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Questions and Answers
What type of muscle is under voluntary control?
What type of muscle is under voluntary control?
- Cardiac muscle
- Skeletal muscle (correct)
- Smooth muscle
- Involuntary muscle
The muscle belly is the thin portion of the muscle located between the tendons.
The muscle belly is the thin portion of the muscle located between the tendons.
False (B)
What is the term for the end of a muscle attached to a stationary bone?
What is the term for the end of a muscle attached to a stationary bone?
origin
A second-class lever is characterized by the load being located between the _____ and the fulcrum.
A second-class lever is characterized by the load being located between the _____ and the fulcrum.
Match the type of lever with its features:
Match the type of lever with its features:
Which muscle action is responsible for standing on your toes?
Which muscle action is responsible for standing on your toes?
Third-class levers always produce a mechanical advantage.
Third-class levers always produce a mechanical advantage.
Muscles usually work in _____ pairs to produce movement.
Muscles usually work in _____ pairs to produce movement.
What movement occurs when the diaphragm contracts?
What movement occurs when the diaphragm contracts?
The serratus anterior muscle assists in elevating the scapula.
The serratus anterior muscle assists in elevating the scapula.
What is the primary function of the muscles that move the pectoral girdle?
What is the primary function of the muscles that move the pectoral girdle?
The _____ muscle originates on the occipital bone and permits adduction of the scapula.
The _____ muscle originates on the occipital bone and permits adduction of the scapula.
Match the following muscles with their actions:
Match the following muscles with their actions:
What is the primary action of the biceps brachii at the elbow joint?
What is the primary action of the biceps brachii at the elbow joint?
The triceps brachii acts as the agonist when flexing the elbow joint.
The triceps brachii acts as the agonist when flexing the elbow joint.
What muscle group acts as fixators during shoulder abduction?
What muscle group acts as fixators during shoulder abduction?
The _____ fixes one end of the bone while the other end moves.
The _____ fixes one end of the bone while the other end moves.
Match the following muscles with their actions:
Match the following muscles with their actions:
Which of the following best describes the function of the diaphragm?
Which of the following best describes the function of the diaphragm?
Muscles are named randomly without any specific reasoning.
Muscles are named randomly without any specific reasoning.
What are the three compartments of the upper limb muscles categorized by?
What are the three compartments of the upper limb muscles categorized by?
The external obliques extend _____ and _____, while the internal obliques extend medially but _____
The external obliques extend _____ and _____, while the internal obliques extend medially but _____
What is the role of synergist muscles during movement?
What is the role of synergist muscles during movement?
The rectus abdominis is the deepest muscle in the abdominal wall.
The rectus abdominis is the deepest muscle in the abdominal wall.
What is the primary action of the occipitofrontalis muscle?
What is the primary action of the occipitofrontalis muscle?
The _____ is responsible for the definition of the '6–8 pack' in abdominal muscles.
The _____ is responsible for the definition of the '6–8 pack' in abdominal muscles.
Match the muscle with its corresponding role:
Match the muscle with its corresponding role:
Study Notes
Voluntary Control
- All skeletal muscles are under voluntary control.
- The muscular system supports body movement and generates heat.
Muscle Anatomy
- Origin: The end of a muscle attached to a stabilized or stationary bone, usually proximal.
- Insertion: The end of a muscle attached to a moving bone, usually distal.
- Muscle belly: The thickened portion of the muscle between tendons.
- Actions: Movements possible when a muscle contracts.
- Reverse Muscle Actions (RMAs): Occur when the origin and insertion are reversed. Some muscles can perform both actions and RMAs.
Levers
- Lever: A rigid structure that can move around a fixed point (fulcrum).
- Load: Resistance against effort.
- Effort: Force required to move a load.
- Bones are levers moved by the effort of muscle action.
Classes of Levers
- First-class: Fulcrum is between effort and load (e.g., looking up at the ceiling).
- Second-class: Load is between effort and fulcrum (e.g., standing on your toes).
- Third-class: Effort is between fulcrum and load (e.g., bending your elbow). They are the most common levers in the body.
Muscle Groups
- Muscles work in groups, often as opposing pairs.
- Agonist: Muscle causing the desired movement.
- Antagonist: Muscle opposing the agonist.
- Synergist: Muscles that stabilize joints during movement, allowing for movement around only one joint.
- Fixators stabilize one end of a bone so the other end can move.
Muscle Compartments
- Compartments are groups of skeletal muscles, their nerves, and blood vessels with specific functions.
Muscle Naming
- Muscles are named based on their direction, size, shape, action, number of origins, location, or origin and insertion.
Facial Muscles
- Permit facial expressions, including the expression of emotions, speech, vocalization, and chewing (mastication).
Eye and Mouth Muscles
- Orbicularis oculi: Closes the eyelid.
- Orbicularis oris: Closes the lips and purses them.
- Occipitofrontalis: Has two bellies:
- Frontal belly: Raises eyebrows and wrinkles the forehead.
- Occipital belly: Raises hair and pulls the scalp posteriorly.
- The bellies are connected by the epicranial aponeurosis.
Mandible Muscles
- Platysma: Pulls the corners of the mouth laterally and inferiorly, depresses the mandible, and permits frowning.
- Masseter and temporalis: Elevate (close) the mandible.
Neck Muscles
- Sternocleidomastoid (two muscles):
- Originates anteriorly and inserts posteriorly.
- Rotates the head and can extend the head at the atlantooccipital joint.
- Capable of RMAs, permitting elevation of the sternum.
Abdominal Muscles
- Protect abdominal viscera and move the vertebral column.
- External obliques: Most superficial.
- Internal obliques: Intermediate.
- Transversus abdominis: Deepest.
- Rectus abdominis: Runs longitudinally along the anterior abdominal cavity, responsible for the "6-8 pack."
Diaphragm
- Bounds the thoracic cavity inferiorly.
- Contracts to move downwards, causing the lungs to expand.
Pectoral Girdle Muscles
- Move the clavicle and scapula or stabilize the scapula during humerus movement.
Upper Limb Muscles
- Move the humerus.
- Pectoralis major: Adducts, medially rotates, and flexes the arm.
- Deltoid: Abducts, medially/laterally rotates, and flexes/extends the arm.
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Description
Test your knowledge on muscle anatomy and how muscle contractions facilitate body movement. This quiz covers topics such as muscle origin, insertion, and the mechanics of levers in the muscular system. Understand the various classes of levers and their applications in human movement.
