MUSCULAR SYSTEM Muscle Fibers Cardiac: Only in heart. Striated/Branched/involuntary. Joined by intercalated discs. Contract at a steady rate. Skeletal: Attach to skeleton. Straited/Cigar-shaped/voluntary. Slow to fast contraction. Non-rhymthic. Smooth: Walls of visceral organs. No striations/fusiform/involuntary. Slow contraction. Rhythmic contractions. Cardio = heart Muscle Functions 1.Movement 2.Posture 3.Joint Stability 4.Heat Interactive Muscle Functions: mples/animations/Gymnast/index.html Anatomy of a Skeletal Muscle Vocabulary to Know Myofibril = long ribbonlike organelles that push nuclei aside Sarcomere = chains of contractile units making up myofibrils Myosin = thick filaments of muscle cells Actin = thin filaments of muscle cells Motor Unit = one neuron and its skeletal muscles Action Potential = electrical current that causes contractions Sliding Filament Theory = (Pg 163 Fig 6.8) Muscle Contraction Anatomy of a Skeletal Muscle Flash: Muscle Structure and FunctionDemo: Muscle model Anatomy of a Skeletal Muscle ACTIN MYOSIN Micromovement of a Skeletal Muscle ACTIN MYOSIN Micromovement of a Skeletal Muscle Contraction of a Skeletal Muscle as a Whole Graded Responses = different degrees of shortening Can be produced 2 ways: 1.Change of speed of muscle contraction. Muscle Twitches = nerve impulses are delivered too fast for the cells to relax between impulses results are summed and contraction is stronger and smoother. TETANUS = when stimulation is so rapid no relaxation occurs and contractions are completely smooth and sustained. (not to be confused with the disease Tetanus which is a result of a bacteria found on rusty metal) Contraction of a Skeletal Muscle as a Whole 2. Change of number of muscles cells stimulated. More cells stimulated = stronger contraction. fineartamerica.com Getting it DoneProviding Energy for Muscle Contraction Three pathways for ATP generation (pg 165 Fig 6.10): 1.Direct phosphorylation of ADP by creatine phosphate Phosphorylation = adding a phosphate CP = creatine phosphate wellsphere.com I NEED ATP! DIRECT PHOSPHORYLATION with CREATINE PHOSPHATE CP ADP Creatine ATP CP ADP Phospho = phosphate Getting it DoneProviding Energy for Muscle Contraction Three pathways for ATP generation (cont.): 2.Anaerobic Respiration Glycolysis (splitting glucose) Lactic Acid Formation ANAEROBIC RESPIRATION Glycogen Glucose Pyruvic Acid Lactic Acid ATP NO OXYGEN! Getting it DoneProviding Energy for Muscle Contraction Three pathways for ATP generation (cont.): 3. Aerobic Respiration Glycolysis (splitting glucose) Krebs Cycle (36 ATP) (in mitochondrion) AEROBIC RESPIRATION Glucose Pyruvic Acid Fatty Acids ATP OXYGEN CO 2 mitochondrion H2OH2O ATP Getting it DoneProviding Energy for Muscle Contraction Muscle Fatigue = when muscles are no longer able to contract when stimulated. Oxygen Debt = Cause of muscle fatigue due to prolonged muscle activity. The person cannot take in enough oxygen to supply the needs of the muscle cells. Muscles convert to Lactic Acid fermentation. mobovivo.com Types of Muscle Contractions Isotonic Contractions = myofilaments slide, muscle shortens, movement occurs. Isometric Contractions = myofilaments try to slide but cant, muscle stays longer, no movement occurs. Isotonic Isometric healthuse.com Isotonic or Isometric? scienceblogs.com Muscle Tone = state of continuous partial contraction Result of systematic contraction of motor units throughout the muscle. dailymail.co.uk Exercise and Muscles Use it or Lose it! Unused muscles will atrophy (loose the ability to function). Types of Exercise: 1.Aerobic/Endurance Muscular Benefits: strength resistance to fatigue flexibility Increased blood supply More mitochondria Exercise Exercise and Muscles Use it or Lose it! Types of Exercise: 2. Resistance Muscular Benefits: strength increase in size Increased cell size and connective tissue. SteroidsCBC1266A5107&blnFromSearch=1&productcode=US thebsreport.wordpress.com Types of Body Movements Origin = attachment point of muscle to bone (or less moveable tissue structure). Insertion = attachment point of muscle to the moveable bone. abcbodybuilding.com Types of Body Movements Refer to pg Fig 6.13 Flexion Extention Hyperextension Abduction Adduction Rotation Circumduction Pronation Supination Inversion Eversion Dorsiflexion Plantar flexion Types of Muscles Muscles cant push they can only pull as they contract. Therefore, one set of muscles works against another set. This relationship allows a wide variety of movements. Types of Muscles Prime mover = most responsible for the movement Antagonist = opposes or reverses the movement Antagonist Prime mover Types of Muscles Synergist = muscle that stabilizes muscles; not involved in causing movement. Types of Muscles Fixator = muscle that stabilizes the origin of a prime mover; not involved in causing movement. Naming Skeletal Muscles Muscles are named based on 7 criteria: 1.Direction of muscle fibers. Rectus = (straight) runs parallel to a line. Ex. Rectus femoris runs parallel to the femur. Oblique = (slanted) runs in a slant to a line. Ex. External Oblique Naming Skeletal Muscles Muscles are named based on 7 criteria: 2. Relative size of the muscle. Maximus = largest Ex. Gluteus maximus. Minimus= smallest Ex. Gluteus minimus. Longus = long Ex. Peroneus longus. Naming Skeletal Muscles Muscles are named based on 7 criteria: 3. Location of the muscle. Named for the bone with which they are associated. Ex. Temporalis and Frontalis. Temporalis Bos Frontalis No, this is HUMAN anatomy! Frontalis Naming Skeletal Muscles Muscles are named based on 7 criteria: 4. Number of Origins. Bi = 2 ; Tri = 3 ; Quad = 4 Ex. Biceps, Triceps, Quadriceps 5. Location of orgins and insertions Named for attachment sites. Ex. Sternocleidomastoid attaches at the sternum (sterno) and clavicle (cleido) and inserts on the mastoid process (mastoid) Naming Skeletal Muscles Muscles are named based on 7 criteria: 6. Shape of the muscle Named for a distinctive shape Ex. Deltoid (means triangular) 7. Action of the muscle Named for their action. Ex. Flexor (flexes) extensor (extends) adductor (adducts) Flexor GROSS ANATOMY! Gross Anatomy = study of larger anatomical features First, lets review movements. Types of Body Movements Refer to pg Fig 6.13 Flexion Extention Hyperextension Abduction Adduction Rotation Circumduction Pronation Supination Inversion Eversion Dorsiflexion Plantar flexion Interactive muscle IDGROSS ANATOMY! Gross Anatomy = study of larger anatomical features Pages : Know Muscle Names and Actions Pages : Know Muscle Names and Actions Now lets see how the muscles cause those movements.tutorial.html Assignment: Make your own Table of Muscles and Actions. In the first column, write the name of the muscle. In the second column, write what it does IN YOUR OWN WORDS. In the third column, write the anatomical description of the action. MUSCLE NAMEACTIONACTION (OWN WORDS) FrontalisRaises eyebrowsLifts eyebrows up. Biceps bronchii Flexes elbow and supinates forearm Lifts forearm up and twists forearm out. MUSCLE DEVELOPMENT During fetal development muscles are built in sections like earthworms and then nerves added. MUSCLE DEVELOPMENT Muscular Problems: Muscular Dystrophy Inherited disease Muscles enlarge due to fat and connective tissue deposits. Muscle fibers degenerate and atrophy. Flash: Duchennes Muscular Dystrophy MUSCLE DEVELOPMENT Muscular Problems: Myasthenia Gravis Attacks adults Drooping eyelids, difficulty swallowing and talking, weakness and fatigue. Shortage of acetylcholine receptors at neuromuscular junctions. Death usually occurs due to respiratory failure. Myo = muscle asthen = weakness gravis = heavy