Bones Flashcards
Bone Functions (5)
- SUPPORT: (Structural framework for tissues)
- PROTECTION for vital organs
- MOVEMENT: Bones act as levers
- STORAGE of minerals (Ca, Phosphate), fats
(triglycerides), WBC’s - HEMATOPOIESIS: Blood cell formation
BONE MARKINGS:
What is a Projection?
Sites of attachments
BONE MARKINGS : Types of projections:
“Tuberosity”
Large rounded projection
BONE MARKINGS : Types of projections:
“Trochanter”
Large tubercles on a femur
BONE MARKINGS : Types of projections:
“Epicondyle”
Eminence above a condyle
BONE MARKINGS: Types of projections:
“Crest”
Prominent ridge of bone
BONE MARKINGS : Types of projections:
“Line”
Low narrow ridge of bone
BONE MARKINGS : Types of projections:
“Spine”
Pointed Projection
BONE MARKINGS : Types of projections:
“Process”
Prominent Projection
Bone markings: Openings and depressions
“Foramen”
Hole in bone
Meatus
Tunnel
Fissure
Narrow cleft
Sinus
Cavity
Fossa
Depression
Notch
Depression
Groove
Furrow
PROJECTIONS (bone markings)
- Tuberosity
- Trochanter
- Tubercles
- Epicondyle
- Crest
- Line
- Spine
- Process
- Large rounded projections
- large tubercles on a femur
- small rounded projection
- Eminence above a condyle
- Prominent ridge of a bone
- Low, narrow ridge of a bone
- Pointed projection
- Prominent Projection
OPENINGS AND DEPRESSIONS: (Bone markings)
- Foramen
- Meatus
- Fissure
- Sinus
- Fossa
- Notch
- Groove
- Hole in bone
- Tunnel
- Narrow Cleft
- Cavity
- Depression
- Depression
- Furrow
Foramen
Hole in bone
Meatus
Tunnel
Fissure
Narrow cleft
Sinus
Cavity
Fossa
a depression
Notch
a depression
Groove
Furrow
Bone Texture: COMPACT BONE
1. Description
- Dense & smooth appearing; forms the external layer of bones
Bone Texture: SPONGY BONE
- Composed of “Trabeculae” (an irregular lattice of thin columns)
- Forms a network filled with red bone marrow
Bone Classification
“Long Bone”
(Description & example)
- Shaft w/ 2 ends made mostly compact bone.
(has nothing to do with size) - E.g: Femur/ most bones of appendicular skeleton are long bones
Bone Classification
“Short Bones”
(Description & Example)
- Somewhat cube shaped, equal Length&Width, made mostly of spongy bone
- e.g. - patella, wrist & ankle bones
Bone Classification
“Flat Bones”
(Description & Example)
- Generally thin & flat
- Has 2 parallel plates of compact bone
w/ a layer of spongy bone between (sandwich) - e.g - skull, sternum, ribs
Bone Classification
“Irregular Bones”
(Description & Example)
- Complex shapes that don’t fit w/ the other
categories - Made mainly of spongy bone enclosed by thin
layer of compact bone - e.g.- vertebra, facial bones
Bone Classification
“Sesamoid Bones”
(Description & Example)
Form within tendons
e.g. - patella
Gross Anatomy of a typical long bone:
“Diaphysis”
Bone Shaft
Gross Anatomy of a typical long bone:
“Metaphysis”
The flare that joins the metaphysis & the epiphysis
Gross Anatomy of a typical long bone:
“Epiphysis”
The ends of the bone
Gross Anatomy of a typical long bone:
“Epiphyseal Line”
Growth plate remnant in mature bone
Epiphyseal Plate
Growth plate in long bone near the ends that allows bones to grow (for kids). Later turns into the Epiphyseal line once its mature
Gross Anatomy of a typical long bone:
“Periosteum”
(General description and functions)
A dense white fibrous double layered CT membrane that covers the exterior surface of bone.
It’s the attachment point for tendons and ligaments
Each layer has its own specific characteristics and functions.
Osteoblasts
- Bone depositing (forming) cells
2.Secrete collagen and ground substance
(the organic components of the bone matrix aka Osteoid)
- Responsible for calcification of matrix
Osteoclasts
Bone dissolving & reabsorbing cells
They are large multinuclear cells & use enzymes to dissolve bone matrix.
Arise from hemocytoblasts
Gross Anatomy of a typical long bone:
“Endosteum”
- Delicate CT membrane that covers trabeculae and lines internal canals
- Contains osteoblasts and osteoclasts
Gross Anatomy of a typical long bone:
“Articular Cartilage”
(description & function)
- Thin layer of hyaline cartilage that covers
articulating epiphyseal surfaces. - Facilitates joint movement
Gross Anatomy of a typical long bone:
“Medullary Cavity”
- Space within diaphysis that contains fatty
yellow marrow in adults
Short, Irregular and flat bones
Consist of thin periosteum covered layers of compact bone on outsides and endosteum covered spongy bone sandwiched on the inside
They don’t have shafts or epiphysis
What is hematopoietic tissue?
Red bone marrow. Its where blood cells form (Hematopoiesis)
Re: Hematopoietic Tissue:
What kind of marrow is in newborn’s medullary cavity and all areas of spongy bone?
Red Marrow
Re: Hematopoietic Tissue:
Where is hematopoietic tissue (red marrow) found in adults?
In the heads of Femur & Humerus
In the flat bones and hips
What kind of marrow is in the medullary cavities of long bones in adults?
Yellow marrow (fat)
Osteocytes
(description, function, location)
- mature bone cells that derive from osteoblasts
- function: maintain bone matrix; are the principle cell of bone tissue
- Location: Lie in the “Lacunae”
(the small spaces between lamellae)
Osteoprogenitor Cells:
(where they come from & what they do?)
- Arise from mesenchymal cells
- Give rise to osteoblasts
Osteon aka (Haversian System)
- It is the structural unit of compact bone
- It contains: the haversian canal, canaliculi, osteocytes, lacunae, lamellae,
Haversian System Components
(in order from innermost to outer)
- Haversian Canal: aka Central canal. run longitudinal through bone. contain small BV’s and nerve Fibers
- Canaliculi: Minute canals that radiate in all directions from lacunae. Function is to allow “cell to cell” contact
- Osteocytes - mature bone cells
- Lacunae: Space occupied by osteocyte and surrounding matrix
- Lamellae: Concentric rings of hard calcified intercellular substance
Perforating Canal
aka (Volkmann’s Canal)
Right angled canals that carry vessels & nerves from periosteum to haversian canals.
Interstitial Lamellae
Areas between haversian systems
Circumferential Lamellae
Lie deep to the periosteum and extend entirely around the bone (they are the most outer rings under the periosteum). They don’t have haversian systems aka “Osteons”
Spongy Bone
1.Does not contain osteons/haversian systems
- Irregular latticework of bone called “Trabeculae”
What are the 2 layers of the Periosteum and describe each.
Layer 1: Dense Irregular CT:
Superficial layer, contains BV’s, nerves, lymphatic vessels which all enter bone via nutrient foramina
Layer 2: Osteogenic layer:
Inner layer. consists of osteoblasts and osteoclasts
Name the structure that:
1. Lines the Internal bone surfaces
- Is a delicate CT membrane that covers trabeculae & lines the internal canals
- Contain osteoblasts and osteoclasts
Endosteum
Space within the diaphysis that contains fatty yellow marrow in ADULTS
Medullary Cavity
This layer of hyaline cartilage that covers articulating epiphyseal surfaces & facilitates joint movement
Articular Cartilages
What are the organic chemical components of bone?
- Cells: Osteoblasts, osteoclasts, osteocytes
- Osteoid: ground substance (proteoglycans, glycoproteins) and collagen fibers.
What is the function of the organic chemical component of bone?
Collagen Fibers provide tensile strength and flexibility (ability to bend or twist).
Chemical Composition of Bone
(Inorganic) and function
Calcium Phosphate crystals: function to provide bone w/ its hardness & ability to withstand compressive forces; accounts for 2/3 of bone weight
Osteogenesis: 1. give the “aka” and 2. provide the definition
- aka Ossification
- Process of bone formation
When does Ossification begin in humans?
6th or 7th week of embryonic development
What are the 2 patterns by which ossification occurs?
- Intramembranous Ossification - (Mesenchyme - fibrous CT membrane)
- Endochondral Ossification - (Hyaline Cartilage)
- What is cartilage
- What are the cells of cartilage
- C.T.
- Chondrocytes
Mesenchyme
Definition, composition, and function
Mesenchyme is an embryonic CT
Made of Mesenchymal cells -undifferentiated cells
Function: turn into osteoblasts in process of Intramembranous ossification
Intramembranous Ossification:
6 steps
- Mesenchyme cells cluster & differentiate into osteoblasts - Center of ossification
- Osteoblasts secrete osteoid (glycoproteins, proteoglycans, collagen fibers)
- Osteoblast become surrounded by matrix and deposit calcium phosphate - matrix calcifies. Osteoblast become trapped in lacunae and convert to Osteocytes.
- Osteoid fuses together; forms trabeculae; spaces fill w/ red marrow
- Vascular mesenchyme begin to condense on outside of bone; forms Periosteum
- Osteoblasts secrete osteoid against formed inner surface of periosteum
Intramembranous Ossification:
1. From where do bones form in this process?
- Which (type of) bones are formed in this process?
- DIrectly from mesenchyme
- Flat bones (skull, clavicles)
Endochondral Ossification:
1. From where do bones form in this process?
- Which type of bones are formed in this process?
- From hyaline cartilage:
- most bones in the body
- This process is what lengthens bones
8 Steps of Endochondral Ossification
- Mesenchymal cells differentiate to Chondroblasts which produce cartilage model of the bone.
- Cartilage model grows>chondrocytes in center of shaft “hypertrophy” (grow/enlarge) > triggers cartilage matrix to calcify.
a. Nutrients can no longer diffuse, chondrocytes in center lose nutrients
b. Matrix begins to deteriorate
- Cartilage models are covered by a membrane called Perichondrium> vascularized perichondrium converts to periosteum>cells in the internal layer of the periosteum differentiates into osteoblasts > osteoblasts produce thin plate of compact bone called “Periosteal Bone Collar”
- Periosteal Bud enters the deteriorating matrix & provides nutrient artery, vein, lymphatics, nerve fibers, osteoblasts, and osteoclasts
- Osteoblasts secrete osteoid around hyaline cartilage fragments and establish primary ossification center; expansion is proximal and distal.
- Osteoclasts break down bone covered trabeculae to form medullary cavity
- Bone continues to grow via cartilage mitosis at epiphyses
- Secondary ossification centers appear in the proximal and distal epiphyses of long bones.
Longitudinal Bone Growth:
1. Where does bone growth appear occur on the bone
- Which type of ossification is longitudinal bone growth associated with?
- At the epiphyseal plate
- Endochondral bone ossification
What are the steps of Bone growth at the epiphysea, chondrocytes die, l plates? (5 areas/steps)
- Cartilage Resting Zone:
(uppermost layer near epiphysis) - Chondrocytes anchor epiphyseal plate to bony epiphysis. Chondrocytes non functional in bone growth here - Cartilage Proliferating Zone:
Active area of growth - where chondrocytes grow - Chondrocyte mitosis - Cartilage Hypertrophic Zone: Chondrocytes enlarged. (weakest area of growth plate)
- Calcification Zone: Cartilage matrix calcifies, chondrocytes die = cartilage matrix deterioration. Blood vessels invade; structure of calcified cartilage remain.
- Ossification Zone - Calcified cartilage structures are remodeled; spongy bone forms
An increase in bone thickness or diameter is called what?
Appositional Bone Growth
Bone is continually undergoing bone deposition (osteoblasts) and bone reabsorption (removal by osteoclasts)
What is this called?
Bone Remodeling
Functions/ Reasons for Bone Remodeling:
- Engineers skeleton for effective mechanical use in response to physical stress and compression
- Maintains plasma Ca2+ levels (Calcium Homeostasis)
What happens in Appositional Bone Growth? Function? Explain it
This is how bone grows in diameter and new bone thickness
As bone is stressed (compressed), new bone is deposited on the outside of the bone by osteoblasts (they secrete osteoid underneath periosteum).
At the same time bone is being reabsorbed (degraded) on the inside (on endosteal cavity surface) by osteoclasts. This keeps bone from becoming too dense.
Bone Remodeling: Calcium Homeostasis
- What is it called when calcium levels TOO HIGH in blood?
- Which cells act and what they do?
- Process of getting back to Calcium Homeostasis?
- What is the risk of too much calcium in the blood?
- Hypercalcemia
- Osteoblasts - deposit bone
- Thyroid releases calcitonin > kidneys excrete more calcium > calcium deposits into bone via osteoblasts
- Hypercalcemia can cause life threatening cardiac arrhythmias
Bone Remodeling: Calcium Homeostasis
- What is it called when calcium levels TOO LOW in blood?
- Which cells act and what they do?
- Process of getting back to Calcium Homeostasis?
- What is the risk of too low calcium in the blood?
- Hypocalcemia
- Osteoclasts degrade bone matrix=Ca2+ freed and released back into blood
- Parathyroid release PTH > Osteoclasts simulated to digest bone matrix > ionic calcium & phosphate released back into blood
- Hypocalcemia can cause overexcitability of nerves = spastic paralysis of the diaphragm
What is Osteoporosis?
What the science of it do?
who gets it most?
A bone disorder - low bone mass
Bone reabsorption (osteoclast activity) outpaces bone deposition (osteoblast activity)
mostly in women after menopause
What are the 4 steps of Fracture Repair
- Hematoma (clotting): vascularized bone bleeding>clotting>bleeding stops>clot becomes hypoxic>bone cells die> inflammation
- Soft Callus: chondroblasts and fibroblasts invade hematoma> soft callus formed made of fibrocartilage> this strong callus holds bone together so bone can heal
- Bony Callus: osteoblasts make trabeculae w/in soft callus and connect separate bone parts>process similar to endochondral ossif. occurs
- Bone Remodeling: Mature bone forms (spongy & compact), bulge from initial soft callus removed
Synovial Fluid (location and function)
Location: Joint cavities of knee joint and shoulder joint
Function: reduces friction and lubricates joint
Bursae (what are they, location and function)
They are flattened fluid filled membrane sacs which reduce friction. Located in synovial joint of knee and shoulder
List the general structures of Synovial Joints (5)
- Articular Cartilage (Hyaline)
- Articular Capsule
- Joint Cavity
- Synovial Fluid
- Ligaments (intrinsic, extrinsic, extracapsular, intracapsular)
Which ribs are the true ribs? Which ribs are the false ribs?
True Ribs @ T1-T7 and connect directly to sternum
False Ribs @ T8-T12 do not connect directly to sternum. Rib 11 and 12 are floating ribs
