Chapter 7: Skeletal System
The Skeletal System Introduction P. 182 Bone is an organ made up of tissues: It is made up of the following components. Cartilage Blood Nerves Bone Connective
Bone Classification Long: femur, radius Short: wrist (carpals) and ankle (tarsals) Flat: scapula, ribs Irregular: vertebra Sesamoid (Round) patella
Parts of a Long Bone Epiphysis: ends of a bone Covered with Articular Cartilage Diaphysis: shaft or center portion Periosteum: tough covering Compact Bone: tightly packed tissue Spongy Bone: found at the ends Medullary Cavity: filled with yellow bone marrow.
Microscopic Structure: Osteocytes: bone cells Osteon: cylinder shaped unit Central Canals: blood vessels and nerves surrounded by an osteon. Perforating Canals: (Volkmann s canals) transverse canals Fig. 7.4
Bone Development and Growth Intramembranous Bones: Certain flat bones of the skull are IB. They develop from layers of connective tissue. Osteoblasts: bone forming cells Osteocytes: mature bone cell Primitive connective tissue gives rise to the periosteum.
Endochondral Bones: Most of the bones in the skeleton. Hyaline cartilage is later replaced by bone tissue. Table 7.1 Epiphyseal plate: (growth plate)
Growth at the Epiphyseal Plate Consists of 4 layers Describe each layer EP is responsible for lengthening Long bones continue to lengthen until the EP is ossified. Growth in thickness is due to ossification under the periosteum. Osteoclasts form the medullary cavity
Factors affecting bone development, growth, and repair. Vitamin deficiencies: A,C or D Lack of pituitary growth hormone or excessive secretions. Deficiency of thyroid hormone delays bone growth. Male and female sex hormones Physical Stress/Exercise Nutrition: calcium
Bone Function Support and protection Shape your body and protect vital organs Body Movement Function as levers 1 st, 2 nd, and 3 rd class levers P. 192 Fractures Blood Cell Formation Hematopoiesis: p. 194 Red marrow creates RBC s, WBC s and platelets.
Functions Continued. Inorganic salt storage Bones store calcium and calcium phosphate (phosphorus) Calcium is required for.p. 194 Blood calcium conc. is low: Blood calcium conc. is high: Bones also store sodium, magnesium, potassium, and carbonate ions.
Skeletal Organization 206 bones found in the average human skeleton Axial skeleton: 4 parts: Skull, Hyoid, Vertebral Column, and Thoracic Cage Appendicular skeleton: 4 parts: Pectoral Girdle, Upper limbs, Pelvic Girdle, Lower limbs
Skull: 22 bones: 8 cranial, 14 facial Cranium: Encloses and protects brain Air filled cavities:sinuses Cranium: 8 Frontal, Parietal(2), Occipital, Temporal (2), Spheniod, Ethmoid.
Facial Skeleton: 14 bones Form the basic shape of the face. Provide muscle attachment Maxillary, Palatine, Zygomatic, Lacrimal, Nasal, Vomer, Inferior Nasal Conchae, and Mandible.
Infantile Skull: Incompletely developed bones Connected by fontanels Skull changes shape during childbirth. molding Skull bones are thin, flexible, and less easily fractured.
Vertebral Column Extends from the skull to the pelvis Vertebrae separated by a disc of cartilage. Infant=33 Adult=26?? Vertebral Movements: 5 regions: Cervical, thoracic, lumbar, sacrum, coccyx 4 curvatures Cervical, lumbar: convex Thoracic, pelvic: concave
A Typical Vertebrae: p. 212 Label the Following Structures Body: anterior portion Pedicles: create the anterior border of the vertebral foramen. Laminae: creates the posterior border of the vertebral foramen. Spinous Process: posterior projection Transverse Processes: 45 degree projections (posterior) Superior and Inferior Articulating Processes: interlock the vertebral system Intravertebral Notch: passageways for spinal nerves to reach the spinal cord.
Cervical Vertebrae: Bones of the neck (7 total) C1, Atlas: supports the head C2, Axis: provides a pivot for the atlas C7 is a bony landmark Motion vs injury
Thoracic Vertebrae: Larger than cervical vertebrae. 12 total Spinous processes slope downward, and facets on the sides of bodies articulate with the ribs. Very little motion: Protection on vital organs
Lumbar Vertebrae: Vertebral bodies of lumbar vertebrae are large and strong. (5 total) Transverse bodies project posteriorly at sharp angles. Spinous processes are horizontal. Motion: L4/L5
Sacrum: Formed of 5 fused vertebrae. Triangular structure that has rows of dorsal sacral foramina. United with the coxae (ilium) at the sacroiliac joints.
Coccyx: Composed of 4 fused vertebrae. Acts as a shock absorber when a person sits. Can be bruised or fractured in a fall. Disorders of the Vertebral Column P. 216 Kyphosis, scoliosis, lordosis.
Thoracic Cage: Includes the ribs, thoracic vertebrae, sternum, and costal cartilages. Supports the pectoral girdle Protects viscera Functions in breathing
Ribs 12 pair are attached to 12 vertebrae. True/False/Floating Ribs p. 217 A typical rib has a shaft, head, and tubercles that articulate w/ the vertebrae.
Sternum: 3 parts Manubrium Body Xiphoid Process Articulates with costal cartilages and clavicles.
Pectoral Girdle: Clavicle: Rod-like, s-shaped bones that run b/w the sternum and shoulders. Muscle attachment point Most commonly fractured bone in the body. Scapula: Triangle shaped bone p. 219 (parts) Glenoid cavity, Acromion process, coracoid process, Spine, etc. Articulate with the humerus and provide muscle attachment.
Humerus: P. 221 Fig. 7.45 Reading: Humerus greater and lesser tubercle, anatomical and surgical neck, capitulum, medial and lateral epicondyle, olecranon fossa.
Radius: Thumb side Head, Radial tuberosity, Styloid Process (Know Location)
Ulna: Longer than the radius and overlaps the humerus posteriorly. Olecranon process, styloid process, and trochlear notch. Articulates with the radius laterally and a disc of cartilage inferiorly.
Hand (Carpals) The wrist is made up of a carpus. (8 Bones) Palm=5 metacarpals 5 fingers=14 phalanges
Pelvic Girdle Coxae: each made of 3 bones 1. Illium: largest portion 2. Ischium: lowest portion 3. Pubis: anterior portion
Differences in the Male and Female Pelvis: Function: female w/ childbirth Female pelvis: More flared Pubic arch is broader Sacral curvature is shorter
Lower Limb: Femur: Fig. 7.53 Head, neck, greater trochanter, lesser trochanter, lateral and medial condyle Patella: controls the angle of the PT Tibia: medial Medial and lateral condyles, medial malleolus Fibula: lateral malleolus, non-wt bearing Foot: tarsals, metatarsals, and phalanges
Skeletal System with Age Write 4 statements using your book to describe what happens when bones age.