Skeletal System

Question 1

Skeletal system

Answer 1

Human skeletal system, consist of 206 bones along with numerous tendons, ligaments, and cartilage, is divided into the axial skeleton and the appendicular skeleton

Question 2

Axial skeleton

Answer 2

-Consist of 80 bones that includes the vertebral column, rib cage, sternum, skull, and hyoid bone
-the vertebral column consists of 33 vertebrae classified as cervical vertebrae, thoracic vertebrae, lumbar vertebrae, and sacral vertebrae
-the rib cage includes 12 paired ribs, 10 pairs of true ribs and two pairs of floating ribs, and the sternum, which consist of the manubrium, corpus sterni, and xiphoid process
-the skull includes the cranium and facial bones
-the ossicles are bones in the middle ear
-the hyoid bone provides an attachment point for the tongue muscles
-the axial skeleton protects vital organs including the brain, heart, and lungs

Question 3

Appendicular skeleton

Answer 3

-Consists of 126 bones including the pectoral girdle, pelvic girdle, and appendages
-the pectoral girdle consists of the scapulae (shoulders) and clavicles (collar bones)
-the pelvic girdle consists of two pelvic (hip) bones, which attach to the sacrum
-the upper appendages (arms) include the humerus, radius, ulna, carpals, metacarpals, and phalanges
-The lower appendages (legs) include the femur, patella, fibula, tibia, tarsals, metatarsal‘s, and phalanges

Question 4

Question 5

Joints

Answer 5

-Locations where two or more elements of the skeleton connect
-they can be classified according to range of motion, as well as the material that holds the joint together

Question 6

[joint FUNCTIONAL classification]
Synarthrosis

Answer 6

-either fibrous or cartilaginous
-immovable
-ex. Skull sutures, teeth/mandible

Question 7

[joint FUNCTIONAL classification]
Amphiarthrosis

Answer 7

-Either fibrous or cartilaginous
-slight range of motion
-ex. intervertebral discs, distal tibiofibular joint

Question 8

[joint FUNCTIONAL classification]
Diarthrosis

Answer 8

-Always synovial
-free movement
-ex. wrist, knee, shoulder

Question 9

[joint STRUCTURAL classification]
Fibrous

Answer 9

-held together by fibrous connective tissue
-suture: immovable ex. Skull
-gomphosis: immovable ex. Teeth/mandible
-syndesmosis: slightly movable ex. Distal tibiofibular joint

Question 10

[joint STRUCTURAL classification]
Cartilaginous

Answer 10

-Held together by cartilage
-synchondrosis: hyaline cartilage, nearly immovable ex. First rib/sternum
-symphysis: fibrocartilage, slightly movable ex. intervertebral discs, pubic symphysis

Question 11

[joint STRUCTURAL classification]
Synovial

Answer 11

-Most common type of joint: characterized by a joint cavity filled with synovial fluid
-pivot: allows rotation ex. Atlantoaxial joint
-hinge: allows movement in one plane ex. knee
-saddle: allows pivoting in two planes and axial rotation ex. first metacarpal/trapezium
-gliding: allows sliding ex. Carpals \
-condyloid: allows pivoting in two planes but no axial rotation ex. radiocarpal joint
-Ball and socket: have the highest range of motion ex. hip

Question 12

Functions of the skeletal system (1/2)

Answer 12

-The skeletal system serves many functions including providing structural support, providing movement, providing protection, for producing blood cells, and storing substances such as fat and minerals
-the skeletal system provides the body with structure and support for the muscles and organs
-the axial skeleton transfers the weight from the upper body to the lower appendages
-the skeletal system provides movement with joints and the muscular system
-bones provide attachment points for muscles
-joints including hinge joints, ball-and-socket joints, pivot joints, ellipsoid joints, gliding joints, and saddle joints

Question 13

Functions of the skeletal system (2/2)

Answer 13

-each muscle attached to two bones: the origin and insertion
-the origin remains immobile and the insertion is the bone that moves as the muscle contracts and relaxes
-the skeletal system serves to protect the body
-the cranium protects the brain
-the vertebrae protects the spinal cord
-the rib cage protects the heart and lungs
-the pelvis protects the reproductive organs
-the red marrow manufactures red and white blood cells
-all bone marrow is red at birth, but adults have approximately 1/2 red bone marrow and 1/2 yellow bone marrow
-yellow bone marrow stores fat
-the skeletal system provides a reservoir to store the minerals calcium and phosphorus

Question 14

[the skeletal system has an important role in the following body functions]
Movement

Answer 14

The action of skeletal muscles on bones moves the body

Question 15

[the skeletal system has an important role in the following body functions]
Mineral storage

Answer 15

Bones serve as storage facilities for essential mineral ions

Question 16

[the skeletal system has an important role in the following body functions]
Support

Answer 16

Bones act as a framework and support system for the organs

Question 17

[the skeletal system has an important role in the following body functions]
Protection

Answer 17

Bones surround and protect key organs in the body

Question 18

[the skeletal system has an important role in the following body functions]
Blood cell formation

Answer 18

Red blood cells are produced in the marrow of certain bones

Question 19

Bones

Answer 19

-Classified as long, short, flat, or irregular
-they are a connective tissue with a base of pulp containing collagen and living cells
-bone tissue is constantly regenerating itself as the mineral composition changes
-this allows for special needs during growth periods and maintains calcium levels for the body
-bone regeneration can deteriorate in old age, particularly among women leading to osteoporosis

Question 20

Backbone

Answer 20

-the flexible and curved backbone is supported by muscles and ligaments
-intervertebral discs are stacked one above another and provide cushioning for the backbone
-trauma or shock may cause discs to herniate and cause pain
-the sensitive spinal cord is enclosed in a cavity which is well protected by the bones of the vertebrae

Question 21

Joints

Answer 21

-Areas of contact adjacent to bones
-synovial joints are the most common, and are freely movable
-these may be found at the shoulders and knees
-cartilaginous joints fill the spaces between some bones and restrict movement
-ex. of cartilaginous joints are those between vertebrae
-fibrous joints have fibrous tissue connecting bones and no cavity is present

Question 22

Compact and spongy bone

Answer 22

Question 23

Two types of connective bone tissue include

Answer 23

Compact bone and spongy bone

Question 24

Compact bone

Answer 24

-Compact, or cortical, bone, which consists of tightly packed cells, is strong, dense, and rigid
-running vertically throughout compact bone are the Haversian canals, which are surrounded by concentric circles of bone tissue called lamellae
-the spaces between the lamellae are called the lacunae
-these lamellae and canals along with their associated arteries, veins, lymph vessels, and nerve endings are referred to collectively as the Haversian system
-the Haversian system provides a reservoir for calcium and phosphorus for the blood
-bones have a thin outside layer of compact bone, which gives them their characteristic smooth, white appearance

Question 25

Spongy bone

Answer 25

-Spongy, or cancellous, bone consists of trabeculae, which are a network of girders with open spaces filled with red bone marrow
-compared to compact bone, spongy bone is lightweight and porous, which helps reduce the bones overall weight
-the red marrow manufactures red and white blood cells
-in long bones, the diaphysis consists of compact bone surrounding the marrow cavity and spongy bone containing red marrow in the epiphyses
-bones have varying amounts of compact bone and spongy bone depending on their classification