HAPP MIDTERM REVIEWER: 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.
//haligi or pagkakahulma ng ating katawan

2 Divisions of Skeletal System

Appendicular Body
Arms and Legs, Shoulder, Pelvis
Axial Body
Skull Ribcage, and Vertebral column

Functions of Skeletal System

Support //pagtayo, exercise or physical activity, Protection //some of the bones such as cranium and ribcage protects internal organ,
Mineral Storage // there's a mineral storage sa buto which is hydroxyapatite that consists of calcium and phosphate,
Movement,
Blood cell production

Five types of Bones according to shape

Ø Long bones //huge role sa pagtangkad
Ø Flat Bones
Ø Short Bones
Ø Irregular Bones
Ø Sesamoid Bones

Three major cartilage

Hyaline cartilage- most important among the three.
Elastic Cartilage
Fibrocartilage

Hyaline Cartillage

//most abundant

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. It does not have perichondrium.

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 [composed of calcium and phosphate]) and organic substances (collagen and proteoglycans)

FLEXIBLE.

If hydroxyapatite is absent= Bone will become

BRITTLE.

If Collagen and Proteoglycans are absent= Bone will become

Bone Cells

Ø Osteoblast //nag ccreate ng bone
Ø Osteocyte //cells ng buto
Ø Osteoclast //break ng bone

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

Osteoblast

Known as bone- forming cells.
Responsible in bone resorption or breakdown of hydroxyapatite to Calcium and Phosphate.

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

• Contains blood vessels and has less bone matrix.
• Trabeculae and bone marrow can be found in spongy bone. // nasa loob

Compact Bone

More dense than spongy bone due to more matrix.
//nasa paligid

Long Bones

can be found in upper and lower limbs.

Parts of a Long bone

Epiphysis
Diaphysis (primary ossification center)
Epiphyseal Line

Bone Development

During fetal life our body consist of embryonic skeleton which are compost of fibrous membrane and hyaline cartilage.

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.

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.

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.

Growth at 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.

Zone of Resting

- cells do not divide

Zone of Hyperthropy

Chondrites begin to mature and enlarge

Zone of Proliferation - Chondrites begin to divide- Chondrites begin to divide

- Chondrites begin to divide

Zone of Calcification

- Hypertrophied chondrocytes begin to calcified

Growth in Articular Cartillage

• 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.

Nutrition

- Vitamin D, C, A are essential in creating a strong bone matrix. //Vitamin D is the sunshine vitamin

Hereditary

- genetic factors

Hormones

- growth hormone, sex hormones

Mechanical Stress

- stress on bone tissue can cause osteoblast to produce more matrix and make bone stronger.

Rickets

Insufficient vitamin D in children causes this.
a disease resulting from reduced mineralization of the bone matrix. Children with this may have bowed bones and inflamed joints.

Osteomalecia

- is the adult form of rickets.

Callus Formation

- callus is a mass of tissue that forms at a fracture site and connects the broken ends of the bone.

Hematoma Formation

- formed due to leakage of blood to outside tissue.

Callus ossification

- the fibers and cartilage of the internal callus are replaced by woven spongy bone, which further stabilizes the broken bone.

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.

Functions of Bone Remodeling

Ø Bone growth
Ø Changes in bone shape
Ø Adjustment of the bone to stress, bone repair
Ø Calcium ion (Ca2+) regulation in the body.

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

Calcitonin

- release from thyroid gland when high blood calcium levels hypercalcemia. It inhibits osteoclast from order 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

bone is not broken all the way through

Complete Fracture

bone is broken all the way through

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.

Spiral Fracture

take a helical course around the bone

Dentate fractures

have rough toothed, broken ends.

Linear Fracture

run parallel to the long axis of the bone

Stellate fractures

have breakage lines radiating from a central point

transverse fractures

are at right angles to the long axis

Spiral fractures

take a helical course around the bone.

EFFECTS OF AGING TO SKELETAL SYSTEM

Ø The most significant age-related changes in the skeletal system affect the quality and quantity of bone matrix.
Ø Organic materials in the matric reduces and bones becomes brittle.
Ø Bone mass is at its highest around 30 and men generally have denser bone than women because of the effects of testosterone and greater body weight.
Ø As slow loss of compact bone begins about age 40 and increases after age 45.
Ø 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.

Axial Bones

206 Bones

Skull

has 29 bones

NEWBORN

has 270-350 or 300 in average bones

Vertebral Column

has 26 bones

Ribcage

has 25 bones

Appendicular Bones

(126 Bones)

Pectoral Girdle

(4) bones

Upper Limb

has 60 bones

Pelvic Girdle

has 2 bones

Lower Limb

has 60 bones

AXIAL SKELETON

§ It is composed of skull, auditory ossicles, hyoid bone, vertebral column, and rib cage (thoracic cage).
§ It protects vital organs such as the brain, spinal cord and heart and lung.
//to protect our brain

SKULL or CRANIUM

§ Protects the brain; supports the organs of vision, hearing, smell, and taste; and provides a foundation for the structures that take air, food, and water into the body.

Cranial Bones

//house ng brain

Frontal bone

forms the forehead and the anterior part of the top of the skull

Two large Parietal Bones

form the posterior top and much of the side walls of the skull

Temporal bone on each side of the skull

contains an external auditory meatus (ear canal), a middle ear cavity, and an inner ear labyrinth

Occipital bone

forms the lower, posterior part of the braincase

5. Sphenoid bone

said to be shaped like a bat, and the greater wing is visible on the side of the skull between the frontal and temporal bones

Ethmoid bone

has a vertical projection called the crista galli ("rooster's comb") that anchors the cranial meninges
- forms the roof and upper walls of the nasal cavities, and the upper part of the nasal septum

4 bones that can be visualized in superior view

1. Frontal bone
2-3. Two parietal bones
4. Small occipital bone

Sagittal Suture

Connects two parietal bones at the midline

coronal suture of parietal bone

Connects parietal bone to frontal bone

Lambdoid Suture

Connects parietal bone to occipital bone

Ligamentum nuchae

- an elastic ligament that extends down the neck and helps keep the head erect by pulling on the occipital region of the skull.

Nuchal lines

- a set of small ridges that extend laterally from the protuberance

Squamous suture

Connects parietal bone to temporal bone.

External auditory canal or external acoustic meatus

- prominent large hole features of temporal bone

Mastoid process

- posterior and inferior to the external auditory canal. Important neck muscles involved in rotating the head attach to the mastoid process.

Superior/Inferior Temporal Lines

- attachment points of the temporalis muscle, one of the major muscles of mastication, arch across the lateral surface of the parietal bone.