Uploaded by Eunice Joy Purificacion

SKELETAL SYSTEM

advertisement
SKELETAL SYSTEM
Prepared by
Red Steven Nillo,RMT
LEARNING OBJECTIVES
• Define Skeletal System
• Explain how bones formed
• Explain the physiology of skeletal system
• Be familiar with the pathophysiology of some
disorder associated with skeletal system.
WHAT IS A
SKELETAL SYSTEM
Provides a structural framework in
the body. There are 206 bones in
the human body. More than just
bones; it’s also ligaments and
cartilage and the joints that make
the whole assembly useful.
2 DIVISIONS OF SKELETAL SYSTEM
AXIAL BODY
Skull
Ribcage
Vertebral column
Appendicular Body
Arms and Legs
Shoulder
Pelvis
Support
FUNCTION
OF
SKELETAL
SYSTEM
Protection
Mineral Storage
Movement
Blood cell production
Five types of Bones according to shape
A.Long bones
B. Flat Bones
C. Short Bones
D.Irregular Bones
E. Sesamoid Bones
CARTILAGE
Three major cartilage
Hyaline cartilage- most important
among the three.
Elastic Cartilage
Fibrocartilage
HYALINE CARTILAGE
• Chrondoblasts- produce extracellular matrix
• Chrondocyte- cell that occupies the space of lacunae
in the matrix
• Lacunae- space within the chrondocyte
• Perichondrium- Cover of the cartilage. Consist of two
layers:
Outer Lining: composed of dense irregular connective
tissue.
Inner Lining: consist of few fibers and chrondoblasts
Articular Cartilage- A type
of hyaline cartilage that
covers the ends of bones
where they come together
to form joints. Articular
cartilage does not have
perichondrium, blood
vessels and nerves.
CARTILAGE GROWTH
• Appositional Growth (takes place on the surface)
Perichondrium add new cell cartilage to the outside edge of existing
cartilage. Chrondoblast secretes new matrix and add new
chrondocytes to the outside of the tissue.
• Interstitial Growth
Chrondocyte divide and become chrondoblast to add more matrix
between existing cells within its lacuna.
BONE COMPOSITION
A. Bone Matrix
Consist of inorganic substance (Hydroxyapatite) and organic
substances (collagen and proteoglycans)
If hydroxyapatite is absent= Bone will become FLEXIBLE.
If Collagen and Proteoglycans are absent= Bone will become BRITTLE.
B. Bone Cells
Osteoblast, Osteocyte, Osteoclast
OSTEOGENESIS IMPERFECTA
• Also known as Brittle Bone Disorder
• This connective tissue disease is
caused by mutations that yield
reduced or defective type I collagen.
Type I collagen is the major collagen
of bone, tendon, and skin.
OSTEOBLAST
• Known as bone- forming cells.
• Responsible in collagen and proteoglycans production
Matrix Vesicle- contain hydroxyapatite that once release it
serve as the seed to form hydroxyapatite and mineralized the
matrix.
Ossification or Osteogenesis- process of osteoblast to form
bone by means of appositional growth.
Calcification- takes place during the ossification of bones it
can also occur in other tissues.
OSTEOCYTE
• Inactive cell of the bone but capable to produce
components to maintain the structure of the bone.
OSTEOCLAST
• Known as bone destroying
Responsible in bone resorption or breakdown of hydroxyapatite to
Calcium and Phosphate.
Bone Resorption - process by which osteoclasts break down the tissue
in bones and release the minerals, resulting in a transfer of calcium
from bone tissue to the blood.
SPONGY BONE
VS COMPACT BONE
SPONGY BONE
Contains blood vessels and has less bone matrix. Trabeculae and bone
marrow can be found in spongy bone.
COMPACT BONE
More dense than spongy bone due to more matrix.
LONG BONES
Long bones can be found in upper and
lower limbs.
Parts of a Long bone
• Epiphysis
• Diaphysis (primary ossification
center)
• Epiphyseal Line
GROSS
ANATOMY
OF TYPICAL
LONG BONES
BONE DEVELOPMENT
• During fetal life our body consist of embryonic skeleton which are
compost of fibrous membrane and hyaline cartilage
Two types of bone development process
a. IntramembranousOssification
Endochondral Ossification
INTRAMEMBRANOUS OSSIFICATION
• During 8th week intramembranous ossification of the delicate
connective tissue will start until 2 years of age.
Central of ossification- location of the membrane where ossification
begins.
Fontanel is a large, membrane-covered spaces between the developing
skull bones that have not yet been ossified.
Example:
Skull, mandible, diaphysis of collarbone ,
ENDOCHONDRAL OSSIFICATION
• Formation of bone from hyaline cartilage.
• All of the bones of the body except from flat bones of the skull,
mandible and clavicles are formed by endochondral ossification.
BONE GROWTH
• Bones increase in size only by appositional growth, the formation of
new bone on the surface of older bone or cartilage.
Growth in Bone Length
Growth at Articular Cartilage
Growth in Bone Diameter
GROWTH IN BONE LENGTH
• Female stops growing at the age of 18 and males stops growing at the
age of 21 in the process called epiphyseal plate closure.
• Majority appendicular bones undergo bone growth.
4 ZONES IN THE EPIPHYSEAL PLATE
a. ZONE OF RESTING- CELLS DO NOT DIVIDE
b. ZONE OF PROLIFERATION- CHONDROCYTES BEGINS TO DIVIDE
c. ZONE OF HYPERTROPHY- CHONDROCYTES BEGIN TO MATURE AND
ENLARGE
d. ZONE OF CALCIFICATION- HYPERTROPHIED CHONDROCYTES
BEGINS TO CALCIFIED; CONSIST OF OLDER AND DYING
CHRONDOCYTES.
GROWTH IN ARTICULAR CARTILAGE
• Epiphyses increase in size because of growth at the articular cartilage.
• The process of growth in articular cartilage is similar to that occurring
in the epiphyseal plate.
• The chondrocytes near the surface of the articular cartilage are
similar to those in the zone of resting cartilage of the epiphyseal
plate. In the deepest part of the articular cartilage, nearer bone
tissue, the cartilage is calcified and ossified to form new bone.
GROWTH IN BONE DIAMETER
• Long bones increase in width
(diameter) and other bones
increase in size or thickness
because of appositional bone
growth beneath the periosteum.
FACTORS AFFECTING BONE GROWTH
1. Nutrition- Vitamin D, C, A are essential in creating a strong bone
matrix.
2. Hereditary- genetic factors
3. Hormones- growth hormone, sex hormones
4. Mechanical Stress- stress on bone tissue can cause osteoblast to
produce more matrix and make bone stronger.
RICKETS
• Insufficient vitamin D in
children causes rickets, a
disease resulting from
reduced mineralization of
the bone matrix. Children
with rickets may have
bowed bones and
inflamed joints.
• Osteomalecia- is the adult
form of rickets.
BONE REPAIR
1. Hematoma Formation- formed due to leakage of blood to outside
tissue.
2. Callus Formation- callus is a mass of tissue that forms at a fracture
site and connects the broken ends of the bone.
3.
Callus ossification- the fibers and cartilage of the internal callus are
replaced by woven spongy bone, which further stabilizes the broken
bone.
4. Bone Remodeling- Filling the gap between bone fragments with an
internal callus of woven bone is not the end of the repair process
because woven bone is not as structurally strong as the original
lamellar bone.
BONE REMODELING
• Replacement of old bones by new bones is called bone remodeling.
• In this process, osteoclasts remove old bone and osteoblasts deposit
new bone.
Functions of Bone Remodeling
1. Bone growth
2. Changes in bone shape
3. Adjustment of the bone to stress, bone repair
4. Calcium ion (Ca2+) regulation in the body.
BONE REMODELING
• As a long bone increases in length and diameter, the
size of the medullary cavity also increases, keeping the
bone from becoming very heavy.
• In addition, as the bone grows in diameter, the
relative thickness of compact bone is maintained
as osteoclasts remove bone on the inside and
osteoblasts add bone to the outside
CALCIUM HOMEOSTASIS
• BONE IS THE MAJOR STORAGE SITE FOR CALCIUM IN THE BODY, AND MOVEMENT
OF CA2+ INTO AND OUT OF BONE HELPS DETERMINE BLOOD CA2+ LEVELS.
• HORMONES ASSOCIATED IN CALCIUM HOMEOSTASIS
A. PTH( PARATHYROID HORMONE)- RELEASE FROM PARATHYROID GLAND WHEN
LOW BLOOD CALCIUM LEVELS (HYPOCALCEMIA). IT STIMULATES OSTEOCLAST
BONE RESORPTION ACTIVITY.
B. CALCITONIN- RELEASE FROM THYROID GLAND WHEN HIGH BLOOD
CALCIUM LEVELS(HYPERCALCEMIA). IT INHIBITS OSTEOCLAST FROM
FURTHER BONE RESORPTION.
OPEN FRACTURE (COMPOUND FRACTURE)
Occurs when an open wound
extends to the site of the
fracture or when a fragment of
bone protrudes through the skin
CLOSED FRACTURE( SIMPLE FRACTURE)
Fractured bones does not
perforate the skin.
INCOMPLETE FRACTURE
An incomplete fracture does not
extend completely across the
bone,
COMPLETE FRACTURE
Complete fracture the bone is
broken into at least two
fragments
GREENSTICK FRACTURE
An incomplete fracture on the
convex side of the curve of the
bone.
HAIRLINE OR STRESS FRACTURE
Incomplete fractures in which
the two sections of bone do not
separate there is only a small
crack on the bone.
COMMINUTED FRACTURE
Is a complete fracture in which
the bone breaks into more than
two pieces—usually two major
fragments and a smaller
fragment.
IMPACTED FRACTURE
One fragment is driven into
the spongy portion of the
other fragment.
FRACTURES ARE ALSO CLASSIFIED ACCORDING TO THE
DIRECTION OF THE FRACTURE WITHIN THE BONE
Linear Fracture
Linear fractures run parallel to
the long axis of the bone
FRACTURES ARE ALSO CLASSIFIED ACCORDING TO THE
DIRECTION OF THE FRACTURE WITHIN THE BONE
Transverse Fracture
transverse fractures are at right
angles to the long axis
FRACTURES ARE ALSO CLASSIFIED ACCORDING TO THE
DIRECTION OF THE FRACTURE WITHIN THE BONE
Spiral Fracture
Spiral fractures take a helical
course around the bone
Oblique
FRACTURES ARE ALSO CLASSIFIED
ACCORDING TO THE DIRECTION OF THE
Fracture FRACTURE WITHIN THE BONE
Spiral fractures take a helical
course around the bone
FRACTURES ARE ALSO CLASSIFIED ACCORDING TO THE
DIRECTION OF THE FRACTURE WITHIN THE BONE
Dentate Fracture
Dentate fractures have rough,
toothed, broken ends.
FRACTURES ARE ALSO CLASSIFIED ACCORDING TO THE
DIRECTION OF THE FRACTURE WITHIN THE BONE
Stellate Fracture
Stellate fractures have breakage
lines radiating from a central
point
EFFECTS OF AGING TO SKELETAL SYSTEM
• THE MOST SIGNIFICANT AGE-RELATED CHANGES IN THE SKELETAL SYSTEM AFFECT THE QUALITY
AND QUANTITY OF BONE MATRIX.
• ORGANIC MATERIALS IN THE MATRIX REDUCES AND BONES BECOME BRITTLE.
• BONE MASS IS AT ITS HIGHEST AROUND AGE 30, AND MEN GENERALLY HAVE DENSER BONES
THAN WOMEN BECAUSE OF THE EFFECTS OF TESTOSTERONE AND GREATER BODY WEIGHT.
• A SLOW LOSS OF COMPACT BONE BEGINS ABOUT AGE 40 AND INCREASES AFTER AGE 45
EFFECTS OF AGING TO SKELETAL SYSTEM
• The most effective preventive measure against the effects of
aging on the skeletal system is the combination of increasing
physical activity and taking dietary calcium and vitamin D
supplements. Intensive exercise, especially weight-bearing
exercise, can even reverse the loss of bone matrix.
DISEASES ASSOCIATED WITH SKELETAL SYSTEM
REFERENCES
• Cinnamon Vanputte et al., Seeley’s Anatomy and Physiology 10th
Edition
• Scanlon Valerie et al., Essentials of Anatomy and Physiology Fifth
Edition
Download