Connective Tissues Flashcards
Name the roles of Connective tissues
- Provide binding and structural supporting
- Protection
- Energy storage (adipose)
- Insulation (adipose)
- Transportation (blood)
- Immunity (blood)
- Mineral storage (bone)
What are the 4 primary tissue types
- Epithelial
- Muscle
- Nerve
- Connective
What are the 5 types of connective tissue
- Fibrocollagenous tissues
- Adipose tissue
- Cartilage
- Bone
- Blood
What are some characteristics of CT
give common origin
- few cells compared to epithelia and other tissues
- large amounts of extracellular matrix (ECM) usually made by its
intrinsic cells - common origin: embryonic mesenchyme
What does a -blast and -cyte suffix mean on a cell type
- blast = immature
- cyte = mature
exceptions = fibroblast and adipocyte
What are the 3 main components of the ECM
A. ground substance
B. structural glycoproteins
C. collagen fibers
What is the ground substance
- watery to gel-like
- specific composition gives each connective tissue distinctive properties
- composed of Gags, proteogylcans and glycoproteins
Name 2 main components of ground substance
1) Glycosaminoglycans (GAGs) – long unbranched polysaccaride chains
2) Proteoglycans – many GAG chains (all except hyaluronic acid) linked to a protein core
What about GAGs and proteoglycans allows them to form the ECF
Negatively charged, open conformations; retain water and positive ions (mostly Na+)
What are some of the roles of structural glycoproteins
linking, organising, catalysing
processes
Name some glycoproteins used in cell adhesion
Laminin
Fibronectin
Name a glycoprotein used in elastic fibre formation
Fibrillin
Name a glycoprotein used in bone mineralisation
Osteocalcin
What kind of fibres are found in CT and what are the used for
Collagen and Elastic fibers
- important for the mechanical properties of connective tissues
Where are fibre precursors secreted from and where do they polymerise
secreted by CT and polymerise outside the cell
What do collagen fibres provide to CT and what is their precursor
Tensile strength
Precursor = tropocollagen
What are the features of the different types of collagen and where are each used
Type I : thick bundles, very strong; dermis, bone
Type II: thin, interwoven fibers; cartilage
Type III: delicate branching reticular
Type IV: forms meshwork - important in the basement membrane
What do elastic fibres provide to CT and what is their precursor
Stretch and resilience
Tropoelastin
How does elastin form fibrils and where are elastic fibres found
- Elastin forms fibrils with fibrillin
- arteries, skin, lung, cartilage
What role does fibrocollagenous CT tissue play and what cells make them up
Roles: Structural, supportive, protective
Cell: Fibroblast
What are the different types of fibrocollagenous tissue
Loose CT (areolar) Dense CT Reticular CT (loose CT, but with type 3 collagen)
What are the features of Loose (areolar) CT and what type of fibres make it up
- Amount relative to ground substance
• relatively few fibers
• abundant viscous ground substance - Type I collagen with elastic fibers
What roles do loose CT play
physical, metabolic and defensive support
Give an example of Loose CT
Lamina propria
Give examples of cell of loose CT
Mast cells, macrophages and lymphocytes
Describe the features of dense CT and what types of fibres make it up
Amount - many fibers, little ground substance Organisation - Random - dense irregular CT - Structured - dense regular CT Type I collagen, some elastic fibers
What are the main cells of Dense CT and what are the main roles of Dense CT
Cells: fibroblasts primarily
Role: mechanical support, tensile strength
What are some examples of Dense CT
- irregular CT - dermis, capsules
- regular CT - tendon, ligament
Describe the features of reticular CT and what types of fibres make it up
Amount - few fibers, little ground substance
Organisation - fine branching network
Type - Type III collagen
What are the main cells of Reticular CT and what are the main roles of Reticular CT
Cells: mainly fibroblasts
Role: structural support in some highly cellular tissues
Give some examples of reticular CT
Lymph nodes, spleen, liver and other glands
What are the cells of adipose tissue
Adipocytes
What type of CT does adipose tissue contain
Loose CT
Where is adipose tissue located
Located beneath skin, around internal organs, in bone marrow and breast tissue
What are the 2 types of adipose tissue
White and brown
Describe the characteristics of white adipose tissue
- Unilocular -one space for lipid - Adult - Widespread - Energy store, shock absorber, insulator
What are the characteristics of brown adipose tissue
- Multilocular - many spaces
- Newborn
- Restricted
- Heat source
- Rich in mitochondria (brown)
- more capillaries than white
What are the roles of cartilage
structural- solid but flexible, resists compression
What are the 3 types of cartilage and where can they found
- Hyaline (most prevalent and widespread, found on many joint surfaces)
- Elastic (outer eat, larynx)
- Fibrocartilage (only type that contains type I coll in addition to the type II coll, pubic symphysis)
Why does cartilage have a unique ground substance
Proteoglycans containing chondroitin sulphate and keratan sulphate linked to fibers
What types of fibres are found in each type of cartilage
- Hyaline: Type II collagen
- Elastic: Type II collagen + elastic fibers
- Fibrocartilage: Type II + type I collagen
What are the cells that produce and maintain cartilage
- Chondroblasts (form cartilage)
- Chondrocytes (maintain cartilage)
What are the roles of bone
Structural, shape, locomotion, supportive, protective,
metabolic, synthetic
What is the ground substance of bone called
Osteoid
What types of fibre are found in the ECM
- Type I collagen fibers- layers
(lamellae) in mature bone - Arranged in layers / lamellae 3- 7μm thick
What cells make, maintain and resorb bone
- Osteocytes - maintain bone
- Osteoblasts - secrete osteoid,
form bone - Osteoclasts - resorb bone
What are the roles of blood
- metabolicsupport
- for transport of molecules
and cells to and from tissues - defensive
What is the ground substance of the ECM of blood
Plasma
Name some of the proteins found in blood
- albumins (60%)
- globulins (35%)
- fibrinogen (4%, essential in the clotting of blood – fibrin)
- regulatory proteins (1%, enzymes, proenzymes and hormones)
What cells are found in blood
Formed in bone marrow
- erythrocyte, neutrophil, eosinophil, basophil, lymphocyte, monocyte, platelets
