bio 141

5 Functions of the Skeleton

Support, Protection, leverage, storage of minerals and lipids, production of blood cells

How many bones do babies start out with?

300

Bone tissue is ______ tissue

connective

Bone Matrix has.....

inorganic salts, i.e. Minerals

Osteogenic Cells

Stem cells - give rise to osteoblasts

Found in the periosteum and along endosteum

Osteoblasts

Bone-forming Cells - mature into osteocytes•

Found along periosteum and endosteum

• Synthesize and secrete pre-bone matrix = osteoid

• Osteoid hardens around osteoblast -becomes osteocyte

• Does not divide

Osteocytes

Mature Bone Cells - Derived from Osteoblasts

• Surrounded by thin layers of Bone Matrix

• Live in Lacuna - connect via Canaliculi - 'inside' bone

• Maintain the matrix (dissolve and rebuild), secrete enzymes, regulate calcium

Osteoclasts

Large Multi-Nucleated Cells

Osteolysis

Secrete acid and enzymes, break down bone tissue, release minerals

Long Bones grow through ___________ ossification

endochondral

Red Marrow production is called.....

Hemopoiesis

How many long bones

90

Where are Flat Bones

Roof of Skull, Sternum, Ribs, Scapula

where are Irregular Bones

vertebrae, pelvis, skull

examples of Short Bones

carpal and tarsal bones

Sutural Bones

along "seams" of skull

How many flat bones are there?

36

sesamoid bones

Found within a tendon/ligament. Formed through endochondral ossification.

Yellow Bone Marrow

fatty tissue found in the medullary cavity of most adult long bones

compact bone (cortical bone)

Has osteons, hard

spongy bone (cancellous bone)

porous bone, red bone marrow, trabeculae

Endosteum

lines the inner surface of bone

• Lines the medullary cavity of long bones

• Covers trabeculae

• Lines the central canal

• Incomplete membrane

• single layer of osteogenic cells, osteoblasts, osteoclasts

Periosteum

covers outer surface of bone - 2 layers

• Outer fibrous

• Mainly collagen

• nerve network - nociceptors: why broken bones hurt!

• Vascular network - Supplies the outer osteocytes - enters Volkmann channels Inner cellular Osteoblasts, osteoclasts, osteogenic cells• Penetrating "Sharpey Fibers" Bind to bone

Trabeculae are covered in.....

endosteum

Tubercle, < Tuberosity, < Trochanter

a projection or bump with a roughened surface - Trochanter is largest

Trochlea

smooth grooved pulley shaped process

Facet

a small, flattened articular surface

Fissure

elongated cleft or Gap

Fossa

shallow depression or recess (ditch)

Fovea

a pit or depression, generally very small

Foramen

small round passageway

Ramus

an extension of bone

Eminence

relatively small projection or bump

Promontory

any projection or prominent bump

Notch

indentations at the edge of a structure

4 fetal fontanels

Anterior, posterior, sphenoidal, Mastoid

Sphenoid Bone

The Base of the calvarium, Many Cranial nerves leave the brain through sphenoid,

Ethmoid bone

Stabilizes face, helps respiratory immunity, helps sense of smell, allows passage of olfactory nerves, protects frontal lobe of brain

Hyoid Bone

Only muscle/ligament attachmentU- shaped in throat, helps withtongue, swallowing, etc.

How many cervical vertebrae are there?

7

How many thoracic vertebrae are there?

12

How many lumbar vertebrae are there?

five

mnemonic for the number of vertebrae

Breakfast at 7, Lunch at 12, Dinner at 5

Vertebral foramen

In Center, Contains the Spinal Cord

Superior and Inferior articular processes

where adjacent vertebrae articulate with each other.

Unique characteristics of Cervical vertebrae

transverse foramina, bifid spinous process tips

Unique characteristics of thoracic vertebrae

Facets for rib articulation, long spinous process

Unique characteristics of lumbar vertebrae

massive body, mammillary process

Name of C1 vertebrae

atlas

Name of C2 vertebrae

axis

typical cervical vertebrae

C3-C6

typical thoracic vertebrae

T2-T8

true ribs

first 7 pairs of ribs

false ribs

Ribs 8-12

floating ribs

11-12

The manubrium articulates with the ___________

clavicle and 1st rib

xiphoid process is made of_________

hyaline cartilage in the proximal portion, and elastic cartilage in the distal portion

Intramembranous Ossification

forms bone without cartilage first

endochondral ossification

process in which bone forms by replacing cartilage (majority of bones)

Primary ossification center

spongy bone in the center of bone

secondary ossification center

at epiphyseal plate

interstitial growth

increase in length of bones

appositional growth

increases the width of bone

Types of Bones formed by intramembranous ossification

flat bones, roofing bones, and mandible

Types of Bones formed through endochondral ossification

oddly shaped bones

Mesenchymal cells differentiate into

osteoblasts

osteoblasts create

osteoid, which calcifies and they become osteocytes.

Cortical bone arises between ________ and __________

periosteum and spongy bone

How many bones are in the body?

206

Simple fracture is ______

closed, doesn't break the skin

A compound fracture is ______

open and breaks the skin

Colles and smith distal radius fracture

colles- outstretched

Smith- wrist flexed

Pott's and Cotton Ankle Fractures

potts- Bimalleolar

Cotton- Trimalleolar

Torus or buckle fracture

Impacted fracture with bulging of periosteum

Common youth fracture.

green stick fracture

incomplete fracture. common youth fracture

Epiphyseal plate fracture is known as _________

Salter Harris fracture

Calcitonin

Lowers blood calcium levels

Where does calcitonin come from?

Thyroid gland (c cells)