Chapter 6 & 7 The Skeleton

Chapter 6 & 7 The Skeleton

Try this Make clockwise circles with your RIGHT foot, while doing this, draw the number 6 in the air with you RIGHT hand what happens to your foot????

Bony Background Adult body 206 bones Jobs of your bones: Protection of your internal organs & soft tissues Support of the body against the pull of gravity Storage for necessary mineral salts (calcium) Production of blood cells Something for your muscles to hold on to so you can move around

Skeletal Facts Skeleton accounts for 20% of body mass about 30 lbs. in a 160 lb. person

The Skeletal System Parts of the skeletal system Bones (skeleton) Joints (articulations) Cartilages Ligaments Divided into two divisions Axial skeleton Appendicular skeleton

Bones of the Human Body Two basic types of bone tissue Compact bone Homogeneous Spongy bone Small needle-like pieces of bone Many open spaces

Flat Classification of Bones Skull, shoulder blades, ribs, sternum, pelvic bone Like plates of armor, protect soft tissues of the brain & organs Long Arms & Legs Provide structural support Thin and flattened Usually curved Thin layers of compact bone around a layer of spongy bone Typically longer than wide Have a shaft with heads at both ends Contain mostly compact bone Short Wrists (carpal) & Ankles (tarsal) Look like blocks & allow wider range of movement Generally cube-shape Contain mostly spongy bone Irregular Vertebral column, kneecaps Variety of shapes Irregular shape Do not fit into other bone classification categories

Classification of Bones on the Basis of Shape Figure 5.1

Gross Anatomy of a Long Bone Diaphysis Shaft Composed of compact bone Epiphysis Ends of the bone Composed mostly of spongy bone Figure 5.2a

Diaphysis = shaft of bone, contains yellow bone marrow in adults Epiphysis = made of spongy bone covered with compact bone, & is surrounded by cartilage = forms a joint Periosteum = tough, fibrous, connective tissue that runs over a bone to the ligaments and tendons. It also provides bone with blood Spongy bone = RBC created

Medullary cavity Where marrow is housed Endosteum Lines the medullary cavity

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Changes in the Human Skeleton In embryos, the skeleton is primarily hyaline cartilage During development, much of this cartilage is replaced by bone Cartilage remains in isolated areas Bridge of the nose Parts of ribs Joints Slide 5.12

Cartilage takes the shape of the bone it will become. Calcium is deposited onto the cartilage, and then it becomes calcified (formation of bone). Osteogenisis or Ossification In the epiphysis = cartilage. As the cartilage cells divide, the bone lengthens. No more dividing = No more growth Epiphyseal plates allow for growth of long bone during childhood

Long Bone Formation and Growth Figure 5.4a Slide 5.14a

Bone Growth Bones are remodeled and lengthened until growth stops Bones change shape somewhat Bones grow in width

Types of Bone Cells Osteocytes Mature bone cells Osteoblasts Bone-forming cells Osteoclasts Bone-destroying cells Break down bone matrix for remodeling and release of calcium Bone remodeling is a process by both osteoblasts and osteoclasts

The Axial Skeleton Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 5.6 Slide 5.20b

The Vertebral Column Vertebrae separated by intervertebral discs The spine has a normal curvature Each vertebrae is given a name according to its location

Cervical (Neck) 7 vertebrae 1 st = atlas C 1 2 nd = axis C 2 C 3 -C 7

Thoracic (Chest) 12 vertebrae T 1 -T 12

Lumbar (Lower Back) 5 vertebrae L 1 -L 5 Withstand the most pressure

5 fused vertebrae Saccrum

Coccyx (tailbone) 4 fused vertebrae Number of vertebrae vary with individual

Structure of a Typical Vertebrae Figure 5.16 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.29

Regional Characteristics of Vertebrae Figure 5.17a, b Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.30a

Regional Characteristics of Vertebrae Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 5.17c, d Slide 5.30b

The Bony Thorax Forms a cage to protect major organs

The Bony Thorax Made-up of three parts Ribs Sternum Thoracic vertebrae

The Ribs 1-7 True Ribs or vertebrosternal 8-12 False ribs Includes 2 floating ribs (11 & 12)

The Sternum Manubrium Top portion Body Center Xiphoid Process Bottom

The Appendicular Skeleton Limbs (appendages) Pectoral girdle Pelvic girdle

The Appendicular Skeleton

The Pectoral (Shoulder) Girdle 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

Bones of the Shoulder Girdle

Bones of the Upper Limb The arm is formed by a single bone Humerus Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 5.21a, b Slide 5.35a

Bones of the Upper Limb The forearm has two bones Ulna Radius Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 5.21c Slide 5.35b

Bones of the Upper Limb The hand Carpals (8) wrist Metacarpals (5) palm Phalanges (5) fingers Figure 5.22 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.36

Bones of the Pelvic Girdle Hip bones Composed of three pair of fused bones Ilium Ischium Pubic bone The total weight of the upper body rests on the pelvis Protects several organs Reproductive organs Urinary bladder Part of the large intestine Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.37

The Pelvis Figure 5.23a Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.38a

The Pelvis Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 5.23b Slide 5.38b

Gender Differences of the Pelvis Figure 5.23c Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.39

Bones of the Lower Limbs The thigh has one bone Femur thigh bone Figure 5.35a, b Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.40a

Bones of the Lower Limbs The leg has two bones Tibia Fibula Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 5.35c Slide 5.40b

patella

Bones of the Lower Limbs The foot Tarsals (Tarsus) (7) ankle Metatarsals sole Phalanges toes Figure 5.25 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.41

Arches of the Foot Bones of the foot are arranged to form three strong arches Two longitudinal One transverse Figure 5.26 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 5.42