defected collagen structure--skin is very stretchy
Two components of CT
cell
extracellular matrix
Two portions of the extracellular matrix and function
Fibers (scaffolding)
Ground substance (filler)
Most common cells of the CT and are responsible for the production of the extracellular matrix
These cells are also important in repair and healing--they proliferate and cause new collagen to form
Fibroblasts
cells of CT that store lipids (as one large lipid droplet), insulation and protection, and secrete leptin (hormone that signals satiety)
Adipocytes (fat cells)
cells of CT that are large round cells with a central nucleus and dark-staining basophilic granules in the cytoplasm
Mast cells
What do the granules in mast cells contain?
Histamine and heparin (involved in the inflammatory response and dilation--prompted to degranulate under certain conditions )
Cells of CT that are phagocytic, antigen-presenting cells (can sometimes have multi nuclei)
Macrophages
Chronic inflammatory cells that deal with immunity
One has a soccer ball looking nucleus that is pushed to one side
One has a dark staining nucleus
Plasma cells
Lymphocytes
a gel-like substance that binds cells and fibers
ground substance
What are the three things in the ground substance that when added with water give it the gel like substance
Glycosaminoglycans (GAGs) proteoglycans
glycoproteins
Extracellular tissue fluid that diffused through and carries nutrients and waste
Fills in the gaps between scaffolding (fibers)
Ground substance
Three major types of CT fibers
Collagen
Elastic
Reticular**
**technically a subtype of collagen fiber
most abundant type of CT fiber, composed of staggered arrangement of tropo___* protein
Collagen
Tropocollagen protein
What is the periodicity of collagen?
67 nm
Type of collagen that is most abundant and strong
found in: CT proper, bone, fibrocartilage, dentin and cementum
Type I
Type of collagen found in:
Hyaline and elastic cartilage (two most abundant types)
Type II
Type of collagen consisting of reticular fibers
Type III
type of collagen that is a component of the basal lamina of the basement membrane
Type IV
Type of collagen that is the anchoring fibrils of the basal lamina
Type VIII
What is a fibroma?
A ball of collagen that is formed on the occlusal line in the buccal mucosa and due to the trauma in that are the fibroblasts go crazy and lay down a lot of collagen
Type of CT fiber that is thinner than collagen type I and forms a delicate supportive web (to support cells that are stuck together and not joined by a junctional complex
Found in the: bone marrow, lymph nodes liver, spleen
Pattern resembles a spider web or the pattern of a giraffe
Reticular fibers
Type III collagen
Type of CT fiber that is a thin branching fiber and composed of ____ protein** and microfibrils
Abundant in walls of some vessels, lungs, bladder, skin
Elastic fibers (highly elastic)
**elastin protein
Label from top left to bottom then to top right to bottom
What is the white space?
Mast cells
Fibroblasts
Collagen fibers
Plasma cells
Elastic fibers
Small Lymphocytes
Capillary with erythrocytes
Large lymphocytes
Mast cell
Elastic fibers
plasma cell
Macrophage with ingested particles
It is filled with ground substance
Elastic Stain (elastic fibers)
Types of CT proper (4)
Loose (areolar) CT
Reticular tissue
Dense irregular CT
Dense regular CT
Two subtypes of loose CT
Areolar
Adipose tissue
found in many areas throughout the body
Loose, irregular arrangement of cells and fibers with abundant ground substance and water
Loose CT
fewer fibers (less collagen visible), more ground substance
more fibers (collagen very visible), less ground substance
Loose arrangement
Dense arrangment
Loose CT
Adipose tissue
Reticular CT
With silver stain (need special stain to see this)
thick collagen fibers, haphazardly arranged, elastic and reticular fibers are also present
Resists forces from different directions, found in dermis (skin) and organ capsules
Dense irregular CT
parallel arrangement of densely packed collagen fibers (little ground substance)
Resist tensile forces
Found in tendons and ligaments
Dense regular CT
Ligaments join
bone to bone
Tendons join
Muscle to bone
Supportive tissues, ECM predominates (2)
Cartilage and bone
semi-rigid, provides support, acts as a shock-absorber
Cartilage
Two cell types in cartilage
Chondroblast
Chondrocytes
Derived from mesenchymal cells that lay down cartilage matrix
Chondroblasts
--blast= forming something or a less mature form of a cell type
Once the cartilage matrix becomes entrapped in the lacunae they are
Chondrocytes
Mature chondroblasts
____ and ____ both originate from mesenchymal cells
Fibroblasts
Chondroblasts
**therefore they are very closely related
cellular layer surrounding the cartilage
Inner layer of the perichondrium is chondrogenic (chondroblsatic)
Outerlater is Fibroblastic
Perichondrium in cartilage
Abundant and highly hydrated extraceullular matrix in cartilage ( two parts)
Fibers: collagen (type I or II) and/ or elastic fibers
GAGs: Chondoitin-4-sulfate and chondrotin-6-sulfate
What is Chondoitin-4-sulfate and chondrotin-6-sulfate
hyaluronic acid + GAGs from large negatively-charge proteoglycans
What are GAGs sometimes referred to as?
Muccopolysccharides
adhesive glycoprotein in cartilage that helps anchor cell and fibers to matrix
Chondroectin
True/False: cartilage is a vascularized tissue
FALSE
NON-vascular
True/False: since cartilage is avascular it has very limited ability to repair itself after
True
True/False: nutrients and waste diffuse through matrix of cartilage
True
Four chondrocytes sitting in their own respective lacunae
Three types of cartilage: extracellular matrix
Hyaline (type II collagen fibers)
Elastic (type II collagen and elastic fibers)
Fibrocartilage (type I collagen)--looks like dense regular CT and has the same type of cartilage)
What is the difference between of the nuclei of fibrocartilage and Dense CT
fibrocartilage: (rounded and plump)
dense CT: spindle shaped
Hyaline cartilage (chondrocytes in lacunae)
Elastic cartilage (chondrocytes in lacunae)
Fibrocartilage chondrocytes in lacunae)
Most common type of cartilage
Found in: articular surfaces of bones, rib cartilage, trachea, and bronchi, larynx, nose
Also provides the framework for endochondral ossification
Hyaline cartilage
What is endochondral ossification?
It occurs in long bones and as the hyaline cartilage forms and grows it is replaced by bone and then it keeps advancing until growth stops
Where is hyaline cartilage found? (6)
Articular surfaces of bones
Rib cartilage
Trachea
Bronchi
Larynx
Nose
Hyaline cartilage matrix, developing bone
similar to hyaline cartilage, more flexible
Locations: ear and epiglottis
Elastic cartilage
Dense, type I collagen
Paralel arrangment (absorbs shock, resists compession)
Chondrocytes more flatted but STILL round compared to fibroblasts No perichondrium
Location: intervertebral discs, TMJ
Fibrocartilage
Locations where fibrocartilage is found
Intervertebral discs, TMJ
Where is elastic cartilage found
Epiglottis and ear
Fibrocartilage (disc)
Bone is composed of (3):
Cells
Type 1 collagen fibers
extracellular matrix that becomes mineralized
Cells of the bone:
Osteoblasts, osteocytes, osteoclasts
What is unique about bone that is unlike other tissue we talked about
It is vascular tissue
What is the vascular system in the bone
Haversian canal system
Bone is covered by:
Periosteum
Functions of bone (4)
Support
Protection
Calcium storage
Hemopoiesis--blood cell production
Come from mesenchymal cells and rim the bone and deposit bone/collagen matrix
Osetoblasts
Mature osteoblasts, located within lacunae (isolated from neighboring cells--not in clusters like with chondrocytes)
Branched (allows communication)
Osteocytes
True/False: since bone is very active you may see both osteoblasts and osteocytes at the same time
TRUE
Macrophage-type cells (resorbs bone)
Different origin
Reside in Howship lacunae (enclave in the bone where it sits)
