Histology Flashcards
What are the 4 basic types of tissue?
- epithelium
- nerve
- muscle
- supporting/connective tissue
Where do you find epithelium?
Lining tubes/covering surfaces
What shape can epithelium be?
- cuboidal
- columnar
- squamous (flat)
What types of cell layer can epithelia be?
- pseudostratified
- stratified
- simple
What is pseudostratified?
Pretends to have many layers
What is stratified?
Many layers
What is simple?
Single layered
Where are simple squamous epithelia found?
Areas that need rapid exchange of substances e.g. lung alveoli and vessels
Where are stratified squamous epithelia found?
Areas exposed to wear and tear e.g. the oesophagus and the vagine
Where are cuboidal epithelia found?
Kidneys, thyroid etc.
What are cuboidal involved in?
- active ion transport
- secretion
- absorption
What do cuboidal contain that squamous do not?
more organelles and cytoplasm
Where are columnar epithelia found?
only in the intestines
what do columnar epithelia do?
- allow effective absorption of nutrients into the body
- maintain an effective barrier
what function do microvilli serve?
increase the cell surface area
what is a tight junction?
(zonula occludens)
a barrier in a contant state of flux that separates outside from inside
what is an anchoring junction?
(zonula adherens)
a barrier that anchors the actin cytoskeleton of adjacent cells
what is a desmosome?
(macula adherens)
anchors adjacent cells
what is a gap junction for?
cell communication
What does the extracellular matrix do?
Acts as a sensor, conveying information from the exterior of the cell to the inside and vice versa
what are the proteins of the ECM responsible for?
cell adhesion
What does loose connective tissue consist of?
- mostly transient immune cells
- little collagen
- Ground substance for O2 and nutrient diffusion
What does dense regular CT consist of?
- sparse cells
- collagen arranged in parallel bundles
- little ground substance
What does dense irregular CT consist of?
- sparse cells, typically fibroblasts
- collagen provides strength
- little ground substance
What sorts of cells are CT cells?
- fibroblasts
- macrophages
- mast cells
- adipocytes
What are the 3 types of CT fibres?
- collagen fibres (strong and flexible)
- reticular fibres (supporting framework)
- elastin fibres (stretch and distension)
How can collagen fibres be broken down?
- mechanical wear
- free radicals
- proteinase cleavage
What happens to damaged collagen?
It is phagocytosed and broken down
What pathological degradation can happen to cartilage (CT)?q
Rheumatoid arthritis
What pathological degradation happens to bone (CT)?
Osteoporosis
Where do you find elastin fribres?
- vocal folds
- lungs
- elastic arteries
- ligaments
- skin
What structure do elastin fibres have?
3D branching network
