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MUSCULAR SYSTEM Human Body: Pushing the Limits / Strength Assignment: CH 6 p223 #1-8

Muscle Functions 1.Movement 2.Posture 3.Joint Stability 4.Heat …and MUSIC? Muscle Music 1:17 watch?v=yZ15vCGuvH0

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-rhythmic. Smooth: Walls of visceral organs. No striations/fusiform/involuntary. Slow contraction. Rhythmic contractions. Cardio = heart 182

Anatomy of a Skeletal Muscle 183

The Nerve-Muscle Connection

Anatomy of a Skeletal Muscle 186 Muscle Structure and Function 3:15

Micromovement of a Skeletal Muscle ACTIN MYOSIN Sliding Filament Theory Muscle Contraction

Anatomy of a Skeletal Muscle ACTIN MYOSIN

Micromovement of a Skeletal Muscle Muscle Structure and Function Interactive with 2 small quizzes

ACTIN MYOSIN ACTIN

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 bacterium 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 Done…Providing Energy for Muscle Contraction Three pathways for ATP generation : 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 Done…Providing 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 Done…Providing Energy for Muscle Contraction Three pathways for ATP generation (cont.): 3. Aerobic Respiration Glycolysis (splitting glucose) Kreb’s Cycle (36 ATP) (in mitochondrion) AEROBIC RESPIRATION Glucose Pyruvic Acid Fatty Acids ATP OXYGEN CO 2 mitochondrion H2OH2O ATP

Loss of 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 can’t, 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. thebsreport.wordpress.com Steroids CBC1266A5107&blnFromSearch=1&productcode=US

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 can’t 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 2. Relative size of the muscle. Maximus = largest Ex. Gluteus maximus. Minimus= smallest Ex. Gluteus minimus. Longus = long Ex. Peroneus longus.

Naming Skeletal Muscles 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 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 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

GROSS ANATOMY! Pages : Know Muscle Names and Actions Pages : Know Muscle Names and Actions Now let’s see how the muscles cause those movements.

MUSCLE DEVELOPMENT During fetal development muscles are built in sections like earthworms and then nerves are added.

MUSCLE DEVELOPMENT Muscular Problems: Muscular Dystrophy Inherited disease Muscles enlarge due to fat and connective tissue deposits. Muscle fibers degenerate and atrophy.

Any Questions?