Musculoskeletal System Lecture Notes

Question-and-Answer flashcards that summarize major concepts of the musculoskeletal system lecture, including analogies, bone structure and function, bone cells, bone growth, joint types, cartilage properties, and muscle composition and architecture.

In the musculoskeletal car analogy, what represents the engine that powers movement?

The muscles, which attach to bones to move the body

In the same analogy, which organ is likened to the fuel pump delivering energy?

The heart, which pumps blood to the muscles

Which body system component is compared to a car’s computer, coordinating all movement?

The brain

Name three structural functions of bone.

Provide a rigid framework for the body, act as levers for movement, and protect vital organs such as the brain, spinal cord, heart, and lungs

What are two organ-level functions of bone?

Hemopoiesis (blood cell production) and storage of minerals like calcium, magnesium, sodium, and phosphorus

Which bone cell builds new bone matrix?

Osteoblast

Which bone cell resorbs bone and is crucial for bone homeostasis?

Osteoclast

What is the role of osteocytes within bone?

They are mostly dormant cells that maintain the bone matrix and can modulate osteoblast and osteoclast activity

Which signaling proteins induce and regulate bone and cartilage formation?

Bone morphogenic proteins (BMPs)

What component of the bone matrix provides tensile strength and flexibility?

Collagen fibers

Which molecules help bone retain water within its matrix?

Proteoglycans

What is the function of albumin in the bone matrix?

It transports essential elements to the matrix

What type of bone tissue forms the dense, superficial layer of bones?

Compact (cortical) bone

What type of bone tissue is deep and porous?

Spongy (cancellous) bone

Give an example of a long bone and name its two main regions.

The femur (or humerus), consisting of the epiphyses (ends) and diaphysis (shaft)

Carpals and tarsals are classified as which type of bone?

Short bones

Vertebrae belong to which bone category?

Irregular bones

Define endochondral ossification.

The developmental process in which cartilage is replaced by bone-like osteoid

At birth, where is the earliest bone tissue found in long bones?

In the diaphysis

Longitudinal bone growth occurs at which specific sites?

Epiphyseal (growth) plates

According to Wolff’s law, what condition is necessary for bone growth and remodeling?

Mechanical loading or stress on the bone

Roughly what percentage of femoral growth occurs at the knee end?

About 70%

Bone growth in width is produced by which process and location?

Intramembranous ossification occurring in the periosteum

Which cells are excessively active in osteoporosis?

Osteoclasts

Excessive osteoblast activity would make bones .

Too stiff

Name two examples of fibrous joints.

Syndesmosis between tibia and fibula, and sutures of the skull

A symphysis such as the intervertebral disc joint is classified as what type of joint?

Cartilaginous joint

List three types of synovial (diarthrodial) joints.

Examples include condyloid, hinge, and ball-and-socket joints (others: saddle, pivot, gliding)

Which structure within a synovial joint produces synovial fluid?

The synovial membrane

What is the primary purpose of articular cartilage?

To cushion joints, decrease shear, and absorb shock

Approximately what percentage of articular cartilage is water?

70–80%

Why does damaged articular cartilage heal poorly?

It lacks blood vessels and nerves

How is articular cartilage nourished and lubricated?

Through compression-driven exchange with synovial fluid

What joint problem can arise from abnormal patellar tracking?

Unequal pressure that erodes parts of the articular cartilage

About what percentage of total body weight is skeletal muscle?

40–50%

What proportion of muscle mass is water?

Approximately 75%

Besides locomotion, name three other functions of skeletal muscle.

Maintaining posture, assisting venous return, and generating body heat (thermogenesis)

Define the muscle property of contractibility.

The ability of muscle to shorten and produce force

Which connective tissue layer surrounds an entire muscle?

Epimysium

What connective tissue surrounds a bundle (fascicle) of muscle fibers?

Perimysium

What cell membrane fuses with the tendon and conducts the action potential in a muscle fiber?

Sarcolemma