Class Notes (839,471)
Canada (511,354)
ANAT 261 (42)
Lecture

3. Cartilage and Bone.pdf

6 Pages
137 Views

Department
Anatomy & Cell Biology
Course Code
ANAT 261
Professor
Craig Mandato

This preview shows pages 1 and half of page 2. Sign up to view the full 6 pages of the document.
Description
Penichondrium Chondrocyte Hyaline cartilage Elastic cartilage Chondrogenic Layer Extracellular Matrix Chond roplast isogenous Group) Perichendrinin Penichondrium Chondrocyte Hyaline cartilage Elastic cartilage Chondrogenic Layer Extracellular Matrix Chond roplast isogenous Group) PerichendrininNaveen Sooknanan McGill Fall 2011 Cartilage: Cartilage and bone are specialized types of CT which secrete a firmer ECM than normal  This is due to the presence of other minerals which harden the matrix Cartilage allows the tissue to support mechanical stress without distortion and also provides support to adjacent soft tissues  This allows for movement and flexibility (such as in the nose and ears)  Cartilage consists of chondrocytes and an extensive ECM contain fibers and ground substance  These cells are located in spaces within the ECM known as lacunae or “chondroplasts” o These cells form groups known as isogenic groups There are three types of cartilage:  Hyaline cartilage (trachea) o Medium hardness  Elastic cartilage (nose, ear and larynx) o Flexible, soft  Fibrocartilage (intervertebral discs) o Hard, won’t be seen in the lab The ECM for these three types of cartilage differs from one another:  Fibers: o Collagen type II in hyaline and elastic cartilage o Elastic fibers in elastic cartilage o Collagen Type I in fibrocartilage  Ground substance stays the same for them all: o Proteoglycans including keratin sulfate and chondroitin sulfate  GAGs including hyaluronic acid, which links protein cored together o Various glycoproteins, including chondronectin Hyaline cartilage can be found in the trachea. During development, hyaline cartilage also turns into long bones  The perichondrium is a CT sheath surrounding the cartilage. It is present everywhere but articulated surfaces (like the head of a bone), it is made up of 2 layers: o The upper fibrous layer contains fibrocytes, which no longer produce fibers o The chondrogenic layer contains chondroblasts which secrete cartilage ECM  The chondrogenic layer is responsible for appositional growth, which produces chondroblasts and ECM 1CH CHNaveen Sooknanan McGill Fall 2011  As ECM is produces, come chondroblasts will become stuck in the ECM and become inactive. These are known as Perichondrium: Elastic Fibers chondrocytes  Chondrogenic Layer o The ECM contains collagen type II o Chondrocytes are bigger than Chondroplast chondroblasts o Through they do not secrete ECM, they can still divide  The division of chondrocytes creates isogenic group within lacunae (spaces) in the ECM o The isogenic groups within a lacunae Hyaline Cartilage Elastic Cartilage are called chondroplasts o These chondroplasts are responsible for interstitial growth  Appositional growth is more important because it is capable of making cartilage from scratch (because it can make chondroblasts) o Interstitial growth can only expand on an already existing piece of cartilage Elastic cartilage is the same as hyaline cartilage except that is contains elastic fiber within the ECM  The elastic fibers cannot be seen with HE staining, but we assume they are there  There are special stains which can turn elastic fibers a dark purple, we don’t see these in the lab, however Regulation of cartilage growth:  Stimulate protein synthesis: o Growth hormone o Thyroid hormone o Testosterone  Retard protein synthesis: o Corticosteroids o Estradiol o Reitnoids (vitamin A)  In the 60s, people thought it was good to feel babies tons of vitamin A, but it led to the development of many short people Bone: Bone is one of the hardest tissues in the body. It can withstand a great deal of stress. The EMC of bone is made of type I collagen (which gives flexibility) and calcified material (which gives bone its hardness)  Tooth enamel is in fact the hardest material in the body  The cell types are: o Osteoprogenitor cells, which are stem cells  These are hard to see in the lab, because they are tiny 2physis Spongy Bone cancellous (spongy) woven immature) lamellar (nature) Development Appear. Diaphysis endochondral COMPACT BONE Circumferential ystem Periosteum Circumferentia Endosteum Interstitial Haversian Canal physis Spongy Bone cancellous (spongy) woven immature) lamellar (nature) Development Appear. Diaphysis endochondral COMPACT BONE Circumferential ystem Periosteum Circumferentia Endosteum Interstitial Haversian CanalNaveen Sooknanan McGill Fall 2011 o Osteoblasts, analogous to fibroblasts and chondroblasts, these are active cells which secrete ECM o Osteocytes are found in lacunae within the ECM  They are inactive and there is only one osteocyte per lacuna (unlike cartilage) o Osteoclasts are large, multinucleated cells involved in bone remodelling  These sit on the periphery of the bone ECM and chew it up  The ECM, produced by osteoblasts, is made of: o Fibers: type I collagen o Ground substance: proteoglycans and glycoproteins  Particularly sialoproteins and osteocalcin o Minerals: crystals of hydroxyapatite (Ca (10 ) 4 6) ) 2  These are calcium crystals mixed with phosphate  For the bone to be put onto a slide, it must first be decalcified in order to the microtome to be able to cut it o This is done by dipping the bone in 5% nitric acid or EDTA which sucks out the calcium, softening the bone to a rubbery texture Looking at the anatomy of the bone, there are three different ways to classify it:  Gross appearance: o Either compact of cancellous (spongy)  Microscopic appearance: o Immature bone is woven while mature bone is lamellar  Developmental appearance: o Intramembranous (flat bones, coming from mesenchymal cells) o Endochonral (long bones, coming from cartilage)  In a typical long bone: o The epiphysis of the bone is at the end, containing spongy bone, while the diaphysis is in the middle, containing compact bone Compact bone is made up of four main layers:  The periosteum (like the perichondrium for cartilage) is a CT sheath al
More Less
Unlock Document

Only pages 1 and half of page 2 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit