the muscular system. muscles are responsible for all types of body movement because ……….! they...
TRANSCRIPT
![Page 1: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/1.jpg)
The Muscular System
![Page 2: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/2.jpg)
The Muscular System
• Muscles are responsible for all types of body movement BECAUSE ……….!• They contract – get shorter• Three basic muscle types are found in
the body• Skeletal muscle• Cardiac muscle• Smooth muscle
![Page 3: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/3.jpg)
Characteristics of Muscles
• Skeletal and smooth muscle cells are elongated and therefore are called • FIBERS
• Contraction of muscles is due to the movement of • MICROFILAMENTS
• All muscles share some terminology• Prefixes myo and mys refer to “muscle”• Prefix sarco refers to “flesh”• Muscle fibers have sarcoplasm
![Page 4: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/4.jpg)
Comparison of Skeletal, Cardiac, and Smooth Muscles
![Page 5: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/5.jpg)
Comparison of Skeletal, Cardiac, and Smooth Muscles
![Page 6: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/6.jpg)
Important Characteristics to Remember
• Skeletal
• Skeletal, striated, voluntary
• Cardiac
• Heart, striated, involuntary
• Smooth
• Visceral, non-striated, involuntary
![Page 7: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/7.jpg)
Muscle Functions
• Produce movement
• Skeletal – move body• Cardiac – pump (move blood)• Smooth – forcing various fluids to
move along –urine, blood, food.
![Page 8: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/8.jpg)
Other Skeletal Muscle Functions
• Maintain posture• Function continuously to maintain sitting or
standing posture despite the pull of gravity
• Stabilize joints• Reinforces joints that have poorly fitting
articulating surfaces
• Generate heat• As ATP is used to power muscle movements ¾
of its energy is lost as heat.
![Page 9: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/9.jpg)
Connective Tissue Wrappings of Skeletal Muscle
• Cells are surrounded and bundled by connective tissue which keeps them from ripping apart
• Endomysium (delicate)—encloses a single muscle fiber• Perimysium (coarse and fibrous)—wraps
around a fascicle (bundle) of muscle fibers• Epimysium (very tough)—covers the entire
skeletal muscle• Fascia—on the outside of the epimysium
![Page 10: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/10.jpg)
Skeletal Muscle Attachments
• Epimysium blends into a connective tissue attachment• Tendons—cord-like structures • Mostly collagen fibers• Often cross a joint due to toughness and small size
• Aponeuroses—sheet-like structures• Attach muscles indirectly to bones, cartilages, or
connective tissue coverings
![Page 11: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/11.jpg)
Skeletal Muscle Attachments• Sites of muscle attachment• Bones• Cartilages• Connective tissue coverings
![Page 12: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/12.jpg)
Connective Tissue Wrappings of Skeletal Muscle
![Page 13: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/13.jpg)
![Page 14: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/14.jpg)
Microscopic Anatomy of Skeletal Muscle
• Sarcolemma—specialized plasma membrane• Myofibrils—long organelles inside muscle cell• Sarcoplasmic reticulum—specialized smooth
endoplasmic reticulum that stores calcium ions until they are released during muscle contraction
![Page 15: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/15.jpg)
Microscopic Anatomy of Skeletal Muscle
• Myofibrils are aligned to give distinct bands• I band = light band• Contains only thin filaments
• A band = dark band • Contains the entire length of the thick
filaments
• Sarcomere—contractile unit of a muscle fiber
![Page 16: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/16.jpg)
Microscopic Anatomy of Skeletal Muscle
• Thick filaments = myosin filaments• Composed of the protein myosin• Has ATPase enzymes• Myosin filaments have heads
(extensions, or cross bridges)• Myosin and actin overlap somewhat
• Thin filaments = actin filaments• Composed of the protein actin• Anchored to the Z disc
![Page 17: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/17.jpg)
Microscopic Anatomy of Skeletal Muscle
• At rest, there is a bare zone that lacks actin filaments called the H zone• Sarcoplasmic reticulum (SR) • Stores and releases calcium• Surrounds the myofibril
![Page 18: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/18.jpg)
Microscopic Anatomy of Skeletal Muscle
![Page 19: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/19.jpg)
Microscopic Anatomy of Skeletal Muscle
![Page 20: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/20.jpg)
Stimulation and Contraction of Single Skeletal Muscle Cells• Excitability (also called responsiveness
or irritability)—ability to receive and respond to a stimulus• Contractility—ability to shorten when
an adequate stimulus is received• Extensibility—ability of muscle cells to
be stretched• Elasticity—ability to recoil and resume
resting length after stretching
![Page 21: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/21.jpg)
The Nerve Stimulus and Action Potential
• Skeletal muscles must be stimulated by a motor neuron (nerve cell) to contract• Motor unit—one motor neuron and all the
skeletal muscle cells stimulated by that neuron
![Page 22: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/22.jpg)
The Nerve Stimulus and Action Potential
![Page 23: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/23.jpg)
The Nerve Stimulus and Action Potential
![Page 24: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/24.jpg)
The Nerve Stimulus and Action Potential
• Neuromuscular junction• Association site of axon terminal of the motor
neuron and muscle
![Page 25: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/25.jpg)
The Nerve Stimulus and Action Potential
• Synaptic cleft • Gap between nerve and muscle• Nerve and muscle do not make contact• Area between nerve and muscle is filled
with interstitial fluid
![Page 26: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/26.jpg)
The Nerve Stimulus and Action Potential
![Page 27: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/27.jpg)
Transmission of Nerve Impulse to Muscle
• Neurotransmitter—chemical released by nerve upon arrival of nerve impulse• The neurotransmitter for skeletal muscle is
acetylcholine (ACh)• Acetylcholine attaches to receptors on the
sarcolemma• Sarcolemma becomes permeable to sodium (Na+)• Sodium rushes into the cell generating an action
potential• Once started, muscle contraction cannot be
stopped
![Page 28: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/28.jpg)
Transmission of Nerve Impulse to Muscle
![Page 29: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/29.jpg)
Transmission of Nerve Impulse to Muscle
![Page 30: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/30.jpg)
The Sliding Filament Theory of Muscle Contraction• Activation by nerve causes myosin
heads (cross bridges) to attach to binding sites on the thin filament• Myosin heads then bind to the next site
of the thin filament and pull them toward the center of the sarcomere• This continued action causes a sliding
of the myosin along the actin• The result is that the muscle is
shortened (contracted)
![Page 31: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/31.jpg)
The Sliding Filament Theory of Muscle Contraction
![Page 32: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/32.jpg)
The Sliding Filament Theory
![Page 33: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/33.jpg)
The Sliding Filament Theory
![Page 34: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/34.jpg)
The Sliding Filament Theory
![Page 35: The Muscular System. Muscles are responsible for all types of body movement BECAUSE ……….! They contract – get shorter Three basic muscle types are found](https://reader038.vdocuments.mx/reader038/viewer/2022103022/56649ce65503460f949b39bb/html5/thumbnails/35.jpg)
1. Attachment 2. Pulling
3. Detachment4. Reactivation