OSTEOLOGY- EXAM #2

State the five functions of the skeletal system?

1. support

2. protection

3. movement

4. mineral storage

5. blood cell production

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

Collagen fibers

What are the inorganic components of bone?

Mineral salts, mainly calcium phosphate

List the 5 shapes of bones found in our bodies

1. Long bones

2. Short bones

3. Flat bones

4. Irregular bones

5. Sesamoid bones

Examples of long bones in body

Femur

Fibula

Metacarpals

Metatarsals

Phalanges

clavicle

Examples of short bones in body

Tarsals and carpals

Examples of flat bones/curved in body

Ribs

Sternum

Scapula

Hyoid

Cranial

Examples of Irregular bones in body

Vertebrae

Coxal

Facial

Sacrum

Examples of Sesamoid bones in body

Embedded in tendons (patella)

What type of ossification develops from Mesenchyme ?

Intramembranous ossification

What is Interstitial growth in bones?

Bone grows from within increasing length

What is Appositional growth in bones?

Bone grows on outer surface increasing width/thickness

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

Nutrient artery

Do bones have nerves running through them?

Yes

Function of Osteoprogenitor cells

Develop into osteoblasts

Function of Osteoblasts

Build new bone by producing bone matrix

Function of Osteocyte

Maintain bone tissue

Function of Osteoclasts

Break down/ reabsorb bone tissue

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

Bone loss would occur leading to weaker bones

List the two main minerals found within bone tissue?

Calcium and phosphate

What is the effect of vitamin C on bone growth and health?

Needed for collagen production + bone formation+ strength

What is the effect of vitamin D on bone growth and health?

Promotes calcium absorption

Supports bone mineralization

What is the effect of vitamin A on bone growth and health?

Helps regulate bone growth

Osteoclasts remove old bone → osteoblasts replace (remodeling)

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

Spongy bone= trabeculae/ spaces

Compact bone= osteons/circles

What type of cartilage is the model for Endochondral Ossification?

Hyaline cartilage

What types of bones undergo Endochondral Ossification?

Most bones of the body, especially long bones.

Describe what is happening during the 1st step of Endochondral Ossification.

A hyaline cartilage blueprint forms

Describe what is happening during the 2nd step of Endochondral Ossification.

A hard bony collar forms around diaphysis

Describe what is happening during the 3rd step of Endochondral Ossification.

The center of the cartilage hollows out as cartilage cells die

Describe what is happening during the 4th step of Endochondral Ossification.

Blood vessels bring osteoblasts/osteoclasts → cartilage is replaced by bone, forming the medullary cavity

Describe what is happening during the 5th step of Endochondral Ossification.

Secondary ossification centers form in the epiphyses → cartilage is replaced by bone.

What types of bones are formed by Intramembranous Ossification?

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

How does appositional growth affect the development of bone?

It increases the thickness/diameter of a bone by adding new bone to the outer surface

Whats another name for Spongy Bone?

Cancellous or trabecular bone

What’s another name for Compact bone?

Cortical bone

What does the Endosteum cover?

Inner cavities of bone

What does Periosteum cover?

Outer surface of bone

Function of Periosteum ?

Growth, repair and nourishment

Function of Endosteum ?

Removal of old bone + replacement with new bone (remodeling)

What does Periosteum contains?

Osteoprogenitor cells and osteoblasts

What does Endosteum contain?

Osteoprogenitor cells, osteoblasts and osteoclasts

Label 1

Epiphysis

Label 2

Diaphysis

Label 3

Distal epiphysis

Label 4

Medullary cavity

Label 5

Endosteum

Label 6

Periosteum

Label 7

Epiphyseal (growth) plate

Label 8

Articular cartilage

Label 9

Spongy bone

What type of bone is found in the diaphysis?

Compact bone

What type of bone is found in the epiphysis?

Spongy bone

Where is metaphysis found and What type of cartilage is found in the metaphysis?

Epiphyseal (growth) plate, Hyaline cartilage

What type of cartilage is articular cartilage?

Hyaline cartilage

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

Plate= still growing

Line= growth is finished

Label 1

Lacunae

Label 2

Interstitial lamellae

Label 3

Osteocyte

Label 4

Lamellae

What is another name for a Haversian System?

Osteon

What is the “bullseye” of this structure called? What is running through here?

The center is the central canal

What runs through the central canal?

Blood vessels and nerves

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

Connected the central canals of osteons

Carry blood vessels and nerves from periosteum to bone

What is the name of the connective tissue structure that covers our bones? How many layers does he have?

Periosteum has 2 layers

What structures attach the periosteum to the bone

Perforating (Sharpey’s) fibers

How does exercise help our bones?

stimulates bone growth/remodeling

helps increase bone strength and density.

Label 1

Zone 1- Resting cartilage

In Zone 1, Chondrocytes are ?

Resting, anchoring the growth plate

Label 2

Zone 2- proliferating cartilage

In zone 2, Chondrocytes are?

Rapidly dividing, pushing the epiphysis away= bone lengthens

Label 3

Hypertrophic cartilage

In zone 3, Chondrocytes ?

Enlarge

Label 4

Calcified cartilage

In zone 4, what happens?

Matrix calcifies and chondrocytes die

Label 5

Ossification (new bone tissue deposited)

In zone 5, what happens?

Osteoclasts remove calcified material and osteoblasts build permanent bone

Which zone is closest to the epiphysis?

Resting cartilage (1)

Which zone is closest to the diaphysis?

Zone of ossification (5)

Which zone has cells that are proliferating and multiplying?

Zone of proliferation (2)

Which zone is being replaced by bone?

Zone of ossification (5)

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

There is more osteoclast activity, bones become weak making it easier for bones to break

Where is the growth hormone released from?

Anterior pituitary gland

Where is the Thyroid hormone released from?

Thyroid gland

Where is the parathyroid hormone released from?

Parathyroid glands

Where is the Calcitonin hormone released from?

Thyroid gland

Where is the Glucocorticoids hormone released from?

Adrenal cortex

Function of Growth hormone and effect on bone growth?

Stimulates bone and body growth

promotes growth at the epiphyseal growth plates.

Function of Thyroid hormone and effect on bone growth?

Supports bone growth and development

Works with growth hormone to promote growth

Function of Calcitonin hormone and effect on bone growth?

Lowers blood calcium by decreasing osteoclast activity

Reduces bone breakdown +Preserve bone

Function of parathyroid hormone and effect on bone growth?

Raises blood calcium by increasing bone resorption.

Function of Glucocorticoids hormone and effect on bone growth?

Helps regulate metabolism

High levels = Inhibit bone growth

Function of Estrogen and testosterone hormone and effect on bone growth?

Promote bone growth and development during puberty

Increases bone density and closure of growth plates

What is actually happening in the condition known as Achondroplasia?

genetic condition where the abnormal Cartilage growth causes the long bones to grow shorter than normal

Risk factors for Osteoporosis?

Age, gender and lifestyle

What causes Achondroplasia?

Mutation in fibroblast growth factor receptor 3

Is Achondroplasia random?

Primarily inherited but can occur due to new mutations.