EEH103 Lecture Notes - Lecture 8: Muscular System, Myocyte, Skeletal Muscle
WEEK 8 NOTES:
MUSCULAR SYSTEM:
- Nervous and muscular systems work together to help us function daily
- Muscular system receives messages from the nervous system, giving it information about
when to perform an action and how to perform it.
- Without the nervous system, the muscular system wouldn’t be able to function
3 types of muscle tissues:
SKELETAL MUSCLE:
Produces movement by acting on the skeleton
oFUNCTIONS:
-MOVEMENT:
Skeletal muscles not only produce movement but also to stop movement
-OPENING OF INTERNAL TRACTS:
Control the movement of various substances
Allow functions, such as swallowing, urination and defecation, to be under voluntary
control
-PROTECTION:
Protect internal organs by acting as an external barrier to external trauma and by
supporting the weight of the organs
-HOMEOSTASIS:
Contribute to the maintenance of homeostasis in the body by generating heat.
oTISSUE:
- Each skeletal muscle is an organ that consists of various integrated tissues including:
The skeletal muscle fibres (muscle cell)
Blood vessels
Nerve fibres
Connective tissue
- Without the innervation of nerve fibres the muscle fibre can not contact
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- TISSUE LEVELS:
- A skeletal muscle fibre (cell) is surrounded by a plasma membrane called the sarcolemma,
which contains sarcoplasm, the cytoplasm of muscle cells.
- Muscle fibre is composed of many fibrils, which give the cell its striated appearance
- The sarcomere is the functional unit f the muscle fibre
oTHE SARCOMERE:
- The striated appearance of skeletal muscle fibres is due to the arrangement of the
myofilaments of actin (thin) and myosin (thick) in sequential order from one end of the
muscle fibre to the other
- Each packet of actin and myosin and their regulatory proteins, troponin and tropomyosin
along with other
proteins is called
a sarcomere.
-The
neuromuscular
junction (NMJ) is
the site where a
motor neurons
terminal meets
the muscle fibre.
This is where the
muscle fibre first
responds to
signalling by the
motor neuron.
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oCONTRACTION:
- A skeletal muscle must:
be stimulated by a nerve ending
propagate an electrical current, or action potential, along its sarcolemma
have a rise in intercellular levels, the final trigger for contraction
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find more resources at oneclass.com
Document Summary
Nervous and muscular systems work together to help us function daily. Muscular system receives messages from the nervous system, giving it information about when to perform an action and how to perform it. Without the nervous system, the muscular system wouldn"t be able to function. Produces movement by acting on the skeleton: functions: Skeletal muscles not only produce movement but also to stop movement. Allow functions, such as swallowing, urination and defecation, to be under voluntary control. Protect internal organs by acting as an external barrier to external trauma and by supporting the weight of the organs. Contribute to the maintenance of homeostasis in the body by generating heat: tissue: Each skeletal muscle is an organ that consists of various integrated tissues including: Without the innervation of nerve fibres the muscle fibre can not contact. A skeletal muscle fibre (cell) is surrounded by a plasma membrane called the sarcolemma, which contains sarcoplasm, the cytoplasm of muscle cells.
