Unformatted text preview: Page 1 Chapter 8-Joints
For this assignment, please read the chapter and answer the questions below.
Please type your answers in red or blue color.
Please note that points may be deducted if answers are not submitted in these
Sentences in italics are meant to help you understand the material- they are not questions. Table 8.2 in the textbook is a good reference for this assignment
1. What is a joint? (1 point) A joint or articulation is the point of connection of two or more bones. These points
provide protection as well as allow for mobility.
2. Compare the structure, function and body locations of bursae and tendon sheaths
Figure 8.4 in the textbook (1 point) Bursae are flattened fibrous sacs lined with synovial membrane and containing a thin film
of synovial fluid. They are found wherever muscles, bones, tendons, or bones are contact
with each other as in the shoulder. Tendon sheaths are elongated bursa that envelope
tendon to reduce friction wherever tendons are crowded together as in the wrist.
3. Joint movements can be nonaxial, uniaxial, biaxial or multiaxial. Define what each of these terms
mean. (4 points) Nonaxial movements mean slipping movements only, uniaxial movements mean
movement in one plane, biaxial movements mean movement in two planes, and
multiaxial movements mean movement in or around all three planes and axes.
4. Compare and contrast the paired movements of flexion and extension with the paired
movements of adduction and abduction. Figure 8.5 in the textbook (4 points) Flexion and extension refer to decreasing or increasing the angle of a joint and bringing
the two articulating bones together along the sagittal plane. Abduction and adduction are
used to describe movements towards or away from the midline of the body. Adduction is
the movement of a limb or other part towards the midline of the body. Abduction is the
movement of a limb or other part away from the midline of the body.
5. How does rotation differ from circumduction? (1 point) Rotation means to turn a bone around its own long axis, while circumduction means to
move a limb so that it describes a cone in space, an action that involves a variety of
6. What is the specific role of the menisci of the knee? (1 point)
Chapter 8 BIO 201 Page 2
The knee menisci deepen the articulating surface of the tibia to prevent side-to-side
rocking of the femur on the tibia and to absorb shock transmitted to the knee joint.
7. What is the role of the anterior and posterior cruciate ligaments of the knee? (1 point) The cruciate ligaments prevent anterior/posterior displacement of the articulating bone
and help to secure the joint.
8. Explain why sprains and cartilage injuries take so long to heal? (1 point) Cartilage and tendons are both connective tissues with very poor blood supplies.
9. List the functions of the following components of a synovial joint- fibrous layer of the capsule,
synovial fluid and articular cartilage. Figure 8.3 in the textbook (3 points) The function of the synovial joint are those in which the articulating bones are separated
by a fluid-containing joint cavity. This arrangement permits substantial freedom of
movement, and all synovial joints are freely movable diarthroses. Most joints in the body
are synovial joints, (one example is the hip joint).
The fibrous layer is composed of dense irregular connective tissue that is continuous with
the periostea of the articulating bones. It strengthens the joint so that the bones are not
Synovial fluid, which is also found within the articular cartilages, provides a slippery,
weight-bearing film that reduces friction between the cartilages. Without this lubricant,
rubbing would wear away joint surfaces and excessive friction could overheat and
destroy the joint tissues.
Articular cartilage is a glassy-smooth hyaline cartilage covers the opposing bone surfaces
as articular cartilage. These thin (1 mm or less) but spongy cushions absorb compression
placed on the joint and thereby keep the bone ends from being crushed.
10. List and describe the 2 major types of classification for the Joints-Figures 8.1 and 8.2 (2 points). Fibrous joints, the bones are joined by the collagen fibers of connective tissue. No joint
cavity is present. The amount of movement allowed depends on the length of the
connective tissue fibers. Most fibrous joints are immovable (immobile).
Synovial joints are those in which the articulating bones are separated by a fluidcontaining joint cavity. This arrangement permits substantial freedom of movement, and
all synovial joints are freely movable diarthroses. 11. Look at the Focus on Synovial Joints on pages 262 and 263. List out the shapes of the joint
surfaces and define the types of movements of each type of synovial joint. (6 points) Plane joints - articular surfaces are flat allowing only short gliding or transitional
Hinge joints - cylindrical projection of one bone fits into a trough-shaped surface on
another. Motion is along a single plane and resembles that of a mechanical hinge.
Chapter 8 BIO 201 Page 3
Pivot joints - Rounded end of one bone protrudes into a sleeve or ring composed of bone
of another. The only moment allowed is uniaxial rotation of one bone around its own long
Condyloid joints - the oval articular surface of one bone fits into a complementary
depression in another, angular motions
Saddle joints - resemble condyloid joints but allow more movement
Ball-and-socket joints - spherical head of one bone articulates with the cup-like socket of
another, muliaxial moving freely.
12. What are some common joint injuries? (1 point) Sprains, cartilage, and dislocation.
13. Inflammatory and Degenerative Condition of joints- briefly describe bursitis, tendonitis,
osteoarthritis (OA), rheumatoid arthritis (RA) and gouty arthritis. (5 points) Bursitis- An inflammation of bursae, the fluid filled sacs that cushion the joints.
Tendonitis- Is the inflammation of the tendon, a thick tissue that connects muscles to
Osteoarthritis (OA)-Inflammation of one or more joints.
Rheumatoid arthritis (RA) - A chronic autoimmune inflammatory disease that affects the
Gouty arthritis- A type of arthritis that causes inflammation of joints due to excess uric
acid. Chapter 8 BIO 201 ...
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- Fall '14
- joints, Synovial joint, Gouty arthritis