NCLEX : Musculoskeletal System and Anatomy

Study concepts, example questions & explanations for NCLEX

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Example Questions

Example Question #2 : Muscle Physiology

A nurse is examining a patient who has muscle pain and fatigue after working out. He determines that the patient has muscle strain. This is generally caused by which of the following?

Possible Answers:

The actin and myosin filaments have been pulled past their ability to overlap

There is damage to ligamentous attachments

Excessive contraction causes tetany in the muscle body

Hypertrophy is causing swelling of the muscle fiber

Correct answer:

The actin and myosin filaments have been pulled past their ability to overlap

Explanation:

Muscle strain is often caused by over stretching, during which actin and myosin heads are pulled to the extent that they are no longer overlapping, possibly to the point of causing tears in muscle tissue. Tears in ligaments are sprains, rather than strains.

Example Question #1 : Muscle Physiology

Which is the only muscle type that is non-striated?

Possible Answers:

Voluntary

Smooth muscle

Skeletal muscle

Cardiac muscle

Correct answer:

Smooth muscle

Explanation:

The only type of muscle that is not striated is smooth muscle. Smooth muscle does not use sarcomeres for contraction - rather, each muscle cell is a spindle that is covered in a mesh of contractile fibrils. These fibrils contract in unison when calcium enters the cell.

Example Question #1 : Muscle Physiology

Which of the following is the smallest unit of contractile tissue in cardiac and skeletal muscle cells?

Possible Answers:

The myofibril

The sarcomere

Myosin filament

Actin filaments

Correct answer:

The sarcomere

Explanation:

The smallest contractile unit in muscle tissue is the sarcomere. Myofibrils are made up of many sarcomeres attached end-to-end at a series of dark lines (hence the term "striated") called Z lines. Each sarcomere contains actin and myosin filaments, which pull together during contraction to shorten the sarcomere.

Example Question #61 : Musculoskeletal System And Anatomy

The sliding filament theory of muscle contraction involves the __________ attaching to __________ and then pulling during the power stroke. 

Possible Answers:

myosin . . . tropomyosin

actin head . . . myosin

myosin head . . . actin

troponin . . . actin

Correct answer:

myosin head . . . actin

Explanation:

The sliding filament theory of muscle contraction involves the myosin head attaching to actin and then pulling during the power stroke. Troponin is a protein attached to tropomyosin, a thin strand wrapping around the actin filament. When calcium enters the cell, troponin moves toward it, pulling the tropomyosin strand away from actin binding sites and allowing the myosin head to bind. 

Example Question #241 : General Biology

Which of the following molecules binds to troponin during muscle contraction, triggering tropomyosin to move away from the actin binding sites and allowing the myosin head to form a cross bridge?

Possible Answers:

ATP

ADP

Sodium

Calcium

Correct answer:

Calcium

Explanation:

During a muscle cell action potential, calcium enters the cell via t-tubules, which are specialized invaginations of the sarcoplasmic reticulum. Calcium binds with troponin, which pulls the tropomyosin strand away from actin binding sites and allows myosin heads to bind. Neither sodium nor potassium bind to troponin, and ATP and ADP both bind to myosin, rather than troponin.

Example Question #62 : Musculoskeletal System And Anatomy

Which of the following is the name of the modified endoplasmic reticulum found in muscle cells?

Possible Answers:

The sarcomere

The myoplasmic reticulum

The t-tubule

The sarcoplasmic reticulum

Correct answer:

The sarcoplasmic reticulum

Explanation:

Muscle cells have a specialized endoplasmic reticulum called the sarcoplasmic reticulum. The sarcoplasmic reticulum regulates the calcium ion concentration in the cytoplasm of striated muscle cells, and so plays a significant role in muscle contraction and relaxation. The T-tubule is a specialized invagination of the sarcoplasmic reticulum, and the sarcomere is the single contractile unit of a muscle fibril. There is no muscle structure called the mycoplasmic reticulum.

Example Question #61 : Musculoskeletal System And Anatomy

The articulation between the intervertebral disc is what type of joint?

Possible Answers:

Diarthrotic

Synovial

Cartilaginous

Synarthrotic

Correct answer:

Cartilaginous

Explanation:

The intervertebral disc articulate with the vertebrae via cartilaginous symphysis joints. These joints are amphiarthrotic, meaning that they allow for slight mobility. 

Synovial joints are all diarthrotic and characterized by a flexible joint capsule filled with synovial fluid. Synarthrotic joints have no movement - examples include the skull bones and the joints of the teeth to the jaw.

Example Question #1 : Joints

The head of the femur articulates with what structure of the hip joint?

Possible Answers:

The obturator foramen

The glenoid fossa

The patella

The acetabulum 

Correct answer:

The acetabulum 

Explanation:

The head of the femur articulates with the acetabulum, a concave surface on the pelvis formed by the union of three bones: the ilium, the ischium, and the pubis. 

The obturator foramen is a large opening in the pelvis formed by the pubis and the ischium bilaterally. It does not form any joints but rather allows the passage of the obturator artery, nerve, and vein.

The glenoid fossa is the surface onto which the head of the humerus articulates in the shoulder, and the patella is a part of the knee.

Example Question #1 : Joints

Which of the following structures is a type of synovial fluid sac between bones and overlying tissues?

Possible Answers:

Ligament

Bursa

Capsule

Tendon

Correct answer:

Bursa

Explanation:

Bursae are synovial fluid sac between bones and overlying tissues. They provide a cushion between the bone and tendons or musculature around them, allowing for reduced friction and painless movement.

A tendon is a connective tissue point of attachment of muscle to bone, while a ligament is a connective tissue attachment from bone to bone. A capsule is a fibrous, fluid filled structure surrounding a synovial joint.  

Example Question #61 : Musculoskeletal System And Anatomy

Individuals who grind their teeth are at risk of causing damage to which of the following joints?

Possible Answers:

The temporomandibular joint

The intermetacarpal joint

The xiphisternal joint

The pisotriquetral joint

Correct answer:

The temporomandibular joint

Explanation:

Bruxism, or involuntary tooth grinding, can cause inflammation and damage in the temporomandibular joint, which is the articulation between the condyle of the mandible and the temporal bone. 

The xiphisternal joint is between the xiphoid process and the body of the sternum. The intermetacarpal joints are formed between the metacarpal bones of the hand, and the pisotriquetral joint is between the pisiform and triquetrum of the wrist.

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