Download - L8 II Connective Tissue Part 2
-
8/2/2019 L8 II Connective Tissue Part 2
1/25
Connective Tissues Part 2
-
8/2/2019 L8 II Connective Tissue Part 2
2/25
ObjectivesDiscuss the structural and functional
characteristics of bone
Discuss the process of bone formationDiscuss structural and functional
characteristics of cartilage and adipose
tissue
-
8/2/2019 L8 II Connective Tissue Part 2
3/25
Bones
Cells + type I collagen (osteoid)mineralzies by
deposition of calcium hydroxyapatite rigid bones Cells
Osteoblasts
Produce osteoid and mediate its mineralisation
Lined up along bone surfaces Osteocytes
Assist in bone nutrition
Inactive osteoblasts trapped within formed bone
Oscteoclasts
Involved in constant turn over and refashioning ofbone
Erodes bone
-
8/2/2019 L8 II Connective Tissue Part 2
4/25
Bone cells
Osteoblasts & Osteocytes Osteoclasts
-
8/2/2019 L8 II Connective Tissue Part 2
5/25
Structure of bone
-
8/2/2019 L8 II Connective Tissue Part 2
6/25
Structure of bone
-
8/2/2019 L8 II Connective Tissue Part 2
7/25
Structure of bone
Haversian system
AKA osteon
basic unit, hollow
laminated rod ofcollagen and calciumphosphate
Haversian canal
hollow core of haversiansystem; nutrientchannel
-
8/2/2019 L8 II Connective Tissue Part 2
8/25
Structure of bone
Volkmanns canal
Perforating holeswithin the compact
bone Run within osteon
perperdicular toHaversian canal
Connects Haversiancanal to each otherand to the periostem
-
8/2/2019 L8 II Connective Tissue Part 2
9/25
Bone structure
Lacunae
deposition of successivelamellaediameter of
Haversian canaldecreases and osteblastsare trapped asosteocytes spaceenclosing it is known aslacunae
-
8/2/2019 L8 II Connective Tissue Part 2
10/25
Structure of bone
Compact / corticalbone
Many haversiansystems are
bundled togetherin parallel
Cancellous /spongy/ trabecular
bone Haversian system
branch out
-
8/2/2019 L8 II Connective Tissue Part 2
11/25
Structure of bone
Compact bone/cortical bone
Hard outer layer of
bones Porosity 5-30%
Account s80% oftotal bone mass in
adults Gives bone smooth,
white solidappearance
-
8/2/2019 L8 II Connective Tissue Part 2
12/25
Structure of bone
Cancellous /trabecular bone
Interior of the bone
Porous 20% of bone mass
Allow room forblood vessels and
marrow
-
8/2/2019 L8 II Connective Tissue Part 2
13/25
Compact and trabecular bone
-
8/2/2019 L8 II Connective Tissue Part 2
14/25
Functions of the bone
Mechanical function
Protection : protect internal organs (brain, heart, lungs) Structure: frame that supports body
Movement: function with skeletal muscles, tendons,ligaments, joints to execute movement
Sound transduction: overshadowed hearing
Synthetic function
hematopoiesis
Metabolic function Mineral storage (calcium and phosphorus)
Growth factor storage (insulin-like growth factor,transforming growth factor, bone morphogenetic
proteins
-
8/2/2019 L8 II Connective Tissue Part 2
15/25
Functions of the bone
Metabolic function Fat storage : yellow bone marrow (store fatty
acids)
Acid
base balance: absorb / release alkalinesalts (pH buffer)
Detoxification: remove heavy metals and foreignobjects from the blood; gradually secretes these
objects Endocrine organ: release osteocalcin (regulates
blood sugar and fat deposition)
-
8/2/2019 L8 II Connective Tissue Part 2
16/25
Bone formation
Endochondralossification
Formation of acontinuously growingcartilage model which isprogressively replacedby bone
Bones formed are calledcartilage bones
Long bones, pelvis,bones of the base of theskull
-
8/2/2019 L8 II Connective Tissue Part 2
17/25
Bone formation (Endochondral)
Permits functionalstresses during skeletalgrowth
Model of the long bone
first formed in a solidhyaline cartilageelongates into a dumb-bell shaped mass
(consisting of diaphysisand epiphysis)
-
8/2/2019 L8 II Connective Tissue Part 2
18/25
Bone formation (Endochondral)
Cartilage matrix in thediaphysis becomescalcified periosteumdevelopsprimitive
mesenchymal cells andblood vessels invade thespacesprimitivemesenchymal cells
differentiate intoosteoblasts andhematopoeitic cells ofbone marrow
-
8/2/2019 L8 II Connective Tissue Part 2
19/25
Bone formation (Endochondral)
Cartilage at the end ofthe diaphysis regress andossify semilunarcartilage (epiphysis)
Epiphysial plate:interface between shaftand epiphysis
Cartilage proliferatescontinouslyelongation of bone
-
8/2/2019 L8 II Connective Tissue Part 2
20/25
Bone formation (Intramembranous)
Occurs within membranes of primitive mesenchymaltissue
Mesenchymal cells differentiate into osteoblasts(synthesis and secrete osteoid)mineralizationfollowsosteoblasts are trapped into lacunae tobecome osteocytes
Collagen fibers are arranged in random interlacing
bundles
woven bone Bones of the vault of the skull, maxilla and mandible
-
8/2/2019 L8 II Connective Tissue Part 2
21/25
Bone formation (Intramembranous)
-
8/2/2019 L8 II Connective Tissue Part 2
22/25
Cartilage
Predominance ofproteoglycans in theetxracellular matrix
Hyaline cartilage
Contains few fibers
Fibrocartilage
contains abundantcollagen fibers
Elastic cartilage
Contains elastic fibers
-
8/2/2019 L8 II Connective Tissue Part 2
23/25
Cartilage Most cartilage are devoid of blood vessels
Hyaline cartilage
Nasal septum, larynx, tracheal rings Elastic cartilage
External ear and external auditory canal
epiglottis
Fibrocartilage Articular cartilage
Intervertebral discs
-
8/2/2019 L8 II Connective Tissue Part 2
24/25
Adipose tissue Storage of fat
Develop from liboblasts
-
8/2/2019 L8 II Connective Tissue Part 2
25/25
Have a nice day...!