Epithelium & Connective tissue Flashcards
What are the 4 tissue types?
- Epithelium: binds surfaces
- Connective: binds cells together to form a functional framework
- Muscle: Key exitable tissue
- Neural
What is the form and function of simple squamous tissue?
Form - thin, flat and delicate in a single layer
Function - Found on well protected organs where rapid absorption must take place (alveoli) or to form smooth surfaces (blood vessels)
What are the characteristics of stratified squamous cells and where are they commonly found?
- Made from layers of cells and so are more resistant and can withstand some mechanical stress. Held together by connective tissue
- Found on skin where it is keratinized, also found in the oral cavity
What is the form of simple cuboidal cells and what are their function?
- Single layer of cube-like cells with large nuclei
- Found in places where absorption takes place (e.g kidney tubules)
What are simple columnar cells and what is their function?
- Longer cells with nuclei restricted to the base in a single layer
- Often found on absorbing/secreting tissues where they protect from chemical stress
- Sometimes contain cilia in order to increase the surface area
What is pseudostratified columnar tissue?
- Appearance of layers however all cells are attached to the bottom
- Often ciliated for the movement of substances (e.g nasal cavity)
What is the glandular epithelium?
Any epithelium that secretes substances, from a single cell to an organ
What are the different types of glands?
- Simple unbranched
- Compound branched
- Tubular
- Alveolar (sacs)
- Tubuloalveolar (sac connected to a tube)
What is the complexity of a gland related to?
The complexity of the substances it secretes
What are the 3 classifications of connective tissue?
Connective tissue proper, supporting connective tissue and fluid
What are the characteristics of connective tissue proper?
- Formed from extracellular fibres (e.g collagen) suspended in a viscous base of glycoproteins
- Formed from mixed cell populations
- Can be dense or loose
What are the characteristics of supporting connective tissue?
- Densely packed & uniform
- Strong
What is the fluid connective tissue and give 2 examples
- Cells suspended in fluid
- Blood and lymph
What are collagen fibres formed from?
- 3 alpha-helical strands linked together to form fibrils which H-bond to form a fibre
Where are collagen fibres found?
- Major components of tendons & ligaments
- Underpins all connective tissue
What are the properties of reticular fibres?
- Similar components to collagen however with a more mesh-like structure
- Used to hold a functional tissue within place in an organ
What is the function of elastic fibres?
Allow connective tissue to have flexibility
Name 5 different types of tissue found in connective tissue proper
- Fibroblasts
- Fibrocytes
- Adipocytes
- Immune cells
- Mesenchymal cells
What is the function of fibroblasts?
- Most common type of cell found
- Secrete pro-collagen to make collagen
- Also secrete hyaluronan which creates viscous base solution
What are fibrocytes?
Differentiated fibroblasts which maintain and repair connective tissue
What is the defining property of adipocytes?
Contain lipid droplets
What are mesenchymal cells?
The stem cells of the connective tissue
What are the properties of regular dense connective tissue proper?
- Tightly packed & aligned with the force exerted on the tissue
- Strong in one direction but often weak in another
- High levels of collagen
What are the properties of irregular dense connective tissue proper?
- Meshlike structure counteracts stress in multiple directions
- Forms capsule around many organs
What is the function of elastic dense connective tissue proper?
Allows stretching of connective tissue
What are the 2 types of loose connective tissue?
Adipose - insulation and packing to absorb shock
Reticular tissue - Supporting framework for cells within tissues
How is the matrix in cartilage different to that found in collagen?
- More gel like due to proteoglycans formed from proteins and chondroitin sulfates
- Chondrocytes create the matrix by secreting chondroitin sulfates
What are the 3 types of cartilage?
Hyaline - most common, resistant and dense
Elastic - made of collagen and elastic fibres, can change shape and return to form
Firbocartilage - heavily packed with a high resistance to mechanical stress, found in the joints
How does bone differ from cartilage?
Collagen is surrounded by calcium salts which are secreted by osteoblasts
