Chapter 7 Skeletal System

Give several examples of how bones support and protect body parts.

-bones of the lower limbs, pelvis, and backbone support the bodys weight -bones of the skull protect the eyes, ears, and brain -bones of the rib cage and shoulder girdle protect the heart and lungs -bones of the pelvic girdle protect the lower abdomen and reproductive organs

Bones of the head, neck, and trunk compose the __________ skeleton; bones of the limbs and their attachments compose the ___________ skeleton.

axial, appendicular

List the bones of the axial skeleton and of the appendicular skeleton.

axial- skull, hyoid bone, spinal column, sacrum, coccyx, ribs, sternum. appendicular- pectoral girdle: scapula and clavicle; upper limbs: humerus, radius, ulna, carpals, metacarpals, phalanges; pelvic girdle: hip bones, sacrum, and the coccyx form the pelvis; lower limbs: femur, tibia, fibula, patella, tarsals, metatarsals, phalanges.

Active, living tissue found in bone include_____________.

blood, nervous tissue, bone tissue

Define a typical vertebra.

drum shaped body which forms the thick, anterior portion of the bone

Describe the characteristics of the three major types of joints.

fibrous joints: lie between bones and are held together by a thin layer of dense connective tissue. ex) suture cartilaginous joints: hyaline cartilage connects the bones. ex) separate the vertebrae Synovial joints: allow free movement

Name the bones that fuse to form a hip bone.

ilium, ischium, pubis

Which bones compose the thoracic cage?

ribs, thoracic vertebrae, sternum

List five major parts of a long bone.

epiphysis- articulates with another bone proximal epiphysis- attachment to the nearest trunk of the body distal epiphysis- attachment furthest to the trunk of body articular cartilage- outer surface of the articulating portion of the epiphysis is coated with a layer of hyaline cartilage diaphysis- the shaft of the bone, fuses with the epiphysis to create the epiphyseal line during bone growth

What terms describe movements possible at synovial joints?

extension, dorsiflexion, plantar flexion, hyperextension, abduction, adduction, rotation, circumduction, pronation, supination, eversion, inversion, retraction, protraction, elevation, depression

Name the six types of synovial joints

plane, hinge, pivot, condyloid, saddle, ball and socket

List and describe other functions of the bones.

Blood cell formation: red marrow- formation of red blood cells (erythrocytes), white blood cells (leukocytes) and blood platelets yellow marrow- stores fat Storage of Inorganic Salts: stores calcium- when the blood is low in calcium the parathyroid hormone stimulates osteoclasts to break down bone tissue, releasing calcium salts from the extracellular matrix into blood stores small amounts of magnesium, sodium, potassium, and carbonate ions

Physical exercise pulling on muscular attachments to bones stimulates ____________.

bone tissue to thicken and strengthen

Name the living tissues

connective tissues, blood and nerve supply, tendons, ligaments, and cartilage

Describe the microscopic structure of compact bone.

the osteocytes and layers of extracellular matrix concentrically clustered around a central canal from a cylinder-shaped unit called an osteon.

Match the parts listed on the left with the bones listen of the right.

1) foramen magnum A. maxilla 2) mastoid process B. occipital bone 3) palatine process C. temporal bone 4) sella turcica D. femur 5) deltoid tuberosity E. fibula 6) greater trochanter F. humerus 7) lateral malleolus G. radius 8) medial malleolus H. sternum 9) radial tuberosity I. tibia 10) xiphoid process J. sphenoid bone 1) b. 2) c. 3) a. 4) j. 5) f. 6) d. 7) e. 8) i. 9) g. 10) j.

Match the movement on the left with the appropriate description on the right.

1) rotation A. turning the palm upward 2) supination B. decreasing the angles between parts 3) extension C. moving a part forward 4) eversion D. moving a part around axis 5) protraction E. moving a part toward a midline 6) flexion F. turning the foot plantar laterally 7) pronation G. increasing the angle between parts 8) abduction H. lowering a part 9) depression I. turning the palm downward 10) adduction J. moving a part away from midline 1) d. 2) a. 3) g. 4) f. 5) c. 6) b. 7) i. 8) j. 9) h. 10) e.

Explain how the bones of the lower limb articulate.

A large, round head at the proximal end of the femur projects medially into the acetabulum of the hip bone. On the dead, a pit called the fovea capitis marks the attachment of a ligament. Greater trochanter and lesser trochanter provide attachments for the muscles of the lower limbs and buttocks. At the distal end of the femur, two rounded processes, the lateral and medial condyles, articulate with the tibia of the leg. A patella, or kneecap, also articulates with the femur on its distal anterior surface.

Explain how an adult skull differs from that of an infant.

An infants skull is not developed completely, consisting of fibrous membranes, called fontanels, connecting the cranial bones which enables an infants skull to pass through the birth canal easily. Eventually the fontanels close as the cranium bones grow. Adult skulls are more easily fractured than an infants since infants skull bones are thin and flexible.

Distinguish between the axial and appendicular skeletons.

Axial- bony and cartilaginous parts that support and protect the organs of the head, neck, and trunk. Appendicular- consists of the bones of the upper and lower limbs and the bones that anchor the limbs to the axial to the axial skeleton.

List the substances normally stored in bone tissue.

Calcium, phosphorus, magnesium, sodium, potassium, and carbonate ions.

Explain how structures of cervical, thoracic, and lumbar vertebrae differ.

Cervical: 7 vertebrae that composes the bony axis of the neck Thoracic: larger than cervical vertebrae, long spinous process which slopes downward, T1-T9 have costal facets that articulate with the ribs Lumbar: in the small of the back (loin), support more weight

Explain how the bones of the upper limb articulate.

Humerus has a rounded head on its upper end that fits the glenoid cavity of the scapula. Greater tubercles and lesser tubercles provide attachments for muscles that move the upper limb and shoulder. At the lower end of the humerus are two smooth condyles that articulate with the radius on in the lateral side and the ulna on the medial side. Above the condyles on either sides are epicondyles, which provide attachments for muscles and ligaments of the elbow.

Describe how the foot is adapted to support the body.

The calcaneus helps support body weight and provides the attachment for the muscles that move the foot.

How do compact and spongy bone differ in structure?

The compact bone is tightly packed tissue in the wall of the diaphysis. The spongy bone is thin layers of compact bone forming the epiphysis.

Explain the function of an epiphyseal plate.

The epiphyseal plate is a band of cartilage that is left between the primary and secondary ossification centers. This plate includes rows of young cells that are undergoing mitosis and producing new cells. As the epiphyseal plate thickens due to the new cells, bone length is increased.

Describe the structure of the vertebral column.

The vertebral column extends from the skull to the pelvis and forms the vertical axis of the skeleton, composed of bony parts (vertebrae) that are separated by pads of fibrocartilage called intervertebral discs and are connected to one another by ligaments.

Describe the development of an intramembranous bone.

They develop in the fetus from membranelike layers of unspecialized connective tissues at the sides of the future bones. Dense networks of blood vessels are contained within these connective tissues. Some of the partially differentiated progenitor cells enlarge and further differentiate into bone forming cells called osteoblasts. The osteoblasts deposit bony matrix around themselves, forming spongy bone tissue in all directions within the layers of connective tissues. When an extracellular matrix completely surrounds osteoblast, they are called osteocytes. Cells of the membranous tissues that persist outside the developing bone give rise to the periosteum. Osteoblasts on the inside of the periosteum form a layer of compact bones over the surface of the newly formed spongy bone.

What are the differences among true, false, and floating ribs?

True: first 7 pairs that join the sternum directly by their costal cartilages. False: remaining 5 pairs cartilages do not reach the sternum directly but joins at the cartilages of the 7th rib Floating: Last 2 pairs have no cartilage attachment site to the sternum

Explain how nutritional factors, hormones, and physical exercise affect bone development and growth.

Vitamin D is necessary for proper absorption of calcium in the small intestine. Growth hormone secreted by the pituitary gland stimulates division of the cartilage cells in the epiphyseal plates. Sex hormones stimulate ossification of the epiphyseal plates. Physical exercise pulling on muscular attachments to bones stresses the bones, stimulating the bone tissue to thicken and strengthen.

Which bones form the pectoral girdle?

clavicles and scapula

Distinguish between the microscopic structure of compact bone and spongy bone.

compact bone: osteocytes and layers of extracellular matrix concentrically clustered around a central canal form a cylinder shaped unit called an osteon, many osteons together form a compact bone spongy bone: composed of osteocytes and extracellular matrix, but cells lie in the trabeculae and get nutrients from substances diffusing into canaliculi that lead to the surface of these thin and bony plates

Discuss the functions parts of the long bone.

epiphysis: articulates with another bone at proximal and distal ends diaphysis: the shaft of the bone, fuses with the epiphysis to create the epiphyseal line during bone growth articular cartilage: a layer of hyaline cartilage that coats the epiphysis periosteum: dense connective tissue that encloses the bone medullary cavity: compact bone in the diaphysis that forms a tube with a hallow chamber

Name the major functions of a bone.

give shape, support body weight and protect internal organs, attachment sites for muscles

Joint movements occur when a muscle contracts and the muscle fiber pull the muscles movable end of attachment to the bone, the __________, toward its fixed end, the ___________.

insertion, orgin

Explain how bones are classified by shape.

long bones- long longitudinal axes and expanded ends. short bones- roughly equal lengths and widths. -sesamoid bones: round bone, small and nodular and develops within a tendon or adjacent to a joint. flat bones- plate-like structures with broad surfaces. irregular bones- a variety of shapes, most are connected to several other bones

Explain how osteoclasts and osteoblasts remodel bone.

osteoclasts, bone-reabsorbing cells, break down the calcified extracellular matrix. they secrete an acid that dissolves the inorganic component of the calcified matrix, and their lysosomal enzymes digest the organic components. after osteoclasts remove the extracellular matrix, bone-building osteoblasts invade the region and deposit new bone tissue in place of the calcified cartilage.

__________ are mature bone cells, whereas __________ are bone-forming cells and _________ are bone-reabsorbing cells.

osteocytes, osteoblasts, osteoclasts

The clavicle and scapula form the ____________ girdle, whereas the hip bones form the ___________ girdle.

pectoral, pelvic

Distinguish between the functions of red marrow and yellow marrow.

red marrow- formation of the RBCs (erythrocytes), white blood cells (leukocytes), and platelets. yellow marrow- stores fat.

What is the function of the pectoral girdle?

supports the upper limbs and is an attachment site for several muscles that move them

Name the three parts of the sternum.

upper manubrium, body, xiphoid process