University:
Kentucky State University
Course:
BIO 301 | Human Anatomy
Academic year:

2020
Views:

229

Pages:

23
Author:

Adowj7b

Muscular system, part 2 Skeletal muscle-functions • Movement • Support and maintain posture (constant partial contraction) • Heat production. Divisions • Axial division Axial muscles support and position axial skeleton • Appendicular division Appendicular muscles support, move, and brace the limbs Categorization based on fascicles • Parallel muscles. • Convergent muscles. • Pennate muscles. • Circular muscles (sphincter). Origin, insertion, action Origin • • • • Fixed end of a skeletal muscle attaches. Most are bones Some are connective tissue sheaths or bands Proximal to insertion in anatomical position Insertion • Movable end of a skeletal muscle attaches Action • Specific movement produced by a skeletal muscle Function Muscles usually work together in groups: • Agonist, Synergist, and Antagonist. 1- Agonist or prime mover • Mostly responsible for producing the movement 2- Synergist • Helps larger agonist work efficiently • Provide additional pull • Stabilize origin Fixators • Synergists that assist by preventing movement at another joint 3- Antagonist Action opposes a particular agonist Axial muscles • • • • Arise on axial skeleton 60% of skeletal muscles in body Position head and spinal column Move rib cage; assist in breathing Appendicular muscles • Remaining 40% of all skeletal muscles • Stabilize or move appendicular skeleton Axial muscles Axial muscle groups: Stabilize/ position head, neck, and trunk 1- Muscles of the head and neck: oMuscles of facial expression. oExtrinsic eye muscles. oTongue. oPharynx. oNeck. Axial muscles 2- Muscles of the vertebral column: o Muscles that stabilize, flex, extend, rotate vertebral column o Several layers Axial muscles 3- Oblique and rectus muscles of trunk o Broad sheets/bands forming muscular walls of thoracic and abdominopelvic cavities 4- Muscles of the pelvic floor: o Span the pelvic outlet. o Support organs of the pelvis Axial muscles Muscles of facial expression • Origins—surface of skull (except for platysma in neck) • Insertions—superficial fascia and dermis of skin • Actions—move skin, allowing facial expression Axial muscles Muscles of mastication • Origins—zygomatic arch, temporal lines, lateral pterygoid plate • Insertion—mandibular ramus and coronoid process • Actions—elevating mandible, sliding mandible side to side, protruding mandible, opening jaw (lateral pterygoid) Axial muscles Closely associated muscles: oMuscles of the tongue—involved in speaking and Chewing. oMuscles of the pharynx—role in swallowing oMuscles of the neck—involved in positioning mandible, hyoid, and larynx Appendicular muscles The appendicular muscles stabilize, position, and support the limbs: • • • • • Pectoral girdle muscle Muscles that move the arm/thigh Muscles that move the forearm/leg Extrinsic muscles of the hand and fingers/foot and toes Intrinsic muscles of the hand/foot

Muscular System, Part 2

of 23

Description

Free up your schedule!

Take 5 seconds to unlock