Bone Tissue Flashcards
Cartilage
Firm, flexible connective tissue found on many joint surfaces
Ligaments
Responsible for bone to bone connection at joints
Tendons
Responsible for attaching muscles to bone
Functions of the Skeleton
- movement
- support
- protection of organs (ex. thoracic cavity)
- blood formation in bone marrow
- Electrolyte balance
- Acid-base balance
- Detoxicification (idk how)
Osteology
Study of bone
(Bone is a connective tissue)
Mineralization / Calcification
Process of harding bones
Tissues present in bone
- Blood
- Bone marrow
- Cartliage
- Adipose tissue
- Nervous tissue
- Fibrous connective tissue
4 Groups of Bone Shapes
Flat Bones: Thin, often curved bones (ex. Ribs)
Long Bones: Rigid levers for movement (ex. humerus and fibula)
Short Bones: glide within joints (ex. carpals of wrists) often “cube-like” length, width, height are the same
Irregular Bones: complex shapes (ex. vertebrae)
Long bone anatomy
- Compact and spongy tissue
- Marrow in medullary cavity
- Epiphysial Line: remnant of growth plate
- Articular Cartilage: smooths joints
- Endosteum
- Periosteum
What are the two heads and the shaft of long bones called?
Two heads are called Epiphyses
Shaft is called Diaphyses
Anatomy of Epiphyses
Filled with spongy bone
Epiphysial line found in between
(remnant of growth plate)
Articular Cartilage
Anatomy of Flat Bones
Similar to Plasma Membrane
Spongy bone (trabeculae is surrounded by compact bone)
Triple layer bone
Osteogenic Cells
Stem cells found in:
- Endosteum: membrane lining the inner surface of bony wall
- Inner periosteum
- Central Canals
Osteoblasts
Bone-forming cells
What are Osteocytes?
What holds and connects them?
mature bone cells
Lacunae: cavties that house osteocytes
Canaliculi: small canals that connect lacunae
Osteoclasts
bone-dissolving cells
(bone-dissolving macrophages to be more specific)
Osteocyte Development Process
Osteoclast Development Process
Bone Matrix
1/3 organic:
collagen and large protein-carbohydrate complexes
2/3 inorganic:
85% hydroxyapatite
10% calcium carbonate
5% other inorganic material
What makes up Compact Bone
Osteons = basic unit of bone
Makes up:
- Concentric lamallae (tree like circles of bone)
- Circumferential lamallae (Lamallae that form the outer rings of bone tissue
- Central canal
- Perforating canal
Osteons
Makes up Compact bone
Lamallae + Central Canal makes an osteon
Spongy Bone
Spicules: rods and spines of bone
Trabeculae: thin plates of bones
Spaces are filled with bone marrow
(Lightweight but strong)
Two types of Bone Marrow
Red Bone Marrow:
Hematopoietic tissue: both red and white blood cells are made here
Yellow Bone Marrow:
Mainly fat
Types of bone marrow located on the body
Red marrow:
Found on Axial Skeleton, parts of pelvic girdle, promixal heads of humerus and femur
Yellow marrow:
Long bones of limbs
Ossification/Osteogensis
Bone formation
Begins with mesenchyme (an embryonic connective tissue)
Intramembranous Ossification
Produces flat bones of Skull and most of Clavicle
Bone develops in a fibrous sheet resembling the dermis
Endochondral Ossification makes what bones?
Where does it develop from?
Most bones are formed this way
Bone develops from hyaline cartilage model
Bone Elongation
Bones growing longer at epiphysial plates
Where is the Metaphysis located?
What is it made of?
plates made of hyaline cartilage
Area located between the diaphysis and epiphysis
Bone Elongation Process: Zones of the Metaphysis
- Zone of Resting Cartilage (C)
- Zone of Cell Proliferation (P)
- Zone of Cell Hypertropy (H)
- Zone of Calcification (C)
- Zone of Bone Desposition (D)
CPHCD
Appositional Growth
Growth in diameter and thickness of bone
Intramembranous Ossification at Surface
- Osteoblasts in periosteum deposit matrix
- Once matrix hardens(calcification), cells become osteocytes
- Circumferential lamellae are formed
Osteoclasts widen medullary cavity
How do bones remodel themselves?
Absorption (eating) of old bone and deposition (producing) of new bone
Wolf’s Law of Bone
Bone shape is determined by mechanical stress
Bone adapts to withstand stress
Form follows function
Nutritional Factors of Bone
Calcium and Phosphate
Raw materials for calcified ground substance
Nutritional Factors of Bone
What does Vitamin A do?
Promotes formation of glycosaminoglycans (protein-carb fibers)
Nutritional Factors of Bone
Vitamin C
(Ascorbic Acid)
Promotes collagen cross-linking
Nutritional Factors of Bone
What is Vitamin D needed for?
Lack of Vitamin D causes?
(Calcitriol)
Necessary for calcium absorption by small intestine and reduces urinary calcium loss
Lack of vitamin D leads to unablity to absorb calcium, leads to weak bones
Hormonal Factors
Calcitonin
- Secreted by thyroid gland
- Stimulated osteoblasts in children and pregnant women
Hormonal Factors
Growth Hormone
- Promotes intestinal absorption of Calcium
- Stimulates growth plates and bone elongation
Hormonal Factors
Estrogen and Testosterone
Stimulate long bone growth during adolescence
Hormonal Factors
Parathyroid Hormone
- secrete by parathyroid gland
- stimulates bone reabsorption to boost level of calcium in blood
Osteopenia
- Loss of bone
- Bone absorption is fastor that Bone deposition
- Fractures are more common, heal slowly
What happens to bones after age 35?
Osteoblasts are less active than osteoclasts
What happens to bones after age 40?
- Women lose 8% of bone mass per decade
- Men lose 3% of bone mass per decade
Fractures
Stress Fracture
Caused by repeated abnormal trauma, stress-induced
Fractures
Pathological Fracture
Fractures in bone weakened by diseases such as osteoporosis
Fractures
How are fractures classifed?
- Breaking of skin
- Direction of Fracture
- Separation of Bone Pieces
Fractures
Closed Reduction Treatment
Nonsurgical manipulation of fragments for healing (Ex. fiberglass cast)
Healing 8-12 weeks
Fractures
Open Reduction Treatment
Surgical Setting involving plates, screws, or pins for healing
Closed Fracture
Skin is not broken
Open Fracture
Skin is broken through
Bone sticks out of skin
Complete Fracture
Bone is broken in two or more pieces
Incomplete Fracture
Partial fracture that extends only partway across bone, pieces remained joined
Nondisplaced Fracture
Portions of bone are still in correct anatomical alignment
Displaced Fracture
Portions of bone are out of anatomical alignment
Comminuted Fracture
Bone is broken in three of more pieces
Greenstick Fracture
Bone is bent towards oneside and has incomplete fracture on opposite site
(common injury found in children)
Hairline Fracture
Fine crack in which sections of bone remain aligned, common in skull fractures
Impacted Fracture
One bone fragment is driven into the marrow cavity or spongy bone of other
(Bone is compressed into itself vertically causing injury)
Depressed Fracture
Broken protion of bone forms a concavity
(injury commonly found in skull fracture)
Linear Fracture
Fracture parallel to long axis of bone
Transverse Fracture
Fracture perpendicular to long axis of bone
Oblique Fracture
Diagonal Fracture, between linear and transverse
Spiral Fracture
Fracture caused by twisting stress placed on bone
(Skiing accident)
Healing Process of Bone Fracture
- Hematoma Formation (H)
- Soft Callus Formation (S)
- Hard Callus Formation (H)
- Bone Remodeling (B)
HSHB
What is Osteoporosis?
What areas are vunerable?
Bone disease where bones lose mass and are prone to pathological fractures
Hip, wrist, vertebrae are especially vunerable
Kyphosis
Large thoracic curvature
due to osteoporosis
Treatments to Osteoporosis
Bis-phosphonates and parathyroid hormone
Prevention of Osteoporosis
Weight training excerise, good calcium consumption and protein
Structural Disorders of Bone
Acromegaly
Hypersecretion of adult growth hormone
Results in thicking of bones and soft tissues, noticable in faces, hands, and feet
Structural Disorders of Bone
Osteitis Deformans/Paget Disease
Excessive Osteoclast consumption of bone, osteoblasts attempt to compensate by rapid production of bone, which causes weak bones
Most common in males over 50 years old
Structural Disorders of Bone
Osteosarcoma
Bone cancer usually affecting limb bones of adolescents and young adults
Produces large tumors near the knees
Lethal if not treated quickly, death caused by spreading to lungs
Structural Disorders of Bone
Rickets
Defective calcification of bone in children, result of insufficent sunlight or vitamin D consumption
Causes bone-softening or deformity in lower limbs
Periosteum
Membrane of blood vessels and nerves that wrap on external layer of bones
Endosteum
Layer of reticular connective tissue lining internal surfaces of a bone
Nutrient Foramen
Hole in a bone that allows a passage of blood cells into bone tissue
