Movement of thigh and Leg
- Grouped according to anterior, medial, or posterior
- Most anterior muscles flex femur at hip, extend leg at knee
- Most posterior muscles extend thigh, flex leg
- Medial muscles all adduct thigh
- All three groups enclosed by fascia late
- Include flexion, extension, abduction, adduction, circumduction, and rotation
- Thigh flexor pass in front of hip joint
- liposoas: primary mover of flexion
- Tensor fasciae latae
- Rectus femoris
- Assisted by medial adductors and sartorial
Thigh extensor
- Hamstring muscles: prime movement of extension
- Quadricep femoris arise from four separate heads that form the flesh of front and side of thigh
- All insert into the quadricep tendon which then inserts into the patella, ad then via patellar ligament, into the livid tuberosity
- powerful knee extensor |
Smooth Muscle
Smooth Muscle Tissue: Found in walls of hollow organs |
not striated |
Involuntary: cannot be controlled consciously |
4 Main characteristics of Muscle Tissue
Excitability |
Contractility |
Extensibility |
Elasticity |
Ability to receive and respond to stimuli |
Ability to shorten forcibly when stimulated |
Ability to be stretched |
Ability to recoil to resting length |
Compression of abdominal viscera
Four paired muscles
- Rectus abdominis
- external obliques
- internal obliques
- transverse abdominis |
Head Movement and Trunk Extension
Anterolateral neck muscles |
Intrinsic Muscles of the back |
Move head |
extend trunk and maintain posture |
Myofibrils
Myofibrils |
myofibril features |
densely packed, rodlike elements |
Striation |
80% of muscle cell volume |
sarcomas |
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Myofilaments |
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molecular composition of muofilaments |
Sliding filament Model of Contraction
Contraction |
Sliding filament model of contraction |
the activation of cross bridges to generate force |
During contraction, thin filaments slid past thick filaments, causing actin and myosin to overlap more |
shortening occurs when tension generated by cross bridges on thin filaments exceed forces opposing shortening |
When nervous system stimulates muscle fiber, myosin heads are allowed to bind to action forming cross bridges |
contraction ends when bridge become inactive |
Mastication ad tongue movement
Muscle of mastication |
four pairs all innervated by cranial nerve V |
prime mover of jaw closure: tempralis and master |
grinding movement; pterygoids |
chewing role: buccinator |
Fascicle Arrangements (cont.)
pennate |
different forms |
short fascicles attach obliquely to central tendon running length of muscle |
Unipennate: fascicles attach only to one side of tendon |
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Bipennte: fascicles insert from opposite sides of tendon (rectus femurs) |
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Multipennate: appears as feathers inserting into one tendon (example deltoid) |
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Movement of Ankels and Toes
- Muscles of anterior compartment
- primary toe extensors and ankle dorslifexors
- Tibialis anterior
- Extensor digitorum longus
- Fibuaris tertius
- Extensor hallucis longus
Muscles of the lateral compartment of the leg
- Plantar flexion and eversion of the foot; stabile lateral ankle and lateral longitudinal arch of foot
- Fibularis longus
- Fibularis brevis
Muscles of the posterior compartment f the leg
- act to plantar flex the ankle
- All are innervated by tibial nerve
- Divided into Superficial muscles and deep muscles |
Humerus Movement
- nine Muscles cross shoulder ring
- Insert on and move humerus
- Some originate from scapula, other from axial skeletion
-action include flexion, extension, adduction
- Three prime movers of arm
1) pectorals major
2) latissimus dorsi
3) Deltoid
- Rotator cuff muscles act as synergist and fixators;originate on scapulae reinforce shoulder capsule; prevent dislocation
1) supraspinatus
2) infraspinatus
3) teres minor
4) subscapularis |
Swallowing Muscles
Sternocleidomastodi muscle divides neck into two triangles
- Anterior muscles are divided based on location to the hyoid bone: supra hyoid and infra hyoid
- Tongue and buccinator muscles push food back towards pharynx, where muscles in posterior mouth and pharynx complete swallowing process
- Epiglottis closes over larynx while muscles in walls of pharynx propel food forward to stomach
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Facial Expressions
Facial expression muscles are different because they insert into skin not bone |
Facial expression muscles consists of two groups |
Important nonverbal communication |
Muscles of the scalp |
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muscles of the face |
Muscle Action and Interaction
muscle can only pull; never push |
3 main function group |
what one muscle group does the other undoes |
Prime mover: major responsibility for producing specific movement |
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Antagonist: opposes or reverses particular movement |
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Syngerist: Helps prime mover; adds extra force to same movement; reduces undesirable or unnecessary movement; Fixator: type that immobilizes bone or muscle organ rather than enhancing movement of Prime movers |
Myofibrils
Striations |
sarcomere |
myofilaments |
Stripes formed from repeating series of dark and light bands along length of each myofibril |
Smallest contractile unit of muscle fiber |
Actin myofilaments: Thin filament; extend across I band and partway in A band |
A band= dark region |
Contains A band with half of an I band at each end |
myosin Myofilaments: Thick filaments: extend length of A band |
I band= lighter region |
Muscle Fiber Microanatomy
Sarcolemma |
Sarcoplasma |
muscle fiber plasma membrane |
muscle fiber cytoplasm |
Muscle Functions
Produce movement |
Maintain posture and body position |
Stabilize joints |
Generate heat as the contract |
Responsible for all locomotion and manipulation |
Skeletal Muscle
Skeletal muscle tissue |
Skeletal muscle fibers |
packaged into skeletal muscles: organs that are attached to bone and skin |
Longest of all muscle and have striations (stripes) |
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also called voluntary muscle: can be consciously controlled |
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Fascicle Arrangements
All skeletal muscle consists of bundles of fibers |
The most common patterns of arrangement |
Variation results i muscles with different shapes and functional capabilities |
Circular: fascicles arranged in concentric rings |
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Convergent: broad organ; fascicles converged toward single tendon insertion |
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parallel: Fascicles parallel to long axis of traplike muscle (striation) |
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Fusiform: Spindle shaped muscle with parallel fibers (bicep brachia) |
Swallowing Muscles (Cont)
Infrahyoid Muscles |
Suprahyoid Muscles |
- four strap like muscles |
Four deep muscles involved in swallowing |
Depressed hyoid bone and larynx during swallowing and speaking |
1) Form floor or oral cavity 2) Anchor tongue 3) Elevated hyoid bone 4) Move larynx during swallowing |
Breathing
Inhailing |
Expiration |
contraction of the muscles enlarge the rib cage |
Relaxation of muscles decrease size of rib cage |
Diaphram divides thoracic and abdominal cavities |
Skeletal Muscle Anatomy
Nerve and blood Supply |
Connective tissue sheaths |
Attachments |
each muscle receives a nerve, artery, and veins |
Muscles covered in connective tissue |
muscle span joints and attach to bone |
consciously controlled skeletal muscles has nerves supplying every fiber to control activity |
Support cells and reinforces whole muscles |
Muscles attach to bone in two places Insertion: Attachment to movable bone: Orgion: attachment to oimmovable bone |
Contracting muscles fivers require huge amounts of oxygen and nutrients |
Epimysium: Dense irregular connective tissue surrounding entire muscle; may blend with fascia |
Direct Attachment: Epimysium fused to periosteum of bone or perichondrium of cartilage |
need waste products removed quickly |
Perimysium: Fibrous connective tissue surrounding fascicles |
Indirect: Connective tissue wrapping extend beyond muscle as roselike tendon or sheetlike aponeurosis |
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Endomysium: Fine areolar connective tissue surrounding each muscle fiber |
Scapula and arm
- Most are the extrinsic shoulder muscles
- act in combination to fit shoulder girls; Move it to increase range of arm movements
- action: elevation, depression, rotation, lateral and medial movements, protraction and retraction
Two groups of muscle
- Muscle of the anterior thorax
- muscles of the posterior thorax |
Movement of Wrist, Hand, and Fingers
- Divide into anterior and posterior muscles
- Most anterior muscles are flexors
- Most posterior muscles are extensors
- further divided into superficial and deep muscles
- Action: Movement of wrist, finger, thumb, as well as pronation and supination of forearm
- Pronator teres and pronator quadratus pronate forearm
- Supination: synergist with biceps brachia in forearm supination
Anterior Muscles
- Consist of five superficial and three deep muscles
- Most arise from common flexor tendon attached to medial epicondyle of humerus
- Most tendons of insertion held in lace at wrist be flexor retinaculum
Posterior Muscles
- consists of four superficial and four deep muscles
- All are innervated by the radial nerve or its branches
- Most arise from common flexor tendon attached to lateral epicondyle of humerus
- Most tendons of insertion help in lace at wrist by extensor retinaculum |
Cardiac Muscle
Cardiac muscle tissue: is found only in heart |
makes up bulk of heart walls; striated |
involuntary; cannot be controlled consciously |
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