2 Ch. 10 Muscular system-- Study Guide Critically read Chapter 10 pp Also read Tables 10.4 and 10.5 (pp )Comprehend Terminology (those in bold in the textbook) within the reading scope aboveStudy-- Figure questions, Think About It questions, and Before You Go On (section-ending) questions (within the reading scope above) . Before You Go On Questions 1-6 (on p. 325) and Questions (on p. 349).Do end-of-chapter questions—Testing Your Recall— 2, 11-13, 17-20True or False– 110-222
3 I. Introduction & connective tissues of a muscle
4 § Introduction of Muscles 600 Human skeletal musclesThe study of muscles– M___________
5 § The Functions of Muscles Movement of body parts and body contents– ExamplesMaintain posture and prevent unwanted movement— resist the gravity etc.Communication –Control of openings and passageways– Examples-- eyelids, __________________Heat production– 85% of our body heat is from skeletal muscle contraction
6 § Connective Tissues of a Muscle 5. Tendon4. Deep fascia3. Epimysium2. PerimysiumMuscle fascicle1. EndomysiumMuscle fiber
7 Connective Tissues of a Muscle Endomysiumthin areolar tissue around each muscle fiberallows room for ____________________Perimysiumslightly thicker layer of connective tissuesurrounds bundle of cells called a fascicleEpimysiumcovers whole muscle bellyblends into CT sheets called fascia (next slide)
8 Location of Fascia Deep Fascia Femur Skin Deep fascia found between adjacent muscles; no fatSuperficial fascia (adipose tissue; hypodermis)between skin and musclesSuperficial FasciaDeep FasciaFemurSkin
9 § Ways of Muscle Attachments To bone directly--epimysium is continuous with periosteum of a boneEx.– intercostal musclesTo bone indirectly--epimysium continues as tendon that merges into periosteumEx.-- many including biceps brachii to scapulaTo fascia or tendon of another muscle--To collagen fibers (dermis)--Ex.--muscles for facial expressionTo a broad sheetlike tendon, aponeurosis--Ex.--certain abdominal muscles (Fig )
15 Skeletal Muscle types —based on fascicle direction-2 Fusiform musclesFeatures:biceps brachii m., gastrocnemius of the calfParallel muscles; long, uniform width, having parallel fasciclesrectus abdominis m., sartorius of the thigh, zygomaticus majorConvergent muscle; fan-shaped, broad at origin and tapering to a narrower insertionpectoralis major of the chestFig
17 Skeletal Muscle type—based on fascicle direction-3 Pennate muscles (feather-shaped)fascicles insert obliquely on a tendon, like the shaft of the featherUnipennate—fascicles approach the tendon from one side; palmar interosseus (hand) (Fig.)Bipennate—fascicles approach the tendon from both sides; rectus femoris (thigh) (Fig.)Multipennate--like feathers with their quills on a single point; deltoid (shoulder) (Fig.)Circular muscles (sphincters)Features:orbicularis oculi (eyelids), orbicularis oris, urethral and anal sphincters10-17
21 III. Action of muscle groups and muscle innervation
22 § 4 categories of muscles based on actions Action— movement produced by a musclePrime mover or agonistproduces . . .Example: in flexing the elbow, the prime mover is the brachialisSynergist aids the prime moverMay stabilize the nearby jointOr modify the direction of movementExample: works with brachialis, biceps brachii as a synergist to flex the elbow* In some textbooks 1 and 2 are opposite.
23 § 4 categories of muscles based on actions Antagonist is a muscle that . . .opposes the _____________Moderates the speed or range of the agonist; preventing excessive movement and injuryExample: Triceps brachiiFixator is a muscle that . . .prevents _______________Elbow flexion– the rhomboids holds the scapula in place (Fig )10-23
25 In-class activity Question--Muscle Actions during Elbow Flexion ID which specific muscle of the upper arm is responsible for the above action. (based on the text)Prime mover (agonist) = ?Synergist = ?Antagonist = ?Fixator = ?
26 § Skeletal Muscle Innervation Cranial nerves arising from the brainexit the skull through foraminanumbered I to XII (Fig )Innervate muscles of the ______________Spinal nerves arising from the spinal cordMuscles elsewhere are supplied by these nervesFrom spinal cord and exit the vertebral column through intervertebral foramina (Fig. 13.1, 8.23b)
31 § How Muscles are Named Terminologia Anatomica system of Latin names developed in 1895updated since thenEnglish names for muscles are slight modifications of the Latin names.Table 10.1 = terms used to name muscles; Examples:Major = large (Criteria: ____); pectoralis majorDeltoid = triangular (Criteria: _____); DeltoidQuadriceps = having 4 heads; quadriceps femoris etc.
32 § Learning Strategy (start with Fig. 10.4a and b) Explore the location, origin, insertion and innervation of 160 skeletal musclesuse tabular information in this chapter.Increase your retentionexamining models and atlasespalpating yourself (atlas B)observe an articulated skeletonsay the names aloud and check your pronunciation
36 § Muscles of Respiration Breathing requires the use of musclesDiaphragm (prime mover of inspiration)external intercostal musclesinternal intercostal musclesContraction of first 2 produces inspirationExpiration-- ??Contraction of last produces-- forced expirationNormal expiration requires little muscular activity
37 1. Muscles of Respiration- Diaphragm Muscular dome between thoracic and abdominal cavitiesMuscle fascicles converge from the margins (Origin) toward a fibrous central tendon (Insertion)Contraction flattens itIncreases/decreases the vertical dimension of the thoraxCentral tendon
38 2. External/internal Intercostals External intercostalsO- inferior margin of rib above; I- superior border of next lower ribextend downward and anteriorly from rib to ribpull ribcage up/down (when contract)Internal intercostalsO- and I- opposite of that in external intercostalsextend upward and anteriorly from rib to ribpull ribcage downward/upward (during forced expiration)
39 3. Breathing-a mechanical step Mechanism of normal quiet inspiration (expiration are opposite)—Diaphragm contracts and move downwardExternal intercostals muscles contract the ribs elevated Chest volume: intra-alveolar pressure: Air flows inward; why?Deeper inspiration, 2 neck muscles are involved
40 Inspiration Contraction of external intercostal muscles Contraction Elevation of ribs & sternumIncrease side-to-side and front-to-backdimensions of thoracic cavity (X & Y axes)Externalintercostalmuscles(relaxed)Contractionof externalintercostalmusclesElevatedrib cageSternumContractionof diaphragmDiaphragm(relaxed)vertical (Z axis)dimension increases in thoracic cavityBefore inspirationInspirationContractions of external intercostalmuscles causes elevation of ribs,which increases side-to-sidedimension of thoracic cavity
41 Size of thorax on contraction of inspiratory muscles 760Size of thorax oncontraction ofinspiratory musclesSize of lungs as theyare stretched to fillthe expanded thorax759 mm HgDuring inspiration
42 4. Muscles in breathing Muscles of active expiration Accessory inspirationInternalintercostalmuscles1. Sternocleidomastoid2. ScalenusMusclesof activeexpiration1. Externalintercostalmuscles2. DiaphragmAbdominalmusclesMajormuscles ofinspiration
43 Active expiration Contraction of abdominal muscles Passive expiration Relaxationof externalintercostalmusclesContractionof internalintercostalmusclesContraction of internal intercostalmuscles flattens ribs andsternum, further reducingside-to-side and front-to-backdimensions of thoracic cavityContractionof abdominal musclesPosition of relaxedabdominal musclesRelaxation ofdiaphragmContractions of abdominalmuscles cause diaphragm tobe pushed upward, furtherreducing vertical dimensionof thoracic cavityPassive expirationReturn of diaphragm, ribs, and sternumto resting position on relaxation ofinspiratory muscles restores thoraciccavity to preinspiratory sizeActive expiration
44 § Muscles of the Abdomen 4 Pairs of sheetlike musclesexternal oblique (most superficial)internal obliquetransverse abdominal(the first three: from superficial to deep)rectus abdominalFunctionssupport the viscerastabilize the vertebral columnhelp in respiration, urination, defecation and childbirth
45 Aponeuroses (broad fibrous sheet-like tendons)– tendons of the oblique and transverse muscles Rectus abdominis-- wrapped by rectus sheathLinea alba (“white line”)– at the median line where aponeuroses meet
46 External Oblique & Rectus Abdominal vertical, straplike from pubis (O) to xiphoid process (I)3 tendinous intersectionsrectus sheath encloses rectus abdominalThey meet at the median line called linea albaExternal abdoominal obliqueSuperficial (O-Ribs 5-12; to I-pelvis and linea alba)Fibers downward and anteriorlyThe aponeurosis of external oblique forms inguinal ligamentExternal obliqueRectus abdominis
47 Internal oblique & transverse abdominis Fibers pass upward and anteriorlyPerpendicular to those of external obliqueTransverse abdominalHorizontal fiber orientationDeepest layerTransverse abdominisInternal oblique
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