Unit 4 Part 2 -- Muscles
"The Governator!"
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Anatomy and Physiology of Muscles
- Location and Action of muscles in the human body
- Location, origin, insertion and function of major muscles in the cat
- Smiling Vs. Frowning
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When you smile, you use around 17 muscles.
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When you frown, you use around 40 muscles.
I. Skeletal Muscle Groups
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Head
- Frontalis – Raises eyebrows and skin of forehead.
- Orbicularis oris – Puckers lips. "Kissing muscle"
- Orbicularis oculi – Closes eye. "Winking muscle"
- Zygomaticus – Elevates corners of mouth. "Smiling muscle"
- Depressor anguli oris – Lowers corner of lips (muscle for frowning)
- Levator Labii – raises lips
- Depressor Labii – Lowers lip
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Muscles of Mastication (Chewing)
- Temporalis – Elevates mandible.
- Masseter – Closes jaw.
- Mentalis – Raises Chin
- Neck
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Sternocleidomastoid – Behind ears to neck.
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Together they flex head on chest
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Separately it tilts the head to the side.
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Chest
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Pectoralis major
- Located on chest.
- Flexor of upper arm.
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Pectoralis minor
- Small triangular muscle located deep (beneath) the Pectoralis Major
- Downward rotation and stabilization of the scapula.
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Pectoralis major
- Back Muscles
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Trapezius – Back of head to neck.
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Elevates shoulders and extends head
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"Shrugging and Gargling muscle"
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- Latissimus dorsi
- Located on lower back.
- Extensor of upper arm.
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Shoulder
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Deltoid – Located on shoulder.
- Abductor of upper arm.
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Deltoid – Located on shoulder.
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Upper Arm
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Biceps brachii
- Flexor of lower arm.
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Triceps brachii
- Extensor of lower arm.
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Biceps brachii
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Lower Arm
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Wrist Flexors
- Flex wrist
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Wrist Extensors
- Extend wrist
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Wrist Flexors
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Trunk
- External oblique – Outermost layer of abdominal wall.
- Internal oblique – Middle layer.
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Transversus abdominus – Innermost layer.
- Together the three abdominal wall muscles are antagonists to the diaphragm and assist in defecation, urination, vomiting, and childbirth.
- Rectus abdominus – Middle of abdomen and flexes the trunk.
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Respiratory Muscles
- Intercostals – Between the ribs (Internal for exhaling/expiration and external for inhaling/inspiration)
- Diaphragm – Between thorax and abdomen
- Thigh
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Iliopsoas – Flexor of thigh and trunk (if thigh is still)
- Postural muscle of trunk (Keeps trunk from falling backwards).
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Gluteus maximus – Buttocks
- Extensor of thighs.
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Adductor muscles / Groin muscles(magnus, brevis, and longus)
- Adduct thighs.
Magnus Brevis Longus All 3 Together
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Hamstrings – Semimembranosus, Semitendinosus, and Biceps femoris.
- Flexes lower leg (calf to thigh)
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Quadriceps femoris – Rectus femoris and Vastus muscles (lateralis, medialis, and intermedialis)
- Extend lower leg.
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Sartorius – Longest muscle in body.
- Flexes calf on thigh and thigh on pelvis and rotates leg.
- Lower Leg
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Tibialis anterior – Shin muscle
- Dorsiflexes foot
- Responsible for shinsplints
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Gastrocnemius – Calf
- Plantar flexes and inverts the foot
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Peroneus (fibula) Group – longus, tertius,brevis
- Plantar flexion and eversion of foot.