A&P 100 Chapter 6 - Skeletal System: Bone Tissue

The 6 key functions of the skeletal system

1. support

2. protection

3. movement

4. control of mineral content

5. hemopoesis

6. triglycerides storage

strength in our skeleton comes from the microscopic lattice of _____________ and ______________

calcium, phosphate

the skeleton allows for movement but also ________ movement at joints at the same time

limits

the skeleton is the major storage reservoir for ________

calcium

the skeleton also serves as a storage reservoir for __________ & ___________

phosphorus, iron

within certain bones is ________ bone marrow, responsible for blood cell production

red

blood cell production is called _____________

hemopoesis

triglycerides (lipids & fats) are stored and release within the ________ bone marrow

yellow

the main portion of the bone, long, tubular, cylindrical - tends to be predominantly made of compact bone is the ________________

diaphysis

the ends of the bones, proximal & distal portions - tends to have projections & fossas that contributes to articulations with other bones is called the _____________

epiphysis

portion b/w the diaphysis and epiphysis is called the ___________

metaphysis

the metaphysis also contains the ___________ growth plate which later becomes the ___________ line (approx age 20)

epiphyseal

the skin surrounding bones, made of dense irregular connective tissue is called _______________

periosteum

the periosteum merges with _________ and contains many sensory nerve endings and is held in place by perforating __________ fibers that mesh with bone matrix

tendons, sharpey's

the cartilaginous tissue found at the ends of bones, covers the epiphysis and reduces friction, allows movement at joints is called ___________ _____________

articular cartilage

the central cavity within the bone is called the __________ cavity, also called the marrow cavity

medullary

the medullary cavity is the location of the ___________ bone marrow

yellow

the medullary inner membrane is called ____________

endosteum

the 1st hardest material in the body is __________ and the 2nd is ____________ extracellular matrix.

enamel, bone (lamellae)

the extracellular matrix of bone is made up of 3 main ingredients, they are....

(WCC)

water 15%

collagen fibers 30%

crystallized mineral salts 55%

what is the percentage of water in bone extracellular matrix?

15%

what is the percentage of collagen fibers in bone extracellular matrix?

30%

what is the percentage of crystallized mineral salts in bone extracellular matrix?

55%

the most abundant compound in bone extracellular matrix is ___________ ____________

calcium phosphate

the 2nd most abundant compound in bone extracellular matrix is ___________ ____________

calcium hydroxide

calcium phosphate + calcium hydroxide = ______________

hydroxyappatite

hydroxyapatite + fluoride, potassium, sulphate and iron = _________________

calcification

the 4 main types of cells in bone are:

osteogenic cells

osteoblasts

osteocytes

osteoclasts

the unspecialized stem cells derived from mesenchyme cells are called _____________ cells

osteogenic

can osteogenic cells undergo cell division/mitosis?

yes

the bone builders called ____________ synthesize __________ fibers and initiate calcification

osteoblasts, collagen

osteoblasts take ____________ from blood and put it into bone

calcium (Ca2)

cells that destroy bone are called ____________

osteoclasts

osteoclasts take __________ from bone and put it into the blood

calcium

osteoblasts are responsible for bone ____________, the laying down of minerals and collagen fibers to create the extracellular matrix

deposition

osteoclasts are responsible for bone ____________, the breakdown of bone extracellular matrix

resorption

deposition and resorption are processes in bone ___________

remodeling

mature bone cells, which maintain daily metabolic activities of the bone cell such as exchange of nutrients, removal of wastes are called _________________

osetocytes

the two major portions/types of bone are ___________ bone & ___________ bone

compact, spongy (cancellous)

compact bone is made up of ____________, _____________ & ____________ and has little or no space b/w cells

calcium, phosphate & collagen (and other minerals)

the matrix of compact bone is called _____________ and is a ________ ________ connective tissue

lamellae, dense irregular

the 3 types of lamellae are ___________, ____________ & __________ lamellae

concentric, interstitial, circumferential

rings of hard, extracellular matrix surrounding each central canal called __________ __________

concentric lamellae

located b/w osteons but not part of an osteon are called _________ ___________

interstitial lamellae

surround the medullary cavity or lie underneath the periosteum, along the superficial edge of the bone is the ___________ ____________

circumferential lamellae

the perpendicular canals that run superficial to deep that carry blood & lymphatic vessels and nerves that penetrate from the periosteum are called __________ canals or ____________ canals

perforating, volkmann's

the parallel canals that run deep & longitudinally along the shaft of the bone, also carrying blood & lymph vessels as well as nerves are called ___________ canals or ___________ canals

central, haversian

spaces within lamellae where osteocytes can be found, also called "little lakes" ___________

lacunae

small channels that radiate in all directions from each lacunae, filled with ECF, also called little canals ____________

canaliculi

the repeating units of all components of compact bone around 1 central canal is called ___________ system or __________

haversian, osteon

bone that has the appearance of lattice, irregular pattern of bone tissue distribution, air/fluid filled is referred to as ______________ bone

spongy

Bone diagram

true/false, spongy bone has no osteons?

true

spongy bone is a greater/lesser blood supply?

greater

spongy bone requires more blood because what is produced there?

RBC, WBC & platelets

once RBC's, WBC's & platelets are produced in spongy bone tissue, they are deposited into the bloodstream to migrate to the s_______ and other l______ tissue where they are stored until reaching maturity.

spleen, lymph

the matrix or lamellae of spongy bone is called __________ and has a coral reef appearance

trabeculae

___________ bones have spongy bone throughout but more concentrated in the ends

long

bones that are predominantly spongy bone

flat, some irregular and all cuboidal

bone formation, also known as _____________ and _____________

Ossification, Osteogenesis

bone formation begins in the ________ week of development

6th

the 2 types of bone formation are ___________ and __________

Intramembranous, endochondral

bone formation that begins b/w 2 membranes, used by flat & skull bones and mandible

intramembranous

bone formation that replaces cartilage, more common in long bones

endochondral

intramembranous bone formation (4)

1. development of ossification center

2. calcification

3. formation of trabeculae

4. development of periosteum

step ___ of intramembranous bone formation; chemical messages cause mesenchymal cells to cluster and develop into osteoblasts, which secrete bone extracellular matrix. ____________________________________

1

development of ossification center

step ___ of intramembranous bone formation; osteoblasts become osteocytes, which extend projections into canaliculi; calcium and minerals are deposited and the matrix hardens. _____________________

2

calcification

step ___ of intramembranous bone formation; matrix continues to harden and forms trabeculae that fuse with one another to form spongy bone, blood vessels & connective tissue enter spaces and red bone marrow is formed. _________________________________

3

formation of trabeculae

step ___ of intramembranous bone formation; outer layer of mesenchyme develops into the periosteum; compact bone replaces spongy bone on cortex of bone, spongy bone remains in the middle; eventually bone conforms into adult size and shape. ____________________

4

development of periosteum

endochondral bone formation (6)

1. development of cartilage model

2. growth of cartilage model

3. development of primary ossification center

4. development of marrow cavity

5. development of secondary ossification center

6. formation of articular cartilage and epiphyseal growth plate

step ___ of endochondral bone formation; chemical messages initiate the mesenchymal cells to develop into chondroblasts, which begins cartilage extracellular matrix formation. cartilage is formed w/ perichondrium membrane surrounding the entire model. ________________________________

1

development of the cartilage model

step ___ of endochondral bone formation; chondroblasts develop into chondrocytes, with further deposition of cartilage extracellular matrix. 2 types, interstitial & appositional growth. _______________________________

2

growth of the cartilage model

step ___ of endochondral bone formation; nutrient artery penetrates into the middle of the cartilage initiating activity of osteoblasts; perichondrium becomes periosteum; local cartilage calcifies into bone. ______________________________

3

development of the primary ossification center

step ___ of endochondral bone formation; osteoclastic activity cause a marrow cavity to form with in the shaft of the diaphysis. ________________________________

4

development of marrow cavity

step ___ of endochondral bone formation; epiphyseal plate is formed from penetration of epiphyseal arteries; growth occurs outwards from the epiphysis, cartilage continues to be converted into bone. __________________________________

5

development of secondary ossification center

step ___ of endochondral bone formation; final stage of ossification where hyaline cartilage becomes the articular cartilage we see in adulthood. _________________________________

6

formation of articular cartilage and epiphyseal plate

replication of chondrocytes accompanying new matrix, results in __________________ growth.

interstitial (length)

deposition of extracellular matrix on cartilage surface and periphery results in __________________ growth.

appositional (width/thickness)

Bone Growth Model

____________ plate - hyaline layer of cartilage in the metaphysis that consists of 4 main zones, from which new bone is laid down. This becomes the _______________ line after the person has stopped growing in length

epiphyseal

step ___ of bone growth; _______________ cartilage zone. the layer nearest to the epiphysis; consists of small chondrocytes that anchor the epiphyseal plate to the bone. the cells are not involved in bone growth.

1

resting

step ___ of bone growth; _______________ cartilage zone. large chondrocytes that replicate and divide to replace old/dying chondrocytes

2

proliferating

step ___ of bone growth; _______________ cartilage zone. large mature chondrocytes situated in columns

3

hypertrophic

step ___ of bone growth; _______________ cartilage zone. mostly dead chondrocytes, areas is calcified and osteoblasts invade to lay down new extracellular bone matrix to convert it from calcified cartilage to new diaphysis and new blood vessels are formed

4

calcified

bone tissue will lay down along lines of _________. also known as ___________ law

stress, wolf's

examples of bone stress

trauma

infection

cancer

aging

factors that affect bone growth

minerals

vitamins

hormones

minerals

calcium

phosphorus

fluoride

magnesium

manganese

vitamins

vitamin A

Vitamin C

Vitamin D

Vitamin B12/K

promotes osteoblAsts

Vit A

needed for Collagen formation

Vit C

helps with absorption of calcium in GI tract

Vit D (Digestive)

Vit D converted in Calcitriol by Kidneys

helps build bone proteins

Vit K & B12

hormones: from thyroid & insulin like growth factors, in response to human growth hormone, help to promote bone growth

T3 & T4

(Thyroid Hormone)

Arterial bone-blood supplies

periosteal artery - thru volkmann's / perforating

nutrient/diaphyseal artery

metaphyseal artery

epiphyseal artery

importance of calcium

- chemical reactions

- blood clotting

- muscle contractions

concentration of calcium in body must remain b/w:

9-11 mg/100ml

too much Ca2+ and heart __________

stops (stays contracted)

too little Ca2+ and respiration ___________

stops (not enough muscle fibers are stimulated)

too little Calcium: ___________

too much Calcium: ___________

Hypocalcemia

Hypercalcemia