THE SKELETAL SYSTEMTHE SKELETAL SYSTEM

Allied Health Sciences OneAllied Health Sciences One

Linda Crawford, RN ClassLinda Crawford, RN Class

The Skeletal SystemThe Skeletal System

• The Skeletal The Skeletal System is the System is the bony framework bony framework of the body.of the body.

• It consists of 206 It consists of 206 individual bones individual bones in adults.in adults.

The Functions of The Functions of The Skeletal SystemThe Skeletal System

1.1. Supports the body and provides Supports the body and provides itit’’s shape.s shape.

2.2. Protects internal organs.Protects internal organs.

3.3. Movement and anchorage of the Movement and anchorage of the muscles.muscles.

4.4. Provides mineral storage.Provides mineral storage.

5.5. Hemopoiesis (What?!)Hemopoiesis (What?!)

Bone FormationBone Formation

• While a person is still an embryo, the While a person is still an embryo, the skeleton is made of cells called skeleton is made of cells called osteoblastsosteoblasts..

• The osteoblasts change to cartilage.The osteoblasts change to cartilage.• At 8 weeks, the cartilage is replaced by At 8 weeks, the cartilage is replaced by

minerals. This is minerals. This is ossification.ossification.• The microscopic cells of which bones are The microscopic cells of which bones are

composed are called composed are called osteocytesosteocytes..

Bone FormationBone Formation

• Ossification is not complete by the time Ossification is not complete by the time a baby is born, so the bones are still soft a baby is born, so the bones are still soft and flexible. This makes the birth and flexible. This makes the birth process easier.process easier.

• Babies have a Babies have a ““soft spotsoft spot”” on their heads on their heads to allow the head to fit through the birth to allow the head to fit through the birth canal. It is called a canal. It is called a fontanelfontanel. .

LONG BONESLONG BONES

Long bones are just what they Long bones are just what they sound like. Long bones are found sound like. Long bones are found in the arms and legs. They are in the arms and legs. They are hollow cylinders of hard, compact hollow cylinders of hard, compact bone. That makes them strong, bone. That makes them strong, yet light enough to move easily.yet light enough to move easily.

Structure ofStructure ofLONG BONESLONG BONES

• DIAPHYSISDIAPHYSIS –– long part or long part or shaft of the bone. shaft of the bone.

• EPIPHYSISEPIPHYSIS –– ends of the ends of the bone.bone.

• MEDULLARY CAVITYMEDULLARY CAVITY –– center of the shaft. Filled center of the shaft. Filled with with yellow bone marrowyellow bone marrow which is mostly fat cells. which is mostly fat cells. But it also contains the cells But it also contains the cells that form white blood cells that form white blood cells or or leukocytesleukocytes..

Structure ofStructure ofLONG BONESLONG BONES

• ENDOSTEUMENDOSTEUM –– lining of the lining of the marrow canal.marrow canal.

• PERIOSTEUMPERIOSTEUM –– tough, fibrous tough, fibrous tissue covering the outside of tissue covering the outside of the bone.the bone.

• COMPACT BONECOMPACT BONE –– type of type of bone in the shaft or diaphysis.bone in the shaft or diaphysis.

• SPONGY BONESPONGY BONE - type of bone - type of bone in epiphysis. Contain in epiphysis. Contain red red marrowmarrow where red blood cells where red blood cells are made.are made.

Bones can changeBones can change……

• Where less strength is Where less strength is needed in a bone, needed in a bone, some of the hard bone some of the hard bone dissolves and leaves dissolves and leaves spongy bone.spongy bone.

• OsteoblastsOsteoblasts are the are the bone cells that deposit bone cells that deposit new bones.new bones.

Two Parts per Skeleton!Two Parts per Skeleton!

• The skeleton is made up The skeleton is made up of two different parts of two different parts –– the the AXIALAXIAL and the and the APPENDICULARAPPENDICULAR

• The AXIAL Skeleton The AXIAL Skeleton contains the skull, spinal contains the skull, spinal column, ribs, sternum column, ribs, sternum (breastbone) and the (breastbone) and the hyoid bone. hyoid bone.

The AXIAL SkeletonThe AXIAL Skeleton

• The skull consists of The skull consists of 22 bones itself 22 bones itself –– 8 8 are cranium bones are cranium bones and 14 are facial and 14 are facial bones.bones.

• The The mandiblemandible is is the lower part of the lower part of the jaw and is the the jaw and is the only movable skull only movable skull bone. bone.

Bones of the SkullBones of the Skull

• 1 frontal1 frontal• 2 parietal2 parietal• 2 temporal2 temporal• 1 occipital1 occipital• 1 ethmoid1 ethmoid• 1 sphenoid1 sphenoid

Bones of the SkullBones of the Skull

• 2 nasal2 nasal• 1 vomer1 vomer• 2 inferior concha2 inferior concha• 2 maxilla2 maxilla• 2 lacrimal2 lacrimal• 2 zygomatic2 zygomatic• 2 palatine2 palatine• 1 mandible1 mandible

THE SPINETHE SPINE……A.K.A. The Vertebral ColumnA.K.A. The Vertebral Column

• Encloses the spinal cordEncloses the spinal cord• Vertebrae Vertebrae –– separated by separated by

pads of cartilage called pads of cartilage called intervertebral discsintervertebral discs

• Cervical vertebrae (7) Cervical vertebrae (7) • Thoracic vertebrae (12)Thoracic vertebrae (12)• Lumbar vertebrae (5)Lumbar vertebrae (5)• SacrumSacrum• CoccyxCoccyx

Ribs and SternumRibs and Sternum

• Sternum divided into 3 parts Sternum divided into 3 parts –– The bottom tip The bottom tip is the is the XIPHOID PROCESSXIPHOID PROCESS

• There are 12 pairs of ribs. The first 7 are There are 12 pairs of ribs. The first 7 are true true ribsribs and are connected to the sternum by and are connected to the sternum by cartilagecartilage

• The next 3 are The next 3 are false ribsfalse ribs –– cartilage connects cartilage connects them to 7them to 7thth rib (not the sternum) rib (not the sternum)

• The last 2 are The last 2 are floating ribsfloating ribs..

Bones of theBones of the APPENDICULAR SkeletonAPPENDICULAR Skeleton

• SCAPULA (shoulder blade)SCAPULA (shoulder blade)• HUMERUS (upper arm)HUMERUS (upper arm)• RADIUS & ULNA (lower arm)RADIUS & ULNA (lower arm)• CARPALS (wrist bones)CARPALS (wrist bones)• METACARPALS (hand bones)METACARPALS (hand bones)• PHALANGES (fingers)PHALANGES (fingers)

Bones of theBones of the APPENDICULAR SkeletonAPPENDICULAR Skeleton

• PELVIS (3 bones PELVIS (3 bones –– ilium, ischium, pubis) ilium, ischium, pubis)• Femur (upper leg Femur (upper leg –– strongest bone in the strongest bone in the

body)body)• Tibia & fibula (lower leg)Tibia & fibula (lower leg)• Patella (knee cap)Patella (knee cap)• Tarsal bones (ankleTarsal bones (ankle• Calcaneus (heel bone)Calcaneus (heel bone)• Metatarsals (foot bones)Metatarsals (foot bones)

AssignmentAssignment……

• Get a copy of the worksheet Get a copy of the worksheet Label Label the Diagrams.the Diagrams.

• This consists of four drawings that This consists of four drawings that you will label according to the you will label according to the instructions.instructions.

• You may use the textbook as a You may use the textbook as a resource. (Chapter 6; pages 83-resource. (Chapter 6; pages 83-103)103)