A&P150 - Osteology Exam

Cerritos College

A

Proximal Epiphysis

B

Diaphysis

C

Distal Epiphysis

D

Spongy Bone

E

Articular Cartilage

F

Epiphyseal Line

G

Periosteum

K

Compact Bone

H

Medullary Canal

What type of bone is found in the diaphysis?

Compact Bone

What type of bone is found in the epiphysis?

Spongy Bone

What type of cartilage is found in the metaphysis?

Hyaline cartilage (growth plate)

What type of cartilage is articular cartilage?

Hyaline Cartilage

What is the difference between the epiphyseal plate and the epiphyseal line?

• Epiphyseal plate → cartilage that allows bones to grow longer

• Epiphyseal line → remnant of the plate after bone growth has stopped

Name a major difference in the microscopic anatomy between compact and spongy bone.

Compact bone has osteons (central canals), while spongy bone has trabeculae and no osteons

What type of cartilage is the model for Endochondral Ossification?

Hyaline Cartilage

“Within cartilage, I am changing you into bone.”

What types of bones undergo Endochondral Ossification?

Produces majority of bones in the body

Describe what is happening during the steps of Endochondral Ossification

A hyaline cartilage model is gradually replaced by bone.

1. Cartilage model forms → creates the shape of the future bone.

2. Bone collar forms → bone develops around the outside.

3. Primary ossification → bone replaces cartilage in the shaft (diaphysis).

4. Medullary cavity forms → a hollow space develops inside the shaft.

5. Secondary ossification → bone replaces cartilage in the ends (epiphyses).

6. Growth plate remains → allows the bone to grow longer.

What types of bones are formed by Intramembranous Ossification?

Flat bones of skull, some facial bones, mandible and central portion of clavicle

How does appositional growth affect the development of bone?

Growth from outside, increases in width

Results in thicker bones

How does interstitial growth affect the development of bone?

Growth from within, increase in length

Results in longer bones

Function of Osteoprogenitor (Osteogenic) cells and location

Stem cell that divides (mitosis) —> then becomes osteoblast

Location: Periosteum and bone marrow

Function of Osteoblasts and location

“B” Builds Bone

Location: Periosteum and endosteum

Function of Osteocytes and where do they live

Matured osteoblast, maintain matrix

Live in Lacuna

Function of Osteoclast

Resorb bone

Dissolve and make new bone tissue

What would happen if osteoclast activity was greater than osteoblast activity?

Osteoporosis

Two main minerals found within bone tissue.

Calcium and phosphate

Effects of Vitamin C on bone growth and health

Promotes collagen production

Effects of Vitamin D on bone growth and health

Promotes absorption of calcium and phosphate into blood (calcification of bone)

Effects of Vitamin A on bone growth and health

Activates osteoblasts

State the five functions of the skeletal system

1. Protect internal organs

2. Stores and releases fats and minerals

3. Produces (all) blood cells

4. Facilitates movement

5. Supports the body

What is the major protein fiber running through the bony matrix?

Collagen Fibers

What are the inorganic components of bone?

Mineral salts, primarily calcium phosphate (hydroxyapatite), which give bone its hardness and strength.

List the shapes of bone and give an example of each

1. Long Bones (Femur, Humerus, Phalanges, Radius)

2. Short Bones (tarsals, carpals)

3. Flat Bones (ribs, scapula, hyoid, cranial, sternum)

4. Irregular Bones (vertebrae, coxal, facial bones, sacrum)

5. Sesamoid Bones (patella)

Name the blood vessel that enters the bone through the diaphysis.

Nutrient Artery and Vein

Do bones have nerves running through them?

Yes, through the nutrient foramen

Growth Hormone (release location, function and effect on bone growth)

Location: anterior pituitary gland

Function: Cartilage proliferation @ epiphyseal plate (bone elongation/length)
Effect: Little growth hormone results in shorter stature in child

Thyroid Hormone (release location, function and effect on bone growth)

Location: thyroid gland

Function: stimulates metabolic rate of osteoblasts

Effect: little too thyroid hormone —> shorter stature

Calcitonin (release location, function and effect on bone growth)

Location: thyroid gland

Function: calcium deposition in bone, inhibits osteoclast activity, inc. blood calcium

Parathyroid (release location, function and effect on bone growth)

Location: gland

Function: dec. blood calcium by encouraging bone resorption by osteoclasts

Estrogen and Testosterone function

stimulate osteoblasts —> promote epiphyseal plate growth + closure

What is actually happening in the condition known as Achondroplasia?

A/chondro/plasia

A = w/o

Chondro = cartilage

Plasia = growth

• mutated form of the receptor is constitutively active —> severely shortened bones

Zone 1

Resting Cartilage

• anchor to hold bone in place, chondrocytes are resting

Zone 2

Proliferating Cartilage

• engine of growth, form vertical columns (starch of coins)

• what pushes epiphysis away from diaphysis (lengthening bone)

Zone 3

Hypertrophic Cartilage

• cells stop dividing and enlarge (hypertrophy)

• further stretches growth plate

Zone 4

Calcified Cartilage

• enlarged cells calcify surrounding matrix and block nutrients

• chondrocytes die —> empty calcified tunnels

Zone 5

Ossification

• blood vessels invade empty cavities (zone 4)

• osteoblasts lay down real, permanent bone, osteoclasts dissolve temporary calcification

Which zone is closest to the epiphysis?

Zone 1, Resting Cartilage

Which zone is closest to the diaphysis?

Zone 5, Ossification

Which zone has cells that are proliferating and multiplying?

Zone 2, Proliferating Cartilage

Which zone is being replaced by bone?

Zone 5, Ossification

What is actually happening in the condition called Osteoporosis? What is happening to the bones?

• Deterioration of bone tissue and inc. bone fragility

• Rate of bone resorption (osteoclasts) outpaces rate of bone formation (osteoblasts) —> laying down less bone

What is another name for a Haversian System?

The “Target”

• osteons

What is the “bullseye” of this structure called?

What is running though here?

Central Canal

• blood vessels & nerves

What is the function of Perforating (Volkman’s) canal’s?

• runs perpendicular to osteons

• blood vessels

• connects mult. central canals

What is the name of the connective tissue structure that covers our bones?

How many layers does it have?

Periosteum

• Fibrous Layer

• Osteogenic Layer

What is the name of the structures that attach to the periosteum structure to the bone?

Perforating (Sharpey’s) Fibers

How does exercise help our bones?

Weight-bearing exercises inc. bone density, stimulates osteoblasts to build more bone

#1

Lacunae

#2

Interstitial Lamellae

#3

Osteocytes in lacunae

#4

Lamellae