Gross A&P Chapter 7

• Structural Support

• Storage (for nutrients and other chemicals)

• Blood Cell Production (in the long bones)

• Protection

• Movement

 Functions of Skeletal System

• Bones

• Cartilage

• Tendons

• Ligaments

Parts of Skeletal System

Long bones, short bones, sesamoid bones, flat bones, irregular bones

Tyoes of Bone shapes

Long Bones

• longer than they are wide

• blood cell formation

• Ex. arms, legs

Short bones

• equal width and length

• Ex. carpal bones, tarsal bones

Sesamoid Bones

• embedded in a tendon

• Ex. patella

Flat Bones

• thin an flat plate-like bones

• broad surfaces that stick together

• Ex. cranial bones

Irregular Bones

• anything that doesn’t fit in the other categories

• Ex. vertebral bones, facial bones (ethmoid, sphenoid, lacrimal)

What gives bones its structure?

• Collagen provides strength and resilience

• Inorganic salts provide structure to resist crushing forces

Long Bone Parts

Epiphysis - expanded bone

Articular Cartilage - hyaline cartilage covering articular parts (points of bone that interact in a joint)

Diaphysis - shaft of the bone (long part)

Metaphysis - Between epiphysis and diaphysis

Epiphysial Plate - area of growth

Medullary Cavity - area in the diaphysis often filled with marrow, vessels, and nerves

Two types of Marrow in bone

Red Marrow

Yellow Marrow

2 types of bone emebranes

Periosteum, endosteum

Periosteum

• fibrous connective tissues wrap around and continue off the bone

• ends of tendons and ligaments attach

• contains some bone cells

Endosteum

• connective tissues

• contains bone cells

• provides internal support

Compact Bone

• continuous extracellular matrix with no gaps (cell to cell contact)

• weight-bearing to resist compression

• seen mainly in diaphysis

Spongy Bone

• irregular interconnected spaces between bony plates

• lighter weight

• room for blood vessels and other things to pass through the bone

Ossification

the hardening of tissue into bone

Endochondral Development

• arises from cartilage involving the deposition of salts in the matrix, followed by absorption and replacement by true bony tissue

• important for long bones

• stops around 2 years old

Intramembranous Development

• development of osseous tissue without prior cartilage formation

• stops at 18 years old in females

• stops at 21 years old in males

Epiphyseal Plate Development

• bone tissue replaces hyaline cartilage in the center of the diaphysis

• As spongy bone is deposited, a band of cartilage remains between ossification centers (epiphyseal plate)

• Damage may slow or cease the bone’s lengthening

Layers of Epihyseal Plate

Zone of resting cartilage

Zone of proliferating cartilage

Zone of hypertrophic cartilage

Zone of calcified cartilage

Zone of resting cartilage

• Resting cells do not aid in growth

• anchors the epiphyseal plate

• at the edge

zone of proliferating cartilage

• young cells undergoing mitosis

• extracellular matrix thickens plate

zone of hypertrophic cartilage

• older cells

• enlarges plate - lengthens bone

zone of calcified cartilage

• dead cells and calcified extracellular matrix

• calcified cartilage that merges with actual bone

• strongest bone cartilage

vitamin that helps produce collagen

vitamin C

Vitamin we get from eggs, dairy, inactive forms from UV light

Vitamin D

Factors that affect bone veleopment

• nutrition

• exposure to sunlight

• physical exercise

• hormonal secretions

Thyroxine hormone

ossifies cartilage at the epiphyseal plate

Rickets (children) and Osteomalacia (adults) are caused by what?

Vitamin D Deficiency

Dwarfism and Gigantism are caused by what?

deficiency or excess of growth hormones

at what age is ossification nearly complete?

Males - 25

Females - 23

Effects of male and female sex hormones

• promote bone cell formation

• cause the long bones to grow considerably at puberty

• stimulate ossification at the epiphyseal plates

• effect of estrogen is stronger than testosterone

The ongoing process of building and resorbing bone means we replace how much of our skeleton each year?

10 - 20%

Calcitonin

• lowers blood calcium and increases the amount of osteoblast activity

• stimulates replacement of cartilage in epiphyseal plates

Parathyroid Hormone

• increases blood calcium levels

• increases number and activity of osteoclasts

Osteomalacia

bone softening

Osteopenia

midway danger zone of bone loss

Osteoporosis

bone density test 2.5% or lower than average adult

causes of bone loss

lack of calcium, eating disorders, overactive thyroid, untreated celiac, consuming gluten, chemotherapy, certain meds (steroids), bad diet, lack of exercise, smoking, alcohol, carbonated beverages

what do the bones of the skull protect?

eyes, ears, and brain

what do the bones of the rib cage and shoulder protect?

heart and lungs

what do the bones of the pelvic girdle protect?

lower abdomen and internal reproductive organs

Red Marrow

• in spaces of spongy bone

• site of red blood cell production

• produces RBC, WBC, platelets

• oxygen-carryin pigment hemoglobin

Yellow Marrow

• stores fat

• has the ability to revert to red marrow

Hematopoiesis

process of blood cell formation

Salts account for how much of extracellular weight?

70%

Axial Skeleton

Skull

hyoid bones

vertebral column

thoracic cage

ribs and sternal bones

Appendicular Skeleton

• pectoral girdle

• upper extremity

• pelvic girdle

• lower extremity

Skull

encloses and protects the brain, and its surface provides attachments for muscle that make chewing and head movements possible

Frontal Bone

• forms forehead, roof of nasal cavity, and roof of orbits

• supraorbital foramen

• frontal sinuses

Parietal (2)

• form side walls and roof of cranium

• sagittal suture

• coronal suture

Temporal (2)

• form walls and flow of cranium

• squamous suture

• external acoustic meatus

• mandibular fossa

• mastoid process

• styloid process

• carotid canal

• jugular foramen

• internal auditory meatus

Occipital

• forms back of skull and base of cranium

• lambdoid suture

• foramen magnum

• occipital condyles

• external occipital protuberance

Sphenoid

• forms parts of the base of the cranium, sides of the skull, and sides of the orbits

• sella turcica

• butterfly shaped

• greater/lesser wings

• lateral/medial pterygoid plates

Ethmoid 

• forms part of the roof and walls of the nasal cavity, the floor of the cranium, and walls of the orbits

• cribiform plates

• olafactory foramina

• crista galli

• superior/middle nasal conchae

foramen rotundum

passageway for maxillary nerve

foramen ovale

passageway for mandibular nerve

formanen spinosum

passageway for the middle meningeal

foramen lacerum

closes in adulthood

internal acoustic meatus

facial and vesicular nerves

cartoid canal

cartoid artery

jugular foramen

jugular vein

hypoglossal canal

hypoglossal nerve

Maxilla

• Form upper jaw, anterior roof of

• mouth, floors of orbits, and sides and

• floor of nasal cavity

• Alveolar processes

• Palatine process

Palatine (2)

• Form posterior roof of mouth and

• floor and lateral walls of nasal cavity

Zygomatic (2)

• Form prominences of cheeks and

• lateral walls and floors of orbits

• Articulates with zygomatic

• process on temporal bone

Lacrimal (2)

• Form part of the medial walls of the orbit

• Groove that leads from

• orbit to nasal cavity

• Lacrimal fossa - passageway for tear ducts

Nasal (2)

• Form bridge of nose

• Hyoid bone

• Inferior to mandible

• Not connected to any bone

• Base for tongue

Vomer

• Forms inferior portion of nasal

• septum

• Vertical division of nose

• Inferior Nasal Concha (2)

• Extend into nasal cavity from its

• lateral walls

Mandible

• Forms lower jaw

• Body

• Ramus

• Mandibular condyle

• Coronoid process

• Alveolar processes

• Mandibular foramen

• Mental foramen

What are Fontanels?

soft parts between bones

Occipital fontanel

above occipital bone

sphenoidal fontanel

by the sphenoid bone

mastoid fontanel

behind ears meeting point btw temporal and occicpital

Auditory Ossicles

malleus

incus

stapes

Vertebral Column

• Extends from the skull to the pelvis

• 26 vertebrae separated by intervertebral discs

• Supports head and trunk

• Allows bending

• Protects spinal cord

Concave

curve inwards

Convex

curves outwards

Intervertebral Discs

• Between vertebra

• Cushions

• Allows movement

Nucleus pulposus

soft jelly like substance in interverterbal discs

Annulus fibrosus

thicker tisuue surrounding

Vertebrae Body

drum-shaped

anterior and posterior longitudinal ligaments

Vertebrae Projections

• Pedicles

• Laminae

• Spinous process

• Transverse process

• Superior and inferior articular processes

Vertebrae Facets

• Intervertebral foramen

• Vertebral foramen

Cervical vertebrae

• 7 vertebrae

• Transverse foramina

• C2-C6 – Forked processes

Atlas

• Supports head

• No body or spine

• Ring with transverse processes

Axis

• Dens projects upward into atlas

• Allows head to turn from side to side

Thoracic Vertebrae

• 5 vertebrae

• Equipped with stronger/thicker bodies to support more weight

• Thinner transverse processes

• Short, thick spinous processes are nearly horizontal

Lumbar Vertebrae

• 5 vertebrae

• Equipped with stronger/thicker bodies to support more weight

• Thinner transverse processes

• Short, thick spinous processes are nearly horizontal

Sacrum

• 5 fused vertebrae

• Spinous processes form median sacral crest

• Nerves and vessels pass through posterior sacral foramina

• Pelvic cavity posterior wall

• Vertebral foramina form sacral canal

Coccyx

• 4 fused vertebrae

• Pelvic floor muscle attachments

Thoracic cage

• Supports pectoral girdle and UE

• Protects the viscera in the thoracic and upper abdominal cavities

• Plays a role in breathing

• Includes ribs, thoracic vertebrae, sternal bones, and costal cartilages

Ribs

• Costal cartilage

• Long, slender shaft curves around and slopes downward

• Head and tubercles articulate with vertebra

• Costal groove serves as muscle attachments

True Ribs

Ribs 1 - 7

False Ribs

Ribs 8 - 10

Floating Ribs

Ribs 11 - 12

Sternum

• Flat, elongated bone

• Manubrium

• Body

• Xiphoid process

• Sternal angle

Pectoral Girdle

• Supports the Upper Extremity

• Attachment for muscles that move the UE

• Clavicles (2)

• Scapulae (2

Clavicle

• Slender, rod-like bones

• S-shaped

• Run horizontally from manubrium to scapula

• Attachment for muscles of the UE, chest, and back

• Sternal end - connects to sternum

• Acromial end - connects to acromion on scapula