Muscular System and Levers
36 Questions
3 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is primarily generated by the muscular system besides body movement?

  • Electricity
  • Heat (correct)
  • Light
  • Energy

    • All skeletal muscles are under involuntary control.

    False

    What is the term for the end of a muscle that is attached to a moving bone?

    insertion

    The muscle belly is the thickened portion between tendons.

    <p>muscle belly</p> Signup and view all the answers

    Which type of lever has the load located between the effort and the fulcrum?

    <p>Second-class lever</p> Signup and view all the answers

    What is the name of the joint that acts as the fulcrum when looking up at the ceiling?

    <p>atlanto-occipital joint</p> Signup and view all the answers

    Match the lever types with their examples:

    <p>First-class lever = Like a see-saw Second-class lever = Like a wheelbarrow Third-class lever = Bending your elbow</p> Signup and view all the answers

    The load is always at the end of a third-class lever.

    <p>True</p> Signup and view all the answers

    What is the primary function of the diaphragm?

    <p>To permit breathing</p> Signup and view all the answers

    The latissimus dorsi permits lateral rotation of the arm.

    <p>False</p> Signup and view all the answers

    What muscle is responsible for abducting the scapula?

    <p>Serratus anterior</p> Signup and view all the answers

    The _____ flexes the arm at the elbow joint.

    <p>biceps brachii</p> Signup and view all the answers

    Match the muscles to their primary actions:

    <p>Gastrocnemius = Plantar flexion of the foot Biceps brachii = Flexion of the arm at the elbow Gluteus maximus = Extension of the leg at the hip joint Serratus anterior = Abducts the scapula</p> Signup and view all the answers

    Which muscle originates on the occipital bone?

    <p>Trapezius</p> Signup and view all the answers

    The gluteus medius is located above the gluteus maximus.

    <p>False</p> Signup and view all the answers

    Which muscle group is often referred to as the hamstrings?

    <p>Flexor compartment of the thigh</p> Signup and view all the answers

    The vastus lateralis, vastus medialis, and vastus intermedius all originate on the _____ .

    <p>femur</p> Signup and view all the answers

    Match the muscle with its action:

    <p>Triceps brachii = Extension of the forearm at the elbow joint Rectus femoris = Flexion of the leg at the hip joint Pectoralis major = Medial rotation and adduction of the arm Tibialis anterior = Dorsiflexion of the foot</p> Signup and view all the answers

    What is the role of the flexor compartment of the thigh?

    <p>Flexion of the distal lower limb at the knee joint</p> Signup and view all the answers

    Moderate-intensity exercise helps protect against muscle injuries.

    <p>True</p> Signup and view all the answers

    What is the main function of the gluteus maximus?

    <p>Extension of the leg at the hip joint</p> Signup and view all the answers

    The _____ originates on the scapula and humerus and allows for extension of the forearm at the elbow joint.

    <p>triceps brachii</p> Signup and view all the answers

    Which muscle acts as the agonist during elbow flexion?

    <p>Biceps brachii</p> Signup and view all the answers

    Fixators stabilize the joints to allow for movement at other joints.

    <p>True</p> Signup and view all the answers

    What is the role of synergist muscles during joint movement?

    <p>To stabilize intermediate joints when contracted.</p> Signup and view all the answers

    The ___________ stabilizes one end of the bone so that the other end can move.

    <p>fixator</p> Signup and view all the answers

    Which muscle is responsible for depressing the mandible?

    <p>Platysma</p> Signup and view all the answers

    Muscles are organized into __________, which are groups of muscles, their nerves, and blood vessels.

    <p>compartments</p> Signup and view all the answers

    The triceps brachii acts as the agonist during elbow flexion.

    <p>False</p> Signup and view all the answers

    Match the muscle to its action:

    <p>Masseter = Elevates the mandible Orbicularis oris = Closes and purses lips Biceps brachii = Flexes the elbow Transversus abdominis = Compresses abdominal contents</p> Signup and view all the answers

    Which muscle acts on the anterior portion of the skull to raise the eyebrows?

    <p>Frontal belly of the occipitofrontalis</p> Signup and view all the answers

    What would occur if both the biceps brachii and triceps brachii contract simultaneously?

    <p>Stabilization of the elbow joint</p> Signup and view all the answers

    The rectus abdominis runs __________ along the anterior of the abdominal cavity.

    <p>longitudinally</p> Signup and view all the answers

    The main function of the external obliques is to protect the abdominal viscera.

    <p>False</p> Signup and view all the answers

    What type of connective tissue forms tendinous intersections?

    <p>Dense connective tissue</p> Signup and view all the answers

    The ___________ is the deepest muscle layer in the abdominal region.

    <p>Transversus abdominis</p> Signup and view all the answers

    Study Notes

    Muscular system

    • All skeletal muscles are under voluntary control
    • Generate heat
    • Origin - end of muscle attached to stabilized or stationary bone
    • Insertion - end of muscle attached to moving bone
    • Muscle belly is the thickened portion between tendons
    • Muscle actions are the movements possible when the muscle contracts
    • Reverse muscle actions (RMAs) result when the origin and insertion are reversed
    • Levers can lift loads using effort
    • Effort - force required to move a load
    • Bones are levers that are moved by the effort of muscle action

    Types of levers

    • First-class levers: fulcrum is between effort and load, like a see-saw or pair of scissors, rare in the human body
    • Second-class levers: load is between effort and fulcrum, like a wheelbarrow, produce a mechanical advantage, little effort to move load a short distance
    • Third-class levers: effort is between the fulcrum and the load, like forceps, most common levers in the body, always produce a mechanical disadvantage, a lot of effort to move small loads a short distance

    Muscle groups

    • Most muscles work in opposing pairs
    • Agonist - exerts effort to move lever (bones of forearm)
    • Antagonist - opposes agonist
    • Synergist - stabilizes intermediate joints when contracted

    Muscle organization

    • Muscles are organized into compartments
    • Compartments - groups of skeletal muscles, their nerves, and their blood vessels
    • Specific functions

    Muscle naming

    • Direction: Transversus abdominis muscles run perpendicular to the midline
    • Size: Latissimus dorsi muscles are the widest of the back
    • Shape: Serratus anterior muscles have a saw-shape at the anterolateral portion of the chest
    • Action: External anal sphincter decreases the diameter of the anus
    • Number of origins: the biceps brachii have two origins
    • Location: the occipitofrontalis has has a frontal and occipital belly
    • Origin and insertion: the sternocleidomastoid originates on the sternum and inserts on the mastoid process of the temporal bone

    Muscles of the face

    • Facial muscles permit facial expressions
    • Expressions of emotions
    • Speech and vocalization
    • Chewing or mastication

    Muscles of the eye and mouth

    • Orbicularis oculi closes the eyelid
    • Orbicularis oris: closes the lips, purses the lips
    • Occipitofrontalis: two bellies - frontal and occipital
    • Frontal belly: raises eyebrows, wrinkles forehead
    • Occipital belly: raises hair (pulls scalp posteriorly)
    • Bellies connected by the epicranial aponeurosis

    Muscles that move the mandible

    • Platysma: pulls the corners of the mouth laterally and inferiorly, permits frowning, depresses the mandible
    • Masseter and temporalis: elevate the mandible

    Muscles of the neck

    • Two sternocleidomastoid muscles
    • One on each side of the neck
    • Originates anteriorly (manubrium) and inserts posteriorly (temporal bone)
    • Rotates the head
    • Extends the head at the atlanto-occipital joint
    • Capable of RMA - Elevation of sternum

    Muscles of the abdomen

    • Protect the abdominal viscera
    • Move the vertebral column
    • External, internal, and transversus abdominis muscles
    • External obliques - most superficial
    • Internal obliques intermediate to external obliques and transversus abdominis
    • Transversus abdominis - deepest muscle
    • Fascicles of the abdominal muscles are arranged at angles to one another
    • Rectus abdominis - runs longitudinally along the anterior of the abdominal cavity
    • Divided by tendinous intersections
    • Responsible for definition of the “6–8 pack”
    • Diaphragm permits breathing
    • Bounds the thoracic cavity inferiorly
    • Circular muscle with origins on many bones and tissues
    • Inserts on the central tendon
    • Contracts, it moves down the lungs expand

    Muscles that move the pectoral girdle

    • Move the clavicle and scapula, or
    • Stabilize the scapula during movement of the humerus
    • Serratus anterior - abducts the scapula
    • RMA: Elevation of the ribs
    • Trapezius muscle - rotates, adducts, depresses, and stabilizes the scapula

    Muscles that move the upper limb

    • Move the humerus
    • Pectoralis major- adducts, medially rotates, and flexes the arm
    • Deltoid muscles - abducts, medially/laterally rotates, flexes/extends the arm
    • Latissimus dorsi - extends, adducts, and medially rotates the arm
    • RMA: elevation of the vertebral column and torso

    Muscles that move the forearm

    • Move the radius and ulna
    • Biceps brachii: two heads (originate on the scapula), inserts on the radius, flexes the arm at the elbow joint, supinates the hand
    • Triceps brachii: originates on scapula and humerus, inserts at the olecranon of the ulna, extends the forearm at the elbow joint
    • Brachioradialis: flexes the arm at the elbow joint, controls speed of movement, supinates and pronates the hand

    Muscles that move the lower limb

    • Gluteal muscles function to move the femur
    • Gluteus Maximus - one of the largest muscles in the body, extends the leg at the hip joint, laterally rotates the femur at the hip joint
    • RMA: extension of the torso
    • Gluteus medius - abducts, and medially rotates the femur

    Flexor compartment of the thigh

    • Includes the “hamstrings” - flex the distal lower limb at the knee joint, extend the leg at the hip joint
    • Biceps femoris - two heads (long and short), lateral hamstring
    • Semitendinosus - intermediate hamstring
    • Semimembranosus - medial hamstring

    Extensor compartment of the thigh

    • The “quads” - four muscles, anterior to the flexor compartment of the thigh, extend the distal lower limb at the knee joint, flex the leg at the hip joint (rectus femoris)
    • Vastus lateralis, vastus medialis, and vastus intermedius - all originate on the femur
    • Rectus femoris originates on the ilia
    • All insert on the patellar tendon

    Medial compartment of the thigh

    • Gracilis: originates on the pubis, adducts the thigh at the hip, medially rotates the thigh, flexes the leg around the knee joint

    Muscles that move the foot

    • Soleus and gastrocnemius: superficial posterior compartment of the leg
    • Soleus: originates at the fibula and tibia, inserts at the calcaneal (Achilles) tendon, permits plantar flexion of the foot at the ankle joint
    • Gastrocnemius: originates on the femur, inserts at the calcaneal tendon, permits plantar flexion of the foot at the ankle joint, flexes the lower limb at the knee joint
    • Tibialis anterior: originates on the tibia, inserts on the metatarsals and tarsals, permits dorsiflexion of the foot at the ankle joint, supination (inversion) of the foot at intertarsal joints

    Homeostatic imbalances of the muscular system

    • Muscle injuries are often activity-related
    • Regular, moderate-intensity exercise helps protect against injury
    • Stretching, good nutrition, and sleep also help!
    • Minor injuries include spasms, cramps, and muscle soreness
    • Spasm - involuntary contraction of a muscle or group of muscles
    • Painful spasms are called cramps
    • Most common cause - dehydration
    • Other causes: injury, overuse, prolonged periods in one position, and inadequate blood flow to muscle(s)
    • Muscle soreness - often due to microscopic damage to muscles
    • May be accompanied by swelling or inflammation
    • May be delayed (24–48 hours following high-intensity exercise)
    • Minor injuries (e.g.strains) should be treated with PRICE - Protection rest ice compression and elevation

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Explore the structure and function of the muscular system, including muscle control and types of levers in the body. Understand the roles of muscles, origins, insertions, and how mechanical advantages are achieved through levers. Test your knowledge on muscle actions and lever classifications.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser