BGYB30H3 Lecture 16 Notes Muscles 2-Nov 3

24 views2 pages
user avatar
Published on 11 Aug 2010
School
UTSC
Department
Biological Sciences
Course
BIOD27H3
BGYB30H3 Lecture 16 Notes
-skeletal muscles attach to bones by tendons and function by positioning and moving the
skeleton
-somatic motor neurons cause contraction of skeletal muscles
-loouµov[ulZ]}Áv}v]}v vv[u}µoÇZ}u}v
-smooth muscles are muscles of internal organs that influence movement of materials around,
in and out of the body
-primary extrinsic control of smooth muscles originates from autonomic nervous system
-some smooth muscles can contract spontaneously and can be modulated by hormones
-cardiac muscle is only found in the heart and pumps blood around the body
-cardiac muscles can contract and relax spontaneously
-primary extrinsic control of cardiac muscles also arises from the ANS
-cardiac and skeletal muscles have striations only
-muscles have many nuclei and mitochondria
-origin of skeletal muscles is the point connected to the bone that is most stationary and closest
to the trunk
-insertion is the point of the muscle-bone attachment that is most mobile and distant from
the trunk
-flexor muscles bring bones closer together (e.g. biceps)
-extensor muscles bring bones farther apart (e.g. triceps)
-antagonistic muscle groups have opposite effects on one another (e.g. when bicep relaxes,
triceps contract)
-most joints have one flexor and one extensor
-collections of muscle cells work together as a unit
-muscle fibres are in groups called fascicles that are connected by connective tissue
-nerve cells and blood vessels are found between fascicles
-muscle cells are long and cylindrical
-muscle fibres are parallel and ensheathed in connective tissue
-muscles are coated by tendons
-muscle cytoplasm is called the sarcoplasm while plasma membrane is called the sarcolemma
-muscle ER is called the sarcoplasmic reticulum
-small fibres in the muscle fibre are myofibrils, which contract due to releasing calcium
-t-tubules are found between terminal cisternae of adjacent myofibrils
-thin and thick filaments compose the myofibril
-t-tubules allow depolarization of sarcolemma to reach interior of muscle fibres
-membrane of t-tubule is continuous with sarcolemma
-lumen of t-tubule is continuous with EC fluid
-terminal cisternae store calcium
-cytosol between myofibrils contains glycogen and mitochondria
-muscles have contractile protein and elastic fibres
-one muscle fibre contains >1000 myofibrils
-myofibrils contain six proteins in which two are contractile, two are regulatory and two are
accessory
www.notesolution.com
Unlock document

This preview shows half of the first page of the document.
Unlock all 2 pages and 3 million more documents.

Already have an account? Log in

Document Summary

Skeletal muscles attach to bones by tendons and function by positioning and moving the skeleton. Somatic motor neurons cause contraction of skeletal muscles. Smooth muscles are muscles of internal organs that influence movement of materials around, in and out of the body. Primary extrinsic control of smooth muscles originates from autonomic nervous system. Some smooth muscles can contract spontaneously and can be modulated by hormones. Cardiac muscle is only found in the heart and pumps blood around the body. Primary extrinsic control of cardiac muscles also arises from the ans. Origin of skeletal muscles is the point connected to the bone that is most stationary and closest to the trunk. Insertion is the point of the muscle-bone attachment that is most mobile and distant from the trunk. Flexor muscles bring bones closer together (e. g. biceps) Extensor muscles bring bones farther apart (e. g. triceps) Antagonistic muscle groups have opposite effects on one another (e. g. when bicep relaxes, triceps contract)