Chapter 6: Muscular System (PDF)

Hi everyone I am Amna I am sharing with you my notes that I combined all the resources in it so it becomes more easier to you to study (book,Dr,etc)...

Hi everyone I am Amna I am sharing with you my notes that I combined all the resources in it so it becomes more easier to you to study (book,Dr,etc) If you have any requirements please feel free to contact me on this email [email protected] Best of luck!! Chapter 6 The Muscular System partAFB Lecture Presentation by Patty Bostwick-Taylor Florence-Darlington Technical College © 2018 Pearson Education, Ltd.  The Muscular System Muscles are responsible for all types of body movement Three basic muscle types are found in the body 1. Skeletal muscle 2. Cardiac muscle 3. Smooth muscle © 2018 Pearson Education, Ltd.  Murch I Skeletal Cardiac Smooth I classification type Branched ; organs that attach Elongated cells to send * Packaged into Sk m. cover the Skeleton. , Cylindrical Description Strictions ~ Intercalated discs X voluntary/Voluntary Involuntary via nervous Control System Control Involuntary(Chl InvoluntarySe viaANs + hormones Catecholamines (symp Stimulation). & stretching Location Skeletal Muscles & Heart wall wallsisan Ex Arrector pili : muscles attached to hair follider. * Body Motility a Constitution of the bulk of wall *. force fluids bother substances Functions througbut internal body channels > - propels Substances (wine foodstifs baby ( a , Nucleus Multi nucleated 1 - 2 nuclei uni-nu cleated CT Sheaths 3: [Epimysium-Endomysium only Endomyrum only Endomysium PerimySium - Speed of ContractionSlow to fast Slow protectionts the = Very Slow moving thepen Us.. touching Inthught (constant fast heart nate will lead to failure)" Gradual change" Slow Contraction = goodpressure-strong blood pumping stimulate the receptors of uterine contr Rhythmic NO Yes;if= Dysrhythmia Yes , in some locationof body! (depends on  Muscle Types Skeletal muscle cells are surrounded and bundled by connective tissue Endomysium—encloses a single muscle fiber Perimysium—wraps around a fascicle (bundle) of muscle fibers Epimysium—covers the entire skeletal muscle > blends with the Fascia—on the outside of the epimysium - deep fascia ↳ Stabilize/covers/protects 4 CT surrounds some muscles the body layer in Surrounds the structure Smusch the muscle. England ↳piM © 2018 Pearson Education, Ltd.  sites of muscle attachment Muscle Types oBones (tendons · ocartilages OCT coverings (Aponeurosis) The epimysium of skeletal muscle blends into a connective tissue attachment muscle end start can or by a Tendons—cordlike structures · materia Mostly collagen fibers Often cross a joint because of their toughness and small size flat Aponeuroses—sheetlike structures of fibrous tissue Attach muscles indirectly to bones, cartilages, or Y connective tissue coverings skin or © 2018 Pearson Education, Ltd.  Muscle Types Smooth muscle No striations Involuntary—no conscious control Found mainly in the walls of hollow visceral organs Loading… (such as stomach, urinary bladder, respiratory passages) Spindle-shaped fibers that are uninucleate fusiform Contractions are slow and sustained © 2018 Pearson Education, Ltd.  Muscle Types Cardiac muscle Striations Involuntary Found only in the walls of the heart Uninucleate Branching cells joined by gap junctions called intercalated discs Contracts at a steady rate set by pacemaker © 2018 Pearson Education, Ltd.  Muscle Functions -Mobility Blocomotion Whereas all muscle types produce movement, I skeletal muscle has three other important roles: Maintain posture and body position 2 (maintaining body posture) Stabilize joints 3 if shoulder separated from is the joint-Dislocation - Generate heat 4 ↳ ATP >heat F = © 2018 Pearson Education, Ltd.  Stimulation and Contraction of Single Skeletal Muscle Cells I can eat easily Special functional properties of skeletal muscles Irritability (also called responsiveness)—ability to neurotransmitter released by receive and respond to a stimulus Ex : a a cellneve Contractility—ability to forcibly shorten when an adequate stimulus is received Extensibility—ability of muscle cells to be stretched Elasticity—ability to recoil and resume resting length after stretching => © 2018 Pearson Education, Ltd.  Microscopic Anatomy of Skeletal Muscle Sarcolemma—specialized plasma membrane Myofibrils—long organelles inside muscle cell Light (I) bands and dark (A) bands give the muscle its striated (banded) appearance Dark A light I -> -> © 2018 Pearson Education, Ltd.  Chapter 9 Muscles and Muscle Tissue 313 Table 9.1 Structure and Organizational Levels of Skeletal Muscle CONNECTIVE TISSUE STRUCTURE AND ORGANIZATIONAL LEVEL DESCRIPTION WRAPPINGS Muscle (organ) A muscle consists of hundreds to thousands of Covered externally by muscle cells, plus connective tissue wrappings, the epimysium Epimysium Muscle blood vessels, and nerve fibers. ↳ D Irr 2T.. Tendon Fascicle Fascicle (a portion of the muscle) A fascicle is a discrete bundle of muscle cells, Surrounded by segregated from the rest of the muscle by a perimysium Part of fascicle Perimysium connective tissue sheath. ↳D. Irr. CT Muscle fiber (cell) % Muscle fiber A muscle fiber is an elongated multinucleate Surrounded by 9 cell; it has a banded (striated) appearance. endomysium Nucleus Endomysium ↳ ACT Sarcolemma Part of muscle fiber Myofibril Myofibril (complex organelle composed of bundles of Myofibrils are rodlike contractile elements — myofilaments) that occupy most of the muscle cell volume. Composed of sarcomeres arranged end to end, they appear banded, and bands of adjacent myofibrils are aligned. Sarcomere Sarcomere (a segment of a myofibril) A sarcomere is the contractile unit, composed — of myofilaments made up of contractile Sarcomere proteins. Thin (actin) filament Thick (myosin) filament Myofilament, or filament (extended macromolecular structure) Contractile myofilaments are of two types— — thick and thin. Thick filaments contain Thick filament Head of myosin molecule bundled myosin molecules; thin filaments contain actin molecules (plus other proteins). The sliding of the thin filaments past the thick filaments produces muscle shortening. Elastic filaments (not shown here) provide elastic recoil when tension is released and help maintain myofilament organization. Thin filament Actin molecules  Microscopic Anatomy of Skeletal Muscle Banding pattern of myofibrils I band = light band Contains only thin filaments Actin > - filaments Z disc is a midline interruption A band = dark band Contains the entire length of the thick filaments - Myosin Filaments H zone is a lighter central area M line is in center of H zone © 2018 Pearson Education, Ltd.  Microscopic Anatomy of Skeletal Muscle ↳ Lies between 22discs Sarcomere—contractile unit of a muscle fiber Structural and functional unit of skeletal muscle Organization of the sarcomere Myofilaments produce banding (striped) pattern Thick filaments = myosin filaments Thin filaments = actin filaments © 2018 Pearson Education, Ltd.  Microscopic Anatomy of Skeletal Muscle Thick filaments = myosin filaments Composed of the protein myosin -Acts on energy Contain ATPase enzymes to split ATP to release energy for muscle contractions Possess projections known as myosin heads Myosin heads are known as cross bridges when they link thick and thin filaments during contraction © 2018 Pearson Education, Ltd.  Microscopic Anatomy of Skeletal Muscle Thin filaments = actin filaments Composed of the contractile protein actin Actin is anchored to the Z disc At rest, within the A band there is a zone that lacks actin filaments called the H zone During contraction, H zones disappear as actin and myosin filaments overlap © 2018 Pearson Education, Ltd.  The Nerve Stimulus and Action Potential Skeletal muscles must be stimulated by a motor neuron (nerve cell) to contract ↳ motor this neuron with all the muscle fiber supplied by a mor Motor unit—one motor neuron and all the skeletal ↳muscle cells stimulated by that neuron S S - O No © 2018 Pearson Education, Ltd.  The Nerve Stimulus and Action Potential Neuromuscular junction (Synapse... Association site of axon terminal of the motor neuron and sarcolemma of a muscle ↳ plasma MMB of the muscle cell Neurotransmitter Loading… Chemical released by nerve upon arrival of nerve impulse in the axon terminal While Ap is happening Acetylcholine (ACh) is the neurotransmitter that stimulates skeletal muscle The only one # Stimulation © 2018 Pearson Education, Ltd. 1 Nerve. Impulse reached 2 + Ca2 Channels cat enter axon terminal Chapter 6: The Muscular System 215 open;. 3. Vesicles release Ach 4 Ach. differe synaptic cleft in binds to receptors in Sarcolemma Myelinated axon Nat in Nerve of motor neuron. 5 Depolarization happens - Let out impulse Axon terminal of Nucleus neuromuscular Acetic acid. AChE break ACh 6 - junction choline ↓ Sarcolemma of the muscle fiber Ends the process 6 Me Synaptic vesicle containing ACh 1 Nerve impulse reaches axon terminal of motor neuron. Axon terminal of motor neuron Mitochondrion 2 Calcium (Ca2+) channels Ca2+ Ca2+ open, and Ca2+ enters the axon Synaptic terminal. cleft Sarcolemma Fusing synaptic vesicle Sarcoplasm 3 Ca2+ entry causes some ACh of muscle fiber synaptic vesicles to release their Folds of contents (the neurotransmitter ACh receptor sarcolemma acetylcholine) by exocytosis. 4 Acetylcholine diffuses across the synaptic cleft and binds to receptors in the sarcolemma. Ion channel in 5 ACh binds and opens channels Na+ K+ sarcolemma opens; that allow simultaneous passage ions pass. of Na+ into the muscle fiber and K+ out of the muscle fiber. More Na+ ions enter than K+ ions leave, producing a local change in the electrical conditions of the membrane (depolarization). This eventually leads to an action ACh Degraded ACh Anichanne potential. Ion channel closes; Actic Na+ ions cannot pass. 6 The enzyme acetylcholinesterase breaks down ACh in the synaptic cleft, ending the process. Acetylcholinesterase K+ Figure 6.5 Events at the neuromuscular junction. & 1: 1 > propagation AP -  Mechanism of Muscle Contraction: The I Sliding Filament Theory Ca2+ ATP What causes filaments to slide? Calcium ions (Ca2+) bind regulatory proteins on thin filaments and expose myosin-binding sites, allowing the myosin heads on the thick filaments to attach Each cross bridge pivots, causing the thin filaments to slide toward the center of the sarcomere Contraction occurs, and the cell shortens During a contraction, a cross bridge attaches and detaches several times ATP provides the energy for the sliding process, which continues as long as calcium ions are present © 2018 Pearson Education, Ltd. Figure 6.7 Diagrammatic views of a sarcomere. Myosin Actin Z H Z I A I (a) Relaxed sarcomere Z Z I A I (b) Fully contracted sarcomere © 2018 Pearson Education, Ltd. :  Contraction of a Skeletal Muscle as a Whole Graded responses we don't have partial contraction Muscle fiber contraction is “all-or-none,” meaning it will contract to its fullest when stimulated adequately Within a whole skeletal muscle, not all fibers may be stimulated during the same interval Different combinations of muscle fiber contractions little fore may give differing responses ↳ ↳ Huge fore Graded responses—different degrees of skeletal muscle shortening titany © 2018 Pearson Education, Ltd.  Contraction of a Skeletal Muscle as a Whole Graded responses can be produced in two ways By changing the frequency of muscle stimulation How frequent is the stimulation By changing the number of muscle cells being stimulated at one time How many fibers stimulated ? are 1 Stimulation. 2 Contraction. 3 Relaxation - normal contraction © 2018 Pearson Education, Ltd.  Contraction of a Skeletal Muscle as a Whole in moving 8 Muscle response to increasingly rapid stimulation Muscle twitch happens because of frequent stimulation Single, brief, jerky contraction Not a normal muscle function © 2018 Pearson Education, Ltd.  Contraction of a Skeletal Muscle as a Whole Muscle response to increasingly rapid stimulation (continued) In most types of muscle activity, nerve impulses are delivered at a rapid rate As a result, contractions are “summed” (added) together, and one contraction is immediately followed by another stronger each time Tension - Flanus Or summing of - 2) tractions Stimuli unfared freed in complete Complete tetanus tetanus © 2018 Pearson Education, Ltd.  Contraction of a Skeletal Muscle as a Whole Muscle response to increasingly rapid stimulation (continued) When stimulations become more frequent, muscle contractions get stronger and smoother The muscle now exhibits unfused (incomplete) tetanus dea" Tetany Spasm medical condition dircare caused by bacterial infection - Antitetanus Soxif j - ↓ becomes thick not contracting diaphragm , condition > may end respect - > RIP failure - in g Erelaxing - resp - © 2018 Pearson Education, Ltd.  Contraction of a Skeletal Muscle as a Whole Muscle response to increasingly rapid stimulation (continued) Fused (complete) tetanus is achieved when the muscle is stimulated so rapidly that no evidence of relaxation is seen Contractions are smooth and sustained NoRelaxation © 2018 Pearson Education, Ltd.  Contraction of a Skeletal Muscle as a Whole muscle contraction More frequent stimulation = more Muscle response to stronger stimuli Muscle force depends upon the number of fibers stimulated Contraction of more fibers results in greater muscle tension When all motor units are active and stimulated, the muscle contraction is as strong as it can get sifno paralysis ; Stimulus (nerve) for musce to contract you need 2 things [nuishment (0 - , Glucs2) if supply no 5 Muscle Stop working ↳ FATIGUE © 2018 Pearson Education, Ltd.  Providing Energy for Muscle Contraction From where does the muscle gets energy ? ATP Only energy source that can be used to directly power muscle contraction muscle cell Stored in muscle fibers in small amounts that are quickly used up After this initial time, other pathways must be utilized to produce ATP © 2018 Pearson Education, Ltd.  ↳Mainsource of energy oxidative phosphorylation ↓ Adenosine phosphate diphosphate ↑ E 12. Have to gluesse be present 1. Give PtoADP 13. & 2 ADP+ P ATP 2 generate =. inthe muscles. 3 Energy energy = sourness ↳ Accumulationof LA pain=cramps = Not a good source of energy ! Not a good sourceofenergy large diameter-no pain inleseWhile excersive  Providing Energy for Muscle Contraction Direct phosphorylation of ADP by creatine phosphate (CP)—fastest L Creatine phosphate Muscle cells store CP, a high-energy molecule exhausted After ATP is depleted, ADP remains CP transfers a phosphate group to ADP to regenerate ATP CP supplies are exhausted in less than 15 seconds 1 ATP is produced per CP molecule Galina A CADD 1 / : < 15 seconden © 2018 Pearson Education, Ltd.  Providing Energy for Muscle Contraction D Name : AR/DP + -OctHO + A Location : Mitochondria ↳ removed 32 1 : by D ATP Gluore uses 02 into : : Choose broken down Aerobic respiration ATP released : 32 ATP's Duration : Slow / hourr Supplies ATP at rest and during light/moderate exercise A series of metabolic pathways, called oxidative phosphorylation, use oxygen and occur in the mitochondria Glucose is broken down to carbon dioxide and water, releasing energy (about 32 ATP) This is a slower reaction that requires continuous delivery of oxygen and nutrients · One of the sources of water in the body is from pathway this © 2018 Pearson Education, Ltd.  Providing Energy for Muscle Contraction A TP released ATP Name: AG/LAF : 2 Sk M lactic acid Pyric acid Location : Liver ,. > - a e ↳ Muscle uses : Soreness Duration : Fast reaction/so-bose Anaerobic glycolysis and lactic acid formation Yo Sec.. Reaction that breaks down glucose without oxygen Glucose is broken down to pyruvic acid to produce about 2 ATP Pyruvic acid is converted to lactic acid, which causes muscle soreness pain This reaction is not as efficient, but it is fast Huge amounts of glucose are needed © 2018 Pearson Education, Ltd.  muscle contraction Muscle Fatigue and Oxygen Deficit nerve int Unable to contract ↓ Stimulus blood supply : If muscle activity is strenuous and prolonged, muscle fatigue occurs Suspected factors that contribute to muscle fatigue include: Ion imbalances (Ca2+, K+) agendept Q required > - to get is Oxygen deficit and lactic acid accumulation rid of accumulated L Decrease in energy (ATP) supply ancreasing lactic acid Black of ATPcauses the muscle to contract After exercise, the oxygen deficit is repaid by less rapid, deep breathing © 2018 Pearson Education, Ltd.  Types of Muscle Contractions mobile Isotonic contractions = with movement-lifting my Myofilaments are able to slide past each other during contractions The muscle shortens, and movement occurs Example: bending the knee; lifting weights, smiling Isometric contractions without movement-pushing the wall = Muscle filaments are trying to slide, but the muscle is pitted against an immovable object Tension increases, but muscles do not shorten Example: pushing your palms together in front of you © 2018 Pearson Education, Ltd.  Muscle Tone filers contracts & do (reax) Muscle tone · When some some Ithey alternate State of continuous partial contractions Result of different motor units being stimulated in a systematic way (different Intervals Muscle remains firm, healthy, and constantly ready for hard action murchefibers contraction - · The process of alternating Involuntary process by ANS © 2018 Pearson Education, Ltd.  31 : 28 Effect of Exercise on Muscles 38 21 : min 58 : 10 ① ② Exercise increases muscle size, strength, and endurance③ T BEST running , walking , swimming Aerobic (endurance) exercise (biking, jogging) results in stronger, more flexible muscles with greater resistance to fatigue Improve mode sleeping pattern / + enhance Makes body metabolism more efficient · ⑧ Improves func good Cardiorespiratory fune. & Improves digestion, coordination better of nervous system. If Resistance (isometric) exercise (weight lifting) ⑧ increases muscle size and strength either Cell number ; Individual muscle fibers enlarge ↳ pertrophy & murcles Can Carry more weight-increase stength © 2018 Pearson Education, Ltd. Figure 6.11 The effects of aerobic training versus strength training. (a) (b) © 2018 Pearson Education, Ltd.  Chapter 6 The Muscular System Part B Lecture Presentation by Patty Bostwick-Taylor Florence-Darlington Technical College © 2018 Pearson Education, Ltd. Table 6.2 The Five Golden Rules of Skeletal Muscle Activity Loading… © 2018 Pearson Education, Ltd.  Types of Body Movements Muscles are attached to no fewer than two points starting point 1. 1 Origin: attachment to an immovable or less movable bone Origin is usually fixed; it doesn't move Ending point 2.. Insertion: attachment to a movable bone 2 When the muscle contracts, the insertion moves toward the origin Body movement occurs when muscles contract across joints © 2018 Pearson Education, Ltd.  Types of Body Movements Flexion Bending Decreases the angle of the joint % Brings two bones closer together - Typical of bending hinge joints (e.g., knee and elbow) O or ball-and-socket joints (e.g., the hip) > - Extension Returning the part from the flexion position C Opposite of flexion Increases angle between two bones · Typical of straightening the elbow or knee > 1808 Extension beyond 180º is hyperextension - © 2018 Pearson Education, Ltd.  Types of Body Movements Rotation Movement of a bone around its longitudinal axis Common in ball-and-socket joints Example: moving the atlas around the dens of axis (i.e., shaking your head “no”) = Externate = Internal rotation © 2018 Pearson Education, Ltd.  Types of Body Movements Abduction Movement of a limb away from the midline Adduction Opposite of abduction Loading… Movement of a limb toward the midline © 2018 Pearson Education, Ltd.  2 joints fure Cogether = 1 bone Types of Body Movements joints I - Boney /Immorable I /fibrous) relatively Shoulder freely · o slightly moving Disc Circumduction (Synoviall pe ↳ Allows little movement between 2 vertebrae Combination of flexion, extension, abduction, and adduction Common in ball-and-socket joints Proximal end of bone is stationary, and distal end moves in a circle © 2018 Pearson Education, Ltd.  Dorsal-Back side upper or Special Movements plantar-soleof thefeet Dorsiflexion Lifting the foot so that the superior surface approaches the shin (toward the dorsum) Plantar flexion Pointing the toes away from the head Dorsal of gloot ①shinbone © 2018 Pearson Education, Ltd.  dar Special Movements Inversion To the Inside AskPr Turning sole of foot medially Eversion Tothe outside Turning sole of foot laterally © 2018 Pearson Education, Ltd.  position : Special Movements supine-lay on your back only in the forearm pron = lay on your face Supination Forearm rotates laterally so palm faces anteriorly Radius and ulna are parallel Pronation sto the midline Forearm rotates medially so palm faces posteriorly Radius and ulna cross each other like an X © 2018 Pearson Education, Ltd.  Special Movements Opposition Moving the thumb to touch the tips of other fingers on the same hand © 2018 Pearson Education, Ltd.  Interactions of Skeletal Muscles in the Body Muscles can only pull as they contract—not push In general, groups of muscles that produce opposite actions lie on opposite sides of a joint © 2018 Pearson Education, Ltd.  https://youtu.be/6aLFGenLrsI?si=ae1dsIL45hu8QjYH Interactions of Skeletal Muscles in the Body Prime mover—muscle with the major responsibility for a certain movement opposite to the prime mover >udrsHamsn t Antagonist—muscle that opposes or reverses a nflecia prime mover it has the opposite action ofthe prime mover & Synergist help prime Synergist—muscle that aids a prime mover in a- mover brachioradiation ↑ briachialis movement or reduces undesirable movements & biceps Fixator—specialized synergists that hold a bone still or stabilize the origin of a prime mover ↳ Deltoid muscle ↳ fixes the tendon of the prime mover. E biops © 2018 Pearson Education, Ltd. 1. Which term describes the muscle that has the major responsibility for a 1. Which muscle type is primarily responsible for initiating and executing certain movement? a specific movement in the body? A) Antagonist A) The muscle that maintains joint stability B) Prime mover B) The muscle that performs an opposing action C) Synergist C) The muscle with major responsibility for movement prime mover D) Fixator D) The muscle that assists in fine-tuning movement 2. What is the role of an antagonist muscle? 2. In a movement, which muscle type counteracts the prime mover’s A) It aids the prime mover in a movement. action, ensuring controlled motion? B) It opposes or reverses a prime mover. A) The muscle providing additional force to the prime mover C) It stabilizes the origin of a prime mover. B) The muscle that stabilizes the bone or joint involved D) It is the main muscle responsible for a movement. C) The muscle that produces a reversing effect D) The muscle that leads in movement direction Antagonist 3. Which type of muscle aids the prime mover in a movement or reduces undesirable movements? 3. Which type of muscle acts to reduce unwanted or excess motion in a A) Fixator joint, enhancing the effectiveness of the primary mover? B) Antagonist A) The stabilizing muscle securing the origin of movement B) The muscle that directly initiates movement C) Synergist synergist D) Prime mover C) The muscle that assists by neutralizing unhelpful movements 4. What is the function of a fixator muscle? D) The muscle responsible for opposing the main movement A) It assists the prime mover in performing a movement. 4. When a movement requires the stabilization of a bone or joint to allow efficient action by the prime mover, which muscle type is most B) It opposes the prime mover. involved? C) It stabilizes the origin of a prime mover or holds a bone still. A) The muscle primarily responsible for producing movement D) It has the major responsibility for a movement. B) The muscle that provides resistance to the prime mover C) The muscle that acts as a helper by preventing unwanted motions D) The specialized muscle that anchors the origin of the prime mover fixator  Chapter 6: The Muscular System 227 (a) A muscle that crosses on the anterior side of a joint produces exion xample Pectoralis major (anterior view) 6 (b) A muscle that crosses on the posterior side of a joint produces extension xample atissimus dorsi (posterior view) The latissimus dorsi is the antagonist of the pectoralis major. (c) A muscle that crosses on the lateral side of a joint produces abduction xample eltoid middle bers (anterolateral view) (d) A muscle that crosses on the medial side of a joint produces adduction xample Teres major (posterolateral view) The teres major is the antagonist of the deltoid. These generalities do not apply to the knee and ankle because the lower limb is rotated during development. The muscles that cross these oints posteriorly produce flexion, and those that cross anteriorly produce extension Figure 6.14 Muscle action. The action of a muscle can be inferred Play A&P Flix Animation by the muscle’s position as it crosses a joint.  Skeletal muscles Naming : ~ Way/ By: Example Image Ex Rectus > Straight - 1. Direction of oblique > - angled musche fiber Transverse- Horizontal circular - orbiqularus 2. Size of the Big Major = = Maximus musche Small Minor = = Minimus 3 Location. of Temporali Temporal= Gone the muscle region of Pectoralis-Ant chest number. 4 Triceps-three heads of origins Sterm= on Sternum. Location 5 of the Sternocidomastoid muscles origin Insertion muscle 6. shape of Deltoid-delta = X the muscle 17 Trapezius Triangle = = quadrature quadrangular ) = = 7. Action the muscle of Flexor-causes flexion Extensor- Causer extension Pronator- Causer pronation  way of naming The muscle Naming Skeletal Muscles Muscles are named on the basis of several criteria Straight Rectus - > Arrangement Angled oblique > - By direction of muscle fibers Transverse -> Horizontal /I O III , orbiqularus E circular- Example: rectus (straight) > orbiqularns , , muschs , eye = Loading… because its circular By relative size of the muscle Example: maximus (largest) Maximus Big Major = = Minimus Small= Minor= © 2018 Pearson Education, Ltd.  Naming Skeletal Muscles Muscles are named on the basis of several criteria (continued) Ant of the chest pectoratio region = By location of the muscle Example: temporalis (temporal bone) ↳ By number of origins Example: triceps (three heads) © 2018 Pearson Education, Ltd.  Naming Skeletal Muscles Muscles are named on the basis of several criteria (continued) By location of the muscle’s origin and insertion "Sterncledsmastoid" muscle Example: sterno (on the sternum) By shape of the muscle · Delta, quadrangular = Example: deltoid (triangular) ↳ muscle quadrature = By action of the muscle & causes flexion causer extension Example: flexor and extensor (flexes or extends a bone) pronator pronation = Abductor Abduction = © 2018 Pearson Education, Ltd.