📖 Anatomy
FACIAL MUSCLES SPECIFIC IN EMOTIONAL EXPRESSION
Anatomy|
Muscle
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Emotion
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Epicranius
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Surprise
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Orbicularisoculi
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Squinting
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Orbicularisoris |
Pouting |
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Nasalis
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Smelling
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Zygomaticus
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Smiling
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Buccinator
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Chewing
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Mentalis
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Doubt
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Triangularis
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Sadness
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Platysma
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Sadness
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Masseter
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Chewing
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Temporalis
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Sternness
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Pterygoid
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Conternation
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Genioglossus and Styloglossus
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Swallowing, Speaking, Chewing
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The Muscles of Facial Expression
AnatomyThe Muscles of Facial Expression
- These lie in the subcutaneous tissue and are attached to the skin of the face.
- They enable us to move our skin and change our facial expression. They produce their effects by pulling on the skin but do not move the facial skeleton.
- These muscles surround the facial orifices and act as sphincters and dilators.
- All facial muscles receive their innervation from the branches of the facial nerve (CN VII)-temporal, zygomatic, buccal, marginal mandibular, cervical.
Cardiac Muscle
AnatomyCardiac Muscle
Fibres anastomose through cross bridges
Fibres are short, connected end to end at intercalated discs, also striated, contract automatically
Light microscopic Structure:
Short fibres connected at intercalated disks, 85 - 100 µm long, 15 µm
same bands as in skeletal muscle, 1 or 2 nuclei - oval and central, in perinuclear area is a sarcoplasmic reticulum, intercalated discs lie at the Z line
Electron microscopic structure:
Between myofibrils lie the mitochondria, 2,5 µm long mitochondria, dense cristae
and are as long as the sarcomere, fibres have more glycogen than skeletal muscle fibres
myofilaments, actin and myosin are the same as in skeletal muscle, the sarcoplasmic reticulum differs in that there is no terminal sisterna. The sarcotubules end in little feet that
sit on the T-tubule
Intercalated Disc:
on Z lines, fibres interdigitate,
3 types of junctions in the disc
Transverse Part:
zonula adherens
desmosomes
Lateral Part:
Gap junctions (nexus) - for impulse transfer
Mechanism of Contraction:
slide - ratchet like in skeletal muscle, certain fibres are modified for conduction, Impulses spread from cell to cell through gap junctions, Purkinje cells are found in the AV bundle
they have less myofibrils, lots of glycogen and intercalated discs
Connective tissue coverings:
Only endomycium in cardiac muscle, Blood vessels, lymph vessels and nerves lie in the endomycium
Muscles of the larynx -Extrinsic muscles
AnatomyMuscles of the larynx
Extrinsic muscles
suprahyoid: raise larynx, depress mandible for swallowing
infrahyoid: lower larynx for swallowing
both stabilize hyoid for tongue movements