Term
| Where do muscles develop from? |
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Definition
mesoderm:
-myotomes originate from somites, and somitomeres are the first seven myotomes of the head; small
-splanchnic mesoderm |
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Term
| How are muscles organized? |
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Definition
into 4 groups:
musculature of visceral organs
pharyngeal arch muscles
axial muscles
limb muscles |
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Term
| What does the musculature of the visceral organs include? Where does it develop from? |
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Definition
| smooth cardiac muscle; develops from the splanchnic mesoderm |
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Term
| What does the pharyngeal arch muscles include/what does it develop from? |
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Definition
skeletal muscles of pharynx, muscles of the head and neck.
Develops from the fourth thru seventh somitomeres |
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Term
| examples of pharyngeal arch muscles? |
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Definition
pharynx-throat
larynx- voice box
chewing muscles
muscles of facial expression
trapezius |
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Term
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Definition
| lie anterior and posterior to the body axis |
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Term
| what are axial muscles include? |
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Definition
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Term
| Function of axial muscles? |
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Definition
| move the trunk and maintain posture |
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Term
| Explain the development of axial muscles |
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Definition
| myotomes in trunk area split into a dorsal and a ventral mass. (epaxial mass=epimere) and (hypaxial mass= hypomere) Each epimere and hypomere divede into medial and lateral parts |
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Term
| WHAT do the epaxial (epimere) regions of myotomes develop? What are the parts? |
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Definition
deep muscles of the back
-medial part: muscles that move and stabilize vertebrae
-lateral part: erector spinae muscles- extend spine |
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Term
| what do the hypaxial (hypomere) regions of myotomes develop? What are the parts? |
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Definition
Muscles of the trunk and neck
-medial part include psoas major (flex spine) and quadratus lumorum (tilt spine to one side)
-Lateral part: includes respiratory muscles (intercostal muscles) Anterior abdominal wall muscles (internal/external obliques and transveres abdominus) muscles of the pelvic floor |
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Term
| What do limb muscles arise from? |
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Definition
| lateral parts of hypomeres of nerby myotomes (mesenchyme cells into limb buds) |
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Term
| Muscle mass develops where (into what) for limb muscles? |
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Definition
| Both dorsal(extensors) and ventral(flexors) to skeleton of limbs? |
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Term
| What are three types of muscle? |
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Definition
| skeletal, cardiac, smooth |
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Term
| Skeletal muscle tissue is packaged into- and is % of body weight |
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Definition
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Term
| Where is cardiac muscle tissue? |
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Definition
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Term
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Definition
| occupies the walls of hollow organs |
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Term
| What are the functions of muscle tissue? |
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Definition
| movement, maintainance of posture, joint stabilization, heat generation |
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Term
| How is movement a function of skeletal muscle? |
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Definition
skeletal muscle is attached to skeleton and moves body by moving bones.
smooth muscle squeezes fluids and other substances through hollow organs |
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Term
| How does muscle tissue maintain posture? |
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Definition
| enables the body to remain sitting or standing |
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Term
| How does skeleton muscle generate heat? |
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Definition
| muscle contraction produce heat, healps maintain normal body temperature |
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Term
| What are functional features of muscle tissue? |
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Definition
| contractility, excitability, extensibility, elasticity |
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Term
| How is contractility a functional feature of muscle tissue? |
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Definition
| long cells shorten and generate pulling force |
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Term
| How is excitability a functional feature of muscle tissue? |
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Definition
| electrical nerve impulse stimulates the muscle cell to contract |
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Term
| How is Extensibility a functional feature of muscle tissue? |
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Definition
| can be stretched back to its original length by contraction of an opposing muscle |
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Term
| How is elasticity a functional feature of muscle tissue? |
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Definition
| can recoil after being stretched |
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Term
| Is each skeletal muscle an organ? |
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Definition
| Yes, even though it is mostly muscle tissue, it also contains connective tissue, blood vessels, and nerves |
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Term
| How are skeletal muscle cells arranged? |
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Definition
| into fascicles, groups of muscle cells |
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Term
| What binds skeletal muscles and its fibers together? What are they continuous with> |
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Definition
| connective tissue sheaths continuous with tendons |
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Term
| What are 3 connective tissue sheaths of skeletal muscle? |
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Definition
epimysium
perimysium
endomysium |
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Term
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Definition
| dense regular connective tissue surrounding entire muscle |
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Term
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Definition
| surrounds each fascicle (group of muscle fibers) |
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Term
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Definition
| a fine sheath of connective tissue wrapping each muscle cell. |
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Term
| What are features of muscle attachments? |
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Definition
most skeletal muscles run from one bone to another.
One bone will move--other bone remains fixed.
Origins and insertions |
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Term
| What are origins and insertions? |
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Definition
origin- less movable attachment
insertion- more movable attachment |
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Term
| How do muscles attatch to origins and insertions? What is an indirect attachment? |
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Definition
connective tissue.
Indirect- connective tissue forms a tendon or aponeurosis |
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Term
| What do bone markings present? What are bone markings? |
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Definition
| where tendons meet bones: tubercles, trochanters, and crests. |
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