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Ch. 7 Bone Tissue
Tissues and Organs of the skeletal system, Histology of Osseous Tissue, Bone Development, Physiology of Osseous Tissue & Bone Disorders
86
Anatomy
Undergraduate 1
11/15/2009

Additional Anatomy Flashcards

 


 

Cards

Term
Functions of the Skeletal System
Definition

Support

 

Protect

 

Body Movement

 

Hemopoiesis

 

Mineral Storage

 

Acid-Base Balance

Term
Support
Definition
Function of the Skeletal System
Term
Protection
Definition
Function of the Skeletal System
Term
Body Movement
Definition
Function of the Skeletal System
Term
Hemopoiesis
Definition
Function of the Skeletal System
Term
Acid-Base balance
Definition
Function of the Skeletal System
Term
Mineral Storage
Definition
Function of the Skeletal System
Term
Shapes of Bones
Definition
Long Bones & Flat Bones
Term
Structure of a Flat Bone
Definition

External and Internal surfaces of flat bone are composed of compact bone, which is dense, rigid, hard, and unyielding.

Middle layer is spongy bone with a diploe layer. (Diploe- honeycomb trabeculae). Shock absorption. No marrow cavity.

 

Term
Structure of Long Bones
Definition

Shaft(diaphysis)

 

Epiphyses

 

Articular Cartilage (hyaline)

 

Periosteum

 

Epiphyseal Plate or line

 

Term
Shaft (diaphysis)
Definition

Long Bones

Cylinder of Compact Bone

 

Contains marrow (medullary cavity) which is lined with endosteum

Term
Epiphyses
Definition

Long Bones

Enlarged proximal and distal ends.

 

Spongy bone covered with layer of compact.

 

Where joints are covered with articular cartilage to absorb shock (no bone on bone) and create less stress.

Term
Aticular cartilage (hyaline)
Definition
Covers the joint surface of long bones
Term
Periosteum
Definition

Long Bones

peri- around           steum- bone

 

covers remainder of bone

 

highly sensitive with nerve activity

 

outer fibrous layer of collagen fibers continuous with tendons

 

perforating (Sharpey's) fibers penetrate bone matrix

 

inner osteogenic layer important for healing and growth

Term
Epiphyseal Plate or Line
Definition

Long Bones

 

Depends on age

Term
Epiphyseal Plate or line
Definition

Long Bones

 

depends on age

Term
General Features of Bone
Definition

Epiphysis (2)

 

Diaphysis

 

Periosteum and Articular Cartilage

 

Compact Bone

 

Spongy Bone

 

Medullary Cavity or Marrow Cavity

 

Yellow Marrow

 

Endosteum

 

Nutrient Foramen

Term
4 Basic Cells Found in Bony Tissue
Definition

Osteoblasts

 

Osteoclasts

 

Osteogenic Cells

 

Osteocytes

Term

Osteogenic Cells

 

Definition

reside in endosteum, periosteum, or central canals

 

pre-cursor/stem cells/will become something

 

arise from fibroblasts and become only source for new osteoblasts

 

multiply continuously and differentiate into amitotic osteoblasts in response to stress or fractures

Term
Osteoblasts
Definition

can only come from osteogenic cells

 

form and help mineralize organic matter of matrix

 

creates hardness/firmness

Term
Osteocytes
Definition

are former osteoblasts that have become trapped in the matrix they formed

 

in lacunae connected by gap junctions inside canaliculi

 

signal osteoclasts and osteoblasts about mechanical stresses

Term
Osteoclasts
Definition

develop in bone marrow by the fusion of 3-50 of the same stem cells (osteogenic) that give rise to monocytes found in blood

 

reside in pits called resorption bays that they have eaten into the surface of the bone (so they can dissolve bone cells)

 

tear down/remodel bone tissue

Term
Compact Bone
Definition

Concentric Lamellae

 

Lacunae

 

Canaliculi

 

Perforating (volkman's) Canal

 

Osteon (blood vessel inside)

 

Central Canal (Haversian)

Term
Osteon
Definition
Structural unit of compact bone
Term
Haversian (central) canal
Definition

Compact Bone

 

where blood vessels and nerves pass

 

vertical

Term
Perfoating (Volkman's) canal
Definition

Compact Bone

 

crosses matrix and feeds into central canals

 

perforates side

Term
Canaliculi
Definition

Compact Bone

 

channels, provide nourishment

 

connect the osteocytes

 

Communicate between concentric rings

 

lateral extensions

Term
Lacunae
Definition

Compact Bone

 

space for osteocytes

Term
Lamellae
Definition

Compact Bone

 

Concentric rings

Term
osteocyte
Definition

Compact Bone

 

bone cells

 

maintain bony matrix

 

star-shaped; looks like nerve cell

Term
Spongy Bone
Definition

Spongelike appearance formed by rods and plates of bone called trabeculae; spaces filled with red bone marrow

 

Trabeculae have few osteons or central canals

 

Provides strength with little weight

 

Term
How does a bone cell get nourished?
Definition

Blood and Bone marrow

 

no osteocyte is far from blood or bone marrow

Term
Bone Marrow
Definition

Soft tissue that occupies the medullary cavity of a long bone or the spaces in the trabeculae of spongy bone

 

Red

 

Yellow

 

Gelatinous

Term
Red Marrow
Definition

looks like thick blood

 

mesh of reticular fibers and immature cells

 

Hemopoietic

 

found in vertebrae, ribs, sternum, pelvic girdle, and proximal heads of femur and humerus of adults

Term
Yellow Marrow
Definition

fatty marrow of long bones in adults

 

DOES NOT make blood

 

storage of minerals

Term
Gelatinous Marrow
Definition

created in old age

 

yellow marrow replaced with reddish jelly

Term
Intramembranous Ossification
Definition

Produces flat bones of skull and clavicle only!

 

Fibrous membrane develops directly into bone

Term
Endochondral Ossification
Definition

How all other bones are made

 

bones start out as cartilage and turn into bones

 

Has a cartilage phase that IMO did not have

 

6 step process

Term
Primary Ossification Centers
Definition
Steps 1-3 of Endochondral Ossification
Term

Primary Ossification Centers Step 1

 

Definition
1) synthesis of the cartilage during development that will become bone someday
Term
Primary Ossification Centers Step 2
Definition

taking the cartilage and transforming it to bone

 

formation of the primary ossification center, bony collar, and periosteum

Term
Primary Ossification Centers Step 3
Definition

fills medullary cavity with blood to start the activity in bone

 

vascular invasion, formation of primary marrow cavity, and appearance of secondary ossification center

Term
Secondary Ossification Centers Step 4
Definition

Secondary Ossification Center built

 

enlargement of marrow cavity in epiphysis

Term
Secondary Ossification Centers Step 5
Definition

establish epiphyseal plate

 

growth at ends of bones; not in middle

Term
Secondary Ossification Centers Step 6
Definition
Bone stops growing, epiphyseal plate fuses
Term
Secondary Ossification Center
Definition

Begins to form in the epiphyses near time of birth

 

Same stages occur as in primary ossification center

 

result is center of epiphyseal cartilage being transformed into spongy bone

 

Hyaline cartilage remains on joint surface as articular cartilage, junction of diaphysis and epiphysis, and each side of epiphyseal plate has a metaphysis

Term
The Metaphysis
Definition

Bone elongation

 

transitional zone between head and shaft of developing long bone- 5 zones

 

1) reserve cartilage

 

2) proliferation

 

3) hypertrophy

 

4) calcification

 

5) deposition

Term

Zone of reserve cartilage

 

Definition
hyaline cartilage
Term
zone of proliferation
Definition

chodrocytes multiply forming columns of flat lacunae

 

chondro = build

cyte = cell

Term
zone of hypertrophy
Definition

cell enlargement

 

hyper = increase

 

trophy = size

Term
zone of calcification
Definition
mineralization of matrix
Term
zone of bone deposition
Definition

chodrocytes die and columns fill with osteoblasts

 

osteons formed and spongy bone is created

Term
Bone Growth and Remodeling
Definition

Bone grows by both appositional growth and by interstitial growth from the cartilage within the bone

 

athletes or active adults have greater bone mass and density

Term
Interstitial growth
Definition

bones increase in length by interstitial growth of the epiphyseal plate

 

an open epiphyseal plate has room to grow, but once plate closes and it become an epiphyseal line, the plate cannot grow any longer

 

in late teens, early 20's- growth plates begin to close in different bones (cartilage depleted and replaced with spongy bone; now called epiphyseal line)

 

Term
Appositional Growth
Definition

bones increase in width

 

osteoblasts lay down matrix in layers parallel to the outer surface

 

osteoclasts dissolve bone on inner surface

 

bone marrow cavity widens as diameter of bone increases

 

if one outpaces the other, bone deformities can occur (osteoporosis, Paget disease)

Term
Physiology of Bone
Definition

Always Remodeling- bone is dynamic and active tissues all life long

 

Every week recycle 5-7% of bone mass

 

Each day 1/2 gram of Ca++ may leave/enter the skeleton

 

spongy bone is replaced every 3-4 years

compact bone is replaced every 10 or so years

Term
Physiology of Bone- Mineral Absorption & Diet
Definition

mineral deposits (Ca++ and Pi) made when bone is injured or strength is needed- needed to rebuild

 

Diet of bones = vitamin C, C, A, and several minerals (Ca++)

Term
Physiology of Bone- Bone resoprption
Definition

dissolving via osteoclasts

 

bone remodeling is based on the amount of Ca++ and Pi deposition vs. resorption

Term
Physiology of Bone- Bone Remodeling
Definition

can be performed by 3 hormones: calitonin, calcitriol, and the parathyroid hormone

 

happens because of mechanical and gravitational forces (Wolff's Law)

 

needs Ca++ and Pi to rebuild

 

Depends on Dietary intake, waste removal, and mineral exchange

Term
Physiology of Bone- Bone remodeling
Definition

based on the amount of Ca++ and Pi deposition vs. their resorption

 

bone is the reservoir for Ca++ and Pi

 

Ca++ and Pi homeostasis is vitally important for muscle contraction, blood clotting, nerve communication, etc.

 

**all about the Ca++ and Pi laid down and removed**

Term
Physiology of Bone- Wolff's Law
Definition

is a normal response

 

Bone accommodates the forces applied to it by altering its amount and distribution of mass (SAID principle)

 

SAID = Specific Adaptations to Impose Demands

 

when body cannot keep up to demands, injuries occur

 

Perfect ex. of form of the bone follows functional experience

 

Ex) greater trochanter vs. greater tubercle: trochanter is a huge process that gets bigger from muscles pulling on it

Term
Physiology of Bone- Wolff's Law Contd.
Definition

Long Bones are thickest midway along diaphysis

 

Curved bones are thickest where they tend to buckle

 

Trabeculae form struts along lines of compression

 

Large bony projections occur where heavy muscles attach

 

All match the demands placed upon it

Term
Bone Remodeling- Calcitriol
Definition

1 hormone that regulates homeostasis of bone

 

formed from vitamin D produced by the skin -> liver -> kidneys

 

kidney makes calcitriol

 

Function: increase blood Ca++ conc. ; makes sure there is enough Ca++ in circulating blood


If constantly lacking calcitriol, bones soften

 

acts as a hormone but is considered a vitamin (usually added to your diet especially if you don't get much sunlight)

 

Term
Physiology of Bone- Calcitonin
Definition

Secreted by thyroid gland (found in neck) when Ca++ conc. rises too high

 

Functions(2):both lower Ca++ in blood

1) reduces osteoclast activity by as much as 70% in 15 min.

2) Within an hour increases the # and activity of osteoblasts

 

Important role in children; little effect in adults- deficiency not known to cause disease in adults

Term
Physiology of Bone- Parathyroid Hormone (PTH)
Definition

Secreted by the parathyroid glands

 

Released when Ca++ blood level too low

 

4 Functions: to raise Ca++ levels

 

 

Term
1st line of defense against Ca++ level drop via PTH
Definition
1) PTH binds to osteoblasts causing them to release osteoclast-stimulating factor that stimulates osteoclast multiplication and activity
Term
2nd line of defense against Ca++ level drop via PTH
Definition
2) promotes Ca++ resorption by the kidneys
Term
3rd line of defense against Ca++ level drop via PTH
Definition
3) promotes calcitriol synthesis in the kidneys
Term
4th line of defense against Ca++ level drop via PTH
Definition
4) inhibits collagen synthesis and bone deposition (building) by osteoblasts
Term
Negative feedback loops in Ca++
Definition

Correction for Hypercalcemia

 

Correction for Hypocalcemia

Term
Hypercalcemia
Definition
a decrease in blood calcium concentration
Term
Hypocalcemia
Definition
an increase in Ca++ blood concentration
Term
Other Factors Affecting Bone
Definition
  • 20 or more hormones, vitamins, and growth factors not well understood
  • Bone growth especiall rapid at puberty

- hormones stimulate proliferation of osteogenic cells and chondrocytes in growth plate

-adolescent girls grow faster than boys and reach their full height earlier (estrogen has stronger effect)

-males grow for a longer time

  • growth ceases when plates close

-steroids may cause premature closing and short adult stature

 

Term
Fracture Healing- Hematoma & Granulation Formation
Definition

hema = blood

 

toma = pool/packet

 

broken vessels from a blood clot pool form granulated tissue

Term
Fracture Healing- Soft callus
Definition
Fibrous tissue formed by fibroblasts and infiltrated by capillaries
Term
Fracture Healing- Hard callus
Definition
Soft callus of fibrocartilage replaced by hard callus of bone in 6 weeks (temp. splint)
Term
Fracture Healing- Remodeling
Definition
Occurs over next 6 months as spongy bone is replaced with compact bone
Term
Treatment of Fractures- Closed reduction
Definition
fragments are aligned with manipulation and casted by MD
Term
Treatment of Fractures- Open reduction
Definition
surgical exposure and repair with plates, wires, screws, etc
Term
Treatment of Fractures- Traction
Definition

not used in elderly due to risks of long-term confinement to bed, otherwise cast immobilization

 

hip fractures are pinned and early walking is encouraged

Term
Treatment of Fractures- Electrical stimulation
Definition
both stimulation and ultrasound are used on fractures that take longer than 2 months to heal (non-union)
Term
Bone Disorders- Osteoporosis
Definition
  • Most common bone disease
  • Trabeculae thins
  • Bones lose mass & become brittle due to loss of both organic matrix and minerals
    • -risk of hip fracture, wrist and vertebral column
    • post hip fracture 20% mortality rate
    • deformities in bone are common as well
  • Postmenopausal white women at greatest risk
Term
Bone Disorders- Osteoporosis Contd.
Definition

ERT (Estrogen Replacement Theory) slows bone resoprtion, but best treatment is prevention (exercise and Ca++ intake) 1,000 mg/day ages 25-40

 

Risks: smoking, diabetes, poor diet in Ca++, Vitamin D & C

 

No cure, can slow its progression

 

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