Skeletal System

axial skeleton

Long axis of body

Skull, vertebral column, rib cage

appendicular skeleton

Bones of upper and lower limbs

Girdles attaching limbs to axial skeleton

compact (corticol)

Dense outer layer of bone; smooth and solid

spongy bone

Honeycomb of flat pieces of bone deep to compact called trabeculae

trabeculae

the honeycomb in spongey bone, and has flat pieces of bone deep to compact named ____

spongey (diploe)

Short, Irregular, and Flat Bones have a _____ layer…which is covered by compact bone

shock and forces

spongey bone can absorb _____ better than compact bone

Periosteum

Covers the outer surface of the bone

Endosteum

Lines the internal cavities and surfaces of the bone

Hyaline cartilage

what type of cartilage covers the articular (joint) surfaces of short, irregular, and flat bones

diaphysis

Tubular shaft that forms the long axis of long bones

medullary cavity

long bones are composed of compact bone surrounding the _______

Epiphyses

Proximal and distal rounded ends of long bone

external compact

internal spongy

epiphyses of long bones are characterized by ______ bone and ______ bone

Articular cartilage (specifically hyaline cartilage)

epiphyses of long bones are covered by ______ at the joint surfaces

metaphysis

region that contains the epiphyseal plate (growth plate) or epiphyseal line (remnant of the growth plate in adults)

Outer fibrous

the Periosteum of long bone has a ______ layer that’s composed of dense irregular connective tissue.

Provides protection and serves as an attachment point for tendons and ligaments

osteogenic layer

the Periosteum of long bone has a ______ layer that contains stem cells, specifically osteogenic cells.

osteogenic cells

These cells are crucial for bone growth (in width) and repair, and are located in the osteogenic layer of the periosteum of long bones

endosteum

Covers internal bone surfaces of long bones, lines the medullary cavity, and covers the surfaces of the trabeculae within spongy bone

periosteum

endosteum

what layers of long bones contain osteogenic cells

red

Adult long bones have little ____ marrow

trabecular cavities

diploe

red bone marrow is found within ______ of spongey bone and ______ of flat bones

osteogenic cells

mitotically active stem cells in the periosteum and endosteum

osteoblast

bone lining cells

when osteogenic cells are stimulated, they differentiate into ____ or ____. Some persist as osteogenic cells though

osteoblasts

cells that secrete on mineralized bone matrix or osteoids

collagen

calcium binding proteins

osteoblast include _____ and _____

90%

collagen is ___% of bone protein

osteocytes

mature bone cells and are trapped osteoblasts

bone matrix

what do osteocytes monitor and maintain?

Respond and communicate mechanical stimuli to osteoblasts and osteoclasts so bone remodeling can occur

how do osteocytes act as stress or strained stressors

osteoclasts

derived from hematopoietic stem cells

Giant multinucleate cells for bone resorption

osteon (haversian system)

the fundamental building block of compact bone

elongated cylinder, running parallel to the long axis of the bone

lamellae

central (haversian) canal

two things that are in/ composed in osteons

lamellae

Circular layers of bone matrix

the arrangement is crucial for resisting stress, especially in twisting forces (arranged in different directions)

central canal

located at the center of the osteon containing blood vessels to nourish the bone

perforating canals

perpendicular to osteons

lacunae

what in cortical bone contains osteocytes?

canaliculi

canals that connect lacunae to each other and central canal

trabeculae

honeycomb appearance in spongy bone that has no osteons

lamellae and osteocytes

trabeculae contain irregularly arranged ___ and ___ interconnected by canaliculi

cells and fibers

collagen fibers

organic components of bone

collagen fibers in bone

contributes to structure, provides tensile shrink and flexibility

65%

minerals contain ___% of bone by mass

minerals

Calcium phosphate

inorganic components of bone

hardness

compression

minerals in bone are responsible for ____ and resistance to _____

ossification (osteogenesis)

process of bone tissue formation

second month of development

the formation of the bony skeleton begins in the …

early adulthood

postnatal bone growth continues until …

lifelong

bone remodeling and repair continues until…

endochondral ossification

type of ossification where bone forms by replacing hyaline cartilage

skeleton

Cartilage

endochondral ossification forms most of the ____ and includes bones called _____ bones

intramembraneous ossification

type of ossification where bone develops from the fibrous membrane

membrane

flat

intramembranous ossification is when bones called ____ bones form _____, like the clavicle and cranial bon

5-7%

bone homeostasis recycles __-__% of bone mass every week

3-4

10

spongy bone is replaced every ___ years

Compact bone is replaced every ___ years

Crystallize

older bone becomes more brittle as we age

Calcium salts ____, and bone fractures more easily

Remodeling

Repair

bone homeostasis consist of bone ____ and bone ____

periosteum

endosteum

bone remodeling occurs at surfaces of both ____ and ____

deposition

bone remodeling

____ is the crystallization process where calcium and phosphate turn into bone

osteoblasts

what begins the deposition process in bone remodeling?

Resorption

bone remodeling

____ is the process of dissolving bone and releases minerals into the blood

osteoclasts

what bone cells are involved in bone resorption

bone remodeling

_____ occurs continuously but regulated by genetic factors and two control loops

blood calcium stress

hormonal controls determine whether and when bone remodeling occurs based on changing…

mechanical

____ stress determines where bone remodeling occurs

parathyroid hormone (PTH)

this hormone is produced by parathroid glands and increases BL calcium

Ca2+

PTH hormone removes ___ from bone regardless of bone integrity

calcitonin

this hormone is produced by the thyroid gland and in high doses, lowers blood calcium levels temporarily

Wolff’s law

this states that bone will adapt to the stress that is applied to it

mechanical

___ stress causes strain

If there is a strain… minimal essential strain threshold, then bone remodeling occurs

joints

sites where two or more bones meet

fibrous joints

what type of joint?

sutures, syndesmoses, gomphosis

cartilaginous joints

what type of joint?

synchondroses, symphysis

Articular cartilage

Joint cavity

Articular capsule

Synovial fluid

Reinforcing ligaments

Nerves and blood vessels

6 general structures of synovial joints

phagocytic

synovial fluid in synovial joints contains ___ cells to remove microbes and debris

capsular ligament

type of reinforcing ligament that is a thickened part of the fibrous layer in synovial joints

extracapsular ligament

type of reinforcing ligament that is outside of the capsule in synovial joints

intracapsular ligament

type of reinforcing ligament in synovial joints that is deep to the capsule and covered by synovial membrane

fatty pads

these in synovial joints are for pushing between fibrous layer of capsule and synovial membrane or bone

articular discs

these in synovial joints are fibrocartilage that separate articular surfaces to improve the fit of bone ends, stabilize joints, and reduce wear and tear

The shape of articular surface

Ligament number and location

Muscle tone

3 factors influencing stability of synovial joints

Because of poor vascularization

why do partial tears repair very slowly?

Reinforcing ligaments

What is stretched or torn in a sprain?

Caused by bacteria

acute forms of arthritis

osteoarthritis or rheumatoid arthritis

chronic forms of arthritis