Skeletal System [Applied Science 25%] Flashcards
What is a joint?
An articulation between two bones in the body.
How is the skeletal system divided?
AXIAL SKELETON: The bones of the head, trunk, and vertebrae.
APPENDICULAR SKELETON: The bones of the shoulder girdle, pelvic girdle, and limbs.
What are the 5 types of bones in the human body?
- Flat bones
- Short bones
- Long bones
- Sesamoid bones
- Irregular bones
What are flat bones?
These bone types protect the internal organs and provide a large surface area for muscles to attach. They are somewhat flat and thin but may be curved (i.e. the ribs).
What are short bones?
These bones are cube-shaped and provide stability with a limited amount of movement.
Examples include the carpals (bones in the wrist) and tarsals (bones in the ankle).
What are long bones?
These bones support body weight and facilitate movement. They are longer than they are wide, typically a cylinder shape.
Examples include the femur (thigh bone), the tibia and fibula (bones of the lower leg), and the humerus (upper arm bone between the elbow and shoulder).
What are sesamoid bones?
These bones are small and round, usually found in joints and within tendons.
They reinforce and protect tendons from stress and wear and tear.
The patella (kneecap) is an example of a sesamoid bone.
What are irregular bones?
These bones serve a variety of purposes, including protecting vital organs. They have complex shapes, like the vertebrae.
Describe the general structure of a bone.
Bone is composed of 50 to 70 percent minerals, 20 to 40 percent organic matrix, 5 to 10 percent water, and less than 3 percent lipids (fats).
The way bone is structured allows it to provide support and protection as well as store calcium and bone marrow.
What is bone marrow?
The soft, spongelike tissue in the center of most bones containing stem cells of red or white blood cells or platelets.
Red bone marrow holds stem cells that develop into red blood cells, white blood cells, and platelets, which aid in blood clotting.
Yellow marrow stores fat cells for energy.
What is cancellous bone? (Bone Structure)
Also known as spongy bone. The meshwork of spongy tissue (trabeculae) of mature adult bone, typically found at the core of vertebral bones and the ends of the long bones.
What is compact bone? (Bone Structure)
A denser material, also known as cortical bone, making up the hard structure of the skeleton.
The fibers in this bone are arranged in a honeycomb pattern, which allows nerves and blood vessels to pass through the honeycomb and supply the bone with oxygen and nutrients.
What is the periosteum?
This is a vascular connective tissue that covers the bone (except joints) and is responsible for repairing, protecting, and growing bones
What is osteogensis?
The process of bone formation or remodeling. Throughout life, old bone is continually replaced with new bone.
What is myositis ossificans?
A condition when bone tissue forms within a muscle or other soft tissue as a result of trauma or injury.
What is cartiladge?
Firm, flexible connective tissue that pads and protects joints and structural components of the body.
What is Wolff’s Law?
This law states that changes in form and function of a bone will be adaptive to the loads placed upon it.
In other words, strength training helps to build stronger bones.
What are the 3 types of joints, and how are they classified?
Joints are classified by the type of tissue they contain: fibrous, cartilaginous, or synovial
What is a fibrous joint?
Joints with fibrous connective tissue joining two bones that allow for very little movement.
What are cartilaginous joints?
These joints are joined by either fibrocartilage, the most rigid and strong cartilage, or hyaline cartilage, which is softer and more widespread.
These joints are slightly movable and are further divided into primary and secondary joints.
- Primary: epiphyseal (growth) plates
- Secondary: intervertebral discs (layers of cartilage between vertebrae)
What are synovial joints?
The most common, moveable joints in the body. They are fluid-filled joints found between bones that move against one another.
What is the articular capsule in synovial joints?
In synovial joints, bones are separated by a synovial joint cavity made of dense, irregular connective tissue. The outside of this cavity is an envelope surrounding the synovial joint.
What are the 6 categories of synovial joints?
- Ball-and-socket joint: Also known as an enarthrodial joint, this joint allows a wide range of movement in many directions. Examples are the shoulder and hip joints.
- Saddle joint: The sellar or saddle joints are like ball-and-socket joints but cannot rotate. Examples include the trapezium and the first metacarpal joint (joint between the thumb and wrist).
- Hinge joint: The hinge joints include the elbows, ankles, and knee joints. They allow a wide range of movement in one plane (direction).
- Gliding joint: The arthrodial or gliding joints of the body include the tarsals and metatarsal of the foot. In these joints, two flat bones press up against each other.
- Pivot joint: Trochoidal or pivot joints rotate around a long axis (line that runs parallel to the joint). The radioulnar joint of the forearm is a pivot joint.
- Condyloid joint: Also known as an ellipsoid joint, these joints move in two directions—one direction primarily with a small range in another direction. Rotation is not allowed in these joints. The radiocarpal joint at the wrist is a prime example.
What is arthrokinematics?
Joint motion.
