Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The Skeletal System

Functions of Skeletal System Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  provides a framework for body  protects vital organs like brain and spinal cord  helps us lift and move due to attached muscles  stores minerals (calcium)  bone marrow produces blood cells

The Skeletal System Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Parts of the skeletal system  Bones (skeleton)  Joints

Bones of the Human Body Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  the skeleton has 206 bones  two basic types of bone tissue  Compact bone  solid bone, does not bend easily  Spongy bone  covers the space in which marrow is stored

Bone Marrow Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  red bone marrow is found in infant bones and in the flat bones of adults  site where red blood cells develop  yellow bone marrow is in most adult bones  made up of connective tissue filled with fat

Classification of Bones on the Basis of Shape Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Classification of Bones Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Long bones  typically longer than wide  form the legs and arms examples: femur (thigh), humerus (arm)

Classification of Bones Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Short bones  small, cube shaped bones  consist of an outer layer of compact bone with an inner layer of spongy bone  examples: wrist, ankle and toe bones

Classification of Bones Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Flat bones  large, flat surfaces that cover organs or provide a surface for large areas of muscle  thin layers of compact bone around a layer of spongy bone  examples: skull, shoulder blades, pelvis

Classification of Bones Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Irregular bones  irregular shape  specialized bones with specific shapes  example: ears, vertebrae, face

Classification of Bones Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Sesamoid bones  formed in a tendon near joints  example: patella (kneecap), some bones of hands and feet

Classification of Bones on the Basis of Shape Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 5.1

Bone Extensions and Depressions Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  sites for attaching muscles and tendons  extensions – grow out from the bone surface  depressions or cavities – indentations

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Bones of the Skeletal System

Divisions of the Skeletal System Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Divided into two parts:  Axial skeleton – skull, backbone, breastbone, ribs  Appendicular skeleton – hips, shoulders, limbs

The Axial Skeleton (green) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The Spinal Column Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  consists of 5 sets of vertebrae  cervical: neck  thoracic: connect to ribs  lumbar: middle back  sacrum: lower back  coccyx: tailbone  vertebrae separated by thick, cartilaginous discs (cushion the vertebrae and help in movement and flexibility)

Structure of a Typical Vertebrae Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bones of the Chest Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Sternum – breastbone  12 pairs of ribs:  true ribs (7) – joined to spinal column and sternum  False ribs (3) – attached to spinal column and 7 th rib  Floating ribs (2) – do not attach to sternum or other ribs

The Appendicular Skeleton Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  limbs  pectoral girdle (shoulders)  pelvic girdle (hips)

The Appendicular Skeleton (orange) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The Pectoral (Shoulder) Girdle Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  composed of two bones  clavicle – collarbone  scapula – shoulder blade  these bones allow the upper limb to have exceptionally free movement

Bones of the Shoulder Girdle Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bones of the Upper Arm Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Humerus  attaches to the scapula and clavicle Figure 5.21a, b

Bones of the Lower Arm Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings forearm has two bones which attach to the carpals or wrist bones Ulna Radius Figure 5.21c

Bones of the Hand Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Carpals – 8 wrist bones  Metacarpals – 5 bones of the palm  Phalanges – finger bones Figure 5.22

Bones of the Pelvic Girdle Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Hip bones  Composed of three pairs of fused bones  ilium  ischium  pubic bones  Point of attachment for the legs  Pubic symphysis – cartilage connecting the two pubic bones

The Pelvis Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bones of the Upper Leg Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  femur – thigh bone  longest bone in the body  meets the tibia and fibula, at the kneecap (patella) Figure 5.35a, b

Bones of the Lower Leg Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Tibia  Fibula Figure 5.35c

Bones of the feet Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Tarsals – ankle bones  largest tarsal is the calcaneus or heel  Metatarsals – sole  Phalanges – toes Figure 5.25