Skeletal System [Applied Science 25%]

Question 1

What is a joint?

Answer 1

An articulation between two bones in the body.

Question 2

How is the skeletal system divided?

Answer 2

AXIAL SKELETON: The bones of the head, trunk, and vertebrae.

APPENDICULAR SKELETON: The bones of the shoulder girdle, pelvic girdle, and limbs.

Question 3

What are the 5 types of bones in the human body?

Answer 3

1. Flat bones
2. Short bones
3. Long bones
4. Sesamoid bones
5. Irregular bones

Question 4

What are flat bones?

Answer 4

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).

Question 5

What are short bones?

Answer 5

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).

Question 6

What are long bones?

Answer 6

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).

Question 7

What are sesamoid bones?

Answer 7

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.

Question 8

What are irregular bones?

Answer 8

These bones serve a variety of purposes, including protecting vital organs. They have complex shapes, like the vertebrae.

Question 9

Describe the general structure of a bone.

Answer 9

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.

Question 10

What is bone marrow?

Answer 10

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.

Question 11

What is cancellous bone? (Bone Structure)

Answer 11

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.

Question 12

What is compact bone? (Bone Structure)

Answer 12

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.

Question 13

What is the periosteum?

Answer 13

This is a vascular connective tissue that covers the bone (except joints) and is responsible for repairing, protecting, and growing bones

Question 14

What is osteogensis?

Answer 14

The process of bone formation or remodeling. Throughout life, old bone is continually replaced with new bone.

Question 15

What is myositis ossificans?

Answer 15

A condition when bone tissue forms within a muscle or other soft tissue as a result of trauma or injury.

Question 16

What is cartiladge?

Answer 16

Firm, flexible connective tissue that pads and protects joints and structural components of the body.

Question 17

What is Wolff’s Law?

Answer 17

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.

Question 18

What are the 3 types of joints, and how are they classified?

Answer 18

Joints are classified by the type of tissue they contain: fibrous, cartilaginous, or synovial

Question 19

What is a fibrous joint?

Answer 19

Joints with fibrous connective tissue joining two bones that allow for very little movement.

Question 20

What are cartilaginous joints?

Answer 20

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.

1. Primary: epiphyseal (growth) plates
2. Secondary: intervertebral discs (layers of cartilage between vertebrae)

Question 21

What are synovial joints?

Answer 21

The most common, moveable joints in the body. They are fluid-filled joints found between bones that move against one another.

Question 22

What is the articular capsule in synovial joints?

Answer 22

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.

Question 23

What are the 6 categories of synovial joints?

Answer 23

1. 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.
2. 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).
3. Hinge joint: The hinge joints include the elbows, ankles, and knee joints. They allow a wide range of movement in one plane (direction).
4. 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.
5. 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.
6. 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.

Question 24

What is arthrokinematics?

Answer 24

Joint motion.

Question 25

What is joint position?

Answer 25

The position where bones make contact with one another.

Question 26

What is a close-packed joint position?

Answer 26

In this joint position, the joint is the most stable, connective tissue is taut, and the articulating bones have the greatest area of contact with one another.

(i.e. knee extension)

Question 27

What is a loose-packed joint position?

Answer 27

Describes any possible joint position other than the closed-packed position.

This is often during movement when the joint capsule is lax and neighboring bones are not aligned.

Question 28

What are tendons?

Answer 28

These connect muscle to bone and serve as a mechanical bridge to transmit the force created by muscle contraction.

When the muscle shortens or contracts, this connective tissue transfers that force to the bone at an attachment site.

The angle and length of attachment of this tissue to the bone affect how the muscle acts on the affected bone.

These connective tissues are strong, relatively inflexible, and can withstand the force generated by heavy loads without being injured.

For example, the flexors of the foot can support a load of more than eight times one’s body weight. A muscle alone could not withstand the same amount of tension.

Question 29

What is the golgi-tendon organ and what does it do?

Answer 29

The proprioceptive sensory organ that senses muscle tension in a tendon and inhibits muscle action.

This organ responds to changes in muscle tension. It prevents the overstretching or tearing of a muscle by sensing the rate and force of muscle tension and inhibits muscle action in the same muscle through a feedback loop.

Question 30

What is muscle spindle and what does it do?

Answer 30

The proprioceptive sensory organ that senses muscle stretch in a muscle and promotes muscle action.

It detects the rate and force of muscle stretch but promotes muscle contraction instead of inhibiting it.

Question 31

What are ligaments?

Answer 31

Tough bands of connective tissue made of collagen and elastin connecting bone to bone, forming joints.

Question 32

What is elastin?

Answer 32

A highly elastic connective tissue allowing many tissues to retain their shape

Question 33

What are the 3 ligament location types?

Answer 33

The location of a ligament can be extrinsic, intrinsic, or capsular with respect to the joints.

Question 34

Extrinsic Ligament

Answer 34

This type of ligament is located on the outside of the joint. An example is the lateral collateral ligament (LCL), which resists abnormal movement away from the midline, termed varus stress.

Question 35

What is varus stress?

Answer 35

An abnormal joint movement away from the midline of the body (i.e., bowlegged).

Question 36

Intrinsic Ligament

Answer 36

Ligament location type. The anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) are situated inside the knee joint to resist anterior and posterior (forward and backward) movement of the tibia, respectively.

Question 37

Capsular Ligament

Answer 37

Ligament location type. The medial collateral ligament (MCL) is this type of ligament, so called because it is continuous with the joint capsule. It resists valgus stress at the knee by keeping the joint approximated.

Question 38

What is valgus stress?

Answer 38

An abnormal joint movement toward the midline of the body (i.e., knock-kneed).

Question 39

What is the role of cartilage?

Answer 39

This tissue resists compressive forces, makes bones more resilient, and offers support and flexibility in some areas.

Question 40

Why is cartilage recovery a slow process?

Answer 40

Because there are no nerves or blood vessels in cartilage.

Question 41

What is the perichondrium?

Answer 41

The connective tissue enveloping cartilage everywhere except at a joint.

Question 42

What do the two layers of perichondrium consist of?

Answer 42

The inner layer consists of chondroblasts, which are cells that play a role in making new cartilage, and the outer layer consists of fibroblasts, which are cells that produce collagen for growth.

Question 43

What is articular cartilage?

Answer 43

A type of cartilage covering the end of long bones that provide smooth bone-on-bone contact in freely moving joints.

Question 44

What are nociceptors?

Answer 44

Pain-sensitive nerve endings found in periosteum and endosteum bone coverings.

Articular cartilage covers the ends of moving bones to block the pain signal and reduce compressive stress.

Question 45

What are the 3 types of cartilage found in the body?

Answer 45

1. Hyaline cartilage
2. Fibrocartilage
3. Elastic cartilage

Question 46

What is hyaline cartilage?

Answer 46

This deformable but elastic type of cartilage is the most widespread. It is found in the nose, trachea, larynx, bronchi, and the ends of ribs as well as at the ends of bones in the form of articular cartilage.

A transparent cartilage found on most joint surfaces and in the respiratory tract, which contains no nerves or blood vessels.

Question 47

What is fibrocartilage?

Answer 47

This tough tissue is found in the intervertebral discs and at the insertions of tendons and ligaments. It also forms the lateral or medial meniscus in the knee. Contains type I & type II collagen.

Question 48

What is elastic cartilage?

Answer 48

This is the most pliable form of cartilage. It gives shape to the external ear, the auditory tube of the middle ear, and the epiglottis.