Muscles Flashcards
General Actions of Every Muscle
Prime Mover: Responsible for producing specific movements
Antagonist: Reverse specific movement
Synergist: Helps primers add extra force to same movement, reduces unnecessary movement
Fixator: Synergist that immobilizes bone or muscles orgin.
Epicranius Frontal Belly
Pulls scalp back so eyebrows lift and forehead wrinkles
Epicranius Occipital Belly
Pulls scalp back so eyebrows lift and forehead wrinkles
Corrugator Supercili
Muscle close to eye, wrinkles forhead
Zygomaticus
Draws mouth superiorly, smiling and dimples
Risorius
Retracts mouth, “insincere smile”
Levator Labii Superioris
Elevate upper lip
Depressor Labii Inferioris
Depression of lower lip
Depressor Anguli Oris
Frowning
Temporalis and Masseter
Prime Movers of jaw closure
Buccinator
Holds food between teeth, compresses cheek
3 Prime movers of arm
Pectoralis Major, Latissimus Dorsi, Deltoid
Muscles of Rotator Cuff
Supraspinatus, infraspinatus, teres minor, subscapularis
Muscles of Elbow Joint
Brachialis, Biceps Brachii, Brachioradialis
Muscles of Posterior Extensor
Triceps Brachii, Anconeus
Muscles of Forearm
Flexor Retinaculum, Pronator Teres, Pronator Quadratus
Muscles of Crossing Hip & Knee Joint
illiopsoas, illiacus and psoas major (Flexion of thigh)
Rectus Femoris (Extends Knee, flexes thigh)
Medial Adductors and Sartorius (flexes abducts, rotates thigh)
Muscles of Hamstring
Biceps Femoris, Semitendinosus, Semimembranosus, Adductor magnus, longus, brevis, Pectineus, Gracilis, Gluteus Maximus/medius/minimus
Piriformis, obturator externus, obturator internus, gemellus
Muscles of Lower Leg
Tibialis Anterior, Extensor Digitorum Longus, Extensor hallucis longus, Fibularis tertius (toe extensors and dorsiflexion)
Fibularis longus and Fibularis Brevis (Plantar flexion and eversion of the foot)
Gastrocnemius, soleus, plantaris, popliteus, flexor digitorum longus, flexor hallucis longus, tibialis posterior (plantar flex ankle)
Muscles of Mastication
Pterygoids - Lateral and Medial, grinding
Genioglossus - protracts tongue
Hyoglossus - depresses tongue
Styloglossus - retracts and elevates
Muscles of Neck
Sternocleidomastoid - Major head flexor
Scalenes - lateral head movement
Splenius Capitis and Cervicis Portions - head extension, rotation, lateral bending
Semispinalis capitis - synergist w/ sternocleidomastoid
Muscles of the Back
Erector Spinae Group - iliocostalis, longissimus, spinalis
Semispinalis and Quadratus Lumborum - Synergist in extension rotation
Trapezius - Supports Arm
Levator Scapulae - Elevates scapula
Rhomboids - Retraction of scapula
Cycle of Muscle Contraction
- AP travels down neuron to skeletal muscle fiber. NMJ has axon terminal which have the synaptic cleft between the motor end plate.
- Voltage-gated calcium Channels open and calcium ions diffuse into axon terminals. Causes AcH by exocytosis. AcH binds to ACH receptors that opens cation channels and sodium enters fiber while potassium exits.
- When membrane reaches threshold, AP goes through sarcolemma to T-tubules. Linked with terminal cisternae via calcium and it floods the SR.
- Calcium binds with troponin which reveals binding site on the tropomyosin of the actin and the cross bridge cycle begins. Myosin head is activated by ATP and it is cocked and binds to site on actin. A power stroke occurs as filaments slide toward center of sarcomere.
- Power strokes continue as long as binding sites are exposed on actin. Cycle ends when calcium returns to SR, Troponin reactivated, binding sites covered, AcH replenishes and degrade enzymes through diffusion
6 features of Synovial Joints
- Articular Cartilage
- Synovial Cavity: fluid filled space
- Articular Capsule: External fibrous layer and inner synovial membrane, makes synovial fluid
- Synovial fluid: viscous, filtrated plasma and hyaluronic acid with phagocytes
- Reinforcing ligaments, capsular, extracapsular, intracapsular
- Nerves and blood vessels
4 Extra features of Synovial joints
Fatty Pads
Articular discs
Bursae
Tendon sheath
Elements of Smooth Muscle
Not striated Involuntary contaction Cells electrically coupled by gap junctions some cells self-excitatory spindle shaped fibers are thin and short Endomysium only No sarcomeres, myofibrils or t-tubules
Contraction of Smooth Muscle
- A stimulus (from either an action potential, stretching of the muscle, hormone release, or drugs) triggers the opening of calcium channels that allow calcium into the sarcoplasm
- Calcium binds to calmodulin to form the calcium-calmodulin complex
- The calcium-calmodulin activates the myosin light chain kinase complex which is a phosphorylating enzyme
- Myosin light chain kinase activates the myosin head by adding a phosphate to it, Activated myosin heads bind to thin filaments to form crossbridges. ATP provides the energy for a powerstroke. The force generated pulls the anchoring filaments, shortening the smooth muscle cell. Thus the smooth muscle contraction.
Relaxation of Smooth Muscle
Ca2+ detaches from calmodulin; active transport of Ca2+ into SR and extra cellular fluid; dephosphorylating of myosin.
RA vs Osteoarthritis
RA: Autoimmune, begin at any age, rapid onset, swollen stiff joints, inflammation of synovial membrane and joint capsule, cartilage loss
OA: Later in life, wear and tear, slow progression, joints tender and ache, cartilage deteriorates, tendons, ligaments and bones rub together.
Sources of ATP
Stored Direct Phosphorylation - CP to ATP Glycolysis Lactic Acid Fermentation (anaerobic) Citric Acid Cycle & Oxidative Phosphorylation (aerobic)
Recovery after fatigue
Oxygen reserves replenish
Lactic Acid converted to pyruvic acid
glycogen store are replaced
ATP and CP reserves replenish
Slow Oxidative Fibers
Long Distance Running ATP: Oxidative Contraction Velocity: Slow Mitochondria: many Capillaries: Many Myoglobin content: High/red Glycolytic Enzymes: Low
Fast Oxidative Fibers
Running to the bus ATP: Oxidative Contraction Velocity: Fast Mitochondria: Many Capillaries: Many Myoglobin content: High/red Glycolytic Enzymes: Intermediate
Fast Glycolytic Fibers
Sprinting ATP: Glycolysis Contraction Velocity: Fast Mitochondria: few Capillaries: few Myoglobin content: Low/White Glycolytic Enzymes: High
