Questions and Answers
What are the three types of muscle tissue?
Skeletal, cardiac, smooth
What is skeletal muscle?
Organs that attach to/cover bony skeleton; rapid contraction, but tires easily; striations; voluntary
What is cardiac muscle?
In the heart; involuntary; striated; steady and constant rate of contraction
What is smooth muscle?
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What is another name for muscle cells?
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What are the two types of myofilaments?
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What is a myofilament?
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What are the four characteristics of muscle tissue?
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What is the ability to receive and respond to a stimulus in muscle tissue?
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What is the definition of conductivity in muscle tissue?
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What is contractility in muscles?
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What does extensibility refer to in muscle tissue?
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What is elasticity in muscles?
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What are the functions of muscles?
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What connects each muscle to its nerve, artery, and more than one vein?
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Why do muscles have a rich blood supply?
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What is endomysium?
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What is perimysium?
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What is a fascicle?
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What is the insertion of a muscle?
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What is the origin of a muscle?
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What are direct or fleshy attachments?
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What are steroids in relation to muscles?
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What are indirect attachments?
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What are tendons?
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What is myosin?
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How many myosin molecules make up a myosin filament?
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What are cross bridges in muscle contraction?
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What is actin?
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How are actin molecules arranged?
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What two proteins are associated with actin filament?
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What is tropomyosin?
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What is troponin?
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What happens at rest with tropomyosin and troponin?
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What is needed for muscle contraction?
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What happens when Ca ions bind to troponin?
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What is the sarcoplasmic reticulum?
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What are transverse tubules?
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What functions do the sarcoplasmic reticulum and transverse tubules provide?
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What are terminal cisternae?
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What is a triad in muscle physiology?
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What is a neuromuscular junction?
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What causes muscle contraction?
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What is a motor end plate?
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What are synaptic vesicles?
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What are synaptic clefts?
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What is a motor unit?
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How many muscle fibers does one motor nerve fiber connect to?
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What is acetylcholine?
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What are the steps for muscle contraction?
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What is cholinesterase?
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What are the steps for muscle relaxation?
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What is the source of energy for muscle contractions?
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What is the equation for the formation of ATP?
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What is ATPase?
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What does anything that ends in 'ose' represent?
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What does anything that ends in 'ase' represent?
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What is creatine phosphate?
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What is the equation for creating phosphate?
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In what form is glucose stored?
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What is cellular respiration?
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How many ATP does a glucose molecule provide?
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What is the formula for cellular respiration?
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What are the two steps of cellular respiration?
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What is glycolysis?
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What is aerobic respiration?
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What is the citric acid cycle?
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What is the electron transport chain?
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What is lactic acid formation?
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What is oxygen deficit/debt?
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What is muscle fatigue?
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What are contractures?
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What is a byproduct of cellular respiration?
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What percentage of energy from cellular respiration is lost as heat?
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What is slow twitch/red muscle?
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What is fast twitch/white muscle?
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Muscles can have both slow twitch and fast twitch fibers.
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What is hypertrophy?
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What is atrophy?
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What are myoblasts?
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What is another name for a gap junction?
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When are skeletal muscle fibers contracting?
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What do smooth and cardiac muscle not do?
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When is the heart pumping blood during development?
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How are babies' movements described?
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Which movements precede fine movements?
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Where does development in a kid start?
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When is the natural peak of motor control?
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What percentage of body mass do women's skeletal muscles make up?
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What percentage of body mass do men's skeletal muscles make up?
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Why are muscles not easily infected?
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What is muscular dystrophy?
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What is Duchenne muscular dystrophy?
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What happens to connective tissue and muscle fibers as we age?
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What is sarcopenia?
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By what percentage has muscle strength usually decreased by age 80?
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How can elderly individuals regain or maintain muscle strength?
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Study Notes
Types of Muscle Tissue
- Three types of muscle tissue: skeletal, cardiac, smooth.
- Skeletal muscle: attached to the skeleton, striated, voluntary, rapid contraction but tires easily.
- Cardiac muscle: located in the heart, involuntary and striated, maintains a steady contraction rate.
- Smooth muscle: found in hollow organs, involuntary, non-striated, slow and sustained contraction.
Muscle Structure and Function
- Muscle cells are also known as muscle fibers.
- Myofilaments consist of actin and myosin, essential for muscle contraction.
- Four characteristics of muscle tissue:
- Excitability: responds to stimuli.
- Contractility: can shorten forcibly.
- Extensibility: can be stretched.
- Elasticity: can recoil to original length after stretching.
Muscle Tissue Functions
- Produces body movement, maintains posture, stabilizes joints, generates heat.
- Protects inner organs and forms valves (sphincters) in smooth muscle.
- Each muscle is supplied by a nerve, an artery, and veins for energy use and waste removal.
Muscle Connective Tissue
- Endomysium: fine connective tissue sheath around individual muscle fibers.
- Perimysium: connective tissue layer surrounding fascicles.
- Fascicles: bundles of muscle fibers grouped together.
Muscle Attachments
- Muscle's origin: the immovable attachment point.
- Muscle's insertion: the movable attachment during contraction.
- Direct attachments: muscle epimysium fuses to periosteum or cartilage.
- Indirect attachments: connective tissue extends to form tendons or aponeurosis.
Myofilament Structure
- Myosin is the most abundant muscle protein, forming thick filaments.
- Actin consists of globular structures with binding sites for myosin, forming a double helix filament structure.
- Tropomyosin and troponin are regulatory proteins associated with actin, controlling access to binding sites.
Muscle Contraction Mechanism
- Motor nerve stimulation triggers contraction through the neuromuscular junction.
- Acetylcholine is released, activating muscle fibers by generating an impulse leading to calcium ion release from the sarcoplasmic reticulum.
- Calcium binds to troponin, shifting tropomyosin to expose active sites on actin for myosin binding.
Relaxation and Energy Use
- Cholinesterase decomposes acetylcholine to cease stimulation.
- ATP is crucial for muscle contraction; produced during cellular respiration.
- Creatine phosphate stores energy, quickly converting to ATP when needed.
Types of Muscle Fiber
- Slow-twitch (red) fibers are fatigue-resistant, use aerobic respiration, rich in myoglobin.
- Fast-twitch (white) fibers fatigue quickly, rely on anaerobic processes and creatine phosphate for quick energy bursts.
- Muscles can contain both fiber types, contributing to overall functionality.
Muscle Development and Aging
- Muscle mass typically decreases with age, a condition known as sarcopenia.
- Peak motor control occurs during mid-adolescence.
- Women's skeletal muscles comprise about 36% of body mass, while men's make up about 42%.
- Light exercise can help older adults maintain or regain muscle strength.
Muscle Disorders
- Muscular dystrophy: genetic disorders leading to muscle degeneration, notably Duchenne muscular dystrophy.
- Symptoms typically appear in childhood, progressing to muscle atrophy.
- Muscle strength is often reduced by 50% by age 80 due to aging-related changes.
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Description
Test your knowledge on the different types of muscle tissues in this Anatomy and Physiology Chapter 9 quiz. Explore the characteristics and functions of skeletal, cardiac, and smooth muscles. Perfect for students looking to enhance their understanding of muscle anatomy.