Unit 5 Skeletal Tissue Exam

before birth what does the human skeleton consist of

cartilage

What is cartilage replaced by as a person grows

bone, expect in flexible areas

why are little kids so flexible

their bones are mainly made out of cartilage

skeletal cartilage

made of highly resilient, molded cartilage tissue

what does skeletal cartilage mainly consist of

water

perichondrium

layer of dense connective tissue surrounding cartilage

where is the perichondrium located

around the outside of the bone

what does the perichondrium do

help cartilage resist ourward expansion

what is cartilage made up of

chondrocytes

what do chondrocytes do

make cartilage

what are the three types of cartilage

hyaline, elastic, and fibrocartilage

hyaline cartilage provides

support, flexibility and resilience

hyaline cartilage contains

collagen fibers and is the most abundant type

where can you find hyaline cartilage

joints, ribs, larynx, nose tip

what fibers does elastic cartilage contain

elastic fibers

where can you find elastic cartilage

external ear and epiglottis

what fibers does fibrocartilage contain

thick collagen fibers

where can you find fibrocartilage

menisci of knee and intervertebral discs

what ways does cartilage grow in

appositional and interstitial

appositional growth

cartilage forming cells lay on top of existing cartilage

interstitial growth

grows between existing cartilage

when does calcification of cartilage occur

in youth but can also occur in old age

seven important functions of bones

support, protect, movement, mineral and growth factor storage, blood cell formation, triglyceride storage, hormone production

hematopoiesis

creation of blood

triglyceride (fat) storage

fat, used for an energy source, is stored in bone cavities

osteocalcin

secreted by bones to help regulate insulin secretion

how many bones are in the human skeleton

206

two groups of bones

axial and appendicular

axial skeleton

skull, vertebral column, rib cage

appendicular skeleton

girdles attaching limbs to axial skeleton

long bones

longer than they are wide

short bones

cube shaped

flat bones

thin, flat, slightly curved

irregular bones

complicated shapes

why are bones organs

they contain different types of tissues

are bones avascular or vascular

vascular

what are the three levels of structure

gross, microscopic, and chemical

compact bone

dense outer layer on every bone that appears smooth and solid

spongey bone

made up of a honeycomb of small, needle-like or flat pieces of bone called trabeculae

what are open spaces between trabeculae filled with

red or yellow bone marrow

the periosteum covers what

the outside of compact bone

the endosteum covers

the inside portion of compact bone

bone marrow is scattered throughout what

spongy bone

what does hyaline cartilage cover

area of bone that is a part of a movable joint

what do all long bones have

a shaft, bone ends, and membranes

what is the shaft of the bone called

diaphysis

what does the diaphysis consist of

compact bone surrounding the medullary cavity that is filled with yellow marrow

epiphyses consist of

compact bone externally and spongy bone internally

what does articular cartilage cover

articular surfaces

what is between the diaphysis and epiphysis

epiphyseal line

what occurs in the epiphyseal plate

bone growth

why is yellow marrow, yellow marrow

it is fat tissue

periosteum

white, double layered membrane that covers external surfaces except joints

fibrous layer

outer layer consisting of dense irregular connective tissue consisting of Sharpey’s fibers that secure to bone matrix

osteogenic layer

inner layer abutting bone and contains primitive osteogenic stem cells that give rise to moistly all bone cells

anchoring point for tendons and ligaments

endosteum

what covers the trabecular of spongy bone

the endosteum

where is red blood marrow found

within trabecular cavities of spongy bone

in newborns what contain red marrow

medullary cavities and all spongy bone

in adulats where is red marrow found

heads of femur and humerus, flat bone diploe, and some irregular bones

when can yellow marrow convert to red

whena person becomes anemic

what happens when one is anemic

blood is not transporting as much oxygen as it should

projection

outward buldge of bone

depression

groove-like cut-out that can serve as passageways for vessels and nerves

opening

hole or canal in bone that serves as passageways for blood vessels and nerves

what are the five major cells in the bone tissue

osteogenic cells, osteoblasts, osteocytes, osteoclasts, bone lining cells

osteogenic cells

mitotically active stem cells in periosteum and endosteum

what happens when osteogenic cells are stimulated

they differentiate into osteoblasts

osteoblasts

(builds bone) bone-forming cells that secrete unmineralized bone matrix called osteoid

what is an osteoid made up of

collagen and calcium binding proteins

are osteoblasts mitotic

yes

what are osteocytes

mature bone cells in lacunae that no longer divide

what is an osteocytes job

to maintain bone matrix

what do osteocytes respond to

mechanical stimuli such as increased force on bone or weightlessness

why do osteocytes communicate info to osteoblasts and osteoclasts

so bone remodeling can occur

osteoclasts are derived from

hematopoietic stem cells that become macrophanges

osteoclasts function in

bone resorption (breakdown of the bone)

where are osteoclasts located when active

depressions called resorption bays

why do cells have ruffled (folded) borders

to increase surface area for enzyme degradtion of bone

compact bone is also called

lamellar bone

what does compact bone consist of

osteons, canals, canaliculi, and interstitial and circumferential lamellae

osteon

the structural unit of compact bone

what does an osteon cylinder consist of

several rings of bone matric call lamellae

what do lamellae contain

collagen fibers that run in different directions in adjacent rings

where are bone salts found

between collagen fibers

where does the central canal run trough

the core of the osteon

what does the central canal contain

blood vessels and nerve fibers

what are perforating canals

canals lined with endosteum that occur at right angles to central canal

what does the perforating canals do

connect blood vessels and nerves of periosteum, medullary cavity, and central canal

lacunae

small cavities that contain osteocytes

canaliculi

hair-like canals that connect lacunae to each other and to the central canal

what is interstitial lamellae

lamellae that is not apart of the osteon

circumferential lamellae

deep to the periosteum, but superficial to the endosteum, they extend around the entire surface of the diaphysis. it also helps the long bone to resist twisting

why is spongy bone organized along lines of stress

to help bone resist any stress

bone is made up of

both organic and inorganic components

organic components include

osteogenic cells, osteoblasts, osteocytes, bone-lining cells, osteoclasts, and osteoid

osteoid makes up how much of organic bone matrix and is secreted by what

one third and is secreted by osteoblasts

organic collagen fibers give

the resilience of bone

what is the resilience of bone due to

sacrificial bonds in or between collagen molecules

hydroxyapatites are

mineral salts