L3 - Connective Tissue Flashcards
What are the functions of connective tissue?
Binds, supports, strengthens body structures
Transport system of body (blood)
Site of stored energy reserves (adipose tissue)
Is connective tissue highly vascular?
Yes - with exceptions of cartilage which is avascular and tendons with very little blood supply
Is connective tissue supplied by nerves
Yes - with exception of cartilage
Components of the ECM?
ECM = GS + Fibres
What is hyaluronic acid
viscous slippery substance that binds cells together, lubricates joints and maintains shape of eyeball
Components of Ground substance?
GS = GAGS + Protein + water
What is hyaluronidase and what does it do
Produced by WBCs, sperm and some bacteria
Makes ground substance more liquid so they can move more easily in it
Chondroitin sulphate
support and provide the adhesive
features of cartilage, bone, skin, blood vessels
Keratan sulphate
found in bone, cartilage, cornea of the eye
Dermatan sulphate
found in skin, tendons, blood vessels,
heart valves
Exophthalmos
Autoimmune activation of thyroid gland
Causes fibroblasts in ECM to secrete more ground substance
GAGS + influx of water increases thickness of periorbital tissue
3 types of protein fibres
Collagen
Reticular fibres
Elastic fibres
What is collagen
Strong and flexible fibre that allowing to resist pulling forces
Common in bone, cartilages, tendons and ligaments
What is reticular fibre
Fine bundles of collagen + glycoprotein coating
Made by fibroblasts
Provides strength and support
Found in BM, vessels, adipose tissue, nerve fibres, smooth muscle tissues
What is elastic fibre
Made up of elastin surrounded by fibrillin giving strength and stability
Allows tissue to be stretched
Found in skin, blood vessels and lungs
What causes Marfan syndrome?
Mutation in a gene on
chromosome 15, which codes for fibrillin
Body produces growth factor Transforming Growth Factor beta (TGFb) – increases growth
because does not bind normally to fibrillin to keep it inactive
What is fibrillin
A type of glycoprotein that makes up elastic fibres along with elastin
Binds to transforming growth factor betas (TGFbs) controlling growth.
What are fibroblasts
Secretes components of matrix (fibres and GS)
Migratory
What are adipocytes
Cells that store fat
Found under the skin and around organs
Two common types of cells that make up connective tissue
Fibroblasts
Adipocytes
What are macrophages?
Phagocytic cells (fixed and wandering forms) in CT
What are the names of the different fixed macrophages
Dust cells (lung)
Kupffer cells (liver)
Langerhan’s cells (skin)
What are plasma cells
From B-lymphocyte, which produce antibodies
What are mast cells
Produces histamine that dilates vessels (by increasing permeability of blood vessels)
What are leucocytes
White blood cells of immune system
What are the two types of embryonic CT?
Mucous and mesenchyme
What is mucous CT
Supports umbilical cord of foetus
Contains fibroblasts embedded in GS
What is mesenchyme CT
Gives rise to all CT
Consists of mesenchymal cells in a semi-fluid GS containing reticular fibres
What are the types of mature CT
Loose, Dense, Supporting CT, Fluid CT
3 types of loose CT
Areolar, adipose, reticular
What is areolar CT
Most common form of CT with three types of fibres present (collagen, reticular, elastic)
Widely distributed around almost every structure; “packing material”
What is adipose CT
Found with areolar CT
Two types:
White adipose (energy storage)
Brown adipose (heat production)
What is reticular CT
A fine interlacing network of reticular fibres and reticular cells
Forms stroma of organs, binds smooth muscle tissue cells
What are the 3 types of dense CT
Dense regular
Dense irregular
Elastic
What is dense regular CT
Regularly arranged collagen, often occur in parallel bundles
Shiny white colour
Where is dense regular CT located
Found in tendons, ligaments, aponeuroses
What is dense irregular CT
Collagen fibres irregularly arranged with a few fibroblasts
Provides pulling strength in many directions
Where is dense irregular CT located?
Reticular region of dermis, periosteum of bone, perichondrium of cartilage, joint capsules, membrane capsules around various organs, heart valves
What are the 3 types of cartilage
Hyaline
Fibrocartilage
Elastic cartilage
What is elastic CT
Contains elastic fibres with fibroblasts between them
Allows stretching of various organs
Where is dense elastic connective tissue located?
Lung tissue, walls of elastic arteries, trachea, bronchial tubes, true vocal cords, penis
What are the types of cartilage CT
Hyaline cartilage, fibrocartilage, elastic cartilage
What is hyaline cartilage
Abundant
Relatively weak, for flexibility and movement
Where is hyaline cartilage located
Anterior ends of ribs; respiratory cartilage i.e. nose, trachea, bronchi
Nasal septum, ends of long bones
What is fibrocartilage
Chondrocytes among thick bundles of collagen fibres within ECM
Strongest type of cartilage
Where is fibrocartilage located
Pubic symphysis, intervertebral discs, menisci of knee, portions of tendons that insert into cartilage
What is elastic cartilage
Chondrocytes in threadlike network of elastic fibres
Provides strength and elasticity; maintains shape
Where is elastic cartilage located
Larynx, external ear, auditory tubes
What are the two types of bone tissue
Compact and spongy
What is compact bone tissue
Outer layer of bone and forms the shaft of long bones
Composed of rod-shaped units known as Osteons (Haversian systems)
What is spongy bone tissue
Inner bone tissue that lies underneath compact bone
What is the function of compact bone
Stores calcium and phosphorous
Protection and support
What is the function of spongy bone
Stores triglycerides (yellow) and produces blood cells (red marrow)
What are the 4 cells found in bones
Osteogenic cells
Osteoblasts
Osteocytes
Osteoclasts
What are osteogenic cells
Mesenchymal stem cells that develop and start to lay down collagen
Become trapped and become osteoblasts
What are osteoblasts
Bone-forming cells
Lay down collagen, mineralisation process starts
What are osteocytes
Mature bone cells that maintain bone tissue
Have gap junctions
Involved in exchange of nutrients and waste
What are osteoclasts
Large, multinucleated cells
Break down bone
What happens in a bone fracture (4 steps)
Osteoclasts - absorb dead bone material
Chondroblasts - lay down hyaline cartilage callus
Osteoblasts - lay down new bone
Osteoclasts - remodels new bone
Describe the 4 components of osteons (harvesian systems)
Lamellae - concentric rings of mineral salts for hardness
Lacunae - spaces between lamellae that contain osteocytes
Canaliculi - “canals” that provide routes for oxygen, nutrients and waste
Central canal - blood, lymph, nerves
What are erythrocytes
RBCs - that transport oxygen and carbon dioxide
What are leukocytes
WBCs - that combat disease
What are thrombocytes
Platelet - involved with blood clotting to stop bleeding
What do neutrophils and monocytes (macrophages) do
Phagocytic, engulfing bacteria
What do basophils and mast cells do
Produces histamine that intensify the inflammatory reaction
What do eosinophils do
Effective against parasitic worms and and in acute allergic response
What do lymphocytes do
Involved in immune response (b cells and T cells)
