Feb 19 An P Test #2 Questions Flashcards
What property of muscle tissue allows it to respond to stimuli?
A. Elasticity
B. Contractility
C. Excitability
D. Extensibility
C. Excitability
What connective tissue layer surrounds an entire muscle?
A. Muscular fascia
B. Endomysium
C. Perimysium
D. Epimysium
D. Epimysium
What do actin and myosin filaments form when they interact during contraction
A. A-bands
B. Sarcomeres
C. Cross-bridges
D. Z disks
C. Cross bridges
What structure within a muscle fibre store calcium ions?
A. The terminal cistern are
B. The sarcolemma
C. The myofibril
D. The sarcophagi can reticulum
D. The sarcoplasmic reticculum
Describe the hierarchical organization of muscle tissue
Muscle tissue is organized
Muscle
Fascicles
Muscles fibers
Myofibrils
Myofilaments (actin and myosin)
Sarcomeres
Explain the differences between skeletal, smooth and cardiac muscle tissue
Skeletal: voluntary, moves the body
Smooth: involuntary
Cardiac: involuntary, heart movement
What is the basic functional unit of a muscle fiber called
A. Sarcolemma
B. myofibril
C. sarcomere
D. myofilament
C. Sarcomere
Which type of muscle is responsible for voluntary movements
A. Cardiac muscle
B. Smooth muscle
C. Skeletal muscle
D. Epimysium muscle
C. Skeletal muscle
Discuss the structure and function of the sarcomere in muscle fibers
The sarcomere is the basic unit of muscle contraction
Structure: includes actin, myosin, z disks, a bands, I bands, h zone, and m line
Function: shortens during contraction cis sliding filaments ( actin and myosin)
How do motor neurons stimulate muscle contraction at the neuromuscular junction?
Moto neurons release acetylcholine (ACh) into the synaptic cleft. ACh binds to receptors on the muscle finer. Causing muscle action potentials and leading to muscle contraction
What are the three types of muscle tissue?
A. Epimysium , perimysium, endomysium
B. Contractility, excitability, elasticity
C. Skeletal, smooth, cardiac muscle
D. Actin, myosin , sarcomere
C. Skeletal, smooth , cardiac
What is the role of acetylcholine in muscle contraction?
A. To initiate and action potential in the muscle fiber
B. To shorten the sarcomere directly
C. To break down ATP for muscle relaxation
D. To inhibit acetylcholinesterase at the synapse
A. To initiate an action potential in the muscle fiber
What aer the effects of spastic paralysis on muscle function ?
. Constant stimulation
Muscle fatigue
Respiratory failure
What condition results from organophosphate poisoning affect in acetylcholine receptors?
A flaccid paralysis
B. Myasthenia Travis
C. Muscle fatigue
D. Spastic paralysis
D. Spastic paralysis
What happens to the H zone during muscle contraction?
A. It remains the same size
B. It shortens
C. It gets longer
D. It disappears
D. It disappears
What treatments are available for conditions like myasthenia gravis?
One treatment is neostigmine, which partially blocks acetylcholinesterase to help with muscle weakness
How does curare affect muscle contraction?
A. Causing spastic paralysis by increasing acetylcholine release
B. Induces flaccid paralysis by increasing acetylcholinesterase activity
C. Induces flaccid paralysis by blocking acetylcholine receptors
D. Prevents muscle relaxation by blocking calcium reputake
C. Induces flaccid paralysis by blocking acetylcholine receptors
How does the tropomysin/ troponin complex regulate muscle contraction?
It blocks myosin binding sites on actin. Calcium binding to troponin shifts the complex, exposing these sites and allowing contraction.
What are the roles of the different connective tissue layers ins skeletal muscles?
Epimysium: surrounds the entire muscle
Perimysium : surrounds fascicle ( bundles of fibers)
Endomysium: surrounds individual muscle fibers they support, separate and connect muscle components. They merged to form tendons
How does the sliding filament mechanism explain muscle contraction
Actin filament slide over myosin, shortening Sarcomeres. This process doesn’t change filament length but contract the muscle
What is myasthenia gravis, and how does it impact muscle function
A. Amyotrophic lateral sclerosis (ALS), characterized by motor neuron degeneration causing progressive paralysis
B. Parkinson’s disease, characterized by dopamine deficiency causing rigidity, tremors, and slow movement
C. Muscular dystrophy, characterized by genetic defects causing progressive muscle degeneration and weakness
D. Myasthenia gravis, characterized by antibodies destroying acetylcholine receptors, impairing muscle contraction and causing weakness
D. Myasthenia gravis, characterized by antibodies destroying acetylcholine receptors, impairing muscle contraction and causing weakness
How do changes in the length of Sarcomeres affect muscle contraction?
Sarcomere length affects contraction:
Shortening Sarcomeres= muscle contraction
Lengthening Sarcomeres= muscle relaxation
What is the importance of ATP in muscle contraction
ATP is used by myosin heads to be and during contraction. Also, it is an energy source for muscle contraction
Describe the process by which muscles produce heat during contraction
During contraction, ATP is used by myosin, release it energy. Some energy powers the contraction, while the rest is released as heat. This process maintains body temp.
How do the properties of muscle tissue contribute to its overall function
Muscle tissues properties like Contractility, excitability, extensibility, and elasticity enable movement, posture, respiration, heat production, and organ function
What adaptations occur in the muscle fibres in response to regular excerecise
Regular exercise can lead- to increase muscle size, improved endurance, greater strength, and more capillaries
What is the significance of the neuromuscular junction in muscle physiology?
A. It transmits signals form motor neurons to muscle fibers
B. It regulates the supply of ATP to muscle fibers
C. It is the location where muscle fibers store calcium ions
D. It controls the degradation of acetylcholine in the synaptic sleet
A. It transmits signals form motor neurons to muscle fibers
What is the sliding filament model of muscle contraction
A. Myosin myofilaments slide over actin, lengthening Sarcomeres
B. Actin and myosin myofilaments both shorten to contract Sarcomeres
C. Sarcomeres slide over actin and myosin, causing muscle contraction Lengthening
D. Actin myofilaments slide over myosin, shortening Sarcomeres
D. Actin myofilaments slide over myosin, shortening Sarcomeres
How does extensibility benefit muscle function during rehabilitation?
A. It increases muscle strength significantly
B. It eliminates the needs for warm- up exercises
C. It allows for muscles to stretch without damage
D. It prevents all types of injuries
C. It allows muscles to stretch without damage
What role does elasticity play in muscle recovery post- injury?
A. It enhances the speed of muscle contraction
B. It minimizes pain perception during exercise
C. It reduces blood flow to the injured area
D. It helps muscles return to their resting length
D. It helps muscles return to their resting strength
Why is it important for a muscle to be both extensible and elastic?
A. To rapidly elevate body temperature
B. To boost muscle fiber synthesis
C. To restrict movement during recovery
D. To enable safe stretching and proper contraction
D. To enable safe stretching and proper contraction
Which connective tissue layer surrounds individual msucle fibers
A. Perimysium
B. Epimysium
C.Endomysium
D.sarcolemma
C. Endomysium
How does skeletal muscles primarily differ form smooth muscle in terms of control?
A. Skeletal muscle is controlled by the autonomic nervous system
B. Skeletal muscle contracts involuntarily
C. Skeletal muscle is under voluntary control
D. Skeletal muscle is auto rhythmic
C. Skeletal muscles return is under voluntary control
A 30-year-old woman presents with muscle weakness and fatigue. Upon examination, she has difficulty lifting her arms and maintaining posture. Her medical history reveals a sedentary lifestyle and no regular exercise. The physician suspects an issue related to skeletal muscle function.
What property allows cardiac muscle to contract without external stimulation?
A. Extensibility of the cells
B. Excitability of the fibers
C. Elasticity of the tissue
D. Auto rhythmic properties
D. Autorythmic properties
Which connective tissue layer surrounds individual muscle fibers
B. Endomysium
Why is extensibility portent for muscle function?
A. It enables paid contraction of muscle fibers
B. It prevents in just during intense activity
C. It facilitates efficient energy use during movements
D. It allows muscle to stretch beyond their resting length
D. It allows minuscules to stretch beyond their resting length
How do skeletal muscles aid in respiration?
A. Skeletal muscles expand the sheet cavity during inhalation
B. Skeletal muscles regulates blood flow throughout the body
C. Skeletal muscles contract to produce heat during exercise
D. Skeletal muscles stabilization the spine for better balance
A. Skeletal muscles return expand the chest cavity during inhalation
Why is posture maintenance important for overall health
A. It improves cardiovascular endurance I significantly
B. It enhances muscle flexibility and strength
C. It allows for faster recovery
D. It prevents strain on muscle and joints
D. It prevents strain on muscles and joints
Which type of muscle is primarily responsible for heart contraction?
A. Skeletal muscle
B. Smooth muscle
C. Cardiac muscle
D. Striated muscles
C. Cardiac muscle
What role does smooth muscle play in organ function?
A. Skeletal muscles return expand generates heat during exercise
B. Skeletal muscle enables voluntary limb movement
C. Smooth muscle controls the movement of materials in hollow organs
D. Skeletal muscles return expand aides in quick signalling between nerve cells
C. Smooth muscle controls the movement of materials in hollow organs
How do myofibril a contribute to muscles contraction?
A. They provide
B. They transmit electrical signals to the muscle fibers
C. They store calcium for muscle relaxation
D. They constrain myofilaments that cause contractions
D. They contain myofilaments that cause contraction
What role does sarcolemma play in muscle fibers?
A. It serves as a reservoir for energy during contractions
B. It ensures adequate blood flow to the muscle tissue
C. It link muscle fibers to their respective tendons
D. It encases the cell’s contents, including the sarcoplasm
D. It encases the cell’s contents, including the sarcoplasm
Why are terminal cistern are important in muscle fibers?
A. They help in the formation of myofibrils
B. They connect muscle fibers to motor neurons
C. They regulate blood flow to the muscle tissue
D. They store calcium adjacent to T tubules
D. They store calcium adjacent to T tubules
What is the significance of the Z disk in a sarcomere ?
A. It distinguishes various muscle fiber types
B. It acts as a binging diet for actin filaments
C. It influences the speed of msucle contractions
D. It serves as a storage site for energy in the sarcomere
B. It acts as a binding site for actin filaments
How do connective tissue coverings contribute to muscle function?
A. They store energy for muscle contractions
B. They inhibit muscle fiber contraction
C. They add madd to the muscle structure
D. They support muscles and help transmit contraction forces
D. They support muscles and help transmit contraction forces
What role does the Endomysium play in a fascicle?
A. It connects muscle to bone
B. It surrounds the entire muscle
C. It separates individual muscle fibers
D. It provides blood supply to the muscle
C. It separates individual muscle fibers
Why is the neuromuscular junction critical for muscle contraction?
A. It safeguards muscles form damage during contraction
B. It generates energy requires for msucle activity
C. It stores calcium ions necessary for muscle contraction
D. It enables communication between motor neurons and muscle cells
D. It enables communication between motor neurons and muscle cells
Hoe does the sliding filament model explain muscle contraction?
A. Calcium ions cause myofilaments to dissolve during contraction
B. Myosin filaments pull actin filaments apart
C. Muscle fibers lengthen without changing their structure
D. Actin filaments slide over myosin filaments to shorten Sarcomeres
D. Actin filaments slide over myosin filaments to shorten Sarcomeres
How do myosin heads contribute to muscle contraction?
A. They bind to active sites on actin to form cross-bridges
B. They stabilize the Zdisks during contraction
C. They release calcium ions into the muscle fiber
D. They break down ATP for energy without binding to actin
A. They bind to active sites on actin to form cross- bridges
What is the primary function of tropomyosin in muscle fibers?
A. It transport calcium ions writhing muscle cell
B. It enhances the elasticity of the muscle fibers
C. It provides structural support to the sarcomere
D. It regulates the binding of myosin to actin
D. It regulates the binding of myosin to actin
Why is the H zone significant in Sarcomere structure?
A. It indicates where actin and myosin do not overlap
B. It contains the majority of the myosin filaments
C. It is the site of calcium ions into stage
D. It marks the boundary between adjacent Sarcomeres
A. It indicates where actin and myosin so not overlap
What happens to the sarcomere during muscle contraction?
A. The length of both actin and myosin increases
B. The A band widens while the I band narrows
C. The Z disks move further apart from each other
D. The sarcomere shortens as actin slides over myosin
D. The sarcomere shortened as actin slides over myosin
How do actin and myosin contribute to muscle contraction
A. Actin and myosin change length during contraction
B. Actin slides over myosin to shorten Sarcomeres
C. Myosin binds to calcium to initiate contraction
D. Myosin pulls actin away from each other
B. Actin slides over myosin to shorten Sarcomeres
What occurs to the H zone during muscle contraction
A. The H zone widens due to increase overlap
B. The H zone remains unchanged throughout contraction
C. The H zone becomes more visible in a relaxed state
D. The H zone disappears as Sarcomeres shorten
D. The H zone disappears as Sarcomeres shorten
Why is relaxation important after muscle contraction?
A. It prevents injury by keeping tense
B. It ensures continuous energy supply for muscles
C. Is enhances the strength of subsequent contractions
D. To allows muscles to return to their resting length
D. It allows for muscles to return to their resting length
Which protein complex regulates the interaction between actin and myosin?
A. Actin - binding protein complex
B. Myosin light chain kinase
C. Tropomyosin-troponin complex
D. Calmodulin- calcium complex
Tropomyosin-troponin complex
A 30-year-old woman presents with muscle weakness and fatigue after exposure to a pesticide containing organophosphates. She reports difficulty breathing and has noticeable drooping of her eyelids. Upon examination, she shows signs of flaccid paralysis in her limbs.
Why is the likely cause of her symptoms?
A. Organophosphate poisoning
B. Curare poisoning
C. Myasthenia gravis
D. Duchesne muscular dystrophy
A. Organophosphate poisoning
How does organophosphate affect muscle function?
A. It increases acetylcholine release
B. It enhances receptor sensitivity to acetylcholine
C. It inhibits acetylcholinesterase activity
D. It block calcium channels in muscles
C. It inhibits acetylcholinesterase activity
Which condition is characterized by antibodies destroying acetylcholine receptors
A. Organophosphate poisoning
B. Curare poisoning
C. Duchesne muscular dystrophy
D. Myasthenia gravis
D. Myasthenia gravis
In curare poisoning what type of paralysis occurs?
A. Neuromuscular blockade
B. Muscle atrophy
C. Spastic paralysis
D. Flaccid paralysis
D. Flaccid paralysis
In curare poisoning. What type of paralysis occurs?
A. Neuromuscular blockade
B. Muscle atrophy
C. Spastic paralysis
D. Flaccid paralysis
D. Flaccid paralysis
How does organophosphate exposure affect neurotransmitters at the neuromuscular junction?
A. It increases the release of acetylcholine from nerve endings
B. It disrupts the generation of action potentials in motor neurons
C. It’s blocks acetylcholinesterase, causing acetylcholine to build up
D. It interferes with calcium influx at the synapse
C. It blocks acetylcholinesterase, causing acetylcholine to build up
What is the primary consequence of curare poisoning on muscle function?
A. Blocks acetylcholinesterase activity D from binding to receptors, leading to muscle paralysis
B. Increases acetylcholine release, causing muscle spasms
C. Accelerates breakdown of acetycholine in the synapse
D. Triggers excessive activation of ion channels in muscle cells
A. Blocks acetylcholine from binding to receptors, leading to muscle paralysis
Why is the neuromuscular junction critical for muscle contraction?
A. It stores coliseum ions necessary for muscle relaxation
B. It generates electrical signals that directly cause contractions
C. It provides energy through ATP breakdown during muscle activity
D. It facilitates communication between motor neurons and muscle fibers
D. It facilitates communication between motor neurons and muscle fibers
What role do ligand-gated ion channels play at the postsynaptic membrane?
A. They facilitate the release of neurotransmitters from the presynaptic terminal
B. They prevent entry into the muscle fiber during stimulation
C. They help in the reputake of acetylcholine after muscle contraction
D. They allow sodium influx when acetylcholine binds, triggering action potentials
D. They allow sodium influx when acetylcholine binds, triggering action potentials
What is the primary function of cardiac muscle?
A. To pump blood
B. To mix food in the digestive tract
C. To propel urine
D. To facilitate respiration
A. To pump blood
How do I bands contribute to the structure of a sarcomere?
A. I bands play a role in muscle contraction
B. I bands are made up solely of this filaments
C. I bands are found in the middle of the sarcomere
D. I bands include Z disks and reach the ends of myosin filaments
D. I bands include Z disks and reach the ends of myosin filaments
What is the primary function the M line within the sarcomere?
A. The M connects actin filaments to Z disks
B. The M line regulates calcium ion release during contraction
C. The M line holds myosin filaments in place
D. The M line serves as an attachment point for tropomyosin
C. The M line Holds the myosin filaments in place D
Why does the H zone disappear during muscle contraction?
A. The H zone fills with calcium ions during contraction
B. The Z disks move apart, increasing the myosin filaments
C. The actin filaments slide over the myosin filaments
D. The myosin filaments shorten significantly during contraction
C. The actin filaments slide over the myosin filaments
How do titin filaments affect muscle properties?
A. Titin makes muscles extensible and elastic
B. Titin provides structural support by anchoring actin filaments
C. Titin facilitates the binding of myosin heads to actin
D. Titin regulates the length of myosin filaments during contraction
A. Titin makes muscles extensible and elastic
What neurotransmitter is released at the neuromuscular junction?
A. GABA
B. Glutamate
C. Norepinephrine
D. Acetylcholine
D. Acetylcholine
What triggers the opening of voltage gated Na+ channels in action potential propagation?
A. Hyper polarization of the membrane
B. Binding of a neurotransmitter
C. Depolarization to a threshold potential
D. Influx of K+ ions
C. Depolarization to the threshold potential
What triggers the opening of voltage gated Na+ channels in action potential propagation?
A. Hyper polarization of the membrane
B. Binding of a neurotransmitter
C. Depolarization to a threshold potential D
D. Influx of K+ ions
C. Depolarization to a threshold potential
What role do calcium ions play in muscle contraction?
A. Initiate the depolarization of the muscle cell
B. Provide energy for the power stroke
C. Trigger binding of actin and myosin
D. Maintain the resting membrane potential
C. Trigger the binging of actin and myosin
Which structure wraps around Sarcomeres and carries action potentials into the interior of the muscle fibre
A. Sarcolemma
B. Myofibrils
C. Sarcoplasmic reticulum
D. T- tubules
D. T- tubules
What is the difference between concentric and eccentric isotonic contractions
