SKELETAL SYSTEM
SKELETAL SYSTEM
- the bones of your skeleton. OSSEUS TISSUE.
- Bone tissue is a type of connective tissue. Your skeleton performs several important functions.
➢ SUPPORT and PROTECTION
➢ BODY MOVEMENT – muscles “pull” on bones
➢ BLOOD CELL FORMATION – hemopoiesis ( occurs in red bone marrow
➢ STORAGE of inorganic salts – especially calcium phosphate, but also magnesium, sodium, potassium, carbonates and others
ORGANIZATION – normally 206 bones
- 2 Main Divisions: AXIAL & APPENDICULAR
1. AXIAL: head, neck, trunk
SKULL, HYOID BONE (upper neck, under jaw, mandible)
VERTEBRAL COLUMN (spine/backbone)
THORACIC CAGE (rib cage-12 pairs)
STERNUM
2. APPENDICULAR: limbs and bones connecting the limbs to the:
PECTORAL GIRDLE (scapula & clavicle), UPPER LIMBS (arms)
PELVIC GIRDLE (coxal bones), LOWER LIMBS (legs)
BONE STRUCTURE: “LONG BONE” = typical bone
Major parts:
EPIPHYSIS – expanded ends of bone. ARTICULATES (forms a joint) with another bone.
DIAPHYSIS – shaft of the bone
ARTICULAR CARTILAGE – hyaline cartilage covering the ends of bones
PERIOSTEUM – tough membrane-like covering over entire bone, except for articular cartilage. Connects with tendons and ligaments. Forms bone tissue.
MEDULLARY CAVITY – hollow chamber within the diaphysis connects to spaces in spongy bone. Filled with soft specialized tissue called bone marrow.
• Red Marrow – mainly in spongy bone in adults. Produces blood cells
• Yellow Marrow – fat storage. Replaces much of the red marrow in diaphysis through childhood
ENDOSTEUM – lining of the medullary cavity
Two Types of Bone Tissue
1. COMPACT (cortical) BONE – wall of the diaphysis, solid, strong
2. SPONGY (cancellous) BONE – epiphysis. Covered with a thin layer of compact bone. Many branching, bony “plates”
Microscopic Structure
➢ MATRIX composed of collagen and inorganic salts
➢ OSTEOCYTES (mature bone cells) are enclosed in tiny chambers called LACUNAE and form concentric “ring” (layers) around a passageway called the HAVERSION CANAL
➢ The osteocytes are connected by minute passages called CANALICULI (canaliculus) through which tiny “branches” or processes pass
➢ The circular layers of matrix material and osteocytes, along with the haversian canal, forms a unit called a HAVERSIAN SYSTEM. Compact bone tissue is formed in this way
➢ The haversian canals are interconnected by passages called VOLKMANN’S CANALS. All of these canals contain blood vessels and nerve fibers
[pic]
Bone Development and Growth:
There are two types of bone based on the way the bones form
1. INTRAMEMBRANOUS BONES = broad, flat bones of the skull. These bones form from membrane-like sheets of connective tissue
2. ENCHONDRAL BONES = all other bones.
[pic] Bones first form as hyaline cartilage. The cartilage then gradually changes into bone tissue – a process called OSSIFICATION, which begins near the middle of the diaphysis in an area called the PRIMARY OSSIFICATION CENTER. Later the bone begins to ossify in the epiphysis – these areas are called the SECONDARY OSSIFICATION CENTERS.
[pic]As long as growth is occurring, a “band” of cartilage (called an epiphyseal disk, growth plate) remains between the diaphysis and the epiphysis.
[pic]Bones increase in length as these cartilage cells continue to reproduce and ossify
[pic]Cartilage cells form cells called OSTEOBLASTS. These cells produce bone matrix and once the cell is enclosed in bone matrix it is considered to be a mature bone cell and called an OSTEOCYTE
[pic]Growth in thickness of bone occurs as osteoblasts from beneath the periosteum produce bone matrix and built compact bone just underneath the periosteum
[pic]Bone tissue is constantly being replaced as special cells called OSTEOCLASTS dissolve bone tissue from within the medullary cavity – a process called RESORPTION. At the same time new bone tissue is being added to the outside of the bone.
3 Basic Types of Joints (articulations):
1. SYNARTHROTIC – immoveable joint, such as bones in the skull, these junctions are called SUTURES
2. AMPHIARTHOTIC – slightly moveable joint, vertebrae
3. DIARTHROTIC – freely moveable joint, such as shoulders, hips, knees, elbows, wrists, fingers…
--these joints are enclosed within a fibrous capsule which contains a lubricating fluid called SYNOVIAL fluid. These are called SYNOVIAL JOINTS.
Bones of the Skull
1. Frontal - anterior portion above eyes
2. Parietal – one on each side of the skull, just behind frontal bone
3. Occipital – forms the back of the skull and base of the cranium
4. Temporal – forms parts of the sides and base of cranium
5. Sphenoid – wedged between several other bones in anterior portion of the cranium
6. Maxilla – forms upper jaws
7. Mandilbe – lower jaws, only moveable bone of the skull
Sutures
1. Coronal – between frontal and parietal bones
2. Lambdoidal – between occipital and parietal bones
3. Squamosal – between temporal and parietal bones
4. Sagittal - between parietal bones
Fontanels - “soft spots” of an infant’s skull, see page 138
- anterior fontanel, posterior fontanel, sphenoid fontanel, mastoid fontanel
Foramen Magnum – Large opening through the underside of the skull, spinal cord enters skull
The Rest of the Bones
Ribs – Thoracic Cage, 12 pairs
- True Ribs – first seven pairs, attach directly to STERNUM by costal cartilage
- False Ribs – last five pairs
- Floating ribs – last two pairs
Pectoral Girdle: Shoulder. Two clavicles (collar bones) and two scapula (shoulder blade)
Arms: Upper arm – humerus. Lower arm – radius and ulna.
Wrist – 8 small bones called carpels
Fingers – Metacarpels, Phalanges
Pelvic Girdle: Hips. Two large bones called COXAL BONES
Legs: Upper leg (thigh) - FEMUR. Lower leg – tibia & fibula.
Ankle and Upper foot – 7 bones called TARSALS,
Largest is the heel bone called the CALCANEOUS
Toes – Metatarsals, Phalanges
What About Broken Bones?
• A complete fracture is when the bone has broken into two pieces.
• A greenstick fracture is when the bone cracks on one side only, not all the way through.
• A single fracture is when the bone is broken in one place.
• A comminuted (say: kah-muh-noot-ed) fracture is when the bone is broken into more than two pieces or crushed.
• A bowing fracture, which only happens in kids, is when the bone bends but doesn't break
• An open fracture is when the bone is sticking through the skin.
[pic]
[pic]
[pic]
[pic]
-----------------------
Scared Lovers Try Positions That They Can't Handle.
SKELETON LABELING
................
................
In order to avoid copyright disputes, this page is only a partial summary.
To fulfill the demand for quickly locating and searching documents.
It is intelligent file search solution for home and business.
Related download
- module two anatomy of the athlete
- case study chapter 2 g w
- bones and bone structure
- grade 3 the skeletal system
- the skeletal system coral springs charter school
- the skeletal system
- introduction to anatomy the skeletal system
- chapter 3 skeletal and muscular system subject science
- structures and functions of the skeletal system
- principles and concepts of human movement science
Related searches
- custom skeletal system quiz
- skeletal system quiz labeling
- skeletal system diseases
- anatomy skeletal system game
- skeletal system facts kids
- skeletal system worksheet
- skeletal system main jobs
- skeletal system quiz
- skeletal system diagram
- chapter 6 skeletal system answers
- skeletal system games college
- chapter 6 skeletal system pdf