Ch 6 Bone Tissue Flashcards
Skeletal system is an organ system with tissues that grow and change throughout life
4 components
Bones
Cartilages
Ligaments
Other supportive connective tissues
- Semirigid connective tissue
2 details - Cells
- -chondroblasts -
- -chondrocytes -
- Semirigid connective tissue
- –Weaker than bone, but more flexible and resilient
- —Mature cartilage is avascular - Cells
- –Chondroblasts: Produce matrix
- –Chondrocytes: Surrounded by matrix
- —–Occupy small spaces called lacunae
Functions of Cartilage
- Supporting ___ _____
Examples include the airways in respiratory system and auricle of ear - ___ _____ at articulations
- ________ - Precursor model for _________
Beginning in embryo, cartilage grows and then is replaced by ____
1.Supporting soft tissues
Examples include the airways in respiratory system and auricle of ear
2. Gliding surface at articulations
Smooth surfaces where bones meet
3. Precursor model for bone growth
Beginning in embryo, cartilage grows and then is replaced by bone
Growth patterns of cartilage
Two types of growth:
1.
2.
Two types of growth:
1. Interstitial growth
From within the cartilage
- Appositional growth
Along the cartilage periphery
interstitial growth
-_____in lacunae
-Forms _____ per lacuna
-Each ___ and ____
-New matrix separates the _____, now called _____
-Results:
1.
2.
- Mitosis of chondrocytes in lacunae
- Forms two chondroblasts per lacuna
- Each synthesize and secrete new matrix
- New matrix separates the cells, now called chondrocytes
- Results:
1. Larger piece of cartilage
2. Newest cartilage on the inside
Appositional Growth
-Mitosis of stem cells in ____
-Adds ….
-Produce ____, become ______
Results:
1.
2.
-Mitosis of stem cells in perichondrium
-Adds chondroblasts to periphery
-Produce matrix, become chondrocytes in lacunae
-Results:
1.
2.
Bone
- Bones of skeleton are complex organs containing…
1. Primarily…
2. Extracellular matrix is _____ due to…
- Bones of skeleton are complex organs containing all four tissue types
1. Primarily bone connective tissue
2. Extracellular matrix is sturdy and rigid due to deposition of minerals (calcification)
Function of Bone
- _______
- _______ –
- _____ – ______
- ____
1. Calcium and phosphate
2. Lipids stored in yellow marrow
- Support and protection of more delicate organs
- Movement – attachment site for muscles
- Hemopoiesis – blood cell production in red bone marrow
- Storage of mineral and energy reserves
1. Calcium and phosphate
2. Lipids stored in yellow marrow
Classification and Anatomy of Bones
1. \_\_\_\_ - 2. \_\_\_\_\_\_ - 3.\_\_\_\_ - 4.\_\_\_\_ -
- Long bones
- Greater length than width - Short bones
- Nearly equal length and width - Flat bones
- Thin surfaces - Irregular bones
- Complex shapes
General Structure and Gross Anatomy of Long Bones (1)
1. - 2. - - - 3. - -
- Diaphysis
- -Elongated, cylindrical shaft - Epiphysis
- -Knobby, enlarged regions at each end
- -Strengthens joints
- -Attachment site for tendons and ligaments - Metaphysis
- -Region between diaphysis and epiphysis
- -Contains epiphyseal (growth) plate
General Structure and Gross Anatomy of Long Bones (2)
1. \_\_\_\_\_\_ - - 2.\_\_\_\_\_\_ - -
- Articular cartilage
- Thin layer of hyaline cartilage covering the epiphysis
- Reduces friction and absorbs shock in moveable joints - Medullary cavity
- Hollow, cylindrical space in diaphysis
- In adults, it contains yellow bone marrow
General Structure and Gross Anatomy of Long Bones (3)
- _____
- Covers….
- Contains…
- —Active in ….
- Endosteum
—Covers most internal surfaces of bones
—Contains osteoprogenitor cells, osteoblasts, and osteoclasts
Active in bone remodeling, growth, fracture repair
General Structure and Gross Anatomy of Long Bones (3)
- _____ (continuation from endosteum)
- -Covers …
- -_____ tissue
- -Attached by …..
- -Acts as anchor for ____ and ____
- -Contains ___ and ___
- —Active in ____, ___ and ____
- Periosteum
- Covers external surfaces of bones (except where articular cartilage does)
- Dense irregular connective tissue
- Attached by perforating fibers embedded in the bone matrix
- Acts as anchor for blood vessels and nerves
- Contains osteoprogenitor cells and osteoblasts
- –Active in remodeling, growth, fracture repair
cells of bone
4
osteoprogenitor cells
osteoblasts
osteocytes
osteoclasts
- Osteoprogenitor cells:
2. Osteoblasts:
- Osteoprogenitor cells: Mesenchymal stem cells in endosteum and periosteum; can produce more stem cells or osteoblasts
- Osteoblasts: Form bone matrix (secrete as organic osteoid)
- Osteocytes:
- Osteoclasts:
a. Have ___ ____
b. Often located in a ___ ____
c. Secrete___ ___ and enzymes that dissolve matrix
- Osteocytes: Reside in lacunae; maintain matrix and detect mechanical stress on a bone
- Osteoclasts: Large, multinuclear cells that dissolve bone matrix (osteolysis), releasing Ca++
Have ruffled border
Often located in a resorption lacuna
Secrete hydrochloric acid and enzymes that dissolve matrix
Composition of the Bone Matrix
- ____ components of bone (about __ of bone mass):
- -
- -
- - - ___ components of matrix:
- -Primarily ____
- —Calcium phosphate and calcium hydroxide
- Organic components of bone (about one-third of bone mass):
- Cells
- Collagen fibers
- Ground substance - Inorganic components of matrix:
- Primarily hydroxyapatite
- –Calcium phosphate and calcium hydroxide
Comparison of Compact and Spongy Bone
- ____ bone
- -___and ___
- -External surfaces of ___ and ___ - ____ bone
- -Open lattice of narrow plates called _____
- -_____ of bones
- Compact bone
- -Solid and relatively dense
- -External surfaces of long and flat bones - Spongy bone
- -Open lattice of narrow plates called trabeculae
- -Internal surface of bones
Flat bones within Skull
-Two layers of ____, with ____ (diploe) sandwiched between
Two layers of compact bone, with spongy bone (diploe) sandwiched between
Compact Bone Microscopic Anatomy (1)
- The basic unit of compact bone is the ___
1. Also known as a __ __
2. ___ structures
3. Run parallel to the ___
- The basic unit of compact bone is the osteon
1. Also known as a Haversian system
2. Cylindrical structures
3. Run parallel to the diaphysis
Compact Bone Microscopic Anatomy (2)
- __ __
- Carries vessels and nerves in center of osteon - __ ___
- Rings of bone around central canal
- Central canal
- Carries vessels and nerves in center of osteon - Concentric lamellae
- Rings of bone around central canal
Compact Bone Microscopic Anatomy (2)
- ____
Housed in lacunae between lamellae - _____
- Tiny, interconnecting channels that extend between lacunae
- Allow osteocytes to connect and ___
- Osteocytes
- Housed in lacunae between lamellae - Canaliculi
- Tiny, interconnecting channels that extend between lacunae
- Allow osteocytes to connect and communicate
Compact Bone Microscopic Anatomy (3)
- ___ ___
- Run perpendicular to and help connect multiple central canals
- Passageways for__ and ___ - __ ____
- Rings of bone immediately internal to the periosteum or internal to the endosteum
- Run the ___ of the bone - ___ ____
- Leftover parts of ___ that have been partially resorbed
- Perforating canals
- Run perpendicular to and help connect multiple central canals
- Passageways for blood vessels and nerves - Circumferential lamellae
- Rings of bone immediately internal to the periosteum or internal to the endosteum
- Run the entire circumference of the bone - Interstitial lamellae
- Leftover parts of osteons that have been partially resorbed
Spongy Bone Microscopic Anatomy
- No ___
- Trabeculae contains __ ___
- No osteons
- Trabeculae contains parallel lamellae
ossification
- The formation of bone
- Two patterns:
1. ____ossification - –Develops from ___
- –Produces flat bones of the ___, some ___ bones, mandible, and central portion of clavicle
2. ____ ossification - –Begins with ___ cartilage model
- –Produces ___ of bones in the body
- The formation of bone
- Two patterns:
1. Intramembranous ossification - –Develops from mesenchyme
- –Produces flat bones of the skull, some facial bones, mandible, and central portion of clavicle
- Endochondral ossification
- –Begins with hyaline cartilage model
- –Produces majority of bones in the body
Intramembranous Ossification (1)
- ___ ___ form within thickened regions of ___
- Osteoid undergoes ___
- Woven bone and surrounding _____ form
- ____ ____ replaces woven bone, as ____ and ___ form
- Ossification centers form within thickened regions of mesenchyme
- Osteoid undergoes calcification
- Woven bone and surrounding periosteum form
- Lamellar bone replaces woven bone, as compact bone and spongy bone form
Endochondral Ossification
- The ____ develops
- Cartilage ____, and a _____ forms
- The primary ossification center forms in the _____
- The fetal hyaline cartilage model develops
- Cartilage calcifies, and a periosteal bone collar forms
- The primary ossification center forms in the diaphysis
Endochondral Ossification
- Secondary ossification centers form in the ____
- ____ replaces ____, except the articular cartilage and epiphyseal plates
- Epiphyseal plates ___ and form _______
- Secondary ossification centers form in the epiphyses
- Bone replaces cartilage, except the articular cartilage and epiphyseal plates
- Epiphyseal plates ossify and form epiphyseal lines
Epiphyseal Plate Morphology
- The epiphyseal plate is a layer of ___ ____ at the boundary of the ___ and ___
- Site of ___ ____
Consists of five distinct microscopic zones: 1. 2. 3. 4. 5.
- The epiphyseal plate is a layer of hyaline cartilage at the boundary of the epiphysis and diaphysis
- Site of interstitial growth
- Consists of five distinct microscopic zones:
1. Zone of resting cartilage
2. Zone of proliferating cartilage
3. Zone of hypertrophic cartilage
4. Zone of calcified cartilage
5. Zone of ossification
Epiphyseal Plate Morphology
- Zone of resting cartilage:
Zone of resting cartilage: Farthest from medullary cavity and nearest epiphysis; small chondrocytes in hyaline cartilage
Epiphyseal Plate Morphology
Zone of proliferating cartilage:
Zone of proliferating cartilage: Larger chondrocytes undergoing rapid mitotic cell division; aligned like stacks of coins
Epiphyseal Plate Morphology
Zone of hypertrophic cartilage:
Zone of hypertrophic cartilage: Chondrocytes cease dividing and become enlarged
Epiphyseal Plate Morphology
Zone of calcified cartilage:
Zone of calcified cartilage: Deposited minerals kill the chondrocytes and make matrix opaque
Epiphyseal Plate Morphology
Zone of ossification:
Zone of ossification: Walls between lacunae break down, forming channels that become invaded with capillaries and osteoprogenitor cells
Growth of Bone
Growth of bone
- A long bone’s growth in length is referred to as ___ ___
- –Occurs in _____
- Growth in a bone’s diameter is referred to as _______
- –Occurs in the ____
- A long bone’s growth in length is referred to as interstitial growth
- –Occurs in epiphyseal plate
- Growth in a bone’s diameter is referred to as appositional growth
- –Occurs in the periosteum
Blood Supply and Innervation
- Bone is highly ____
- Four major sets of blood vessels:….
- Nerves accompany blood vessels through the _____
Bone is highly vascularized
Four major sets of blood vessels:
- Nutrient artery and vein:
- Metaphyseal arteries and veins
- Epiphyseal arteries and veins
- Periosteal arteries and veins
Nerves accompany blood vessels through the nutrient foramen
Four major sets of blood vessels:
Nutrient artery and vein:
Metaphyseal arteries and veins:
Epiphyseal arteries and veins:
Periosteal arteries and veins:
Nutrient artery and vein: Supply the diaphysis of a long bone; usually just one nutrient artery and vein per bone
Metaphyseal arteries and veins: Supply the diaphyseal side of the epiphyseal plate
Epiphyseal arteries and veins: Supply the epiphyses
Periosteal arteries and veins: Supply blood to the external circumferential lamellae and superficial osteons
Maintaining Homeostasis and Promoting Bone Growth
Growth, maintenance, and repair depend on:
- -
- -
- -
Growth, maintenance, and repair depend on:
Hormones
Vitamins
Exercise
Effects of Hormones
- Hormones regulate ___ & ___ activity
- Hormones also regulate ____ levels
- Growth hormone stimulates ____growth at ______
- Hormones regulate osteoblast and osteoclast activity
- Hormones also regulate calcium levels
- Growth hormone stimulates cartilage growth at epiphyseal plate
Effects of Hormones
- Thyroid hormone stimulates….
- ___ and ____ have opposite effects on calcium
a. ____ promotes calcium deposit from ___ to ___
b. Parathyroid hormone stimulates ____ to resorb bone and increase levels of ____ in the blood
- Thyroid hormone stimulates metabolic rate of osteoblasts
- Calcitonin and parathyroid hormone have opposite effects on calcium
a. Calcitonin promotes calcium deposit from blood to bone
b. Parathyroid hormone stimulates osteoclasts to resorb bone and increase levels of calcium in the blood
Effects of Vitamins
Vitamins are needed for normal ___ and ___
- -Vitamin A activates __
- -Vitamin C required for _______
- -Vitamin D stimulates ____ from ___ into blood so that calcium is available for bold building
Vitamins are needed for normal bone growth and maintenance
- -Vitamin A activates osteoblasts
- -Vitamin C required for collagen synthesis
- -Vitamin D stimulates calcium absorption from GI tract into blood so that calcium is available for bold building
Effects of Exercise
- Mechanical stress stimulates increase in ____ by increased ___
- Bones of athletes become thicker and stronger as the result….
- Bones lose mass with ___, but this can be slowed or reversed with ____
- Mechanical stress stimulates increase in bone density by increased osteoblast activity
- Bones of athletes become thicker and stronger as the result of repetitive and stressful exercise
- Bones lose mass with age, but this can be slowed or reversed with weight-bearing exercise
Fracture Repair
-Breaks in bones, called ___, can be classified in many ways
-Healing takes a few months or more and occurs in a series of steps: 1. 2. 3. 4.
-Breaks in bones, called fractures, can be classified in many ways
- Healing takes a few months or more and occurs in a series of steps:
1. A fracture hematoma forms
2. A fibrocartilaginous (soft) callus forms
3. A bony (hard) callus forms
4. The bone is remodeled
Aging of the Skeletal System
1.During aging, bone changes in two ways:
—Loses ability to produce….
—-Loses…
~~____: insufficient ossification
- Can result in a decrease in bone mass called ____
- –Increase chances of ____
- During aging, bone changes in two ways:
—-Loses ability to produce organic matrix (mainly collagen)
—-Loses calcium and other minerals
~~Osteopenia: insufficient ossification - Can result in a decrease in bone mass called osteoporosis
- –Increase chances of fractures
