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