INTRODUCTION TO

THE SKELETAL SYSTEM

OBJECTIVES

•BE ABLE TO LIST THE GENERAL FUNCTIONS OF THE SKELETAL SYSTEM

• IDENTIFY THE PARTS OF THE SKELETAL SYSTEM

•DISCUSS THE ACTIVE TISSUES FOUND IN BONE

•CLASSIFY BONES ACCORDING TO SHAPE

HUMAN SKELETON FACTS

•MAKES UP 1/5 OF A HEALTHY BODY’S WEIGHT

•ADULTS HAVE 206 BONES ON AVERAGE

•WE ARE BORN WITH 270 BONES, BUT MANY OF FUSE TOGETHER AS WE GROW

•LONGEST BONE IN THE BODY IS THE FEMUR

•SMALLEST BONE IN THE BODY IS THE STAPES BONE IN THE MIDDLE EAR

DIVISIONS OF THE HUMAN SKELETON

•AXIAL SKELETON: INCLUDES THE BONES OF THE SKULL, RIBS, SPINE, AND STERNUM

•APPENDICULAR SKELETON: INCLUDES THE BONES OF THE ARMS, LEGS, SCAPULA, CLAVICLE, AND PELVIS

AXIAL VS. APPENDICULAR

FUNCTIONS OF THE SKELETAL SYSTEM

1. SUPPORT: GIVES SHAPE & STRUCTURE TO THE BODY

2. MOVEMENT: PROVIDES A RIGID FRAMEWORK AGAINST WHICH MUSCLES CAN PULL

3. PROTECTION: PROTECTS DELICATE INTERNAL ORGANS SUCH AS THE RIB CAGE PROTECTING THE HEART & LUNGS

FUNCTIONS OF THE SKELETAL SYSTEM

4. BLOOD CELL PRODUCTION: SITE OF HEMATOPOIESIS, WHICH IS THE PROCESS THAT PRODUCES RED BLOOD CELLS, PLATELETS AND SOME WHITE BLOOD CELLS FROM THE BONE MARROW

5. STORAGE: STORES MINERALS SUCH AS CALCIUM & PHOSPHORUS

6. ENDOCRINE REGULATION: BONE CELLS RELEASE THE HORMONE OSTEOCALCIN WHICH CONTROLS THE REGULATION OF BLOOD SUGAR AND FAT DEPOSITION

TISSUES OF THE SKELETAL SYSTEM

•BONE

•CARTILAGE

•DENSE CONNECTIVE TISSUE

•BLOOD

•NERVOUS

4 CLASSIFICATIONS OF BONES

• LONG BONES: HAVE LONG LONGITUDINAL AXES AND EXPANDED ENDS

• EXAMPLES: RADIUS, ULNA, FEMUR

•SHORT BONES: ARE CUBE-LIKE, WITH ROUGHLY EQUAL LENGTHS AND WIDTHS

• EXAMPLES: CARPALS AND TARSALS

• SESAMOID (ROUND) BONE: IS A SPECIAL TYPE OF SHORT BONE THAT IS SMALL AND NODULAR AND EMBEDDED IN A TENDON ADJACENT TO A JOINT

• EXAMPLE: PATELLA (KNEE CAP)

4 CLASSIFICATIONS OF BONES

•FLAT BONES: ARE PLATE-LIKE STRUCTURES WITH BROAD SURFACES

•EXAMPLES: RIBS, SCAPULA, AND PARTS OF THE SKULL

•IRREGULAR BONES: HAVE A VARIETY OF SHAPES AND MOST ARE CONNECTED TO SEVERAL OTHER BONES

•EXAMPLES: VERTEBRAE AND MANY FACIAL BONES

PARTS OF THE SKULL

PARTS OF THE SKULL

DIFFERENCES B/W MALES & FEMALES

•MALES HAVE SLIGHTLY THICKER AND LONGER LEGS AND ARMS

•MALES HAVE LONGER AND THICKER PHALANGES

•FEMALES HAVE A WIDER PELVIS AND A LARGER SPACE WITHIN THE PELVIS

•FEMALES HAVE NARROWER RIB CAGES, SMALLER TEETH, LESS ANGULAR MANDIBLES, LESS PRONOUNCED CRANIAL FEATURES, AND CARRYING ANGLE OF THE FOREARM IS MORE PRONOUNCED