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Muscular System Mia Rodriguez - Period 3, Muscular System Mia Rodriguez -…
Muscular System Mia Rodriguez - Period 3
Muscular System Mia Rodriguez - Period 3
Major functions of muscular system
Produce Movement
Maintain Posture
Stabilize Joints
Produce Heat
Names of all the skeletal muscles
Legs
Tibialis anterior /front of shin; lifts foot upward
Extensor digitorum longus/Front lower leg; lifts toes.
Soleus is under gastrocnemius; helps point toes
Gastrocnemius/Calf; points toes
Fibularis Longus/ outer lower leg; turns foot outward and support arch
Hip & Thigh
Iliopsoas – Front of hip; bends thigh at hip.
Pectineus – Upper inner thigh; brings thigh toward body.
Adductor longus – Inner thigh; pulls leg toward midline.
Gracilis – Inner thigh; adducts thigh, flexes knee.
Tensor fasciae latae/outer hip; steadies and thigh sideways
Iliotibial tract/side of thigh, supports leg movement
Rectus femoris/front thigh; straightens knee and bends hip
Vastus medialis/inner front thigh; straightens knee
Vastus lateralis/outer front thigh; straighten knee
sartorius/strap muscle across thigh; bends and rotates leg
Upper Body and Face
Orbicularis oris – Around mouth; puckers lips
Orbicularis oculi – Around eyes; closes eyelids.
Masseter – Jaw; closes mouth
Palmaris longus/middle of forearm; tenses palms and flexes wrist
Frontalis/forehead; raises eyebrows
Pectoralis major/chest; moves arm forward and across
Flexor carpi ulnaris/front forearm; bends wrist toward little finger
Pronator teres – Forearm; turns palm down.
Flexor carpi radialis/front forearm; bends wrist toward thumb
rectus abdominis/abs;bends trunk forward
External obliques/sides of abdomen; twist and bend trunk
Serratus anterior – Side of ribs; pulls shoulder forward.
Deltoid – Shoulder; lifts arm.
Sternocleidomastoid/side of neck; turns and bends head
Brachioradialis/forearm near thumb side; helps bond elbow
Sternohyoid/front of neck; lower hyoid bone
Brachialis – Under biceps; helps bend elbow
Temporalis/side of head;helps close jaw
Biceps brachii – Front of upper arm; bends elbow.
Trapezius – Upper back/neck; lifts and moves shoulders
Triceps brachii – Back of upper arm; straightens elbow.
Zygomaticus – Cheek; lifts corners of mouth (smiling).
Muscle coverings (connective tissue coverings)
Perimysium is fibrous that surrounds fascicles
Endomysium is fine areolar that surrounds muscle fibers
Epimysium is dense irregular connective tissue that surrounds muscle and blends in with fascia
Sliding filament theory of muscle contraction
Contraction occurs with the activation of cross bridges to generate force. This is when actin and myosin filaments slide past each other, overlapping each other, which causes the contraction.
Action potential in a muscle fiber
Signal gets sent from the brain and travels as a neuron to the axon terminal. Hits the motor end plate and enters calcium voltage-gated channels. After depolarization, potassium is released to make membrane potential negative or balanced again. Returning membrane back to resting potential.
Disorders associated with the Muscular system
Rigor Mortis; body stiffens post death, 3-4 hours, intracellular calcium lvls rise due to no ATP
DMD; Duchenne muscular dystrophy is muscular destroying disease common in children
Myasthenia Gravis is disease known for drooping upper eyelids, etc., generalized muscle weakness, autoimmune disease
Cerebral Palsy; spastic paralysis causing muscle weakness, 1 in 278 children, mild to severe
Fibromyalgia; muscle pain, comes from genetics, muscle atrophy, no cure
Myositis; inflammation of muscle, autoimmune, and most common polymyositis
3 types of muscles & their functions
Skeletal tissue: strations, cylindrical, attaches to bones
Smooth tissue: no striations, spindle-shaped, located in visceral organs
Cardiac tissue: contains striations, intercalated disc, and is located on the wall of the heart
Neuromuscular junction
ACh diffuses to NA+ receptors
ACh bonds with to receptors, open gates allowing NA+ to enter
Calcium entry releases ACh to synaptic cleft
Acetylcholinesterase degrades ACh
Voltage gate calcium channel opens entering motor neuron plate
Action potential sent to axon terminal
Sarcomere
Actin filaments that are thin and are part of the I band
Myosin filaments are thick that are part of the A band
Sarcomere is the smallest contractile unit
End with z disc