what does the skeletal system consists of

cartilage, tendons, ligaments, bones

what kind of tissue is cartilage

connective

Cartilage consists primarily of _______ which accounts for its resilience

Water

Skeletal Cartilage contains no ________ or ________

no nerves or blood vessels

Cartilage is surrounded by a layer of dense irregular connective tissue called the _________

perichondrium

The Perichondrium acts like a girdle in order to _____

resist outward expression

The Perichondrium contains the _______ _______ for nutrient delivery

blood vessels

cartilage contains two types of cells, name them

chondroblasts and chondrocytes

What are the three types of cartilage tissue in the body?

1. Hyaline,
2. elastic,
3. fibrocartilage

What are the basic components for all three types of cartilage tissue?

-cells called "Chondrocytes"
-the chondrocytes encased in a small cavity called the "Lacunae"
-all within an "extracellular matrix" containing a jelly like "ground substance and fibers"

Which cartilage is the most abundant in the human body

Hyaline Cartilage

Where are the 4 places skeletal hyaline cartilage can be found

1. Articular cartilage- which covers ens of bones a
2. Costal Cartilage- connects ribs to the sternum
3. Respiratory cartilage- forms the skeleton of the larynx (Voicebox) and reinforce respiratory passageways
4. Nasal cartilage-support the external Nose

The only fiber type in the matrix of Hyaline Cartilage is

Collagen fibers

Elastic Cartilage is similar to Hyaline Cartilage but contains more______?

stretchy elastic fibers

How many places can Elastic Cartilage be found?
Where are those locations?

Elastic Cartilage can be found in 2 places.

1. The External ear
2. and the Epiglottis

Fibrocartilage has _______ collagen fibers

Thick

Where can Fibrocartilage be found

1. Menisci of knee
2. Vertebral disks

What are the two ways Cartilage Grows

1. Appositional Growth
2. Interstitial Growth

What is Appositional Growth

-Growth from the "outside"
-Cells secrete matrix against the external face of existing cartilage

What is Interstitial Growth

-Growth from the "inside"
-Chondrocytes divide and secrete new matrix, expanding cartilage from within

True or False:
Calcification of cartilage only occurs when you are old?

False.
Calcification of cartilage occurs during normal bone growth when you are both young and old.

True or False:
When Cartilage becomes calcified it becomes bone

False.
When Cartilage becomes calcified it hardens, but is not bone.

When does cartilage growth typically end?

adolescence

How many named bones are in the Skeleton

206

What are the 2 groups the skeleton is divided into

1. Axial
2. Appendicular

Match the function of the group:
A. This group helps us manipulate or environment
B. This group protects supports, or carry other body parts.

A. Appendicular
B. Axial

What bones are included in the Axial Skeleton

-Long Axis of the Body
-Skull
-Vertebral column
-Rib cage

Which bones are included in the Appendicular skeleton

-bones of upper and lower limbs
-girdles attaching limbs to axial skeleton

What are the 4 classifications of bones by shape

1. Long Bones
2. Short Bones
3. Flat bones
4. Irregular bones

Long bones are ______ than they are _______

Longer than they are wide

A long bone has a _____ plus two ____ which are often expanded.

Has a "shaft" plus "two ends"

All limb bones are long bones except:

1. patella (kneecap)
2. wrist bones
3. ankle bones

what shape are short bones

Cube Shaped

examples of short bones

wrist and ankle

sesamoid bones

-short bones that form within tendons
-The Patella for example

Flat Bones are

Thin, flattened, and usually a bit curved

Examples of Flat Bones are

-Sternum
-Scapulae
-Ribs
-Skull Bones

Examples of Irregular Bones

-Vertebrae
- Hip Bones

What are the 7 important functions of bones?

-Support -Protection
-Movement -Mineral and growth factor storage
-blood cell formation
-Triglyceride(fat) Storage -Hormone production

Function of Bones:
Support

For body and soft organs

Function of Bones:
Protection

For brain, spinal cord, and vital organs

Function of Bones:
Movement

Levers for muscle action

Function of Bones:
Mineral and growth factor storage

Calcium and phosphorus, and growth factors reservoir

Blood cell formation (hematopoiesis)

in red marrow cavities of certain bones

Triglyceride (fat) storage in bone cavities

Energy source

Hormone production

Osteocalcin
• Regulates bone formation
• Protects against obesity, glucose intolerance, diabetes mellitus

Because they contain different types of tissue, bones are ________

Organs

What are the different tissues bones contain

-Bone (Osseous tissue)
-nervous tissue
-cartilage
-fibrous connective tissue
-muscle and epithelial cells in its blood vessels

What are the three levels of structure we consider bones at:

1. Gross
2. Microscopic
3. Chemical

The External Layer of bone is

Compact bone

The internal layer of bone is

Spongy

describe spongy bone

honeycomb of small needle like or flat pieces called trabeculae

In living bones the open spaces between trabeculae are filled with _______ or _______

Red or Yellow Bone marrow

Short, irregular, and flat bones all consist of __________ of spongy bone covered by compact bone

thin plates

The thin plates of short irregular and flat bones are covered outside and inside by connective tissue membranes called the ____________ and the ___________

periosteum and the endosteum

because short, irregular and flat bones are not cylidrical they have no ______ or ______; and no well defined ______

shaft or epiphyses; and no well defined marrow cavity

In flat bones the spongy bone is called the ________

diploe

With few exceptions all long bones have the same general structure:
-
-
-

-Shaft
-bone ends
-membranes

What is the diaphysis

Tubular shaft that forms the long axis

The diaphysis is made of relatively thick compacat bone that surrounds a central ____________

medullary cavity

the medullary cavity contains _________ and is called the ______ ______ _______

yellow marrow,
yellow marrow cavity

What is the epiphyses

the bone ends

A thin layer of _______ ________ covers the joint surface of each epiphysis

articular cartilage (Hyaline)

Between the diaphysis and each epiphysis of an adult long bone is an

epiphyseal line

What is the periosteum

-covers the external surface of the entire bone except joint surfaces.

What is the endosteum

covers internal bone surfaces

Where is Hematopoietic tissue, red marrow, typically found

-in the trabecular cavities of spongy bone of long bones
-and in the diploe of flat bones

True or False:
Red Marrow in adult long bones are only in the heads of femu and humerus only

True

What are the five major Cells of bone tissue?

Osteogenic cells
osteoblasts
osteocytes
bone lining cells
osteoclasts

Oteogenic Cells

– Mitotically active stem cells in periosteum and endosteum
– When stimulated differentiate into osteoblasts or bone lining cells
• Some persist as osteogenic cells

Osteoblasts

• Bone-forming cells
• Secrete unmineralized bone matrix or osteoid
– Includes collagen and calcium-binding proteins
• Collagen = 90% of bone protein
• Actively mitotic

Osteocytes

• Mature bone cells in lacunae
• Monitor and maintain bone matrix
• Act as stress or strain sensors
– Respond to and communicate mechanical stimuli to osteoblasts and osteoclasts (cells that destroy bone) so bone remodeling can occur

Bone Lining Cells

• Flat cells on bone surfaces believed to help maintain matrix
• On external bone surface called periosteal cells
• Lining internal surfaces called endosteal cells

Osteoclasts

•Derived from hematopoietic stem cells that become macrophages
•Giant, multinucleate cells for bone resorption
•When active rest in resorption bay and have ruffled border
–Ruffled border increases surface area for enzyme degradation of bone and seals off area from surrounding matrix

What are projections and what do they include?

Projections are bone marking that bulge outward from the surface. It includes:
-heads
-trochanters
-spines
-others

Bone markings that are depressions and opening include

-Fossae,
-sinuses
-foramina (foramen)
-grooves

What is the osteon (or the Haversian system)

-the structural unit of compact bone.
-a group of hollow tubes of bon matrix, one placed outside the next like growth rings

Each matrix tube in the osteon is called a

lemella

Compact Bone is also called

Lamellar bone

Running through the core of each osteon is the

central canal (haversian canal)

Running through the central canal are

-blood vessels and nerve fibers

canals that lie at right angles to the central canal that connect blood vessels and nerves of periosteum, medullary cavity, and central canal

perforating canals

What is the lacunae

small cavities that contain osteocytes

what are canaliculi

connect lacunae to each other and central canal

Interstitial lamellae

-incomplete lamellae not part of complete osteon
-fills gaps between forming osteons

Circumferential lamellae

just deep to periosteum
-superficial to enosteum
-extend around entire surface of diaphysis
-resist twisting of long bone

how many bones does a baby have
how many bones does an adult have

270 for babies
206 for adults

What do the organic components of bone include

Bone cells and osteoid

osteoid make up ____ of organic bone matrix secreted by _____

-1/3
-osteoblasts

Osteoid's are made up of

ground substance (proteoglycans and glycoproteins)
Collagen fibers

Resilience of bone due to ______ _______

Sacrificial bonds

sacrificial bonds are located

in or between collagen molecules

The balance of bone tissue consists of inorganic ___________

hydroxyapatites (mineral salts)

hydroxyapatites account for ____% of bone by mass

65%

Hydroxyapatites are mainly tiny _______ _______ ______ in and around collagen fibers

calcium phosphate crystals

Hydroxyapatites are resposible for hardness and resistance to ________

compression

BONE DEVELOPMENT

BONE DEVELOPMENT

Define Ossification

process of bone tissue formation

What are the two types of Ossification

1. Endochondral ossification
2. intramembranous ossification

Essentially all bones below the skull form by

endochondral ossification

In Endochondral Ossification bones form by _____

replacing hyaline cartilage

Endochondral ossification forms all bones below the skull except for the _______

clavicles

Endochondral ossification begins when in development?

late in 2nd month of development

Endochondral ossification begins where?

at the primary ossification center in center of shaft

what are the 5 steps for endochondral ossification

1. A bone collar forms around diaphysis of cartilage
2.central cartilage in diaphysis calcifies, the develops cavities
3.The periosteal bud invades the internal cavities and spongy bone forms
4. The diaphysis elongates and a medullary cavity forms
5. The epiphyses ossify

Intramembranous ossification forms the bones of the :

Bones of the skull (Frontal, parietal occipital temoral)
And the clavicles

Intramembranous ossification begins within fibrous connective tissue membranes formed by _______

mesenchymal cells

What are the 4 major steps of intramembranous ossification

1. Ossification centers appear
2. Osteoid is secreted
3. Woven bone and periosteum form
4. Lamellar bone replaces woven bone & red marrow appears

What are the two types of postnatal bone growth?

1. Interstitial growth
2. Appositional growth

determine the type of growth:
1. Increase in bone thickness
2. Increase in length of long bone

1. Appostional growth
2. Interstitial growth

Bone growth that occurs until young adulthood is controlled by

Hormones