Muscular System Overview and Functions
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Questions and Answers

Which term is used to describe a muscle named for its relative size?

  • Deltoid
  • Sternocleidomastoid
  • Maximus (correct)
  • Temporalis

What is the naming characteristic of the muscle 'Triceps'?

  • By location of origin and insertion
  • By number of origins (correct)
  • By action
  • By shape

The muscle 'Temporalis' is named based on which criterion?

  • Bone location (correct)
  • Shape
  • Action
  • Relative size

What does the term 'Deltoid' indicate about the muscle's shape?

<p>Triangular (A)</p> Signup and view all the answers

What type of muscles are divided into facial muscles and chewing muscles?

<p>Head muscles (B)</p> Signup and view all the answers

What is the primary outcome of the sliding filament theory during muscle contraction?

<p>The muscle is shortened (contracted). (D)</p> Signup and view all the answers

What is the initial energy source muscles rely on for contraction?

<p>Stored ATP. (C)</p> Signup and view all the answers

How does creatine phosphate (CP) assist in muscle energy regeneration?

<p>It provides a phosphate group to ADP to regenerate ATP. (D)</p> Signup and view all the answers

What is one disadvantage of relying on creatine phosphate for muscle energy?

<p>CP supplies are exhausted in less than 15 seconds. (B)</p> Signup and view all the answers

What happens to ATP after initial energy is used in muscle contraction?

<p>ADP remains as the only product. (C)</p> Signup and view all the answers

What is the role of the antagonist muscle in a movement?

<p>Reverses or opposes the action of the prime mover (B)</p> Signup and view all the answers

Which type of muscle movement decreases the angle of a joint?

<p>Flexion (D)</p> Signup and view all the answers

What is the origin in muscle attachment?

<p>The part that is less movable during contraction (D)</p> Signup and view all the answers

Which movement describes a limb moving away from the midline of the body?

<p>Abduction (A)</p> Signup and view all the answers

What describes the term 'fixator' in muscle interactions?

<p>Prevents undesirable movements during a prime mover's action (C)</p> Signup and view all the answers

Which of the following best describes rotation?

<p>A bone moves around its longitudinal axis (D)</p> Signup and view all the answers

During which type of movement do muscles contract to make a circular motion?

<p>Circumduction (D)</p> Signup and view all the answers

What is the primary function of a synergist muscle?

<p>To assist in movement while preventing undesired actions (C)</p> Signup and view all the answers

Which type of movement is the opposite of flexion?

<p>Extension (D)</p> Signup and view all the answers

When a muscle contracts, what happens to the insertion?

<p>It moves toward the origin (B)</p> Signup and view all the answers

What is a characteristic symptom of Dystonia?

<p>Uncontrollable muscle contractions (B)</p> Signup and view all the answers

Which of the following disorders is an autoimmune condition?

<p>Myasthenia gravis (B)</p> Signup and view all the answers

What is the main issue occurring in Amyotrophic lateral sclerosis (ALS)?

<p>Deterioration of motor neurons (B)</p> Signup and view all the answers

Which condition involves the release of damaged muscle tissue components into the bloodstream?

<p>Rhabdomyolysis (A)</p> Signup and view all the answers

What is a common consequence of the condition Tetanus?

<p>Severe muscle spasms (D)</p> Signup and view all the answers

What is the primary role of acetylcholine (ACh) in muscle contraction?

<p>It diffuses across the synaptic cleft to attach to muscle receptors. (B)</p> Signup and view all the answers

What is the synaptic cleft?

<p>The space filled with fluid between a nerve and muscle cell. (D)</p> Signup and view all the answers

What defines a motor unit?

<p>A single neuron and all the muscle fibers it innervates. (B)</p> Signup and view all the answers

Which of the following terms describes the ability of muscle cells to return to their original length after stretching?

<p>Elasticity (A)</p> Signup and view all the answers

How does a nerve impulse effectively cross the synaptic cleft?

<p>Using a neurotransmitter to facilitate the process. (A)</p> Signup and view all the answers

What happens to acetylcholine after it binds to muscle cell receptors?

<p>It is broken down by an enzyme. (B)</p> Signup and view all the answers

What is the function of axon terminals in the neuromuscular junction?

<p>To release neurotransmitters upon nerve impulse arrival. (C)</p> Signup and view all the answers

Which statement is NOT true about motor units?

<p>They are always linked to the same muscle type. (C)</p> Signup and view all the answers

What type of movement does the gluteus maximus primarily perform?

<p>Hip extension (D)</p> Signup and view all the answers

Which muscle is primarily responsible for stabilizing the pelvis during walking?

<p>Gluteus medius (D)</p> Signup and view all the answers

What is the primary action of the iliopsoas muscle?

<p>Hip flexion (C)</p> Signup and view all the answers

Where are the adductor muscles located?

<p>Medial side of the thigh (A)</p> Signup and view all the answers

Which of the following muscles is involved in knee flexion?

<p>Hamstring group (D)</p> Signup and view all the answers

Which group of muscles extends the knee?

<p>Quadriceps group (C)</p> Signup and view all the answers

What is the primary role of the gastrocnemius muscle?

<p>Plantar flexion of the foot (B)</p> Signup and view all the answers

Which muscle runs from the lower vertebrae over the pelvis and attaches to the femur?

<p>Iliopsoas (B)</p> Signup and view all the answers

What is the primary action of the soleus muscle?

<p>Plantar flexion (A)</p> Signup and view all the answers

Which of the following muscles is primarily responsible for hip abduction?

<p>Gluteus medius (D)</p> Signup and view all the answers

Flashcards

Muscle Naming - Size

Muscles are sometimes named based on their relative size, with "maximus" indicating the largest.

Muscle Naming - Bone Location

Some muscles are named based on the bone they're positioned on. Examples are temporalis (temporal bone) and frontalis (frontal bone).

Muscle Naming - Number of Origins

Muscles with multiple attachment points are sometimes named by the number of those attachments. "Triceps" means 'three heads'.

Muscle Naming - Origin & Insertion

Muscles can be named based on their origin (beginning point) and insertion (end point) locations. Examples include the sternocleidomastoid.

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Muscle Naming - Shape

Some muscles get their name from their shape, like the deltoid (triangular).

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Prime Mover

The muscle primarily responsible for a specific movement.

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Antagonist

A muscle that opposes or reverses the action of a prime mover.

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Synergist

A muscle that aids a prime mover by preventing unwanted movements.

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Fixator

A specialized synergist that stabilizes another muscle's origin.

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Origin

The attachment of a muscle to the less movable bone.

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Insertion

The attachment of a muscle to the movable bone.

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Flexion

Decreasing the angle between two bones.

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Extension

Increasing the angle between two bones.

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Rotation

Movement of a bone around its longitudinal axis.

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Abduction

Moving a limb away from the body's midline.

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Gluteus maximus function

Hip extensor, important for activities like climbing stairs and jumping, not crucial for walking.

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Gluteus medius role

Hip abductor that stabilizes the pelvis while walking.

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Iliopsoas muscle's function

Hip flexor muscle; prevents the upper body from falling backward when standing.

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Adductor muscles

Muscles on the inner thigh that bring the thighs together (adduct).

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Hamstring group function

Both hip extension and knee flexion.

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Sartorius function

Flexes the thigh (at the hip).

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Quadriceps group function

Extends the knee.

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Rectus femoris function

Part of the Quadriceps group, extends the knee

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Gastrocnemius function

Muscle of the calf that causes plantar flexion (pointing the foot downwards).

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Soleus function

Another calf muscle, also causes plantar flexion (foot pointing downwards).

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Muscle Strain

A tear in muscle fibers and/or the connective tissues around them.

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Dystonia

A movement disorder where muscles contract uncontrollably.

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Tetanus

A bacterial infection blocking nerve signals to muscles, leading to severe spasms.

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Muscular Dystrophy

Genetic diseases causing abnormal muscle fiber weakening.

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Dermatomyositis

A group of diseases causing chronic muscle inflammation and weakness, often with a skin rash.

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Extensibility of Muscle

The ability of muscle cells to stretch.

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Elasticity of Muscle

The ability of muscle to return to its original length after stretching.

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Motor Unit

A neuron and all the muscle cells it stimulates.

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Axon Terminal

The end of a nerve cell (neuron).

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Neuromuscular Junction

The point where a nerve and muscle cell meet.

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Synaptic Cleft

The space between a nerve and muscle cell.

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Neurotransmitter

A chemical that carries a nerve signal across a gap.

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Acetylcholine (ACh)

The neurotransmitter for skeletal muscle.

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Sliding Filament Theory

The theory explaining muscle contraction where thin (actin) filaments slide past thick (myosin) filaments, shortening the muscle fiber.

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Muscle Contraction Energy Source

Muscles initially use stored ATP for energy to contract, but this supply lasts only 4-6 seconds.

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Creatine Phosphate (CP)

A high-energy molecule in muscle cells that provides energy for ATP regeneration after initial ATP stores are depleted.

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CP's Role in ATP Regeneration

CP donates a phosphate group to ADP, converting it back to ATP, providing energy for muscle contraction.

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How Long Does CP Last?

CP supplies are exhausted in less than 15 seconds, so other energy pathways must be used for longer muscle activity.

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Study Notes

Muscular System Overview

  • The muscular system is responsible for movement.
  • Muscles are attached to bones at two points.
  • The point of attachment to the non-moving or less movable bone is called the origin.
  • The point of attachment to the moving bone is called the insertion.

Muscle Interactions

  • Prime mover: the muscle primarily responsible for a specific movement.
  • Antagonist: the muscle that opposes the prime mover.
  • Synergist: a muscle that assists the prime mover by preventing undesired movements.
  • Fixator: a specialized synergist that stabilizes the origin of a prime mover.

Types of Body Movements

  • Flexion: Decreases the angle of a joint, bringing bones closer together. (Typical of hinge joints like knee and elbow)
  • Extension: Increases the angle between two bones, opposite of flexion.
  • Hyperextension: Extension beyond the anatomical position.
  • Rotation: Movement of a bone around its longitudinal axis. (Lateral rotation and medial rotation)
  • Abduction: Movement of a limb away from the midline.
  • Adduction: Movement of a limb towards the midline, opposite of abduction.
  • Circumduction: Combination of flexion, extension, abduction, and adduction. (Common in ball-and-socket joints).
  • Dorsiflexion: Lifting the foot so that the superior surface approaches the shin (walking on heels).
  • Plantar flexion: Depressing the foot (pointing the toes).
  • Inversion: Turning the sole of the foot medially.
  • Eversion: Turning the sole of the foot laterally.
  • Supination: Forearm rotates laterally so palm faces anteriorly.
  • Pronation: Forearm rotates medially so palm faces posteriorly.
  • Opposition: Move the thumb to touch the tips of the other fingers on the same hand.

Naming Skeletal Muscles

  • Muscles are named by their direction of fibers, relative size, location, number of origins, location of origin and insertion, or shape.
    • Example: Rectus (straight), Maximus (largest), Temporalis (temporal bone), Triceps (three heads), Deltoid (triangular), Flexor/extensor.

Skeletal Muscles of the Body

  • Lists specific muscle groups of the body
  • Includes illustrations showing specific muscles.

Head and Neck Muscles

  • Facial muscles: Responsible for facial expressions. Includes Frontalis (raises eyebrows), Orbicularis oculi (closes eyes), Orbicularis oris ("kissing muscle"), Buccinator (chewing muscle, controls cheeks), Zygomaticus ("smiling muscle").
  • Chewing muscles: Masseter, Temporalis (assists masseter in closing jaw).
  • Neck muscles: Platysma (frowning), Sternocleidomastoid ("prayer muscle" flexes neck, rotates head)

Muscles of Trunk, Shoulder, Arm

  • Anterior muscles: Pectoralis major (adducts and flexes upper arm)
  • Intercostal Muscles (raise and lower rib cage during breathing)
  • Posterior muscles: Trapezius (extends head, stabalizes scapula, shrugs shoulders), Latissimus dorsi (extends and adducts the upper arm), Deltoid (arm abduction
  • Muscles of the abdominal girdle: Rectus abdominis (flexes vertebral column, compresses contents), External and Internal Obliques, Transversus abdominis

Muscles of the Lower Limb

  • Hip and thigh movements: Gluteus maximus and medius
  • Important muscles for walking, climbing stairs, jumping.
  • Iliopsoas (runs from lower vertebrae to the femur, vital for hip flexion, posture)
  • Adductor muscles (press thighs together)
  • Muscles causing movement at the knee joint: Hamstring group (hip extension and knee flexion), Quadriceps group (extends knee), Sartorius (flexes thigh).
  • Muscles of the lower leg: Gastrocnemius (plantar flexion), Soleus (plantar flexion)

Skeletal Muscle Physiology

  • Properties: Excitability, contractility, extensibility, elasticity.
  • Neuromuscular junction: Junction between nerve and muscle cell.
  • Action Potential: Electrical signal that triggers muscle contraction.
  • Transmission of Nerve Impulse: Neurotransmitter Acetylcholine (ACh) passes the signal across the synaptic cleft.
  • Sliding Filament Theory of Muscle Contraction: Thick and thin filaments slide past each other.

Energy for Muscle Contraction

  • ATP (adenosine triphosphate): Muscles utilize stored ATP initially for energy, followed by creatine phosphate (CP) to generate more ATP quickly.
  • Aerobic respiration: Glucose is broken down to produce a large amount of ATP (about 32 ATP per 1 glucose molecule). Requires continuous oxygen.
  • Anaerobic glycolysis: Glucose is broken down to produce a smaller amount of ATP (about 5%) quickly without oxygen (lactic acid forms), but can only supply energy for 30-60 seconds.

Muscle Fatigue and Oxygen Debt

  • Muscle fatigue is temporary loss of contractile ability.
  • Common cause: oxygen debt; lactic acid buildup, increasing acidity, and lack of ATP.

Disorders of the Muscular System

  • Muscle strain (tearing of muscle fibers/connective tissues).
  • Dystonia (uncontrollable muscle contractions. )
  • Tetanus (bacterial infection causing nerve blocks and spasms).
  • Muscular Dystrophy (genetic diseases).
  • Dermatomyositis (chronic inflammation of muscles and weakness).
  • Amyotrophic lateral sclerosis (ALS)
  • Myasthenia gravis
  • Rhabdomyolysis (damaged muscle tissue releases proteins/electrolytes, which damages the heart and kidneys)

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Related Documents

Unit 4 - The Muscular System PDF

Description

This quiz covers the anatomy and function of the muscular system, highlighting key concepts such as muscle attachments, interactions, and types of body movements. Test your knowledge on prime movers, antagonists, and various joint movements including flexion and extension.

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