Muscle Function and Excitation Quiz

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Questions and Answers

Which muscle is primarily responsible for elevating the eyebrows?

Buccinator

Frontalis (correct)

Masseter

Temporalis

Which muscle is essential for actions such as chewing, drinking, and breathing?

Buccinator (correct)

Zygomaticus

Orbicularis oris

Masseter

When the masseter contracts, what action does it perform?

Lowers the jaw

Opens the mouth

Closes the mouth (correct)

Tilts the head

What is the origin site of the sternocleidomastoid muscle?

Sternum Signup and view all the answers

Which muscle acts as the prime mover for flexing the hip and stabilizing the trunk?

Iliopsoas Signup and view all the answers

Which muscle is primarily utilized for executing a forward thrust or throwing motion?

Pectoralis major Signup and view all the answers

Which muscle assists in the lifting of the body during activities like stair climbing?

Quadriceps Signup and view all the answers

Which muscle acts as an antagonist to the pectoralis major?

Triceps brachii Signup and view all the answers

What process occurs during muscle contraction where actin and myosin slide past each other?

The Sliding Filament Mechanism Signup and view all the answers

Which steps are involved in muscle relaxation?

Reuptake of calcium and breakdown of acetylcholine Signup and view all the answers

What defines the action potential in muscle contraction?

The electrical signal triggering muscle contraction Signup and view all the answers

What describes the recovery stroke in muscle contraction?

The detachment of myosin heads from actin Signup and view all the answers

Which term differentiates muscle contractions that result in a change in muscle length from those that do not?

Isotonic vs. isometric Signup and view all the answers

What is the role of zygomaticus muscles?

To elevate the corners of the mouth during smiling Signup and view all the answers

What advantage does aerobic respiration provide during exercise?

It produces 30 ATP per glucose molecule Signup and view all the answers

What occurs during a muscle twitch?

A brief contraction in response to a stimulus Signup and view all the answers

Which muscles abduct the femur, assisting in shifting body weight during walking?

Gluteus medius and minimus Signup and view all the answers

Which thigh adductor muscle also aids in flexing the knee?

Gracilis Signup and view all the answers

Which muscle is predominantly involved in the action of crossing the legs?

Sartorius Signup and view all the answers

Which combination of muscles is primarily engaged when shooting a ball?

Quadriceps, gluteus maximus, gastrocnemius Signup and view all the answers

Identify the anterior muscles of the lower leg.

Tibialis anterior and extensor digitorum longus Signup and view all the answers

Which muscle is responsible for dorsiflexing the foot and preventing toe scuffing during walking?

Tibialis anterior Signup and view all the answers

Which muscle group primarily assists in flexing the hip joint?

Iliopsoas Signup and view all the answers

Which of the following muscles are best known for their involvement in generating force during sprinting?

Gluteus maximus and hamstrings Signup and view all the answers

Which of the following is the primary function of muscles in relation to glucose?

ATP production Signup and view all the answers

What structure in muscle fibers carries electrical impulses from the sarcolemma?

T-tubules Signup and view all the answers

Which statement is correct regarding muscle fibers?

A muscle fiber is synonymous with a muscle cell Signup and view all the answers

What constitutes the structure of thick and thin filaments in muscle fibers?

Thin filaments are composed of actin, and thick filaments are composed of myosin Signup and view all the answers

Which statement about I bands is accurate?

I bands consist of thin filaments Signup and view all the answers

What is the role of acetylcholinesterase in muscle function?

It breaks down acetylcholine to terminate muscle stimulation Signup and view all the answers

Muscles primarily rely on which process when oxygen is scarce?

Anaerobic respiration Signup and view all the answers

What best describes resting membrane potential in skeletal muscle?

-90 mV Signup and view all the answers

Study Notes

Muscle Function

Muscles absorb glucose for ATP production and glycolysis
Muscle fiber is a muscle cell
Myofibrils are bundles of myofilaments (actin and myosin)
Thick filaments are composed of myosin, thin filaments are composed of actin
I bands consist of thin filaments
Motor unit is one motor neuron and all muscle fibers it supplies
Neuromuscular junction is the connection between a nerve fiber and a muscle fiber
Acetylcholinesterase breaks down acetylcholine to stop muscle stimulation
Anaerobic respiration occurs when oxygen is unavailable (e.g., intense exercise)

Membrane Potential and Muscle Excitation

Resting membrane potential is the difference in charge across the plasma membrane at rest
The resting membrane potential of skeletal muscle is -90 mV
Excitation, contraction, and relaxation are the steps in muscle activity
Muscle excitation involves release of acetylcholine, depolarization of the sarcolemma, and binding of calcium to troponin
Muscle contraction involves binding of myosin heads to actin and power stroke pulling actin

Muscle Relaxation

Muscle relaxation involves reuptake of calcium into the sarcoplasmic reticulum
The sliding filament mechanism describes the process of muscle contraction where actin and myosin slide past each other
Aerobic respiration yields 30 ATP per glucose and requires oxygen (e.g., running)
Power stroke refers to myosin head binding to actin, while recovery stroke refers to detachment
Muscle twitch is a quick contraction in response to a stimulus, muscle tension is the force generated
Isotonic contraction involves muscle length change, isometric contraction involves no change in length
Biceps brachii flexes the elbow, triceps brachii extends it
Brachialis flexes the elbow, triceps brachii extends it
Orbicularis oculi blinks and closes the eye
Orbicularis oris protrudes our lips

Head and Neck Muscles

Zygomaticus major and minor are the smiling muscles
Frontalis elevates eyebrows
Buccinator is a muscle used in airflow, drinking, and chewing
Masseter elevates the mandible, closing the mouth
Sternocleidomastoid is the primary mover of neck flexion, its origin is sternum and clavicle, and insertion is the mastoid process
Trapezius originates from the occipital bone and thoracic vertebrae

Trunk Muscles

Diaphragm is used for defecation, exhalation, and childbirth
External oblique helps in exhalation by pulling the rib cage downward

Shoulder and Arm Muscles

Pectoralis major is the prime mover in forward thrusting, throwing, and pushing
Pectoralis major helps push doors
Deltoid is the main mover of the up and down shoulder movement
Latissimus dorsi and deltoid help in climbing and throwing balls
Latissimus dorsi is the antagonist of pectoralis major

Leg and Foot Muscles

Iliopsoas helps flex the hip and trunk, balancing the trunk during sitting
Gluteus maximus provides lift when climbing stairs
Gluteus medius and minimus abduct the femur, aiding in shifting body weight during walking
Gracilis is a thigh adductor that flexes the knee
Sartorius is used in crossing legs
Quadriceps, gluteus maximus, and gastrocnemius are engaged in shooting a ball
Tibialis anterior and extensor digitorum longus are anterior muscles of the lower legs
Tibialis anterior dorsiflexes the foot, preventing toes from scuffing the ground during walking

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Description

Test your knowledge on muscle function and the process of excitation in muscle fibers. This quiz covers essential topics such as myofilament structure, membrane potentials, and the role of neurotransmitters in muscle contraction. Perfect for students studying muscle physiology or related fields.