Download Chapters 7, 8, 9 Bone Tissue/Joints

Chapters 7, 8, 9
Bone Tissue/Joints
BSC 2085
Professor Tcherina Duncombe
Palm Beach State College
Skeleton
• Support
• Protection
• Movement
• Electrolyte Balance
• Acid – base Balance
• Blood Formation
• Osseous tissue: connective:
blood/marrow/cartilage/adipose/
nervous/fibrous
•Calcification = mineralization
Shapes of Bones
• Long – levers acted upon by
muscles: crowbars
• Short – glide across one another in
multiple directions: width/length
same
• Flat – enclose/protect soft organs:
broad/thin/sandwich-like
• Irregular
7-3
Structure of Long Bone
•
•
•
•
•
•
•
•
•
•
Compact: dense; 3/4
Spongy/Cancellous; 1/4
Marrow/Medullary cavity
Periosteum: osteogenic layer
Endosteum: cells dissolve
bone tissue
Diaphysis: leverage
Epiphysis:tendons/ligaments
Epiphyseal plate/line
Articular cartilage
Nutrient foramina
7-4
Structure of a Flat Bone
• External/internal
surfaces:compact
bone: sandwich-like
• Middle layer:spongy
bone(diploe)/bone
marrow
• Skull fracture may
leave inner layer of
compact bone
unharmed
7-5
Cells of Osseous Tissue (1)
• Osteogenic (stem)cells in periosteum and central canals: continual
mitosis: some give rise to new osteoblasts (nonmitotic)
• Osteoblasts make organic matter of matrix: stim by stress and
fractures:secrete osteocalcin: stim insulin secretion/↑insulin
sensitivity in adipocytes→limit growth of adipose tissue
• Osteocytes = osteoblasts trapped in the matrix they formed
7-6
Cells of Osseous Tissue (2)
• Osteoclasts : bone dissolving cells
• 3-50 stem cells fused
- resorb/deposit matrix→homeostasis →bone density/Ca2+
; PO437-7
Intramembranous Ossification
(enlarge to
osteogenic cells)
(become trabeculae)
•
•
Osteogenesis=bone formation
Produces flat bones of skull/clavicle: develop w/in a fibrous sheet similar to dermis = dermal bones
7-8
Bone:osteogenic/osteoblasts/
osteocytes
osteoclasts
Histology of Compact Bone
• Composite: polymer(collagen) and ceramic
(hydroxyapatite)
•Dry weight :1/3 organic; 2/3 inorganic matter
•Organic matter:collagen, glycosaminoglycans,
proteoglycans, glycoproteins (made by osteoblasts)
•Inorganic matter:85% hydroxyapatite;10% calcium
carbonate
• Other minerals (fluoride, potassium, magnesium)
• Combination: strength/resilience; minerals resist
compression; collagen resists tension
• Bone adapts by varying proportions
7-10
Bone Marrow
• 2 Types
• Red marrow: myeloid tissue
– Hemopoietic = produces blood
cells
– vertebrae, ribs, sternum, pelvic
girdle proximal heads of
femur/humerus in adults
• Yellow marrow
– fatty marrow in adults: no
produce blood
– In long bones
7-11
Intramembranous Ossification
(enlarge to
osteogenic cells)
(become trabeculae)
•
•
Osteogenesis=bone formation
Produces flat bones of skull/clavicle: develop w/in a fibrous sheet similar to dermis = dermal bones
7-12
Stages of Endochondral Ossification: bone from hyaline cartilage
• 6th week development → 20’s
7-13
Fetal Skeleton at 12 Weeks
7-14
Bone Growth/Remodeling
• 2 directions:
- length: elongation= cartilage growth
- width: appositional growth
• Remodeling: Wolff’s Law of bones
- architecture determined by stresses/bone adapts to stresses
- both osteoclasts/osteoblasts
Dwarfism
• Achondroplastic
– long bones stop growing in
childhood
• normal torso, short limbs
– spontaneous mutation
during DNA replication
– failure of cartilage growth
• Pituitary
– lack of growth hormone
– normal proportions with
short stature
7-16
Mineral Deposition
Mineralization = crystallization process
Mineral Resorption
Bone dissolved/minerals released into
blood
• osteoblasts produce collagen fibers
• osteoclasts
- minerals cover the fibers/harden the
•HCl/Acid phosphatase(digests colagen)
matrix
- ions (calcium/phosphate/blood
plasma)
deposited along the fibers
- ion concentration must reach solubility
product
•Abnormal calcification (ectopic)
- may occur in lungs, brain, eyes,
muscles, tendons or arteries
(arteriosclerosis)
Calcium Homeostasis
• Ca2+ (Communication) ; PO43• Muscle/Nervous
7-17
Hormonal Control of Calcium Balance:
negative feedback
• Calcitriol: form of VitD:skin/liver/kidneys: ↑blood calcium conc
• PTH: ↑calcium: parathyroid glands
• Calcitonin: ↓ calcium: thyroid gland: inhib osteoclasts/stim osteoblasts
7-18
Correction for Hypercalcemia
7-19
Parathyroid Glands
• PTH release
–  blood Ca2+ levels
– promotes synthesis of
calcitriol
•  absorption of
Ca2+
•  urinary
excretion
•  bone resorption
Correction for Hypocalcemia
7-21
Types of Bone Fractures: 1) Stress fracture caused by trauma
2) Pathological fracture in bone weakened by disease
Fractures classified by
structural characteristics
break in the skin
multiple pieces
7-22
Healing of Fractures 2
7-23
Fractures and Their Repairs
7-24
Spinal Osteoporosis
7-25
Components of a Lever
• A lever is a rigid object that rotates around a fixed
point called a fulcrum
• Rotation occurs when effort overcomes resistance
– resistance arm and effort arm are described relative to
fulcrum
9-26
Mechanical Advantage
• Mechanical advantage is calculated from the length of the
effort arm divided by the length of the resistance arm
• Contraction of the biceps muscle causes the hand to move
fast and further (MA <1.0)
9-27
First-Class Lever
• Has fulcrum in the middle between effort and resistance
• Atlantooccipital joint lies between the muscles on the back of the
neck and the weight of the face
– loss of muscle tone occurs when you nod off in class
9-28
Second-Class Lever
• Resistance between fulcrum and effort
• Resistance from the muscle tone of the temporalis muscle
lies between the jaw joint and the pull of the diagastric
muscle on the chin as it opens the mouth quickly
9-29
Third-Class Lever
• Effort between the resistance and the fulcrum
– most joints of the body
• The effort applied by the biceps muscle is applied to the
forearm between the elbow joint and the weight of the
hand and the forearm
9-30
Types of
Synovial Joints
9-31
Rheumatoid Arthritis
9-32
Joint Prostheses
9-33