Download 2C Worksheet KEY

BIOL 255 SI, Molly
Unit 2C KEY, 9/28/16
1) Articulations or joints are classified by how they function, Diarthroses are free moving,
Amphiarthroses are slightly moveable and synarthroses are unmovable. 2C 1
2) Articulations are also classified by structure. Fibrous have no synovial cavity and are
composed of fibrous connective tissue that binds so there is little or no movement. An
example would be the sutures on the cranial bones. Syndesmoses are also fibrous connective
tissue but not as tightly fit as a suture. An example would be the distal articulation between
the tibia and fibula. Gomphoses are like a peg in socket such as the teeth in the maxilla and
mandible.2C 1
3) Classify the Fibrous joints:
Look in text book page 252 table 9.1
Structure
Function
Amount of movement
Gomphoses = Synarthroses = immobile
Sutures = Synarthroses = immobile
Syndesmoses = Amphiarthroses = slightly mobile
4) Another classification by structure is the cartilaginous joints, also having no synovial
cavity, with little or no movement. One type is synchondrosis which is hyaline cartilage
between the epiphysis and diaphysis or the epiphyseal plate, or between the first rib and
sternum. Another type is a symphysis which is a broad flat disk of cartilage between bones
and is slightly movable as in the intervertebral disks and the symphysis pubis. 2C 1-2
5) Classify the Cartilaginous joints:
Look in text book page 252 table 9.1
Structure
Function
Amount of movement
Synchondrosis = Synarthroses = immobile
Symphysis = Amphiarthroses= slightly mobile.
6) The final classification by structure is the synovial joint which are freely moving. Their
movement is limited by bone structures or the tension of the connecting ligaments, muscles
and apposition of soft body parts. These joints have synovial cavities which are fluid filled.
Structure
Function
Amount of movement
Synovial = Diarthroses = freely moving.
2C 2
7) In synovial joints the articular capsule encloses the cavity and unites 2 bones. The outer
layer of the fibrous capsule is dense connective tissue which connects to the periosteum and
if the fibers are aligned in the same way it is a ligament. While the inner layer of the
synovial membrane is loose connective tissue which encloses the synovial fluid. 2C 2
8) Saclike structures between adjacent structures are referred to as bursae, and at times
when it is wrapped around a structure it is referred to as a sheath. While the articular discs
that subdivide a synovial cavity is referred to as menisci. 2 C 2-3
9) Movements at synovial joints are caused by muscle contraction. The origin of the muscle is
attached to less movable bone, which is usually located more medially while the insertion is
where it attaches to moveable bone is usually more lateral. 2C 3
10) In angular movements, flexion decreases the angle and extension increases the angle
between two bones, while hyperextension is movement beyond the anatomical position and
lateral flexion is bending along the frontal plane. 2C 3
11) Supporting structures of the knee are the anterior and posterior cruciate ligaments
which prevent hyperextension. If one was to receive a lateral blow to the knee, one might
have damage in the tibial collateral ligament, the medial meniscus and/or the anterior
cruciate ligament.2C7
12) The shoulder is a Ball-and-socket joint in which stability is sacrificed to obtain greater
freedom of movement. The head of the humerus articulates with the glenoid fossa of the
scapula. The hip is also a ball-and-socket joint in which the head of the femur articles with
the acetabulum. Although this joint has good range of motion, its movement is limited by the
deep socket and strong ligaments. 2C 8
13) Joints develop from the mesoderm germ layer or more specifically the mesenchymal
cells. 2C8