BIOL 2403 - A&P - Minich - chapter 7 - skeletal system

What are the functions of the skeletal system?

SUPPORT, PROTECTION, aid in movement, storage of minerals, site for blood cell formation

What four parts do the skeletal system include?

Bones, cartilage ligaments, tendons

how do you classify (describe) bone structure?

Rigidity

How do you classify (describe) cartilage?

Flexible and cushioning

How do you classify (describe) ligaments?

Connects bone to bone

How do you classify (describe) tendons?

Connects muscle to bone

Bone (osseous) is a type of _________ Tissue?

Connective

Bone (osseous) is composed of what?

Four types of cells, extracellular matrix

What are the four types of bone cells?

Osteoprogenitor, osteoblast, osteosite, osteoclast

Genitor=

Generates

Blasts=

build

cytes=

mature

clasts

crashers

Where are osteoprogenitors located?

bone surfaces

where are osteoblasts located

bone surfaces

where are osteocytes located?

trapped inside bone

Where are osteoclasts located

bone surfaces

What are the functions of osteoprogenitors?

STEM CELLS - become osteoblasts

what are the functions of osteoblasts?

produces osteoid (semisolid, organic component of bone matrix) - mineralizes and hardens -> gets trapped in the matrix and becomes osteocytes

What are the functions of osteocytes

maintain bone matrix, regulate activity of osteoblast and osteoclasts

What are the functions of osteoclasts

large multi-nuclear cells involved in BONE RESPORPTION, REMOVAL of bone tissue

osteoblasts start off _______ then mineralize

soft and squishy

What causes the mineralization of osteoblasts?

calcium and phosphorus

What is the composition of the bone matrix

collagen and salt crystals

How much collagen is in extracellular bone matrix?

90%

What does collagen do for bones?

makes it strong and flexible

What do the salt crystals do for bones in the extracellular matrix?

provide hardness

Bone matrix constantly undergoes process of _________ and ________

formation; resorption

Formation involves secretion of ______ by _______ followed by mineralization

osteoid; osteoblasts

resporption involves breakdown of ______________ components by ________

bone matrix; osteoclasts

What two things do resorption release?

hydrochloric acid and enzymes

What are the two types of bone?

compact (cortical/dense) and spongy (trabecular)

How does compact bone look?

smooth and solid

Compact bone is ___% bone mass

80

Definition of osteon

small and cylindrical. basic functional and structural unit of mature compact bone

osteon=

one

osteon will become _________

solid

What is osteon composed of?

central canal (blood vessels and nerves)

lamallae (ring-like layer of bone tissue - surrounds the central canal)

osteocytes are found in spaces (______) between ______________

lacunae; lamellae

what are canaliculi

tiny channels that connect neighboring lacunae in central canal - permitting intercellular contact

Canaliculi allow transport of....

nutrients, gases, wastes between blood vessels and osteocytes

how does spongy bone look?

porous, lattice-like

spongy bone is ___% bone mass

20

what is the definition of trabeculae

lattice and norrow rods. provide great resistance to stresses, but reduces weight. bone marrow fills spaces between

describe the appearance of long bones

greater in length than width

describe the appearance of short bones

length nearly equal to their width

describe the appearance of flat bones and explain why they are shaped that way

they have flat, thin surfaces that may be slightly curved. They provide extensive surfaces for muscle attachment and protect underlying soft tissues

describe the appearance of irregular bones

elaborate, sometimes complex shapes and do not fit into any of the preceding categories

What are the three main sections of long bone?

diaphysis, epiphysis, metaphysis

What is the diaphysis?

elonngated shaft

what is the function of diaphysis?

leverage and major weight support

what is the epiphysis?

knobby region at the ends of long bone

What kind of cartilage covers the epiphysis?

hyaline

what is the metaphysis

regio between diaphysis and epiphysis

epiphysial growth plate

thin layer of hyaline cartilage that provides for lengthwise bone growth (until the age of 25)

What epiphysial plate turns into the _______________

epiphysial line

What are the linings of bone (two types)

periosteum and endosteum

periosteum covers ______surface of bone

outer

what are the two layers of periosteum

outerfibrous and innercellular

What does the outerfibrous layer of periosteum do?

protects; anchors blood vessels and nerves to bone surfaces; attachment site for ligaments and tendons

what does the innercellular layer of the periosteum include?

osteoprogenitor cells, osteoblasts, osteoclasts

What does endosteum do?

covers internal surfaces of bone

What does endosteum include?

osteoprogenitor cells, osteoblasts, osteoclasts

what is the gross anatomy of other bone classes?

outer compact bone, inner spongy bone, no medullary cavity

bones are highly ________

vascular

blood vessels enter and exits the bone through a ________

foramen

nerves that supply bone accompany _______

blood vessels

bone marrow is the ______ CT of bone

soft

red bone marrow is _________ (blood cell forming)

hemopoietic

bone marrow contains ___________ CT, ________ blood cells, and ____

reticular; immature; fat

where is red bone marrow located in children?

in the spongy bone and medullary cavity of long bones

yellow bone marrow is the product of _________________ that turns into a _______ substance

red bone marrow; fatty

yellow bone marrow can __________________ red bone marrow

convert back to

Cartilage is ________ connective tissue

semi-solid

What is cartilage composed of?

cells and extracellular matrix

extracellular matrix in cartilage

gel-like ground substance RICH IN WATER

extracellular matrix in cartilage allows cartilage to be ....

highly compressible (NO CALCIUM)

extracellular matrix in cartilage is reinforced by what?

fibrous proteins (elastin and collagen)

cartilage is composed of which cells?

chondroblasts and chondrocytes

Chondro=

cartilage

cartilage has ____ blood vessels

no

cartilage is often covered with fibrous membrane-

perichondrium

peri=

around

What are the type major types of bone cartilage?

hyaline, elastic, fibrous

Hyaline cartilage is the ________ abundant cartilage. it is reinforced with _______ collagen

abundant; thin

What are some examples of hyaline cartilage in the body

articular (joint), costal, nasal cartilages

elastic cartilage is the most ______ due to the large amount of ______

flexible; elastin

Where can elastic cartilage be found?

external ear and the EPIGLOTTIS of the larynx only

fibrous cartilage is the most P and _______ resistant. it is reinforced with ____ collagen

stretch; thick

Where can fibrous cartilage be found?

knee, intervertebral discs

What are the two types of cartilage growth?

interstitial and appositional

interstitial=

growing from the inside

What is the process of interstitial growth?

1. chondrocytes divide into two chondroblasts

2. chondroblasts secrete matrix

3. each cell becomes a chondrocyte within its own lacuna

Appositional=

adding layers (grows in layers)

What is the process of appositional growth?

1. the stem cells within the perichondrium divide producing chondroblasts

2. new chondrblasts start producing matrix ADDING A LAYER to the old cartilage

What is the cartilage growth pattern?

1. during early embryonic development: interstitial and appositional

2. as cartilage matures - it becomes semi-rigid, cannot expand -> only appositional growth

3. fully matured cartilage does not grow but will inhibit limited growth after injury

Ossification (osteogenesis)

the formation and development of bone tissue?

When does the development of bone tissue begin?

it begins in the 8th week of embryonic development and continues into childhood and adolescence

ossification=

forms bone

endochondrial=

inside of cartilage