Lecture Outline - Chapter 10

10.1 Tissues of the Skeletal System (p. 204, Fig. 10.1)
	1.	Bone (p. 204, Fig. 10.1)
		a.	Bone contains minerals, especially calcium phosphate.
		b.	Compact bone is made up of osteons, lacunae in concentric circles around a central canal. Canaliculi run through the matrix of bone, connecting lacunae and central canals. 
		c.	Spongy bone contains plates called trabeculae, the spaces of which are filled with red bone marrow for blood cell production.
		d.	Cartilage (p. 204)
			i.	Cartilage is weaker and more flexible than bone, and is slower to heal because of its lack of direct blood supply.
			ii.	Hyaline cartilage has a matrix made of collagen and is found at the ends of long bones and in the nose and trachea.
			iii.	Stronger fibrocartilage has thick rows of collagen fibers and is able to tolerate pressure and tension.
			iv.	Flexible elastic cartilage contains mostly elastin fibers and is found in the external ear and epiglottis.
	2.	Fibrous Connective Tissue (p. 204)
		a.	Fibrous connective tissue contains fibroblasts with collagenous fibers and makes up the ligaments that attach bone to bone at a joint.
	3.	Structure of a Long Bone (p. 204)
		a.	The rounded ends, or epiphyses, of long bones have spongy bone containing red bone marrow. The articular surfaces are protected by an articular cartilage.
		b.	The shaft of a long bone has a medullary cavity filled with fatty yellow marrow.
		c.	Bone tissue is covered by a fibrous connective tissue periosteum that is continuous with ligaments that connect bones at joints.
10.2 Bone Growth and Repair (p. 206)
	1.	Four different cell types are involved in bone growth and repair.
		a.	Osteogenitor cells are located in the periosteum, the endosteum (lining of the medullary cavity), and the central canals of compact bone.
		b.	Osteoblasts are bone-forming cells arising from osteogenitor cells.
		c.	Osteocytes are mature bone cells arising from osteoblasts.
		d.	Osteoclasts resorb bone and may be derived from monocytes.
	2.	Bone Development and Growth (p. 206, Fig. 10.2)
		a.	Intramembranous ossification occurs between flat sheets of connective tissue. Osteogenitor cells become osteoblasts that lay down bone, forming trabeculae. Compact bone is then laid down over the outside surfaces. Skull bones form this way.
		b.	Most bones form by endochondral ossification, with a cartilage model filled in with bone. Osteoblasts fill in areas of the center of the cartilage model that have begun to break down. Compact bone is also laid down under the periosteum.
		c.	The epiphyses of long bones continue to grow from an epiphyseal plate. 
	3.	Remodeling of Bones (p. 207)
		In adults, the actions of osteoclasts and osteoblasts continually remodel bones. 
	4.	Bone Repair (p. 207, Fig. 10.3)
		a.	About 6 to 8 hours after a fracture, a hematoma (large blood clot) forms at the fracture site.
		b.	A fibrocartilage callus fills in the break.
		c.	A bony callus that osteoblasts form replaces the cartilage and lasts for four months.
		d.	Osteoclasts eventually remodel the bone, building a new medullary cavity.
		e.	Fractures are named according to the type of break (e.g., spiral).
			HEALTH FOCUS: You Can Avoid Osteoporosis (p. 208, Fig. 10A)
			i.	Adequate dietary calcium and weight-bearing exercise help reduce the incidence of osteoporosis.
			ii.	Risk factors for developing osteoporosis include being white or Asian, being thin, a family history of osteoporosis, early menopause, smoking, insufficient calcium in the diet, excessive alcohol and caffeine, and inactivity.
10.3 Bones of the Skeleton (p. 209, Fig. 10.4)
	1.	Functions of the Skeleton (p. 209) 
		The skeleton supports the body, protects soft body parts and organs, houses blood-forming tissues, stores calcium and phosphorus salts, and provides a framework for movement.
	2.	Classification of the Bones (p. 209)
		a.	The 206 bones of the body are classified according to their shape.
		b.	Long bones are longer than wide (e.g., the femur, humerus).
		c.	Short bones are cubeshaped (e.g., the carpals, tarsals).
		d.	Flat bones have platelike surfaces (e.g., the skull).
		e.	Round bones are roughly circular (e.g., the patella).
		f.	Irregular bones have varied shapes (e.g., the vertebrae, facial bones).
	3.	Axial Skeleton (p. 210)
		a.	The axial skeleton lies in the midline of the body and consists of the skull, hyoid bone, vertebral column, ribs, and sternum.
		b.	Skull (p. 210, Fig. 10.5)
			i.	 The cranium is made up of eight bones that are incompletely fused in infants, leaving soft spots, or fontanels.
			ii.	Sinuses are found in the cranium. They reduce the weight of the skull and give resonance to the voice.
			iii.	The major bones of the cranium include the frontal bone, two parietal bones, an occipital bone housing the foramen magnum, two temporal bones, a sphenoid bone, and an ethmoid bone. The sphenoid bone makes up the floor of the cranium. The ethmoid bone helps form the orbits and the nasal septum.
		c.	Facial Bones (p. 211, Fig. 10.6)
			The frontal bone of the skull forms the forehead of the face. The lower jaw is made up of the mandible. Zygomatic bones make up the cheekbones, and maxillae form the upper jaw. Two nasal bones form the bridge of the nose.
	4.	Hyoid Bone (p. 211)
		The hyoid bone is located superior to the larynx, anchors the tongue, and serves as a point of attachment for muscles used in swallowing.
	5.	Vertebral Column Supports (p. 212, Fig. 10.7)
		a.	The vertebral column supports the head and trunk, protects the spinal cord and nerves, and is a site for muscle attachments.
		b.	Abnormal curvatures include scoliosis (a sideways curve), kyphosis (the hunchback form), and lordosis (a swayback).
		c.	Each vertebra has facets that articulate with each other and spinous processes that project toward the back. Cervical vertebrae are in the neck region and include the atlas and axis. Thoracic vertebrae are in the upper back and have an extra facet for rib attachment. Thick lumbar vertebrae are in the lower back. Five sacral vertebrae fuse to form a sacrum. The coccyx, or tailbone, is at the base of the vertebral column.
		d.	Intervertebral disks, formed of fibrocartilage, provide a padding between vertebrae.
	6.	Rib Cage (p. 213, Fig. 10.8)
		a.	The rib cage is composed of the thoracic vertebrae, the ribs and their cartilages, and the sternum.
		b.	Ribs (p. 213, Fig. 10.8)
			i.	The 12 pairs of ribs all connect to the thoracic vertebrae.
			ii.	Ten pairs of ribs connect to the sternum via hyaline cartilage.
			iii.	The lower two pairs of ribs are "floating ribs" because they are not attached to the sternum.
		c.	Sternum (p. 213, Fig. 10.8) 
			The sternum (breastbone) protects the heart and lungs. It is made of the manubrium, the body, and the xiphoid process.
	7.	Appendicular Skeleton (p. 214)
		a.	The appendicular skeleton is made up of the pectoral and pelvic girdles, and the arm and leg bones.
		b.	Pectoral Girdle and Arm (p. 214, Fig. 10.9)
			i.	The pectoral girdle consists of the scapula (shoulder blade), and the clavicle (collarbone). The glenoid fossa articulates with the head of the humerus.
			ii.	The humerus is the bone of the upper arm. The radius and ulna make up the lower arm.
			iii.	The hand is made up of eight carpal bones, with five metacarpals and the phalanges of the fingers and thumb.
		c.	Pelvic Girdle and Leg (p. 215, Fig. 10.10)
			i.	The pelvic girdle consists of two heavy coxal bones, fused at the sacrum. Each coxal bone is made up of the ilium, ischium, and pubis, all fused at the acetabulum.
			ii.	The male and female pelves differ somewhat due to different functions. The female pelvis is more flared.
			iii.	The thigh contains the femur, and the lower leg is made up of the tibia and fibula.
			iv.	The ankle contains seven tarsal bones, and five metatarsals make up the arching, middle portion of the foot.
10.4 Articulations (p. 216, Figs. 10.11, 10.12)
	1.	Joints can be immovable, such as those of the skull; slightly movable, such as intervertebral disks; or freely movable.
	2.	Most joints are freely movable synovial joints, held together by ligaments. The joint capsule is filled with lubricating synovial fluid. Menisci (pads of fibrocartilage) help to stabilize the knee joint. Fluid-filled sacs (bursae) can be found in some joints.
	3.	Most movable are the ball-and-socket joints, such as the hip or shoulder. Hinge joints (fingers) can move in one direction.
	4.	Synovial joints are candidates for arthritis, the most common form of which is osteoarthritis.
10.5 Working Together (p. 216)
	The Working Together box (p. 218) illustrates how the skeletal system functions with other body systems to maintain homeostasis.