Cecie Starr | Beverly McMillan

Chapter 5

The Skeletal System

The Skeletal System 5

Key Concepts•The Structure and Functions of Bones•The Skeleton•Joints•Disorders of the Skeleton

The Skeletal System 5

• Joint problems due to:– Disease– Sports injuries– Obesity– Aging– Osteoarthritis

• Traditional vs. nontraditional remedies for arthritis

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5.1 Bone: Mineralized Connective Tissue

• Bones are composed of connective tissue hardened by the mineral calcium

The Structure and Functions of Bones

5.1 Bone: Mineralized Connective Tissue

• Bones– Living cells and matrix– Periosteum

• Osteoblasts– Secretion of collagen and

elastin and other substances

• Osteocytes

Figure 5-1 p88

5.1 Bone: Mineralized Connective Tissue

space occupied by living bone cell

blood vessel

compact bone tissue

spongy bone tissue

osteon(Haversian

system)

Figure 5-1a p88

5.1 Bone: Mineralized Connective Tissue

spongy bone tissue

compact bone tissue

outer layer of dense

connective tissueblood vesselFigure 5-1b p88

5.1 Bone: Mineralized Connective Tissue

• Compact bone– Dense tissue– Osteon (Haversian system)

• Spongy bone– Inside long bone’s shaft– Looks lacy; quite strong

• How do nutrients get to bone tissue?

There are two types of bone tissue.

Figure 5-1 p88

5.1 Bone: Mineralized Connective Tissue

• Early human embryo– Cartilage and membranes

• Bone-forming osteoblasts form around cartilage shaft

• Calcification, blood vessels, and nerves infiltrate the bone tissue

• Epiphysis– Epiphyseal plate of

cartilage

A bone develops on a cartilage model. Forming bone collar

epiphyses

Mature bone of adult

Cartilage model of future bone in embryo

Figure 5-2 p89

Figure 5-2 p89

Forming bone collar

Cartilage model of future bone in embryo

When organs form in embryo, blood vessel invades model; osteoblasts start producing bone tissue; marrow cavity forms

Remodeling and growth continue in newborn; secondary bone-forming centers appear at knobby ends of bone

Mature bone of adult

epiphysesStepped Art

5.1 Bone: Mineralized Connective Tissue

• Osteoclasts and bone remodeling

• Important functions– Keeps bones resilient– Mechanical stress– Repair of broken bones– During growth– Homeostasis of blood calcium levels

• Osteoporosis- causes and treatments

Bone tissue is constantly “remodeled.”

5.2 The Skeletal System: The Body’s Bony Framework

• Bones provide a hard surface against which muscles can exert force to move body parts

The Skeleton

5.2 The Skeletal System: The Body’s Bony Framework

• Vary in size and shape– Long and slender– Short– Flat– “Irregular”

• Complex tissue: associated with joints, blood vessels, and nerves

• Bone marrow– Formation of blood cells– Role of long bones, flat bones, and irregular bones

5.2 The Skeletal System: The Body’s Bony Framework

• Organization of human’s 206 bones – Axial skeleton– Appendicular skeleton

• Ligaments– Connect bones to joints

• Tendons– Attach muscles to bones or other muscles

The skeletal system consists of bones, ligaments, and tendons.

nutrient canal into and from marrow (for blood vessels and nerves)

marrow cavity

compact bone tissue

spongy bone tissue

Figure 5-3 p90

Table 5-1 p90

Axial Skeleton Appendicular SkeletonA Skull bonesCranial bones

Pectoral girdle and upper limb bones

D Facial bones

B Rib cageClavicle (collarbone)SCAPULA (shoulder blade)Sternum (breastbone)HUMERUS (upper arm bone)

RADIUS (forearm bone) ULNA (forearm bone) CARPALS (wrist bones)

C Vertebral column, or backbone

Vertebrae (twenty-six bones)

12 3

5 4Intervertebral disksMetacarpals (palm bones) Phalanges (thumb, finger bones)

E Pelvic girdle and lower limb bones

Pelvic girdle (six fused bones)Femur (thighbone)

Patella (kneebone)

Tibia (lower leg bone)

Fibula (lower leg bone)

Tarsals (ankle bones)Metatarsals (sole bones)Phalanges (toe bones)

ligament(to knee cap)

Ribs (twelve pairs)

5.2 The Skeletal System

Figure 5-4 p91

5.2 The Skeletal System: The Body’s Bony Framework

• Movement• Support and anchor skeletal muscles• Enclose and protect organs• Store calcium and phosphorus • Blood cell formation

Bones have several important functions.

Take home message

What are the parts of the skeletal system?

5.3 The Axial Skeleton

• The axial skeleton supports much of our body weight and protects many internal organs

5.3 The Axial Skeleton

• Brain case with sinuses

• Frontal bone

• Temporal bones

• Sphenoid bone

The skull protects the brain.

5.3 The Axial Skeleton

frontal boneparietal bone sphenoid bone

ethmoid bone

temporal bone lacrimal bone

zygomatic bone

maxilla

occipital boneexternal auditory meatus (opening of the ear; part of the temporal bone)

mandibleFigure 5-5a p92

5.3 The Axial Skeleton

frontal sinus

sphenoid sinus

ethmoid sinus

maxillary sinus

Figure 5-5c p93

5.3 The Axial Skeleton

• Parietal bones

• Occipital bone

• Foramen magnum

• Ethmoid bone

The skull protects the brain.

5.3 The Axial Skeleton

hard palate

maxilla

maxilla

palatine bone

zygomatic bone

vomer sphenoid bone

jugular foramen

temporal bone foramen magnum

occipital boneparietal bone

Figure 5-5b p92

5.3 The Axial Skeleton

• Mandible

• Maxillary bones

• Zygomatic bones

• Lacrimal bone

• Palatine bones

• Vomer bone

Facial bones support and shape the face.

Figure 5-5a p92

5.3 The Axial Skeleton

• Flexible backbone• Protects spinal cord• Thirty-three vertebrae

– Cervical– Thoracic– Lumbar– Sacral– Coccyx

• Intervertebral disks: absorb shocks– Composition– Herniated disk

The vertebral column is the backbone.

5.3 The Axial Skeletoncervical vertebrae (7)

thoracic vertebrae (12)

lumbar vertebrae (5)

intervertebral disks

sacrum (5 fused)coccyx (4 fused)

Figure 5-6 p93

5.3 The Axial Skeleton

• Ribs– Attached to vertebral column– Protection of several organs– Role in breathing

• Sternum– Attached to upper ribs

The ribs and sternum support and help protect internal organs.

Take home messageWhat are the parts of the axial skeleton?

5.4 The Appendicular Skeleton

• The appendicular skeleton includes the bones that support the limbs, upper chest, shoulders, and pelvis

5.4 The Appendicular Skeleton

• Pectoral girdle

• Scapula

• Clavicle

The pectoral girdle and upper limbs provide flexibility.

clavicle

sternumhumerus

ulna

radius

carpals (8)metacarpals (5)phalanges (14)

scapula

Figure 5-7 p94

5.4 The Appendicular Skeleton

• Arm and hand bones– Humerus– Radius and ulna– Carpals; carpal tunnel

syndrome– Metacarpals– Phalanges

• Pectoral girdle

• Scapula

• Clavicle

clavicle

sternumhumerus

ulna

radius

carpals (8)metacarpals (5)phalanges (14)

scapula

Figure 5-7 p94

5.4 The Appendicular Skeleton

• Pelvic girdle– Coxal bones– Pubic arch– Differences between

males and females

• Leg and foot bones– Femur– Tibia and fibula– Tarsals– Metatarsals

pelvissacrum

pubic symphysis

femur

patella

tibia

fibulametatarsals

phalanges

tarsals Figure 5-8 p95

Take home messageWhat are the parts of the

appendicular skeleton?

5.5 Joints: Connections between Bones

• Joints are areas of contact or near contact between bones

• All joints have some form of connective tissue that bridges the gap between bones

Joints

5.5 Joints: Connections between Bones

• Synovial joint– Synovial fluid– Movement

• Cartilaginous joint– Slight movement

• Fibrous joint – No cavity– Generally no movement

5.5 Joints: Connections between Bones

fibrous joint attaches tooth to jawbone

synovial joint (balland socket) betweenhumerus and scapula

cartilaginous jointbetween rib and sternum

cartilaginous jointbetween adjacentvertebraesynovial joint (hingetype) betweenhumerus and radius

synovial joint (balland socket) betweenpelvic girdle andfemur

Figure 5-9a p96

femur

patella

cartilage

ligaments

menisci

tibia

fibula

5.5 Joints: Connections between Bones

Figure 5-9b p96

5.5 Joints: Connections between Bones

flexion at shoulder

hyperextension

extension at shoulder

flexion at knee extension at knee

A flexion and extension

Figure 5-10a p97

5.5 Joints: Connections between Bones

circumduction

rotation

B circumduction and rotation

abduction

adduction abductionabduction

adduction

adduction

C abduction and adduction Figure 5-10bc p97

5.5 Joints: Connections between Bones

supination

pronation

D supination and pronation

Figure 5-10d p97

5.5 Joints: Connections between Bones

Egliding movementbetween carpals

Take home messageWhat is a joint?

Figure 5-10e p97

5.6 Disorders of the Skeleton

• Tissue in bones or joints may break down– Osteoarthritis– Rheumatoid arthritis

– Tendinitis – Carpal tunnel syndrome

• Inflammation is the culprit in repetitive motion injuries

Disorders of the Skeleton

5.6 Disorders of the Skeleton

• Causes and treatments of some joint injuries– Strain– Sprain– Dislocation

Joints are susceptible to strains, sprains, and dislocations.

Figure 5-11 p98

5.6 Disorders of the Skeleton

• Types of bone fractures– Simple– Complete– Compound

• Treatment

• Effect of aging and smoking on healing

Bones break in various ways.

C CompoundCompleteBA Simple

Figure 5-13 p99

5.6 Disorders of the Skeleton

• Causes and treatments of some skeletal disorders– Osteogenesis imperfecta

(OI)– Bone and bone marrow

infections– Osteosarcoma

Genetic diseases, infections, and cancer all may affect the skeleton.

Figure 5-14 p99

5.7 The Skeletal System in Homeostasis

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The Skeletal SystemThe skeleton supports and helps protect soft body parts. Bones, joints, tendons, and ligaments all have essential roles in moving the body and its parts. Bone is a reservoir for calcium, which is vital for many body functions including muscle contractions, the transmission of nerve impulses, and blood clotting. Calcium also is required for the proper functioning of some enzymes and of proteins in the cell plasma membrane.

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Integumentary system

Muscular systemSkeletal muscles attach tobones, which serve as levers forbody movements. Bone calciummay be released as needed tomaintain blood levels required formuscle contractions.

The skeleton provides supportfor skin and the muscles below it.

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Digestive system

Cardiovascular system and blood

Immunity and the lymphatic systemWhite blood cells that function in bodydefenses form in bone marrow.

Bone calcium is available for heartcontractions that pump blood. All types of blood cells form in red bone marrow.

Bone stores dietary calcium and phosphorus. Bones of the rib cage and pelvis protect organs including the stomach, liver, and intestines. Facial bones have sockets for teeth.

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Respiratory system

Urinary system

Nervous systemThe skull protects the brain. Vertebrae protectthe spinal cord. Bone calcium stores may bereleased as needed to maintain blood levelsrequired for transmission of nerve impulses.

The rib cage partially protects the kidneys.The pelvis helps protect the bladder.

The rib cage and sternum protect the lungs.Muscles used in breathing attach to ribs andassociated cartilages.

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Sensory systems

Endocrine system

Reproductive systemPelvic bones protect female reproductiveorgans and associated glands in males.Calcium is available to help nourish a fetusand for milk production in a nursing mother.

Calcium may be released as neededto maintain blood levels required for theformation and secretion of many hormones.

Skull and facial bones surround and protectsensory organs in the head. Calcium inbones helps maintain blood levels required fortransmission of sensory nerve impulses.

Table 5-2 p101