Anatomy Exam 3

Exam 10/4/23

Long bones

Bones longer than they are wide

Femur

Long bone example

Short bones

Bones with equal length and width

Tarsals

Short bone example

Flat bones

Thin, plate like bones

Parietal bone

Flat bone example

Irregular bones

Bones with an undefined shape

Verebra

Irregular bone example

Sesamoid bones

Seed-like bones

Patella

Sesamoid bone example

Epiphyses

A

Diaphysis

B

Medullary cavity

C

Metaphases

D

Epiphyses

Outer ends of long bones, structure that articulates with other bones

Diaphysis

The shaft of long bones

Medullary cavity

Hollow part of long bone shaft storing bone marrow and vasculature

Epiphyseal line

Line where growth plates have closed

Metaphyses

Region where epiphyses and diaphysis meet

Red bone marrow

Found almost everywhere in kids

Red bone marrow

Found in proximal heads of humerus & femur, sternum, ribs, pelvis, and skull in adults

Red bone marrow

Location of RBC synthesis

Yellow bone marrow

Found in medullary cavities of most long bones

Yellow bone marrow

Location of triglyceride storage and synthesis

Red bone marrow

Also known as myeloid tissue

Collagen fibers

Protein fibers of osseous tissue, reinforce bone structure & prevent brittleness

Hydroxyapatites

Provides hard structure for bones

Water

Major component of all tissue of the body

Osteoblasts

Builds bone tissue, removes calcium from blood

Osteoclasts

Breaks down bone, puts calcium into blood

Compact bone

Appears solid, no holes in the bone

Spongy bone

Unorganized, lattice lamella containing lacunae

Spongy bone

Lacks organizational component (central canals, osteons, circumferential/intersitial llamelle)

Circumferential lamellae

Layers surrounding circumference of long bone

Osteons

Structure found in compact bone

1. Osteoblast secretes extracellular matrix around itself to produce a lacuna

2. Lacuna formation finishes and is now considered an osteocyte

3. Can now function in bone tissue formation

Steps of an osteoblast developing into an osteocyte

Osteoblast

Bone-cell progenitor (produces bone)

Osteoclast

Blood-cell progenitor (degrade bone)

Osteogenic cells, osteoblasts, osteocytes

Cells involved in the differentiation process that forms osteoblasts (in order)

Osteogenic cells, osteoblasts

Progenitor cells to osteocytes

Compact bone

Organized, repeating structural units aligned in the same direction

Compact bone

Contains osteons, central canals, concentric lamellae, circumferential/intersitial lamellae, perforating canals

Osteons

Found ONLY in compact bone

Intramembranous ossification

Production of bone tissue within a membrane

Endochondral ossification

Production of bone tissue with a hyaline cartilage template

Intramembranous ossification

Building bone with little structural or location guidance

Endochondral ossification

Building bone with structural and location guidance

Skull bones

Bones formed by intramembranous ossification

Femur, humerus, radius, ulna

Bones formed by endochondral ossification

1. Osteogenic cells find place in membrane

2. Osteoblasts secrete ECM and form lacuna

3. Osteoblasts produce trabeculae

4. Periosteum forms around each trabeculae

Steps of intramembranous ossification

1. Development of hyaline cartilage outlining bone formation location

2. Growth of hyaline cartilage template (marrow cavity & primary ossification center form)

3. Development of medullary cavity and & vessels penetrate to bring osteogenic cells to site of bone formation

4. Secondary ossification center development at both epiphyses

5. Formation of articular cartilage on epiphyseal surfaces & plates

Steps of endochondral ossification

Epiphyseal plate

Formed between epiphysis & diaphysis during endochondral ossification

True

T/F: Hyaline cartilage of epiphyseal plate allows for growth of diaphysis

Reserve cartilage (bank of cartilage withdrawn from to begin growth)

Zone 1

Cell proliferation (mitosis occurs to produce more cells in the zone)

Zone 2

Cell hypertrophy (cells enlarge to make room for bone matrix)

Zone 3

Calcification (bone matrix replaces cartilage template)

Zone 4

Ossification (completing bone matrix of osseous tissue, red bone marrow invades)

Zone 5

Zone 2

Mitosis occurs to produce more cells in the zone

Zone 3

Cells enlarge to make room for bone matrix

Zone 1

Bank of cartilage withdrawn from to begin growth

Zone 4

Bone matrix replaces cartilage template

Zone 5

Completing bone matrix of osseous tissue, red bone marrow invades

Zone 1

Zone on epiphyseal side

Zone 5

Zone on diaphysral side

Calcitriol

Hormone secreted to stimulate calcium absorption from food

Calcitriol

Acts on digestive system to increase dietary calcium absorption

Parathyroid glands

Located on posterior aspect of thyroid, halfway down midline of neck

Calcitonin

Secreted when blood calcium is high, moves calcium from blood to bone

Calcitonin

Stimulates osteoblasts to add calcium to bone

PTH

Secreted where blood calcium is low, moves calcium form bone to blood

PTH

Stimulates osteoclasts to remove calcium from bone

Low blood calcium, high bone density

High calcitonin means…

Hyperparathyroidism- high blood calcium, low bone density (osteoporosis)

High PTH means…

Osteoporosis

Low bone density often caused by deficient osteoblast activity & too much osteoclast activity

Kidney stones

Result from elevated blood calcium, and excess calcium is deposited into stones

Hypoparathyroidism- low blood calcium, normal bone density

No production of PTH means…

Amount of stress on a bone is directly related to the rate of remodeling (more stress, more rapid remodeling)

Wolf’s law of bone remodeling

Frontal bone

A

Right parietal bone

B

Coronal suture

C

Lambdoid suture

D

Temporal bone

E

Mastoid process

F

Zygoma

G

Zygomatic bone

H

Mandible

I

Styloid process

J

Occipital bone

K

Nasal bone

L

Maxilla

M

Sphenoid bone

N

Ethmoid bone

O

Lacrimal bone

P

Sagittal suture

Q

Left parietal bone

R

Sagittal suture

Fusion along right and left parietal bone

Coronal suture

Fusion along parietal bones and frontal bone

Lambdoid suture

Fusion along parietal bones and temporal bone

Parietal bones, frontal bone

Bones involved in fusing the primary (anterior) fontanelle soft spot