Exam 3: Connective Tissue, bone and cartilage Flashcards
Where is connective tissue (CT) found?
In every organ system except the CNS
Characteristics of CT
*Relatively few cells *Abundant matrix *Matrix contains varying amounts of protein fibers * CT is typically classified on the basis of the type of MATRIX, FIBER DENSITY, and FIBER ORGANIZAITON
List the FIVE functions of CT
- Physically supports other tissues 2. Binds tissues together 3.Provides structural framework and opposes gravity 4. Helps to create body CONTOURS 5. Houses Specialized tissues, (i.e): -Blood forming tissues (hematopoietic) -Lymphoid Organs
What are the Three types of of CT?
- Embryonic CT 2. Adult CT -Loose -Dense 3. Special
What are the characteristics of LOOSE ADULT CT?
*high ratio of fibroblast to fibrous components *type I collagen *usually found beneath epithelial tissues of most organs
What are the characteristics of DENSE ADULT CT?
*High Ratio of fibrous components to fibroblast *thicker bundles of collagen than in loose CT *No specific orientation of collagen bundles in dense irregular dense CT *highly ordered bundles of collagen in dense regular CT
What modalities can be associated with Adult CT?
Reticular and Elastic
What modalities can be associated with Special CT?
adipose, cartilage, bone, hematopoietic
Give the location and Function of Type I collagen fibers
General CT and BONE; Tensile strength.
List the steps of Collagen fiber synthesis
- Type I collagen is synthesized as a prePROpeptide 2.The signal (pre-) sequence is cleaved after translocation of the polypeptide into the endoplasmic reticulum (ER) lumen 3.Pro-collagen molecule c̅ terminal non-helical ends (secreted into extracellular matrix by fibroblasts) 4. Terminal non-helical ends are cleaved into form tropoCOLLAGEN. (tropocollagen spontaneously assembles into staggered arrays to for collagen fibers c̅ characteristics 64 nm banded pattern) 5. BOOM collagen
List the steps of elastic fiber synethesis
- Elastin is also synthesized as a prePROprepitde 2.secreted as a propeptide 3. converted to tropoelastin 4.Assembled into amorphous fibers or sheets c̅ the aid of fibrillin
What are the principal cell types found in CT?
Fibroblasts and Fibrocytes; they are also the most numerous
Functions of Fibroblasts and Fibrocytes:
secretion and maintenance of CT matrix secrete precursor fibrous molecules secrete the amorphous components of the matrix, including the glycosaminoglycans.
What are Glycosaminoglycans?
GAGS are large, negatively charged polysaccharides consisting of repeated disaccharide units.
What are the four groups of GAGS
Hyaluronic Acid Heparin and Heparan Sulfate Chondroitin sulfate and Dermatan Sulfate Keratan Sulfate
Where is hyaluronic acid found
cartilage, skin, synovial fluid, and general CT
Where is heparin and heparan sulfate found?
basement membrane, skin, lung, liver, blood vessels, mast cell granules
Where are chondroitin sulfate and dermatan sulfate found?
cartilage, bone, skin, blood vessels, heart, cornea
Where is Keratan Sulfate found?
Cartilage, cornea, and intervertebral disk
What are the common type of resident cells in fibrous CT?
macrophages, mast cells, plasma cells.
What are three types of macrophages?
Monocytes, kupffer cells, microglial cells.
mast cell characteristics:
stain with toluidine blue Large metachromatic granules with histamine and heparin Involved in hypersensitive response to allergens.
Plasma Cell characteristics:
Activate B lymphocytes Large pale nuclie with “clock-face” distribution of chromatin Prominent Golgi
Define carcinoma in situ
tumor cells that have not invaded the basement membrane and remain confined within the epithelial layer.
Define Microinvasive carcinoma
decrease in cadherins, basement membrane breaks down. Collagenase IV breaks down BM allowing tumor cells to invade the subjacent CT
Define Invasive Carcinoma
They secrete: 1. Autocrine Motility Factors 2. Vascular premeability factors 3. Angiogenic factor this can lead to metastasis
Where are adipocytes derived from?
undifferentiated mesenchymal cells and are distinguished by their unique appearance.
What are the two types of adipocytes?
- White fat is distributed throughout the body - unilocular (one fat drop) 2. Brown fat cells contain numerous smaller lipid droplets -multilocular -slightly more cytoplasm -abundant mitochondria, which give them their brown coloration
Identify the following Tissue
adult CT: Reticular Tissue
Identify the following tissue:
Adult CT: elastic Tissue
Identify the following tissue:
Dense Rugular CT, 400x
Identify the following tissue:
Areolar CT, 400x
Identify the following tissue:
Elastic Connective Tissue Is, 100x
Identify the following tissue:
Elastic CT xs, 100x
Identify the following tissue:
Adipose Tissue, 100x
Identify the following tissue:
Adipose Tissue, 400x
Cartliage can be identified based on it’s matrix, list the three types of cartilage
- Hyaline
- Elastic
- Fibrocartilage
T/F Cartilage may form part or all of the Skeletal system in Vertebrates?
True
In Vertebrates, what does the skeletal system begin as?
Cartilage
Characteristics of HYALINE cartilage
- Most common type
- Avascular
- Contains type II collagen Fibers
- surronded by perichondrium
- Translucent, bluish gray
- Solid, but flexible
- chondrocytes are often found in cell groups (resulting from cell division)
List some locations where Hyaline cartilage may be located:
- External auditory meatus
- Larynx
- Tracheal Cartilages
- Bronchial Cartilages
- Fetal Long Bones
- Articular ends of bone
What are the growth patterns of hyaline cartilage?
- Appositional
- Interstitial
Identify the structures below:
A: Fibrous perichondrium
B: Chondrogenic Pericondrium
C: Lacuna
D: Condrocytes
E: Matrix
What are found in the matrix of the cartilage?
- Chondroitin Sulfate
- Collagen Fibers
- Proteoglycans
*
List some fun facts about Elastic Cartilage
- Specialized by the addition of elastic fibers to the matrix
- Surronded by perichondrium
- Yellow color b/c of elastic fibers
- more apaque, felxible, and elastic than hyalin
- chondrocytes mostly located singly
- Type II collagen plus elastic fibers
- found in
- auricle (pinna) of the ear)
- Epiglottis
What features can be associated with fibrocartilage?
- increased collagen in the matrix
- reduced cellularity compared to hyaline cartilage
- Not surronded by perichondrium
- Opaque appearance from fibrous texture
- Type I collagen
- Single sparse chondrocytes
*
Riddle me this, where could I find some fibrocartialge?
- Intervertebral Discs
- Pubic Symphysis
- insertion of some tendons and ligaments
- Closely associated c dense connective tissue or hyaline cartilage
The cells that produce the martilage matrix are called?
- Chondroblast
- Chondrocytes
Chondrocytes occuply small cavities in the ECM Called____?
Lacunae, two chondrocytes my occupy a single lacuna
where is perichondrium found?
outer fibrous layer, and inner chondrogenic layer.
Identify the following tissue:
Elastic Cartilage
Identify the following tissue:
Fibrocartilage
Identify the following tissue:
Hyaline Cartilage, 100x
Identify the following tissue:
Hyaline Cartilage, 400x
Identify the following tissue:
Hyaline Cartilage, 400x
Bone is formed by ______ which become _______
Osteoblasts, osteocytes
Bone is elongated through ______ growth of a _______ _________ model
appositional, hyaline cartilage
t/f, bone is highly vascular and is found in close proximity to capillaries?
True.
The bone matrix consist of _______ which is organic and ________ which is inorganic
osteoid, hydroxyapatite.
Based on the arrangement of the matrix, list the three types of bone tissues
- Woven Bone (development and bone repair)
- Compact Bone (aka lamellar bone)
- Spongy Bone (aka trabecular or cancellous bone)
List the characteristics of compact bone
- Lacks cavities and forms a dense plate on the outside of long/flat bones
- concentric (haversian) lamellae that encircle a central BV(and nerve) forming an osteon or haversian system
- Osteocytes are found between the lamellae located in lacunae connected to each other and the haversian canal via canaliculi
- Volkmann’s canals run perpendicular to the Haversian canals & connect the Hav. Canals to each other and surface of the bone.
Trabecular (spongy) bone characteristics:
- Has a 3-D lattice of branching, bony spicules intertwined to form trabeculae surronding the bone marrow spaces in the long & flat bones.
List the structures on the diagram below
A: Fibrous Periosteum
B: Osteogenic Periosteum
C: Lacuna
D: Lamellae
E: Canaliculus
F: Haversian Canal
G: Volkmann Canal
What are the four macroscopic structures of Bone?
- Peristeum
- Marrow (medullary) cavity
- Endosteum
- Sharpey’s Fibers
List the SEVEN noncollagenous proteins
- Osteocalcin
- Osteonectin
- Osteopontin
- Bone Sialoprotein
- Osteoprotegerin
- Macrophage colog-stimulating factor
- RANKL
Where are osteoprogenitor cells found and how are they formed?
- Stem cells: adult bone lining cells
- They are found in the inner portion of the periosteum, in the endostum, and lining vascular canals of compact bone.
- derived from mesenchyme of the embryonic somite (sclerotome), posses mitotic potential
- Give rise to osteoblast and bone lining cells
Where are osteocytes found and derived from?
- Derived from osteoblasts and are trapped by the matrix they secrete
- found in lacuni
Where are osteoclast cells derived from?
monocyte lineage, which, in turn, is derived from the monocyte precursors in bone marrow.
What is ARF
(activatoin-resportion-reversal-formation)
a cycle that occurs at adult remodeling sites and deuring development
Converts bound calcium to free calcium
How do osteoblasts regulate Osteoclasts?
- PTH is the primary regulator of bone turnover
- Low PTH levels, osteoblasts stimulate bone formation
- High PTH levls, osteoblasts are stimulated to release osteoclast-differntiation factors.
- PTH stimulates the differentiation of monocyte precursors to form osteoclasts and the formation of ruffled borders on osteoclasts
- Elevated PTH levels result in eroded bone and fibrosis of the resulting spaces (osteitis fibrosa)
- PTH hormone binds receptors on teh osteoblast
- osteoblast stimulated to synthesize M-CSF and RANKL
- Ostoblast releases M-CSF
- M-CSF bind to M-CSF receptor on the monocyte that just happend to drop by
- Monocyte now a macrophage and expresses RANK
- RANK binds to RANKL (couples osteoblast and macrophage)
- Macrophage becomes a multinucleated immature osteoclast.
- Osteoblast secretes ostoprotegerin
- osteoprotegerin binds to RANKL with greater affinity than RANK
- Inhibits maturation of osteoclasts
- PTH blocks syn. of osteoprotegerin
- a non-functional osteoclast uncouoples from the osteoblast and becomes a functional osteoclast
- Calcitonin acts to reduce bone resoption.
Identify the bone tissue below
Cancellous bone (spongy Bone)
Identify the bone tissue:
Cancellous bone
Identify the bone tissue below:
Cancellous Bone
Identify the tissue below
Bone (dry ground)
Identify the tissue sample:
Dry ground bone
Identify the tissue sample below:
dry ground bone
Identify the tissue sample below
dry ground bone
