Wk2 L1- Intro to Histology (4 tissue types) Flashcards
LO
- To know the 4 basic tissue types:
Epithelia
Connective
Muscle
Nervous
Histology
The study of micro anatomy of cells and tissues, and how they’re organised into organs
- By understanding the structure and organisations of cells and tissues, we can learn about their function
Dysfunction = Pathology
Types of tissues on the body
Epithelial
- Lines body surfaces and cavities
Muscular
- Specialised contracile cells
Neural
- Transmits info
Connective
- Holds everything together
Epithelium
- Avascular layer of cells, facing a free surface
- Seperates internal from ‘external’ environment
3 key characteristics of epithelium
1) They are in close apposition
- Cell to cell junctions
- Single or multiple layers
2) All epithelial cells rest on a basal lamina (basal membrane)
- BL only visible under EM.
Basal lamina + Reticular lamina = Basement membrane
3) Epithelial cells are polarised
- Apical domain has villi
- Basal domain
- Lateral domain
Basal lamina
- Layer of proteins secreted by the epithelial cells
- Physical support and attachement to underlying tissue
- Filter (regulate passage of entrance to body)
- Each cell creates its own basal lamina
Classifying epithelia
Simple (1 layer of cells)
Stratisfied (multi layered)
- Squamous (flat)
- Cuboidal (width = height)
- Columnar (tall)
Stratisfied cells are named after the uppermost later
Specialist simple squamous epithelia
1) Endothelium
- Lines blood vessels)
2) Mesothelium
- Lines closed internal body cavities and surfaces of organs
Epithelial cell renewal
- Most have a high turnover
- Basal cells (stem cells) divide and migrate upwards, forcing the older cells upwards to be slught off the surface
- Regeneration with quick mitotic division
Connective tissue
- Cells and extracellular materials that provide support and framework for all body tissues
- Contains blood and lymphatic vessels
- Cells of connective tissue are spread out (surrouned by extracellular matrix)
Extracellular matrix
Protein fibres + ground substance
Connective tissue classification
Connective tissue proper
- matrix contains collagen, elastin and reticular fibres
Dense Connective Tissue:
- lots of fibres
- Regular and irregularly organised
Loose Connective Tissue:
- Fewer fibres, more cells
- More ground substance
Specialised Connective Tissue
- Specialised cells, EC. matrix, and function
- Blood
- Adipose
- Cartilage
- Bone
Connective Tissue Cells
Resident:
- Always in that tissue
- Fribroblast is most common
Transient:
- Passing through
- Usually WBC
Muscular Tissue
- Cell shortening (Contract)
- Cells = fibres
Fribres:
- arranged in fascicles held together by irregular CT.
- Fibres joined by junctions
3 Types:
- Smooth
- Cardiac
- Skeletal
Striated skeletal muscle
- Bundle of fused multinucleated muscle fibres
- Cytoplasm (Sarcoplasm) contains myofibrils that contain bands (striations) that make up sarcomeres
- Dark bands = myosin (thick filament)
- Lighter bands = actin (thin filaments)
Neural tissue
- Classified based on function, structure and location
- Nerve cell = neuron
Support Cells:
- Surround neurons, associated to protect, insulate and promote metabolic change
Blood Vessels:
- Promote metabolic exchange
Basic structure of a neuron
Dendrites:
- Short, fine branches to increase recepter SA.
Cell Body (Soma):
- Contains nucleus and organelles
Axon:
- Contains microtubules, mitochondria and vesicles
- 1mm-1m long
Ganglia
- peripheral nervous system cell bodies
- Grey matter
Grey matter
- Cell bodies and a few axons amd dendrites
White matter
Axons
