anaphy

• Bones and joints aren't the only organs that produce movement
• The human body has more than 640 individual muscles
• Muscles cause bones and supported structures to move by alternating between contraction and relaxation
• Functions of Muscle


  • Movement
  • Stability
  • Control of body openings and passages
  • Heat production
• Movement


  • Skeletal muscles attached to bones by tendons cross joints so when they contract, bones they attach to move
  • Smooth muscle found on organ walls, contractions produce movement of organ contents
  • Cardiac muscle produces atrial and ventricular contractions to pump blood from the heart into the blood vessels
• Stability


  Hold bones tightly together, stabilize joints, small muscles hold vertebrae together to stabilize the spinal column
• Sphincters valve-like structures formed by muscles that control movement of substances in and out of passages, e.g. a urethral sphincter prevents or allows urination
• Heat Production


  Heat is released with muscle contraction, helps the body maintain a normal temperature, moving your body can make you warmer if you are cold
• Muscle cells


  • Myocytes, also called muscle fibers, with sarcolemma (cell membrane), sarcoplasm (cytoplasm), and myofibrils (long structures in sarcoplasm)
  • Arrangement of filaments in myofibrils produces striations
• Skeletal Muscle


  • Muscle fibers respond to the neurotransmitter acetylcholine, which causes them to contract
  • Following contraction, muscles release the enzyme acetylcholinesterase to break down acetylcholine and allow the muscle to relax
• Smooth Muscle


  • Multiunit smooth muscle responds to neurotransmitters and hormones, found in the iris of the eye and walls of blood vessels, each cell receives its own synaptic input for finer control
  • Visceral smooth muscle in walls of hollow organs responds to neurotransmitters and stimulates each other to contract and relax in a rhythmic motion (peristalsis)
• Peristalsis


  Rhythmic contraction that pushes substances through tubes of the body
• Neurotransmitters for smooth muscle contraction

  Acetylcholine and norepinephrine can cause or inhibit contractions depending on smooth muscle type
• Cardiac Muscle


  • Intercalated discs connect groups of cardiac muscle fibers so they can contract and relax together, allowing the heart to work as a pump
  • Self-exciting, does not need nerve stimulation to contract, nerves just speed up or slow down contraction
  • Acetylcholine slows heart rate, norepinephrine speeds up rate
• Types of Muscle Tissue

  • Skeletal Muscle
  • Smooth Muscle
  • Cardiac Muscle
• Muscle Group


  • Skeletal Muscle
  • Smooth Muscle
  • Cardiac Muscle
• Skeletal Muscle


  Attached to bones and skin of the face, produces body movements and facial expressions, under voluntary control
• Smooth Muscle


  In walls of hollow organs, blood vessels, and iris, moves contents through organs and causes vasoconstriction, under involuntary control
• Cardiac Muscle


  In the wall of the heart, pumps blood through the heart, under involuntary control
• ATP (adenosine triphosphate)


  A type of chemical energy needed for sustained or repeated muscle contractions
• Ways muscle cells store or make ATP

  • Creatine phosphate (rapid production of energy)
  • Aerobic respiration (uses body's store of glucose)
  • Lactic acid production (small amounts of ATP)
• Oxygen Debt


  Develops when skeletal muscles are used strenuously for several minutes and cells are low in oxygen, pyruvic acid converts to lactic acid which builds up, causing muscle fatigue
• Muscle Fatigue


  Condition in which a muscle has lost its ability to contract, caused by accumulation of lactic acid, interruption of blood supply, or a motor neuron losing ability to release acetylcholine
• Major components of the skeletal muscular system

  • Connective tissue
  • Skeletal muscle tissue
  • Blood vessels
  • Nerves
• Connective Tissue Coverings


  • Fascia
  • Aponeuroses
  • Tendon
  • Epimysium
  • Perimysium
  • Endomysium
• Origin


  An attachment site for a less movable bone
• Insertion


  An attachment site for a more moveable bone
• Muscle Actions


  • Prime mover
  • Synergists
  • Antagonist (agonist)
• Body Movements


  • Flexion
  • Extension
  • Hyperextension
  • Dorsiflexion
  • Plantar flexion
  • Abduction
  • Adduction
  • Circumduction
  • Pronation
  • Supination
  • Inversion
  • Eversion
  • Retraction
  • Protraction
  • Elevation
  • Depression
• The muscle name indicates location, size, action, shape, or number of attachments
• Major Skeletal Muscles of the Head

  • Sternocleidomastoid
  • Frontalis
  • Splenius capitis
  • Orbicularis oris
  • Orbicularis oculi
  • Zygomaticus
  • Platysma
  • Masseter
  • Temporalis
• Major Skeletal Muscles of the Upper Arm

  • Pectoralis major
  • Latissimus dorsi
  • Deltoid
  • Subscapularis
  • Infraspinatus
• Major Skeletal Muscles of the Forearm

  • Biceps brachii
  • Brachialis
  • Brachioradialis
  • Triceps brachii
  • Supinator
  • Pronator teres
• Major Skeletal Muscles of the Wrist, Hand, and Fingers

  • Flexor carpi radialis
  • Flexor carpi ulnaris
  • Palmaris longus
  • Flexor digitorum profundus
  • Extensor carpi radialis longus
  • Extensor carpi radialis brevis
  • Extensor carpi ulnaris
  • Extensor digitorum
• Major Skeletal Muscles of the Respiratory System

  • Diaphragm
  • External intercostals
  • Internal intercostals
• Major Skeletal Muscles of the Abdominal Region

  • External obliques
  • Internal obliques
  • Transverse abdominis
  • Rectus abdominis
• Major Skeletal Muscles of the Pectoral Girdle

  • Trapezius
  • Pectoralis minor
• Major Skeletal Muscles of the Leg

  • Psoas major
  • Iliacus
  • Gluteus maximus
  • Gluteus medius
  • Gluteus minimus
  • Adductor longus
  • Adductor magnus
  • Biceps femoris
  • Semitendinosus
  • Semimembranosus
  • Rectus femoris
  • Vastus lateralis
  • Vastus medialis
  • Vastus intermedius
  • Sartorius
• Major Skeletal Muscles of the Ankle, Foot, and Toes

  • Tibialis anterior
  • Extensor digitorum longus
  • Gastrocnemius
  • Soleus
  • Flexor digitorum longus
• Muscle Strains


  Injuries due to over-stretched muscles or tendons