Term
| Organization of Skeletal Muscle |
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Definition
Epimysium: outer covering of muscle; separates muscle from neighbor muscles
Perimysium: covers fascicles (groups of muscle fibers) within each skeletal muscle
Endomysium: CT layer that covers fiber or individual muscle cell |
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Term
| Blood Supply & Nerve Supply |
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Definition
| Neurovascular bundle- contains the blood vessels and nerve to a muscle; muscle is dependent on its innervation (nerve that supplies each muscle); one nerve can serve multiple muscles |
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Term
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Definition
Must have 2+ attachment points; needs to be connected to bone; 3 CT layers can form:
- 1) Tendons
- 2) Aponeurosis
- 3) Fleshy attachments
- 4)Dermal attachments
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Term
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Definition
| extension of CT sheaths forming cord-like attachment to a bone (periosteum); normally marked by tubercle |
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Term
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Definition
| Broad sheath of CT for attachment of muscle; forms a line on skeletal structure to which it is attached; may also attach to dermis |
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Term
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Definition
| Muscle fibers continue almost to bone (very little CT); skeleton usually smooth and forces are widely distributed along attachment size rather than on one location of bone |
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Term
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Definition
| Muscle fibers attach to CT of dermis; moves skin on face rather than skeleton |
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Term
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Definition
- gives shape to muscles;
- fascicle determines strength and direction to which a muscle pulls;
- the bigger the cross section, the greater the strength;
- the longer/more parallel a muscle is, the more it can shorten (but have the smallest cross section);
- muscle power depends more on total number of muscle cells in muscle;
- force generated by muscle is proportional to its cross section
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Term
| Parallel fascicle arrangement |
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Definition
| long strap-like muscle of uniform width and parallel fascicles; small cross section (weakest muscle); can stretch and shorten more than other muscles |
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Term
| Pennate fascicle arrangement |
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Definition
| Feather shaped; Fascicles insert obliquely on tendon; can be unipennate (all fascicles attach to one side), bipennate (2 sides), or multipennate (bunch of muscles converging on single point,ex: deltoid) |
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Term
| Convergent fascicle arrangement |
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Definition
| Fan shaped; broad origin and narrow insertion; all fascicles exert tension on relatively small insertion point making for a strong muscle (ex: pectoralis major) |
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Term
| Circular fascicle arrangement |
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Definition
| sphincters forming rings around body openings (ex: muscle around eyes) |
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Term
| Fusiform fascicle arrangement |
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Definition
| thick in middle and taper on both ends, forming a belly in middle; contractions are mildly strong (ex: biceps brachhi) |
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Term
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Definition
Origins: proximal attachments with tendons that are usually longer and attach to stable/less movable part
Insertions: distal attachments with shorter tendons that attach to more movable part (joint)
When muscle contracts, brings movable part (insertion) closer to origin |
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Term
| Components of Lever Systems |
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Definition
Lever: elongated rigid object that rotates around a fixed point (ex: bone)
Fulcrum: fixed point around which levers rotate or the axis (ex: joints)
Force/Effort: Effort applied at one end of lever to overcome a load (ex: muscles)
Load: the weight or resistance at some point on the lever that will be overcome by the force (ex: gravity or weights) |
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Term
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Definition
First Class: Load-Fulcrum-Effort like a sea saw, ex: atlooccipital joint
2nd Class: Fulcrum-Load-Effort like wheelbarrow, ex: metatarsalphalangeal joint/lifting weight up on toes
3rd Class: Load-Effort-Fulcrum like flexing forearm; most common in body; designed to increase speed and range of motion at distal end of lever |
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Term
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Definition
| Most effective in causing movement of joint |
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Term
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Definition
| Opposite of agonists; produces joint action opposite to joint of another muscle (flexion & extension) |
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Term
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Definition
| Helps prime movers and reduces undesirable movements that may occur when adding force (only flexing one muscle/preventing another) |
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Term
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Definition
| Stabilizers; anchors, steadies or supports a bone or body part so that an active muscle has a firm base on which to pull |
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Term
| Control System of Muscle Contraction (REWATCH) |
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Definition
1) Brain and Spinal Cord (CNS): sends messages through tracts that will synapse on motor cells on brain stem
2) Spinal and Cranial Nerves (PNS): message leaves brain stem to innervate muscles of head & neck (through cranial nerves) and innervates muscles of body (through spinal nerves)
3) Sensory feedback to brain: carried in peripheral and cranial nerves; info sent back to brain by golgi tendon organs and muscle spindles |
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Term
| Efferent vs. Afferent Information |
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Definition
Efferent info ESCAPES from brain (motor info) and travels via pyramidal tract to alpha motor neurons to skeletal muscle
Afferent info ARRIVES to brain and travels via sensory tract
Both work together to provide coordinated muscle contraction |
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