Anatomy: Generalities

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Questions and Answers

What proportion of the nerve trunk is made up of motor fibers?

80%

70%

50%

60% (correct)

What is the primary consequence of losing motor innervation to a muscle?

Improved muscle coordination

Rapid muscle fiber degeneration (correct)

Increase in muscle size

Enhanced muscle strength

What causes disuse (physiologic) atrophy in muscles?

Genetic predisposition to weak muscles

Excessive physical activity

Injury leading to immobilization

Not using the muscles enough (correct)

Which type of fibers does the nerve trunk NOT primarily contain?

Cognitive fibers Signup and view all the answers

What is the role of atrophy-related signaling upon muscle denervation?

Promotes muscle breakdown Signup and view all the answers

What is a significant effect of disuse atrophy on muscle tissue?

Decrease in muscle size and strength Signup and view all the answers

Which anatomical aspect should be emphasized for understanding muscle innervation?

Specific muscles and their innervation Signup and view all the answers

What physiological response occurs when muscles are not used adequately?

Body begins to conserve energy by breaking down muscle Signup and view all the answers

Which muscle name indicates it has two origins?

Biceps Signup and view all the answers

Which of the following names reflects the size of the muscle?

Gluteus maximus Signup and view all the answers

Which muscle is named for indicating its shape?

Rhomboid major Signup and view all the answers

Which of the following muscles is characterized as having four origins?

Quadriceps Signup and view all the answers

Which anatomical naming convention relates to the attachment point of a muscle?

Attachments/Structure Signup and view all the answers

Identify the muscle name that is derived from its direction of fibers.

Obliquus Signup and view all the answers

Which of the following pairs correctly identifies the smallest muscle?

Gluteus minimus - Smallest Signup and view all the answers

What term refers to a muscle being named for its location under another structure?

Subscapularis Signup and view all the answers

What is referred to as the prime mover in muscle mechanics?

The chief muscle responsible for a specific movement Signup and view all the answers

Which muscle acts as the antagonist during elbow flexion?

Triceps brachii Signup and view all the answers

What role do synergist muscles play in muscle movements?

They stabilize the body while the prime mover acts Signup and view all the answers

What is the correct anatomical classification of the 'origin' of a muscle?

The fixed or stable attachment of the muscle Signup and view all the answers

Which statement accurately describes the relationship between biceps and triceps during elbow extension?

Triceps become the prime movers while biceps act as antagonists Signup and view all the answers

What is one of the main functions of muscle contraction besides movement?

Heat generation Signup and view all the answers

Which of the following muscles can be a prime mover during actions like squatting?

Quadriceps femoris Signup and view all the answers

What is the definition of the 'belly' of a muscle?

The fleshy part of the muscle located between its origin and insertion Signup and view all the answers

Which term describes muscle fibers that run at an angle?

Obliques Signup and view all the answers

What is the meaning of the prefix 'latissimus' in anatomical terms?

Large Signup and view all the answers

In anatomical terminology, which prefix indicates a muscle that is considered short?

Brevis Signup and view all the answers

Which of the following terms means 'away from' in anatomical terminology?

Ab Signup and view all the answers

Which of the following terms translates to 'straight' in the context of muscle fibers?

Rectus Signup and view all the answers

What does the suffix 'minimus' denote in anatomically named muscles?

Small Signup and view all the answers

Which prefix indicates 'many' when describing anatomical structures?

Multi Signup and view all the answers

What does the prefix 'medius' refer to in muscle nomenclature?

Medium Signup and view all the answers

What does the term 'transverse' specifically refer to in relation to sensation?

A band-like sensation across the body trunk Signup and view all the answers

Which condition is characterized by the inability to voluntarily move the lower parts of the body?

Paraplegia Signup and view all the answers

What is the primary cause of cases of paraplegia in hospital settings?

Spinal cord injuries from motor and vehicular accidents Signup and view all the answers

What advice was given regarding exercise in relation to studying?

Exercise is crucial for stress relief. Signup and view all the answers

What is the recommended approach before studying abnormalities in medical conditions?

Understand the normal functions before studying the abnormal Signup and view all the answers

Study Notes

Prime Movers

Prime mover (agonist): Chief muscle responsible for specific movement (e.g., triceps for forearm extension).
Biceps brachii: Prime mover for elbow flexion; triceps become antagonists in this action.

Muscle Anatomy

Origin: Stable attachment point, more proximal part of the muscle.
Insertion: Mobile attachment point, more distal part of the muscle.
Belly: Fleshy, central part of the muscle.

Functions of Muscles

Movement: Facilitates bodily motion.
Heat Generation: Muscle contractions produce heat as a byproduct of metabolism.
Shape and Contour: Influences physical appearance of the body.

Antagonists and Synergists

Antagonist: Muscle that opposes the action of the prime mover (e.g., biceps vs. triceps during elbow movements).
Synergists: Muscles that assist prime movers in their action.

Muscle Innervation and Nerve Supply

Mixed nerve trunk: Comprises 60% motor fibers and 40% sensory fibers, includes sympathetic fibers.
Importance of nerve supply for muscle function and response.

Disuse Atrophy

Caused by insufficient muscle use; leads to fiber degeneration and reduced muscle strength and size.
Body conserves energy by breaking down unused muscle fibers.

Muscle Classification

Number of Heads: Name reflects number of muscle origins (e.g., biceps = two, triceps = three, quadriceps = four).
Attachments: Named for their attachments (e.g., sternocleidomastoid connects sternum and clavicle).
Size: Influenced by naming conventions (e.g., gluteus maximus, medius, minimus).

Muscle Structure

Depth: Reflects attachment particulars and location in the body.
Shape: Names may describe morphology (e.g., deltoid = triangular).
Direction of Fibers: Terminology reflects fiber orientation (e.g., rectus = straight, oblique = angled).

Naming Conventions

Combinations: Names may result from combining attributes (e.g., flexor digitorum longus).
Latin Roots: Significant in anatomical naming (e.g., rectus = straight, multi = many).

Neurological Impact

Paraplegia: Inability to move lower body, often due to spinal cord injury from accidents.

Study Tips

Memorize anatomical terms, muscle innervations, and functions.
Review upper and lower extremity muscles; understand implications of disuse and denervation.
Exercise importance: Crucial for physical health and stress relief.

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Description

Test your knowledge on muscle anatomy, the roles of prime movers, antagonists, and synergists, and the functions of muscles in the human body. This quiz will also cover muscle innervation and the importance of nerve supply in muscle function.