the smallest unit of a muscle fiber.
Contains an A band with an I band at each end.
Is the area between the z discs.
Each sarcomeres align end to end along the myofibril
Every sarcomere goes from one Z disc to another.
Action potential in a muscle filber
Action potential is made because of the changes in Electrical Charges.
Three steps to Action potetial: 1. Generation of end platepotential 2. Depolarization 3. Repolarization.
End plate potential:𝑁𝑎+diffuses into muscle fiber, ACh released from motor neuron binds to the ACh receptors on sarcolemma.
Depolarization: generation and propagation of an actionpotential also known as AP.
Repolarization: Is restoration of resting conditions
Sliding filament theory of muscle contraction
First: The brain sends impulse to motor neuron that reaches the neuromuscular junction and releases actylochine. Than sends the muscle impulse.
Second: Impuse goes through plasma membrane down T tubules that surround the myofibrils. The Sacrcoplasmic reticulum releases Ca^2+ into sarcoplasm that reaches the sarcomere.
Third:Once impulse stops, Ca^2+ returns to the SR and waits fro another impulse, Relaxaion.
Fourth: Myosin head binds to actin and forms cross bridges.
Fifth: Myosin moves doing a powerstroke because of ADP and P being released.
Sixth: ATP binds to myosin releasing actin and forming ATP and P. Now ready to form another crossbridge and the contraction cycle will keep going.
Neuromuscular Junction
First: AP arrives at axon terminal
Second: Voltage-gated calcium channels open and than calcium enters motor neuron
Third: Calcium entry causes release of ACh neurotransmitter that goes into the synpatic cleft
Fourth: ACh diffuses across to ACh receptors to sarcolemma
Fifth: ACH binding to the receptors than opens gates that allows 𝑁𝑎+to enter that results in end plate potential
Sixth: Acetylcholinesterase degrades ACh
Muscle coverings
Epimysium: This muscle covering is made of dense irregular connective tissue and it may blend with fascia.
Perimysium: This muscle covering is made of fibrous connective tissue that surround fascicles.
Endomysium: This muscle covering is made of fine areolar connective tissue that surround each muscle fiber
Disorders
Duchenne muscular dystrophy: It is most common and serious form of muscular dystrophies which is a disorder. It is a muscle destroying disease that appears at childhood.
Appears between 2-7 years old when a child in very clumsy or is consistently falling.
Found mostly in males to be specific 1 in every 3600.
Myastheniagravis: This disease characterized is noticed by drooping upper eyelids and difficulty swallowing and talking. This is because of generalized muscle weakness.