Please enable JavaScript.
Coggle requires JavaScript to display documents.
Muscular System (Muscle Contraction (The brain or spinal cord sends an…
Muscular System
Muscle Contraction
- The brain or spinal cord sends an impulse to the muscle.
- The impulse travels down the motor neuron and reaches a neuromuscular junction
- When the impulse reaches the neuromuscular junction it releases acetylcholine
- This triggers the impulse in the muscle which then travels to the plasma membrane (sarcolemma) and down T tubules surrounding the myofibrils.
- As the impulse passes through the T tubules, it causes the sarcoplasmic reticulum (SR) surrounding the T tubule to release calcium ions (Ca2+) into the sarcoplasm.
- The Ca 2+ eventually reaching the sarcomere.
- The Ca2+ binds to troponin located on the actin filament.
- This causes tropomyosin to move and expose binding sites for myosin.
- The myosin head now binds to actin and forms a crossbridge.
- ADP and Pi are released from myosin.
- This causes the myosin to move.
- ATP binds to myosin causing it to release the actin and reverting ATP into ADP and Pi.
- The myosin is now ready to form another crossbridge and the cycle of contraction will continue until the impulse stops.
- Once the impulse stops, Ca2+ is released from troponin causing tropomyosin to cover the binding sites and prevent contraction.
- Ca2+ returns to the SR and waits for another impulse.
-
Muscles
Muscles of Thigh and Leg
Iliopsoas
Action : flexes hip, Location : illium and lumbar vertebrae
Sartorius
Action : flexes thigh and hip, Location : illium and proximal tibia
Adductor Muscles
Action : adduct thigh, Location : pelvic and proximal femur
Quadracep Group
Action : extend knee, Location : femur and pelvic
Gluteus Maximus
Action : extends hip, Location : sacrum and proximal femur
Hamstring
Action : flexes knee and extends hip, Location : proximal tibia
Tibialis Anterior
Action : dorsiflexes and inverts toe, Location : proximal tibia
Gastrocnemius
Action : plantar flexes foot and knee, Location : distal femur and calcaneous
Soleus
Action : plantar flexes foot, Location : proximal fibia and fibula
-
Muscles of Arm
Bicep Brachii
Action : flexes elbow and supinates forearm, Location : scapula of shoulder blade and proximal radius
Tricep Brachii
Action : extends elbow, Location : shoulder girdle and proximal humerus
Deltoid
Action : abducts humerus,Location : scapular spine, clavicle,and humerus
Flexor Carpi Radialis
Action : flexes wrist and abducts hand, Location : distal humerus
-
Flexor Carpi Ulnaris
Action : flexes wrist and adducts hand, Location : distal humerus and posterior ulna
Extensor Digitorium
Action : extends fingers and wrist, Location : distal humerus and phalanges
Extensor Carpi Radialis
Action : extends wrist and abducts hand, Location : humerus
Muscles of Trunk
Pectoralis Major
Action : adducts and flexes humerus, Location : sternum, clavicle, first 6 ribs,proximal humerus
Trapezius
Action : extends neck and adducts scapula, Location : occipital bone, thoracic vertebrae
Rectus Abdominis
Action : flexes vertebral column, Location : pubis, sternum, fifth to seventh ribs
External Obliques
Action : flexes and rotates vertebral column, Location : lower eight ribs and iliac crest
Latissimus Dorsi
Action : extends and adducts humerus, Location : lower spine and iliac crest
Erector Spinae
Action : extends back, Location : iliac crest, ribs 8-12, and vertebrae
Muscles of Head
Frontalis
Action : raises eyebrows, Location : forehead, skin of eyebrows
Temporalis
Action : closes jaw, Location : temporal, temporal bone, and mandible
Orbicularis Oculi
Action : closes and protudes lips, Location : mandible and maxilla
Zygomaticus
Action : raises corner of mouth, Location : cheekbone, skin and muscle at corner of lips
Masseter
Action : closes jaw, Location : temporal bone and mandible
Buccinator
Action : compress cheek, Location : maxilla and mandible
Sternocleidomatoid
Action : fixes neck and rotates neck, Location : sternum, clavicle, and temporal bone
Platysma
Action : pull corners of mouth inferiorly, Location : muscle tissue around mouth
Muscle Tissues
Skeletal
long, cylindrical, and parallel, contain many nuclei
-
-
-
Cardiac
-
long, cylindrical, and branched, has single central nucleus
-
-
Smooth
spindled shape, single cell nucleus
-
-
-