THE SKELETAL THE SKELETAL SYSTEM SYSTEM REVIEWREVIEW

1. How many bones are in the human skeletal system?1. How many bones are in the human skeletal system?2. How many different sections is your skeletal system divided 2. How many different sections is your skeletal system divided into? Identify what they are. into? Identify what they are. 3. What are the functions of the skeletal system?3. What are the functions of the skeletal system?4. Identify the anatomy of the bone. 4. Identify the anatomy of the bone. 5. Identify the different types of joints. 5. Identify the different types of joints. 6. Identify the types of bones. Give an example of each. 6. Identify the types of bones. Give an example of each. 7. Identify the types of connective tissues as well as their 7. Identify the types of connective tissues as well as their function. function.

REVIEW QUESTIONS

1. 2061. 2062. 2 sections; Axial and Appendicular2. 2 sections; Axial and Appendicular3. Protect vital organs, Provide support, assist in movement3. Protect vital organs, Provide support, assist in movement4. The bone is made of an outer layer of hard or 4. The bone is made of an outer layer of hard or compact bonecompact bone, which is very strong, , which is very strong, dense and tough. Inside this is a layer of dense and tough. Inside this is a layer of spongy bonespongy bone, which is like honeycomb, lighter , which is like honeycomb, lighter and slightly flexible. In the middle of some bones is jelly-like bone and slightly flexible. In the middle of some bones is jelly-like bone marrowmarrow, where new , where new cells are constantly being produced for the blood, and blood vessels. cells are constantly being produced for the blood, and blood vessels. 5. Ball & Socket; Pivot; Saddle; Hinge; Ellipsoid (Condyloid); Plane or Gliding – vertebrae5. Ball & Socket; Pivot; Saddle; Hinge; Ellipsoid (Condyloid); Plane or Gliding – vertebrae6. Long bones (Femur); Short bones (carpals); Irregular bones (vertebrae); Flat (cranium)6. Long bones (Femur); Short bones (carpals); Irregular bones (vertebrae); Flat (cranium)7. Cartilage (allows joints to move easily); Ligaments (attaches bone to bone); Tendon 7. Cartilage (allows joints to move easily); Ligaments (attaches bone to bone); Tendon (attaches muscle to bone)(attaches muscle to bone)

Review Questions Answers

Human Skeleton

206 Bones206 Bones Axial skeletonAxial skeleton: (80 : (80

bones) in skull, bones) in skull, vertebrae, ribs, vertebrae, ribs, sternum, hyoid bone sternum, hyoid bone

Appendicular Appendicular SkeletonSkeleton: (126 : (126 bones)- upper & bones)- upper & lower extremities lower extremities plus two girdles plus two girdles

Half of bones in Half of bones in hands & feet hands & feet

Axial Skeleton (80)

Skull Skull Ossicles of the Ossicles of the

middle earmiddle ear Hyoid bone Hyoid bone Thorax or Thorax or

chest chest Vertebral Vertebral

columncolumn

AppendicularAppendicularSkeleton (126)Skeleton (126)

Upper Extremity (64)Upper Extremity (64)Shoulder GirdleShoulder GirdleArmsArmsHandsHandsLower Extremity (62)Lower Extremity (62)Pelvic GirdlePelvic GirdleLegsLegsFeet Feet

Bone Cells

OsteoblastsOsteoblasts – – bone forming cells bone forming cells synthesize and secrete synthesize and secrete unmineralized ground substance and are found in areas of high unmineralized ground substance and are found in areas of high metabolism within the bone metabolism within the bone

OsteocytesOsteocytes – – mature bone cells made from osteoblasts mature bone cells made from osteoblasts that that have made bone tissue around themselveshave made bone tissue around themselves. They maintain . They maintain healthy bone tissue by secreting enzymes and controlling healthy bone tissue by secreting enzymes and controlling the bone mineral content; they also control the calcium the bone mineral content; they also control the calcium release from the bone tissue to the bloodrelease from the bone tissue to the blood. .

Osteogenic cellsOsteogenic cells respond to traumas, such as fractures, by giving respond to traumas, such as fractures, by giving rise to bone-forming cells and bone-destroying cells rise to bone-forming cells and bone-destroying cells

OsteoclastsOsteoclasts – – bone absorbing cell bone absorbing cell – large cells that break down – large cells that break down bone tissue – bone tissue – important to growth, healing, remodeling important to growth, healing, remodeling

Bone lining cellsBone lining cells - made from osteoblasts along the surface of - made from osteoblasts along the surface of most bones in an adult. Bone-lining cells are thought to regulate most bones in an adult. Bone-lining cells are thought to regulate the movement of calcium and phosphate into and out of the the movement of calcium and phosphate into and out of the bonebone

Bone remodeling is a process by both osteoblasts and osteoclasts

Types of Skeletal Cartilage

Hyaline Cartilages: fine collagen fiber matrix- most abundant type- found in articular (movable joint) cartilages, costal cartilages (connect ribs to sternum), respiratory cartilages (in larynx & upper respiratory passageways) & nasal cartilages

Elastic Cartilages: similar to hyaline cartilage, more elastic fibers (very flexible) – found in external ear & epiglottis (larynx covering)

Fibrocartilage: rows of chondrocytes with thick collagen fibers; highly compressible with great tensile strength- found in meniscus of knee and intervertebral discs

Red and Yellow Bone Marrow

The formation of blood cells, The formation of blood cells, ((hematopoiesishematopoiesis), takes place mainly in ), takes place mainly in the red marrow of the bones. the red marrow of the bones.

In infantsIn infants, , red marrowred marrow is found in the is found in the bone cavities. With age, it is largely bone cavities. With age, it is largely replaced by replaced by yellow marrowyellow marrow for fat for fat storage. storage.

In adultsIn adults, , red marrowred marrow is limited to the is limited to the spongy bone in the skull, ribs, sternum, spongy bone in the skull, ribs, sternum, clavicles, vertebrae and pelvis. Red clavicles, vertebrae and pelvis. Red marrow functions in the formation of marrow functions in the formation of RBC’s, WBC’s and blood platelets.RBC’s, WBC’s and blood platelets.

The Vertebral ColumnThe Vertebral Column

Slide 5.28Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Vertebrae separated by intervertebral discs made of cartilage

The spine has a normal S curvature

Each vertebrae is given a name according to its location

Figure 5.14

Types of Vertebrae

Cevical (C1-Cevical (C1-C7)C7)

Thoracic (T1-Thoracic (T1-T12)T12)

Lumbar (L1-L5)Lumbar (L1-L5) Sacrum (S1-S5)Sacrum (S1-S5) Coccyx (C1-C5)Coccyx (C1-C5)

Joints Ball & SocketBall & Socket Pivot Pivot Saddle Saddle HingeHinge Elipsoid Elipsoid

(Condyloid)(Condyloid) Plane or Gliding Plane or Gliding

- vertebrae- vertebrae

Joints

A joint, or articulation, is the place where two bones come together.

Fibrous- Immovable: connect bones, no movement. (skull and pelvis).

Cartilaginous- slightly movable, bones are attached by cartilage, a little movement (spine or ribs).

Synovial- freely movable, much more movement than cartilaginous joints. Cavities between bones are filled with synovial fluid. This fluid helps lubricate and protect the bones (hinge, ball and socket, etc).