Skeletal System Overview and Anatomy

Flashcards covering skeletal system overview, bone classifications, joint types, fractures, disorders, and the axial and appendicular skeletons.

What five structures make up the skeletal system?

Bones, Joints, Cartilage, Tendons (Bone to Muscle), and Ligaments (Bone to Bones).

What are the five primary functions of the skeletal system?

1. Support the body
2. Protection of soft organs
3. Movement due to attached skeletal muscles
4. Storage of the minerals and fats
5. Blood cell formation

What are the characteristics of compact bone and spongy bone?

Compact bone is the hard outer layer of bone. Spongy bone is less dense, consisting of small needle-like pieces of bone (trabeculae) with many open spaces.

How are long bones characterized, and what are two examples?

They are typically longer than wide, have a shaft with heads at both ends, and contain mostly compact bone. Examples include the femur and humerus.

What are the features and examples of short bones and flat bones?

Short bones are generally cube-shaped and contain mostly spongy bone (e.g., carpals, tarsals). Flat bones are thin, flattened, usually curved, with thin layers of compact bone around a layer of spongy bone (e.g., skull, ribs, sternum).

What is the diaphysis of a long bone?

The shaft of the bone, composed of compact bone and serving as the location of yellow marrow (fat).

What is the epiphysis of a long bone?

The ends of the bone, composed mostly of spongy bone and serving as the location of red marrow (blood formation).

What is the function and composition of articular cartilage?

It covers the external surface of the epiphyses, is made of hyaline cartilage, and decreases friction at joint surfaces.

What does the medullary cavity contain in adults versus infants?

It contains yellow marrow (mostly fat) in adults, and red marrow for blood cell formation in infants.

What are the functions of osteocytes, osteoblats, and osteoclasts?

Osteocytes are mature bone cells; osteoblats are bone-farming cells for bone growth; osteoclasts are bone-destroying cells that break down bone matrix for remodeling and release of calcium.

How does bone growth occur at the epiphyseal plates during childhood?

New cartilage is continuously formed while older cartilage becomes ossified (changed to bone). Cartilage is broken down and replaced by bone.

How are fibrous joints, Catilaginous Joints, and synovial joints structurally classified?

Fibrous joints are generally immovable (e.g., cranium bones); Catilaginous Joints are immovable or slightly moveable with fibrocartilage between bones (e.g., ribs, sternum, vertebrate, pelvis); synovial joints are freely moveable joints where bones do not come in contact with each other.

What are bursae and menisci?

Bursae are fluid-filled sacs that cushion joints. Menisci are cartilaginous pads of tissue located between the tibia and femur in the knee joint.

What are the four stages in the repair of bone fractures?

1. Hermatoma (bone-filled swelling) is formed
2. Break is sprinted (immobilized) by fibrocartilage to form a callus
3. Fibrocartilage callus is replaced by a bony callus
4. Bony callus is remodeled to form a permanent path

How does the most common torn meniscus injury occur?

It occurs when the knee joint is bent and the knee is then twisted.

What mechanism causes a torn ACL, and what condition can it lead to if left untreated?

It occurs when the knee is locked with the foot planted and the knee is twisted quickly; left untreated, it can lead to osteoarthritis.

What causes brittle bones and fractures in osteoporosis?

During menopause, estrogen levels drop and the body stops making new bones due to lack of calcium.

What distinguishes osteoarthritis from rheumatoid arthritis?

Osteoarthritis is the most common type caused by wear and tear on joints where cartilage breaks down and bony spurs may develop. Rheumatoid arthritis is an autoimmune disease where the body mistakenly attacks healthy tissues, breaking down cartilage.

What is gout and what causes it?

A type of arthritis that occurs when uric acid builds up in the blood, causing crystals to form in the joint, leading to major inflammation.

How many bones are in the adult human skeleton, and into which two parts is it divided?

There are $206$ bones, divided into the Axial Skeleton (Skull, Vertebral column, Rib cage) and the Appendicular Skeleton (Bones of arms and legs, Bone of shoulder, Pelvis).

Which eight flat bones make up the cranium?

One frontal bone, $2$ Parietal bones, $1$ occipital bone, and $2$ Temporal bones.

What is the Foramen Magnum?

An opening in the occipital bone where the spinal cord joins the brain.

What are Frontanelles and when do they convert to bone?

Fibrous membranes connecting cranial bones in the fetal skull that allow the brain to grow; they convert to bone within $24\text{ months}$ after birth.

What are the characteristics of the maxilla and the mandible?

The maxilla consists of $2$ bones that form the upper jaw. The mandible is the lower jaw, the only moveable bone of the skull, and contains tooth sockets for $16$ teeth.

How are true ribs, false ribs, and floating ribs defined?

True ribs connect directly to the sternum; false ribs attach to the sternum by a common cartilage; floating ribs do not attach to the sternum.

What are the three parts of the sternum, and what is the function of the xiphoid process?

The three parts are the manubrium, body, and xiphoid process. The xiphoid process is the inferior and smallest portion of the sternum and serves as the attachment site for the diaphragm.

What four bones compose the pectoral (shoulder) girdle?

$2$ clavicles (collarbones) that are slender, S-shaped, and structurally weak (take five pounds to break), and $2$ Scalpulas (shoulder blades) that are triangular in shape.

Which bones make up the upper limb?

The humerus (upper arm), radius and ulna (forearm), and carpals, metacarpals, palagenses (hand).