The Muscular System

Do Now:Happy New Year!!Get your ClickerName as many muscles as you can

(anterior & posterior)

Facial Muscles

Shoulder

Abdominal Muscles

Back Muscles

Leg Muscles

Id the Masseter

1 2 3 4 5 6 7

0% 0% 0% 0%0%0%0%

1. 12. 23. 34. 45. 56. 67. 7

1 2 3 4 5 6 7

0% 0% 0% 0%0%0%0%

1. 12. 23. 34. 45. 56. 67. 7

Id the orbicularis oculi

1 2 3 4 5 6 7

0% 0% 0% 0%0%0%0%

1. 12. 23. 34. 45. 56. 67. 7

Id the deltoid

1 2 3 4 5 6 7 8 9

0% 0% 0% 0% 0%0%0%0%0%

Id the rectus abdominis 1. 12. 23. 34. 45. 56. 67. 78. 89. 9

1 2 3 4 5 6 7 8 9

0% 0% 0% 0% 0%0%0%0%0%

Id the sternocleidomastoid1. 12. 23. 34. 45. 56. 67. 78. 89. 9

1 2 3 4 5 6 7

0% 0% 0% 0%0%0%0%

Id the gastrocnemius1. 12. 23. 34. 45. 56. 67. 7

1 2 3 4 5 6 7

0% 0% 0% 0%0%0%0%

Id the biceps femoris1. 12. 23. 34. 45. 56. 67. 7

1 2 3 4 5 6 7

0% 0% 0% 0%0%0%0%

Id the sartorius muscle1. 12. 23. 34. 45. 56. 67. 7

Homework:Find and print a picture of your favorite

athlete (bathing suit preferred to see as many muscles as possible)

Hand label the visible muscles on their body using the muscles we discussed in class

Do Now:Grab your ClickerTake out your HW – athlete pic w/labeled

musclesReview names of muscles from hotlist &

diagram

1 2 3 4 5 6 7

0% 0%

37%

0%

63%

0%0%

1. 12. 23. 34. 45. 56. 67. 7

Id the orbicularis oris

1 2 3 4 5 6 7

22%

78%

0% 0%0%0%0%

1. 12. 23. 34. 45. 56. 67. 7

Id the temporalis muscle

1 2 3 4 5 6 7 8 9

0%

5%

0%

26%

0%

11%

53%

0%

5%

Id the serratus anterior1. 12. 23. 34. 45. 56. 67. 78. 89. 9

1 2 3 4 5 6 7 8 9

12%

0%

82%

6%

0%0%0%0%0%

Id the trapezius1. 12. 23. 34. 45. 56. 67. 78. 89. 9

1 2 3 4 5 6 7 8 9

0% 0% 0% 0%

11%

78%

6%6%

0%

Id the exterior obliques1. 12. 23. 34. 45. 56. 67. 78. 89. 9

1 2 3 4 5 6 7

11%

0%

6%

67%

11%

6%

0%

Id the soleus1. 12. 23. 34. 45. 56. 67. 7

1 2 3 4 5 6 7

5% 5%

32%

0%

5%

21%

32%

Id the semimembranosis1. 12. 23. 34. 45. 56. 67. 7

1 2 3 4 5 6 7

0%

6% 6% 6%6%

11%

67%

Id the semitendonosis1. 12. 23. 34. 45. 56. 67. 7

1 2 3 4 5 6 7

12%

65%

12%

0%0%0%

12%

Id the vastus medialis muscle1. 12. 23. 34. 45. 56. 67. 7

1 2 3 4 5 6 7

0%

100%

0% 0%0%0%0%

Id the rectus femoris muscle1. 12. 23. 34. 45. 56. 67. 7

Do Now: Why do you think that muscle-enhancing supplements (steroids, creatine, andro) are so popular at all levels of fitness and athletics (high school, college, pro, etc.) and do you see any problems with this?

Muscle TissuesCardiac

Involuntary striated muscleDinucleatedCommunicate via intercalated disksNatural contraction cycle determined by

pacemaker cellsSmooth

Lines blood vessels, digestive organs, urinary system, and parts of respiratory system

Involuntary nonstriated muscleCa+ triggers contractions differently (lacks

sarcomeres)Skeletal

Voluntary striated muscleMultinucleated cells called muscle fibersControlled by motor nerve cells

Functions of Skeletal MuscleProduce Movement

Contractions pull on tendons and move bonesMaintain posture and body position

Continuous contractions maintain postureSupport/protect soft tissues

Abdominal wallFloor of pelvic cavity

Guard entrances and exitsVoluntary control of swallowing, defecation, and

urinationMaintain body temp

Some energy from contractions lost as heat

Gross Anatomy of Skeletal Muscle

Each cell is called a “muscle fiber”

Contains several tissues:ConnectiveBlood vessels Nerves – control

contractionsSkeletal muscle

Microanatomy of Skeletal MuscleSarcolemma – cell

membraneSarcoplasm –

cytoplasmMyofibrils – bundles of

myofilaments Thin filaments – actin

proteinsThick filaments – myosin

proteinsSarcoplasmic

reticulum – smooth ER (stores Ca+)

Sarcomeres – repeating units of myofilaments

Muscle Fiber Contractionhttp://www.youtube.com/watch?v=CepeYFvqmk4

Classwork:Draw a flowchart or diagram showing how muscle contraction and relaxation occurs at a cellular level

Muscle Mechanics Muscle cells pull on collagen fibers

producing tension (can only contract!) Amount of tension dependent upon

Frequency of neural stimulation Latent period (2msec) – action

pot. & release of Ca+ Contraction phase (15msec) –

cross bridges form Relaxation phase (25msec) –

tension, cross bridges and Ca+ decrease

# of muscle fibrils activated Motor unit - # muscle fibrils

controlled by singe motor neuron Fine control of movement

determined by size of motor unit Ex. Eye vs. Leg muscles

During sustained contraction – motor units activated on a rotating basis (some rest/some contract)

Muscle ToneTone – resting tension Stabilizes the position of

your jointsAny skeletal muscle not

stimulated on a regular basis will atrophy – fibers become smaller and weaker

Initially atrophy is reversible

Extreme atrophy is permanent

Energetics of Muscle ActivityActive Skeletal Muscle fibril requires 600 trillion

ATP/sec! Sources of ATP

Stored (ADP + Creatine-P ATP)Lasts 15 sec

Aerobic Metabolism (Krebs Oxidative Phosphorylation)Provides 30% of ATP needed during peak exertion

Anaerobic Metabolism (glycolysis)Main E sourceLactic acid builds up Ineffective

Muscle Fatigue – no contraction despite stimulationLack of ATP or lactic acid build up

Recovery Period – returns to pre-exertion levels

Muscle Performance Force and endurance depends on: Types of muscle fibers

Fast Twitch (white) Powerful contractions Fatigue rapidly (few mitochondria)

Slow Twitch (red) Extended contraction (many

mitochondria) Extensive capillary network Myoglobin binds O2

Physical conditioning ( increase power and endurance)Anaerobic

Frequent, brief intense workouts (hypertrophy of muscle fibrils)

Aerobic Sustained low levels of activity Carb-load the day before; drink glucose

rich sports drinks

Muscle ReviewWhat muscle do you use to shrug your shoulders? What muscle would be well developed in a trumpet

player? What is the most likely cause of a muscle cramp? What muscle do you use to stand on your tippy-

toes? What muscle do you use to close your eye-lidsWhat muscle do you use when using a “butterfly”

machine? Compare “white” muscles to “red” musclesA friend wants to bulk up his arms. What would you

suggest to him? What are the 3 sources of energy for muscles?

What limits each?