Wk 4 Flashcards
Connective Tissues
What are connective tissues (CT)?
Are cells that are widely spaced and separated by extracellular matrix (ECM).
- Usually highly vascularised (except tendons, ligaments, cartilage)
- Has a nervous supply
What are the functions of CT?
- Support
- Protection
- Insulation (exterior environment)
- Storing energy reserves (fats)
- Endocrine
- Transportation
What are the CT cell types?
- Immature cells
- Mature cells
What are immature cells?
Name ends with ‘blast’, secrete the ECM (lay down the fibres that create CT).
- Fibroblasts (dense, loose, reticular)
- Chondroblasts (cartilage)
- Osteoblasts (bone)
What are mature cells?
Name ends with ‘cyte’, maintain cell environment.
- Fibrocytes (dense, loose, reticular)
- Adipocytes (adipose tissue)
- Chondrocytes (cartilage)
- Osteocytes (bone)
- Erythrocytes (blood)
What are cell types present in CT proper?
- Fibroblasts, fibrocytes
- Reticular cell (type of fibroblast)
- Adipocytes (store fat)
- Macrophages (eat things that shouldn’t be there)
- Plasma cells (secrete antibodies)
- Mast cells (produce histamine)
- Leukocytes (white blood cells)
What is Extracellular Matrix (ECM)?
Located between cells and fibres it contains protein fibres and ground substance. Provides CT with its properties.
Structure can be:
- Gelatinous
- Fluid
- Semifluid
- Calcified
Function (dictated by structure):
- Supports and binds cells together
- Allows substances to be exchanged pass to and from blood
- Stores water (not bones)
What are protein fibres?
Secreted by the cells.
- Collagen
- Elastic
- Reticular
What is ground substance?
- Water and organic molecules
- Supports the cells
- Allows exchange of substances
What are the types of fibres present in CT proper?
- Collagen (strength, resistance to tension)
- Elastic (strength and stability, stretched & recoiled)
- Reticular (contains collagen but thinner and branched, strength & support)
What is the common origin of CT?
Mesenchyme (loosely organised animal embryonic CT).
What are the types of CT?
- CT proper (connects tissue and organs together)
- Supporting CT
- Fluid CT
What are the types of CT proper?
- Loose (Areolar) CT - fewer fibres
- Dense CT - more fibres
What is loose CT?
Fibres are arranged “loosely” between cells.
What are the types of loose CT?
- Adipose - adipocytes
- Areolar - fibroblasts, immune cell
- Reticular - fibroblasts
What is areolar CT?
- Most abundant CT
- contains fibroblasts (most common), adipocytes, macrophages, mast cell, plasma cell, white blood cells
- has collagen, elastic, reticular fibres
- located around body structures, anchors epithelial to underlying tissue
- provides elasticity, support, strength
What are the three layers of mucosa?
- Epithelium
- Lamina propria (Areolar CT)
- Muscularis mucosae (thin layer smooth muscle)
What is reticular CT?
- contains reticular cells (type of fibroblast)
- has reticular fibres
- located in liver and spleen
- provides supporting network (supports organs)
What is adipose CT?
- contains adipose cells (fat droplet that pushes nucleus & cytoplasm to side of cell)
- located with the areolar CT (subcutaneous layer of skin i.e. heart and kidney bone marrow)
What is dense CT?
Fibres “densely” packed between cells.
What are the types of dense CT?
- Regular - fibroblasts (tension from one direction)
- Irregular - fibroblasts (tension from all over i.e. skin)
- Elastic - fibroblasts
What is dense regular CT?
- contains fibroblasts
- regularly arranged collagen fibres
- forms most ligaments, tendons, aponeurosis
- provides strong attachments between structures
What is the difference between ligaments and tendons?
Ligaments - connects bone with bone
Tendons - connects muscle with bone
What is dense irregular CT?
- contains fibroblasts
- collagen fibres irregularly arranged
- located in the skin
- provides tensile strength (pulling in multiple direction)
