Hsf - Histology (I)

Front 1

name the 3 types of cartilage

Back 1

hyaline, elastic, and fibrocartilage

Front 2

describe hyaline cartilage

Back 2

forms articulating surfaces of most bones, tracheal rings, nasal/laryngeal cartilage, and the bone models in fetuses

Front 3

describe elastic cartilage

Back 3

found in epiglottis and external ear and ear canal

Front 4

describe fibrocartilage

Back 4

intervertebral discs, some symphyses, some tendonous insertions into bone, and the eustachian tube

Front 5

chondrocytes

Back 5

primary cells of cartilage; reside in lacunae

Front 6

perichondrium

Back 6

dense connective tissue sheath that surrounds hyaline and elastic cartilage (but not fibrocartilage)

Front 7

describe development of cartilage

Back 7

originate from mesenchyme

differentiate into chondroblasts, which begin to make matrix around them

once surrounded in matrix, known as chondrocytes

there is interstitial growth (grows from within cartilage)

other mesenchymal cells differentiate into dense CT, making perichondrium

Front 8

describe bone structure

Back 8

made up of cells (osteocytes) and ECM

ECM is largerly made up of hydroxyapatite crystals that contain Ca and P; also contains type I collagen, and ground substance with GAG and glycoproteins and sialoproteins that help bind Ca during mineralization

Front 9

compact bone

Back 9

dense layer that forms the outside of bone

Front 10

cancellous bone

Back 10

meshwork of thin trabeculae or spincules onthe interior of bone, a.k.a spongy bone

Front 11

lamellae

Back 11

organized layers of bone (found in mature bone only)

Front 12

perioteum

Back 12

dense irregular connective tissue sheath that surrounds bone

Front 13

endosteum

Back 13

single layer of flattened cells that surround the inside surfaces of bone

Front 14

osteoprogenitor

Back 14

mesenchymal origin

replicate and differentiate into osteoblasts;

when inactive, they are bone-lining cells of endosteum and periosteum

Front 15

osteoblasts

Back 15

synthesize and secrete bone matrix (osteoid) on growing surfaces

matrix is then mineralized; osteoblast secretes Ca-P vesicles into ECM

Front 16

osteocytes

Back 16

when osteoblast is surrounded by mineralized matrix

have limited ability to synthesize, just help maintain blood calcium levels

connect to eachother via gap junctions

Front 17

osteoclasts

Back 17

hematopoietic origin (bone marrow)

multinucleated phagocytic cell; breaks down calcified matrix by lysosomal action with digests collagen and minerals

Front 18

describe structure of compact bone

Back 18

formed by columns called Haverisan systems or osteons

osteons formed by concentric lamellae that surround core - Haverisan Canal, which contains blood vessels and nerves

canal is interconnected to oblique channels (Volkmann's canal) - allows for distribution from periosteal surface to endosteal surface

Front 19

canaliculi

Back 19

small tennels within the matrix where gap junctions btwn osteocytes connect

Front 20

bone remodeling:
resorbtion
reforming

Back 20

resorbtion - osteoclasts resorb bone from surfaces

reformed - by appositional growth on pre-existing bone surfaces by osteoblasts

Front 21

how osteoblasts reform bone

Back 21

secrete collagen and ground substance of unmineralized bone called osteoid; also secretes small matrix vesicles rich in alkaline phosphatase, which increases local PO4 conc, increasing Ca conc, resulting in deposition of hydroxyapatite crytals

Front 22

2 processes of bone development in fetus

Back 22

intramembranous ossification
endochondral ossification

Front 23

intramembranous ossification

Back 23

forming flat bones of the skull, face, mandible, and clavicle

1-mesenchymal cells differentiate into osteoblasts (blastema), which secrete osteiod into woven bone pattern
2- osteiod becomes calcified
3- other mesenchyme becomes hematopoietic
4- woven bone gradually remodeled into lamellar bone

Front 24

endochondrial ossification

Back 24

forming bones of the axial skeleton and the extremeities

1- cartilage model is formed from mesenchyme, develops the shape of bone and contines to gorw by proliferation of chondrocytes and intersitial growth
2- cartilage growth reaches a size where nutriects cannot provide adequate nutrition by diffusion, since cartilage is vascular
3- oldest cells first hypertrophy, then degenerate
4- surrounding cartilage matrix is calcified
5- bone collar is formed by perichondrial/periosteal cells that differentiate into osteoblasts
6- collar penetrated by artery, which brings osteoprogenitor cells, forming hematopoietic tissue and osteoclasts
7- osteoclasts remove calcfied cartilage, and form marrow cavity
8- osteoblasts lay down osteiod which becomes mineralized; growth contines by appostion of new bone in pre-existing bone; bone collar replaced by adult bone

Front 25

epiphysial plate

Back 25

specialized cartilage; site of chondroblast proliferation and matrix deposition; has zones:

resting (reserve) zone
proliferative zone
hypertrophic zone
calcified cartilage zone (cell death)
ossification/resorption zone

Front 26

Parathyroid hormone

Back 26

raises blood calcium by activation osteoclasts to resorb bone

Front 27

calcitonin

Back 27

lowers blood calcium bu inhibiting osteoclast activity

Front 28

3 vit/min needed for bone growth and maintenance

Back 28

dietary calcium
vit D - promotes absorption (deficiency = rickets)
vit C - collagen synthesis

Front 29

glycoproteins of cartilage

Back 29

chondronectin - promotes adherence of chondrocytes to matrix

Front 30

glycoproteins of bone

Back 30

sialoprotein and osteocalcin - promote bone calcification

Front 31

ground substance of cartilage

Back 31

proteoglycans (PG) and glycoprotein

Front 32

ground substance of bone

Back 32

glycoaminoglycans (GAG) and glycoproteins