Skeletal System Test

Epyphisis

An expanded portion at the end of each long bones

Epyphisis Function

Articulates (forms a joint) with another bone

Ariticular Cartilage

Layer of Hyaline Cartilage

Articular Cartilage Function

Coats the outer surface of the articulating portion of the Epiphysis

Diaphysis

The shaft of the bone between the Epiphysis

Epiphyseal Line

The region where the Epithysis and Diaphysis fuse together during growth

Epiphyseal Plate

While the bone is still growing, the Epiphyseal Line is called this (o/ growth plate)

Periosteum

Completely encloses the bone, except for the Articular Cartilage on the bone’s ends. It is firmly attached to the bone, and periosteal fibers are continuous with the connecting ligaments and tendons. It also helps form and repair bone tissue.

Compact Bone (AKA Cortical Bone)

Tightly packed tissues that mainly compose the wall of the Diaphysis and have a continuous cellular matrix with no gaps

What does Spongey Bone (AKA Cancelous Bone) have on it’s surface?

Thin layer of compact bone

What does Spongey Bone (AKA Cancelous Bone) consist of?

Many branching bony plates called trabeculae

Where are the Trabeculae bony plates developed?

They’re most highly developed in the regions of the Epiphysis that are subjected to compressive forces.

How does Trabeculae help bone weight?

Irregular connecting spaces between these plates help reduce the bone’s weight.

What do Compact and Spongey bones have in common?

Strong and Resist Bending

Name the 2 types of Ossification

Intramembraneous and Endrochondral

What is Intramembraneous Ossification

When a bone forms on or within a fibrous CTmmbrane

Intramembraneous Ossification Ex

Flat Bones

When does Endrochondral Ossification occur

When a bone is formed from Hyaline Cartilage model

How are most bones formed?

Through Endrochondral Ossification

When does Primary Ossification (part of Endrochondral Ossification) occur?

Center hardens as fetus and infant. Starts in 3rd month of prenatal.

When does Secondary Ossification (part of Endrochondral Ossification) develop and harden?

Center develops in child and hardens during adolescence and early adulthood.

When do all bones ossify by?

Age 23 in females and 25 in males

What is Long Bone growth a result of?

Endrochondral Ossification

When is Long Bone growth?

Infancy and childhood

Where do Long Bones lengthen?

At Epiphyseal Plates

Where do Long Bones grown in thickness?

Inside the Periosteum known as Appositional Growth

What controls the rate of bone growth?

Human Growth Hormone (hGH) and Sex Hormones

What do sex hormones do?

Aid in Osteoblast activity (promote new bone growth) and close Epiphyseal Plate

Osteoblasts

Bone building cells

Osteocytes

Mature bone cells

Osteoclasts

Bone remodeling cells

What do Osteoclasts do?

Secret lysosomal enzymes that digest organic matrix for bone resorption

How often is Spongey Bone replaced?

Every 3-4 years

How often is Compact Bone replaced

Every 10 years

What does bone remodeling and repair rely on?

Calcium Homeostasis

What does bone remodeling and repair involve?

A continuous cycle of breaking down old bone tissue (resorption) and replacing it with new bone tissue (formation)

What coordinates bone remodeling and repair?

Osteoclasts (remove bone) and Osteoblasts (build new bone)

What do the hormones Calcitonin and Parathyroid (PTH) do?

Calcitonin and parathyroid hormone (PTH) regulate bone remodeling and repair by balancing blood calcium levels

What are the 2 hormones affecting Calcium Homeostasis?

Parathyroid Hormone (PTH) and Calcitonin

Parathyroid Hormone (PTH) Secretion

Secreted by parathyroid glands when calcium levels are low (osteoclasts)

Calcitonin Secretion

Secreted by thyroid gland when blood calcium levels are high (osetoblasts increase absorption)

During remodeling, how much bone calcium is exchanged each year?

4%

What 4 factors affect bone development, growth, and repair?

1. Minerals

2. Vitamins

3. Hormones (hGH, sex, PTH, Calcitonin, etc.)

4. Exersise

What does a Vitamin D deficiency cause?

Rickets in children and Osteomalacia in adults

What does Vitamin C maintain

Bone Matrix

What does Vitamin A control

Activity of Osteoblasts and Osteoclasts

What does excersise do?

Increase bone growth

How are bones classified?

Shape

Long Bones

Consists of shaft and 2 ends

Long Bones EX

Femur, Humerus

Short Bones

Cubelike

Short Bones EX

Carpals, Tarsals

Flat Bones

Thin, usually curved

Flat Bones EX

Most cranials, sternum, ribs, scapula (irregular)

Fractures

A break in a bone caused by forces that exceed the strength of the osseous tissue in the bone

Pathologic Fracture 

A rarer type of fracture caused by diseases or disorders, like osteoporosis, that weaken the bone to the point of fracturing under normal strain

What are the 2 classes of fractures?

1. Simple

2. Compound

Simple Fracture (AKA Closed Fracture)

Broken bones that remain within the body and don’t penetrate the skin

Compound Fracture (AKA Open Fractures)

Broken bones that penetrate through the skin and expose the bone and deep tissue to the exterior environment

Why are Compound Fractures more serious than Simple Fractures?

They may be complicated by deep infections if pathogens enter the body through the wound

Comminuted Fractures

Severe fractures that involve the breaking of bone into several smaller pieces.

Usual cause for Comminuted Fractures

High energy, traumatic forces

Greenstick Fracture

Incomplete break

Why are Greenstick Fractures seen more in children?

Kids have developing bones that are more flexible than adult bones and therefore tend to bend and only partially break instead of breaking completely.

Avulsion Fracture

Involves a small piece of bone being torn off from the main bone due to extreme force applied to a ligament or tendon

Cause of Avulsion Fractures

Overexertion of muscles or sudden traumatic pulling of part of the body during an accident.

Transverse Fracture

Break at a right angle (90 degrees) to the bone (straight across)

Oblique Fracture

Angle other than 90 degrees (slant across)

Spiral Fracture

Caused by twisting the bone

Compression Fracture

Crushed (depressed)

Comminuted Fracture

Fragments of 3 or more

Fissured Fracture

Incomplete, longitudinal/vertical break of bone

Name the 6 differences between the Female and Male Pelvis

1. Titled forward, broad and shallow

2. Bones lighter, thinner, and smoother

3. Pubic arch 80-90 degree angle, more rounded

4. Acetabula is smaller and further apart

5. Less muscle attachment

6. Larger true pelvis (birth canal)

Cranial Bones (8)

• 1 Frontal

• 2 Parietal

• 1 Occipital

• 2 temporal

• 1 Sphenoid

• 1 Ethmoid

Face Bones (14)

• 2 Maxilla

• 2 Zygomatic

• 2 Palatine

• 2 Inferior Nasal Concha

• 1 Mandible

• 2 Lacrimal

• 2 Nasal

• 1 Vomer

Phalanges

1. Distal (top)

2. Middle

3. Proximal (bottom)

Carpals

• Trapezium

• Scaphoid

• Hamate

• Pisiform

• Triquetrum

• Lunate

Pectoral Girdle Characteristics

• Flexible

• Lightweight

• Shallow socket for limb attachment

Pelvic Girdle Characteristics

• Weight-bearing

• Deep, secure socket for limb attachment

• Massive

Irregular Bones

more than one shape

Irregular Bones EX

Vertebrae

Sesamoid Bone

Develop with a tendon

Sesamoid Bone EX

Patella

Wormian (Sutural) Bone

Tiny bones found in the skull

Bone Functions (6)

1. Support and Shape

2. Protection of organs

3. Body Movement

• BBL - Bones attach to Bones through Ligaments

• BMT - Tendons attach muscle to bone

4. Hematopoiesis: Blood cell formation in the red blood marrow

5. Storage of minerals: Calcium & Phosphorus

6. Energy Storage: Yellow marrow in shaft of bone is made of fatty lipids