Joints

Synathrosis

immovable joint

Fibrocartilage

cartilage that contains fibrous bundles of collagen, such as that of the intervertebral disks in the spinal cord.

articular cartilage

covers the surfaces of bones where they come together to form joints; Articular cartilage reduces friction between bones in the joint during movement and helps to absorb shock.

Meniscus

crescent shaped pads of fibrocartilage lie between the articular surfaces of the bones and are attached to the fibrous capsule.

Components of a synovial joint

-synovial cavity separating articular cartilage -synovial membrane lining synovial cavity -synovial fluid secreted by synovial membrane -joint capsule The inner layer of the articular capsule, is the synovial membrane, which is composed of areolar CT with elastic fibers. The synovial membrane includes accumulations of adipose tissue called articular fat pads.

adbuction/adduction

Abduction is a movement away from the midline - just as abducting someone is to take them away. For example, abduction of the shoulder raises the arms out to the sides of the body. Adduction is a movement towards the midline. Adduction of the hip squeezes the legs together. In fingers and toes, the midline used is not the midline of the body, but of the hand and foot respectively. Therefore, abducting the fingers spreads them out.

Syndesmosis

Fibrous joint in which there is a bigger distance between the articulating surface and more dense irregular CT than in a suture. The dense CT is arranged in as a bundle (ligament). This allows the joint to permit limited movement. Ex. Gomphosis (bones united by fibrous connective tissue, forming an interosseous membrane or ligament)

flexion and extension

Flexion refers to a movement that decreases the angle between two body parts. Flexion at the elbow is decreasing the angle between the ulna and the humerus. When the knee flexes, the ankle moves closer to the buttock, and the angle between the femur and tibia gets smaller. Extension refers to a movement that increases the angle between two body parts. Extension at the elbow is increasing the angle between the ulna and the humerus. Extension of the knee straightens the lower limb.

Hylaine

Hyaline cartilage matrix is primarily made of type II collagen and chondroitin sulphate, both of which are also found in elastic cartilage. Hyaline cartilage exists on the ventral ends of ribs, in the larynx, trachea, and bronchi, and on the articulating surfaces of bones.

Fibrous joints

No synovial cavity and bones are held together by dense irregular tissue that is rich in collagen fiber. The articulating bones are held very tightly together. These fibrous joints permit little to no movement. (consists of inflexible layers of dense connective tissue, holds the bones tightly together)

Which cells produce synovial fluid

The synovial membrane will secrete synovial fluid, a viscous, clear or pale yellow fluid named for its similarity in appearance and consistency to uncooked egg white. Synovial fluid consists of hyaluronic acid secreted by synovial cells in the synovial membrane and interstitial fluid filtered from blood plasma. Forms a thin film over the surface within articular capsules and functions by reducing friction by lubricating joints and absorbing shock, as well as supplying oxygen and nutrients and removing carbon dioxide.

cartilaginous joints

allow only slight movement and consist of bones connected entirely by cartilage. Have a synovial cavity and are united by dense irregular CT of an articular capsule, often by an accessory ligament. This allows considerable movement at a joint. They are classified as freely movable (diarthroses). Covered by a layer of hyaline cartilage called articular cartilage.

Interosseous membrane

flexible membrane connecting radius and ulna & tibia and fibula. Substantial sheet of dense irregular CT that binds neighboring long bones and will permit slight movement.

Diarthrosis

freely movable joints; also known as synovial joints.

knee joint

hinge joint; As the knee is a synovial hinge joint, its function is to permit the flexion and extension of the lower leg relative to the thigh. ... A special characteristic of the knee that differentiates it from other hinge joints is that it allows a small degree of medial and lateral rotation when it is moderately flexed.

Sutures

immovable joints of the skull. A fibrous joint composed of a thin layer of dense irregular connective tissue. They are immovable or slightly movable. They play an important role in shock absorption. Synostosis is when two bones fuse together.

synovial membrane

membrane lining the capsule of a joint; The inner layer of the articular capsule, composed of areolar connective tissue with elastic fibers.

Articular capsule

surrounds the synovial joint, encloses the synovial cavity and unites the articulating bones. Composed of two layers, an outer and inner fibrous membrane. The fibrous membrane contains dense irregular tissue which attaches to the perimysium of the articulating bone.