Flashcards
1
Flashcards do conjunto (70)
- 1What is the function of connective tissue?- supporting framework for the body
- Bind/connect together the body cells and tissues
- connects body cells and tissue
- Provides structural support
- Stores fat
- Transports things - blood
- Protects - ribs
- Aids tissue repair - 2What do connective tissue cells secrete?Extracellular matrix
- 3Where is the stroma found?Underlying tissue in the epithelia
- 43 different types of connective tissue- loose - spacing and packing
- dense- fibrous for protection and attachment
- specialised - Cart ,Bone ,Dent,Enam,Blood - 55 different structural cells in connective tissueFibroblasts
Adipocytes
Chondrocytes
Bone cells
Stem cells - 6What are chondrocytes?Cartilage cells
- 7What's the composition of ECM?Fibres and ground substance
- 8ECM fibres? Which one makes up the larger composition?Collagen and elastin
-Collagen - 9What are the two defence cells?- Macrophages
- Lymphocytes
For non-specific reacitons - 10What is the ground substance?Proteins and fluid
- 11What's the difference between proteoglycans and glycoproteins?Proteoglycans - many sugar side chains, biological shock absorber
Glycoproteins - some sugar side chains - 12What is loose connective tissue composed of?Elastin collagens, reticulin
- 13Role of loose connective tissueforms loose sheets around blood vessels, nerves, tendons - connects muscle to skin
Glue-like function between tissues and supports them metabolically - 14What are the layers of skin from outside to inside?Epidermis, dermis, hypodermis
- 154 examples of different types of cartilageHyaline
Fibro
Elastic
Articular - 16What is hyaline cartilage?- No spaces, all ECM
Dense matrix of collagen fibres and GS
Lines surface of joints
Type 2 collagen - 17What is a cartilage biological shock absorber made up ofHyaluronic acid backbone
Linking protein
Aggrecan molecule - 18What makes bone so hard?It's mineralised
Contains hydroxyapatite - calcium and phosphate - 19What is the function of bone- support
- Protection
- Source of stem cells
- Store of calcium
- Movement and locomotion - 20What is ECM composed of○ Proteins
○ Proteoglycans
Glycoproteins
Hyaluronan (a polysaccharide) - 21What are the functions of collagen?- Tissue scaffolding
- Cell adhesion
- Cell migration
- Cancer
- Tissue repair - 22What is the main characteristic of collagen3 alpha polypeptide chains wound around each other
- 23How are collagens characterised into groups?• Complexity in their structure
• Their splice variants
• Presence of non-helical domains
• Assembly and function - 247 different types of collagenFibril-forming collagen
Fibril-associated collagen with interrupted triple helices (FACIT)
- Network-forming collagens
Microfibrilar collagens
- Anchoring fibrils
Transmembrane collagens
- Endostatin-producing collagen - 25What makes collagen type -1 so special?Heterotrimer, 2 identical alpha 1, 1 alpha 2 chain
- 26Collagen biosynthesis1. Synthesis of PROalpha chain
2. Hydroxylation of secreted prolines and lysines
3. Glycosylation of selected hydroxylysines
4. Self-assembly of 3 proalpha chains
5. procollagen triple-helix formation
6. secretion
7. cleavage of proteins
8. Self-assembly into fibril
9. Aggregation of collagen fibrils to form a collagen fibre - 27Describe the arrangement of fibrils in; tendon, skin, bone and corneaT - parallel arrays aligned along the axis of tension
Skin - fibrils like basket
Bone and cornea - fibril areas arranged in layers - 28What's the role of FACIT collagensinteract with fibril forming collagens to control the diameter
Don't aggregate with each other, they bind fibrillar collagens and control the fibre diameter - 29What are some other functions of collagens- mediate cell signalling
- involves in adhesion, differentiation, growth and cell activity
- traps, stores and delivers growth factors
- Non-collagenous fragments influence development of new blood vessels and formation of a tumour - 30What are the two ways of degrading collagen?- collagenases and cathepsins
- 31What is ECM and what is it's function?Network of maromolecules that occupy the extracellular space
Made up of proteins, proteoglycans and minerals
For strtength support protection, also signal to other cells and store growth factors - 324 proteins in ECM- collagen
- Elastin
Fibronectin
Laminin - 33Proteoglycan in hyaline cartilageChondroitin sulphate
- 34Role of fibronectinAnchor to other cells
- 35What takes place on the collagen 1 matrix?Hydroxyapetite mineralisation
- 36What is intrgrin?Proteins that are used to anchor cells (their cytoskeleton) to each other and ECM
- 37What are integrins made up of?Heterodimers - combination of alpha and beta cells
- 38What are the cell responses mediated by integrins- cell cycle
-Apoptosis
- Differentiaiton
Cells spreading, shape and motility - 39What are the 2 ways of modifying ECM?Plasminogen activators
Matrix metalloproteinases - 40What is matrix metalloproteinases and what takes place- degradation of most ECM proteins during organogenesis
- Degrade/modify matrix
- Release/activate growth factors
- development and normal tissue remodelling
- Altered expression in disease - 41How is cell behaviour regulated?1. Integrin activation initiates new matrix interactions
2. New matrix signals initiate protease secretion
3. Proteases degade matrix
4. Marix fragments regulate cell behaviour
(back to 1) - 42ECM degradation- Attachment - attachment of invasive tumour cell through ECM - receptors
- ECM degradation - focal degradaton of ECM by metalloproteinases
- Locomotion - cell migration - 43Tumour metastasis- Tumour spreads to distant place, gets inside blood vessels
- Growth
- Decrease cell by cell contact
-Breakdown of basement membrane
- Stromal invasion
- Endothelial basement breakdown
- Attach and invade stroma
-Re-grow with angiogenesis - 44What are hydroxyapetite crystals made up of?Hydrated crystaline material of phosphate and calcium
- 45What are the 3 hardest dental tissues?-- enamel
Dentine
cementum - 46What is the percentage of organic material in bone and what is its role there?Mainly collagen
30%
Provides tensile strength - 47What percentage of the bone is inorganic material and what is the role of it?45%
Hydroxyapetite
Compressive strength - 48What are the metabolic functions of the boneHaematopoiesis - produce new blood cells in bone marrow
Calcium homeostasis - levels maintained by intestinal absorption renal excretion and skeletal metabolism - 49What does the bone matrix consist of?Collagen and ground subatance
- 50What types of collagen are in the bone matrix?95% type I
5% type V collagen - 51Cotrial/compact/laminar- 80%
- Dense
- dense, very strong
- consists of Haversian system - 52Trabecular/ cancellous- 20%
- axial skeleton
- determines bone strength - 53Woven bone- Forms quickly during periods of growth and repair
- Remodelled into lamellar bone - 54Lamellar bone- Secondary bone remodelled woven bone
- Stronger, less flexible - 55What type of bone make up a) short b) long bonea) trabecular
b) cortial - 56Haversian system- Series of tubes in the cortical region (outermost region)
- Allow blood vessels and nerves through
- Each canal surrounded by compact bone tissue (concentric lamellae) - 57Alveolar processThickened ridge of bone, contains tooth sockets - that supports the teeth
Outer layer dense cortical bone
Alveolar crest - layer of compact bone, continues around to form inner cortical plate
Inner cortical plate - dense layer of bone around the periphery of the tooth sockets/alveolar process - 58Osteoclasts- Bone resorbing cells
- Multi nucleated
- large - 59Osteoblasts- Bone forming cells
- Synthesis and mineralisation during formation and remodelling - 60When do osteobasts turn into osteocytes?When the osteoblasts get trapped in forming bone
- 61Osteocytes- Originate from osteoblasts which have become embedded in matrix
- Senses mechanical loads and calcium ion loads
- smaller, less ER - 62What is the role of the processes in osteoblastsFor communication
Sense mechanical loads - 63What is the function of osteocytes?- Formation of bone
- Matrix maintenance
- Calcium ions - 64Bone lining cells- Cover inactive bone surfaces
- Originate from osteoblasts
- Mononuclear within bone osteoprogenitor cells or stem cells - 65Osteoprogenitor cells- located in periosteum and endosteum
- Differentiate into osteoblast - 66Mechanism for bone remodelling1. BR initiated by recruitment of osteoclast precursors that mature into osteoclasts
2. BLC erode some ECM, some exposed then leave remodelling site
3. OC bind to exposed ECM digest the matrix forming resorption pit
4. OC stop digesting, die by apoptosis
5. OB line resorption cavity, line layers of osteoid
6. OB make new ECM to fill resorption pit made by osteoclasts, begin to rebuild bone by taking minerals from blood into bone
7. OB trapped in the matrix become OC or die or BLC - 67Systemic factors stimulate bone resorption- Parathyroid hormones
-Vitamin D
- Thyroid hormone
- Vitamin A
- Cortisol - 68Systemic factors stimulate bone remodelling- inflammation
- Tumour necrosis factor
- Interleukin 1 - 69Systemic factors promoting bone formation- Growth hormone
- Parathyroid hormone
- Active vitamin D
- Calcitonin
- Oestrogen
- Andregens - 70OsteoperosisOestrogen inhibits OC action, inhibits OC precursors, enchance survival of OB.
Loss of oestrogen - more bone resorption
Increased number of cytokines which stimulate formation of OC