Term
Skeletal muscle
Makes up nearly ___ the body’s mass |
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Definition
Skeletal muscle
Makes up nearly half the body’s mass |
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Term
| Functions of muscle tissue |
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Definition
Functions of muscle tissue
Movement
Smooth muscle – squeezes fluids and other substances through hollow organs
Maintenance of posture –
Joint stabilization
Heat generation – muscle contractions produce heat |
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Term
skeletal
Functional features (4) |
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Definition
Functional features
Contractility – long cells shorten and generate pulling force
Excitability – electrical nerve impulse stimulates the muscle cell to contract
Extensibility – can be stretched back to its original length by contraction of an opposing muscle
Elasticity – can recoil after being stretched |
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Term
Skeletal muscle tissue – packaged into skeletal muscles
Makes up __ of body weight |
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Definition
Skeletal muscle tissue – packaged into skeletal muscles
Makes up 40% of body weight |
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Term
| Cells of skeletal and smooth muscles (not cardiac) are known as ___ because they are highly elongated |
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Definition
| Cells of skeletal and smooth muscles (not cardiac) are known as fibers because they are highly elongated |
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Term
skeletal
Muscle contraction depends on two types of myofilaments: ____ |
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Definition
Muscle contraction depends on two types of myofilaments
Actin
Myosin |
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Term
skeletal
Plasma membrane is called a _____
Cytoplasm is called _____ |
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Definition
Plasma membrane is called a sarcolemma
Cytoplasm is called sarcoplasm |
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Term
skeletal
Each muscle is an organ
Consists mostly of muscle tissue
Skeletal muscle also contains: (3) |
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Definition
Each muscle is an organ
Consists mostly of muscle tissue
Skeletal muscle also contains
Connective tissue
Blood vessels
Nerves |
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Term
Connective tissue sheaths bind a skeletal muscle and its fibers together
___ – dense regular connective tissue surrounding entire muscle
____ – surrounds each fascicle
(group of muscle fibers)
____ – a fine sheath of connective tissue wrapping each muscle cell |
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Definition
Connective tissue sheaths bind a skeletal muscle and its fibers together
Epimysium – dense regular connective tissue surrounding entire muscle
Perimysium – surrounds each fascicle
(group of muscle fibers)
Endomysium – a fine sheath of connective tissue wrapping each muscle cell |
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Term
skeletal
Connective tissue sheaths are ___ with tendons |
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Definition
| Connective tissue sheaths are continuous with tendons |
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Term
Each skeletal muscle supplied by
__ nerve
__ arter
__ veins |
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Definition
Each skeletal muscle supplied by
One nerve
One artery
One or more veins |
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Term
skeletal
Each ___ has a neuromuscular junction |
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Definition
| Each muscle fiber has a neuromuscular junction |
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Term
skeletal
Nerves and vessels ____ repeatedly |
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Definition
| Nerves and vessels branch repeatedly |
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Term
skeletal
Smallest nerve branches serve ____ |
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Definition
| Smallest nerve branches serve individual muscle fibers |
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Term
skeletal
Neuromuscular junction – signals ____ |
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Definition
| Neuromuscular junction – signals the muscle to contract |
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Term
Origin – __ movable attachment
Insertion – ___ movable attachment |
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Definition
Origin – less movable attachment
Insertion – more movable attachment |
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Term
| The insertion _______ the origin |
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Definition
| The insertion is pulled towards the origin |
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Term
| Many muscles span two or more joints - ____ or - ____ muscles |
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Definition
| Many muscles span two or more joints - biarticular or - multijoint muscles |
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Term
| Muscles attach to origins and insertions by ______ |
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Definition
| Muscles attach to origins and insertions by connective tissue |
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Term
skeletal
Fleshy attachments – connective tissue fibers are ____ |
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Definition
| Fleshy attachments – connective tissue fibers are short |
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Term
| Indirect attachments – connective tissue forms cord-like ___ or flat-sheet like ____. |
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Definition
| Indirect attachments – connective tissue forms a tendon or aponeurosis |
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Term
skeletal
Are huge cells – diameter is _____
Length – _________ |
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Definition
Are huge cells – diameter is 10-100µm
Length – several centimeters to dozens of centimeters |
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Term
skeletal
Striations result from internal structure of _____ |
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Definition
| Striations result from internal structure of myofibrils |
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Term
skeletal
Myofibrils – long rods within ______
Make up __% of the cytoplasm
Like a specialized ___ organelle found in muscle tissue
A long row of repeating segments called ____ = functional unit of skeletal muscle |
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Definition
Myofibrils – long rods within cytoplasm
Make up 80% of the cytoplasm
Like a specialized contractile organelle found in muscle tissue
A long row of repeating segments called sarcomeres = functional unit of skeletal muscle |
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Term
skeletal
A muscle cell may contain ____ sarcomeres. The myofibril in smooth muscles are not arranged in sarcomeres. |
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Definition
| A muscle cell may contain 100,000 sarcomeres. The myofibril in smooth muscles are not arranged in sarcomeres. |
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Term
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Definition
| Z disc (Z line) – boundaries of each sarcomere |
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Term
| Thin (___) filaments – extend from Z disc toward the center of the sarcomere |
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Definition
| Thin (actin) filaments – extend from Z disc toward the center of the sarcomere |
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Term
| Thick (______) filaments – located in the center of the sarcomere |
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Definition
| Thick (myosin) filaments – located in the center of the sarcomere |
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Term
Titin – a ____-like molecule in sarcomeres
Resists over____
Holds ___ filaments in place
Unfolds when muscle is _____ |
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Definition
Titin – a spring-like molecule in sarcomeres
Resists overstretching
Holds thick filaments in place
Unfolds when muscle is stretched |
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Term
skeletal
______ – a specialized smooth endoplasmic reticulum
Contains _____ ions – released when muscle is stimulated to contract
Calcium ions diffuse through cytoplasm
Trigger the sliding _______ |
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Definition
Sarcoplasmic reticulum – a specialized smooth endoplasmic reticulum
Contains calcium ions – released when muscle is stimulated to contract
Calcium ions diffuse through cytoplasm
Trigger the sliding filament mechanism |
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Term
skeletal
Muscle contraction
Ultimately controlled by ___-generated impulse
Impulse travels along the ____ of the muscle cell
Impulses further conducted by ___ – a deep invagination of the ____ |
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Definition
Muscle contraction
Ultimately controlled by nerve-generated impulse
Impulse travels along the sarcolemma of the muscle cell
Impulses further conducted by t tubules
T tubule – a deep invagination of the sarcolemma |
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Term
Skeletal muscle fibers are categorized according to:
How they manufacture ____
How quickly they _____ |
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Definition
Skeletal muscle fibers are categorized according to:
How they manufacture energy (ATP)
How quickly they contract |
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Term
Skeletal muscle fibers are divided into three classes:
_____ fibers (Type I)
Red slow twitch
______ (Type IIx)
White fast twitch
_____ (Type IIa)
Intermediary fibers |
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Definition
Skeletal muscle fibers are divided into three classes:
Slow oxidative fibers (Type I)
Red slow twitch
Fast glycolytic fibers (Type IIx)
White fast twitch
Fast oxidative fibers (Type IIa)
Intermediary fibers |
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Term
Slow oxidative fibers (Type I)
__ color due to abundant _____
Obtain energy from ___ metabolic reactions
Contain a large number of _____
Richly supplied with capillaries
Contract slowly and resistant to fatigue
Fibers are small in diameter |
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Definition
Slow oxidative fibers (Type I)
Red color due to abundant myoglobin
Obtain energy from aerobic metabolic reactions
Contain a large number of mitochondria |
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Term
Fast glycolytic fibers (Type IIx)
Contain little ___ and few ____
About twice the diameter of ____ fibers
Contain more myofilaments and generate more power
Depend on ___ pathways
Contract ___ and tire ___ |
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Definition
Fast glycolytic fibers (Type IIx)
Contain little myoglobin and few mitochondria
About twice the diameter of slow-oxidative fibers
Contain more myofilaments and generate more power
Depend on anaerobic pathways
Contract rapidly and tire quickly |
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Term
Fast oxidative fibers (Type IIa)
Have an intermediate _____
Contract ___ like fast glycolytic fibers
Are ____-dependent
Have high ____ content and rich supply of ____
Somewhat _____-resistant
More powerful than ___ oxidative fibers |
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Definition
Fast oxidative fibers (Type IIa)
Have an intermediate diameter
Contract quickly like fast glycolytic fibers
Are oxygen-dependent
Have high myoglobin content and rich supply of capillaries
Somewhat fatigue-resistant
More powerful than slow oxidative fibers |
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Term
Cardiac Muscle Tissue
Occurs exclusively in heart wall
Forms a thick layer called ______ |
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Definition
Cardiac Muscle Tissue
Occurs exclusively in heart wall
Forms a thick layer called myocardium |
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Term
Cardiac Muscle Tissue
Single cells – not ___ like skeletal muscle
Separated by delicate ____
Cells are ____
Join at ____ discs – complex junctions
Form cellular networks
Each cell contains one centrally-located nuclei |
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Definition
Cardiac Muscle Tissue
Single cells – not fused colonies like skeletal muscle
Separated by delicate endomysium
Cells are branched
Join at intercalated discs – complex junctions
Form cellular networks
Each cell contains one centrally-located nuclei |
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Term
Triggered to contract by Ca2+ entering the _____
1.Signals _____ to release Ca2+ ions
2.Ions diffuse into ____
*Trigger sliding filament mechanism |
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Definition
Triggered to contract by Ca2+ entering the sarcoplasm
1.Signals sarcoplasmic reticulum to release Ca2+ ions
2.Ions diffuse into sarcomeres
*Trigger sliding filament mechanism |
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Term
| Not all cardiac cells are _______ |
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Definition
| Not all cardiac cells are innervated |
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Term
Smooth Muscle Tissue
Found in the walls of _____ organs
Six major locations: |
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Definition
Smooth Muscle Tissue
Found in the walls of visceral organs
Six major locations
Walls of circulatory vessels
Respiratory tubes
Digestive tubes
Urinary organs
Reproductive organs
Inside the eye |
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Term
Smooth Muscle Tissue
Separated by ______
Grouped into sheets in walls of hollow organs
_____ layer – muscle fibers run parallel to organ’s long axis
____ layer – muscle fibers run around circumference of the organ
Both layers participate in ______ |
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Definition
Smooth Muscle Tissue
Cells are spindle-shaped
Contain one centrally located nucleus
Separated by endomysium
Grouped into sheets in walls of hollow organs
Longitudinal layer – muscle fibers run parallel to organ’s long axis
Circular layer – muscle fibers run around circumference of the organ
Both layers participate in peristalsis |
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Term
Smooth Muscle Tissue
Cells are non-striated and contain no ____
___ and ___ filaments are present
Entry of ___ into the ____ signals contraction of the smooth muscle fiber
____ – tiny infoldings of the sarcolemma |
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Definition
Smooth Muscle Tissue
Cells are non-striated and contain no sarcomeres
Thin and thick filaments are present
Entry of Ca2+ into the cytoplasm signals contraction of the smooth muscle fiber
Caveolae – tiny infoldings of the sarcolemma |
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Term
Smooth Muscle Tissue
Contraction is ___ and ____
Takes __ times longer to contract than skeletal muscle fiber
Maintains ____ force for a long time |
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Definition
Smooth Muscle Tissue
Contraction is slow and sustained
Takes 30 times longer to contract than skeletal muscle fiber
Maintains contractile force for a long time |
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Term
Smooth Muscle Tissue
Is innervated by ____ nervous system
Only a few smooth muscle fibers are ____ in each sheet
Impulse spreads through ____
Whole sheet contracts as a unit
Exceptions – __ of the eye and ___ muscles |
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Definition
Smooth Muscle Tissue
Is innervated by autonomic nervous system
Only a few smooth muscle fibers are innervated in each sheet
Impulse spreads through gap junctions
Whole sheet contracts as a unit
Exceptions – iris of the eye and arrector pili muscles |
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