Chapter 10, reviewed and continued Gross and microscopic anatomy of skeletal muscles Nerve to muscle: excitation-contraction coupling Factors affecting how much force is exerted Muscle diversity fast-twitch vs. slow-twitch skeletal vs. cardiac vs. smooth

Muscle metabolism, continued… A new sports drink advertises, “Includes ATP for rapid fueling of exercising muscles!” Are you tempted to buy it? Why or why not? © 2015 Pearson Education, Inc.

Fast-Twitch vs. Slow-Twitch Muscle Fibers Overall function (speed? strength? endurance?) Myosin type (I? II?) SR abundance (low? high?) Mitochondrial density (low? high?) Capillary density Substrates used (carbs? lipids?)

Can exercise training convert fast fibers to slow fibers or vice versa Can exercise training convert fast fibers to slow fibers or vice versa? (Or are we prisoners of our genes?)

The heart: the ultimate slow-twitch muscle 10th Martini, Figure 10-22

Intercalated discs Intertwined cell membranes of adjacent cells Gap junctions Desmosomes

High levels of troponin have been found in a patient’s blood High levels of troponin have been found in a patient’s blood. What could this mean?

Smooth muscle Relaxed (sectional view) Relaxed (superficial view) 10th Martini, Figure 10-23b Smooth muscle Relaxed (sectional view) Relaxed (superficial view) Contracted (superficial view)

Skeletal vs. Cardiac vs. Smooth (Table 10-3) Property Skeletal Muscle Cardiac Muscle Smooth Muscle Fiber size Nuclei Organization of contractile proteins Control mechanism Calcium source Calcium regulation Contraction speed/endurance Energy source

Clinical Case: myasthenia gravis Usually an autoimmune disease (can you think of others?) Acetylcholine (Ach) receptors are attacked Treatment strategies? Figure 10-9

Worksheet: end-of-chapter review questions

10th Martini, Chapter 11: An Introduction to the Muscular System General concepts Fascicle arrangements Levers Naming conventions Lots and lots of muscles!

Muscle fascicles are arranged in different ways PARALLEL CONVERGENT PENNATE CIRCULAR contracted relaxed 10th Martini, Figure 11-1

11-1 Fascicle Arrangement Circular Muscles Also called sphincters Open and close to guard entrances of body For example, orbicularis oris muscle of the mouth © 2015 Pearson Education, Inc.

Parallel vs. Pennate: How does this affect muscle function? On page 334, your textbook says: “A pennate muscle contains more muscle fibers – and thus more myofibrils – than does a parallel muscle of the same size. For this reason, the pennate muscle produces more tension.” This is completely wrong!

Parallel vs. Pennate Muscles: a better explanation? = 1 “unit” of muscle proteins (relaxed) bone bone bone bone contract bone bone contract bone bone contract bone bone bone bone

Muscles and Levers Lever = “a rigid structure … that moves on a fixed point called a fulcrum” Levers move when an applied force (AF) overcomes any load (L) that would prevent movement Bones are levers Joints are fulcrums Muscles provide applied force 10th Martini, Figure 11-2

Optimized for speed or effective force? 10th Martini, Figure 11-2

11-3 Muscle Attachments to Other Tissues Origins and Insertions Origin: fixed point of attachment Insertion: moving point of attachment Most muscles originate or insert on the skeleton Origin is usually proximal to insertion “Knowing which end is the origin and which is the insertion is ultimately less important than knowing where the two ends attach and what the muscle accomplishes when it contracts.” © 2015 Pearson Education, Inc.

11-3 Muscle Attachments to Other Tissues Remember the movement terms from the previous lab? (abduction/adduction, pronation/supination, etc.) Now we can see how muscles achieve these movements!

11-3 Muscle Attachments to Other Tissues Muscle Terminology Based on Function Agonist (or prime mover) Antagonist Synergist

Muscles you will need to know (Exercise 13) Muscles of Facial Expression: occipitofrontalis (frontalis) orbicularis oris levator labii zygomaticus lateral rectus Muscles of Mastication: temporalis Muscles of Tongue, Throat, and Anterior Neck: sternohyoid sternocleidomastoid Muscles of the Neck and Vertebral Column: longissimus cervicis semispinalis thoracis

Muscles you will need to know (Exercise 13) Muscles of the Thorax: Movement of the Scapula: levator scapulae rhomboideus major serratus anterior trapezius Muscles of the Shoulder and Arm: pectoralis major • flexor carpi radialis deltoid • palmaris longus supraspinatus • extensor digitorum coracobrachialis • adductor pollicis triceps brachii biceps brachii brachioradialis

Muscles you will need to know (Exercise 13) Muscles of the Hip and Leg: iliacus gluteus medius sartorius adductor longus adductor magnus quadriceps femoris: rectus femoris, vastus lateralis, vastus medialis, vastus intermedius hamstrings: biceps femoris, semitendinosus, semimembranosus tibialis anterior flexor digitorum longus gastrocnemius

11-4 Naming Skeletal Muscles Names for skeletal muscles can indicate any of the following: 1. Location in the body 2. Origin and insertion 3. Fascicle organization 4. Relative position 5. Structural characteristics 6. Action The following slides are meant to help but do not need to be memorized. © 2015 Pearson Education, Inc.

11-4 Naming Skeletal Muscles 1. Location in the body For example, temporalis muscle 2. Origin and insertion First part of name indicates origin Second part of name indicates insertion For example, genioglossus muscle 3. Fascicle organization For example, rectus (straight), transversus (crosswise), oblique (slanting) © 2015 Pearson Education, Inc.

11-4 Naming Skeletal Muscles 4. Position Externus (superficialis) = Internus (profundus) = Extrinsic Muscles ______ an organ Intrinsic © 2015 Pearson Education, Inc.

11-4 Naming Skeletal Muscles 5. Structural characteristics Nature of origin Biceps (__ heads) Triceps (__ heads) Quadriceps (__ heads) Shape Deltoid (triangle) Orbicularis (circle) Pectinate (comblike) Piriformis (pear-shaped) Platy- (flat) Pyramidal (pyramid) • Rhomboid (parallelogram) • Serratus (serrated) • Splenius (bandage) • Teres (round and long) • Trapezius (trapezoid) © 2015 Pearson Education, Inc.

11-4 Naming Skeletal Muscles 5. Structural characteristics (continued) Other striking features Alba (white) Brevis (short) Gracilis (slender) Lata (wide) Latissimus (widest) Longissimus (longest) Longus (long) • Magnus (large) • Major (larger) • Maximus (largest) • Minimus (smallest) • Minor (smaller) • Vastus (great) © 2015 Pearson Education, Inc.

11-4 Naming Skeletal Muscles 6. Actions Abductor = Adductor = Depressor = Extensor = Flexor = Levator = Pronator = Supinator = Tensor = © 2015 Pearson Education, Inc.