CT and Epithelial Flashcards
3 major functions of epithelium
- covering,lining/protecting
- absorption
- secretion
Basis of Epithelial classifications
Layering and shape or cells at surface
What do Tight junctions do?
Seals adjacent cells
Adherens junctions “belts” function
- Anchor cells to neighbors via cadherins
- stabilize and strengthen
Desmosomes “spot welds” function
- anchor to neighboring cells via cadherin
- keratin filaments
Gap junctions function
-mediate communication and nutrition exchange
Define metaplasia
Alteration in adult tissue resulting in significant change from normal expression
Define dysplasia
Changes in cell expression are associated with disease
-key event is breaking through basal lamina
3 Components of CT
Cells
Protein fibers
Ground substance
Embryonic origin of CT
Embryonic mesenchyme
4 Permanent connective tissue cells
Fibroblasts
Adipocytes
Macrophages
Mast cells
4 Transient CT cells
Plasma cells
Lymphocytes
Neutrophils
Eosinophils
Fibroblasts functions
Secrete fibers, ground substance and growth factors
Myofibroblasts appear after damage
Macrophage function
Survives for months
Phagocytosis, secrete cytokines, present antigens, sense wounds
Mast cells function
Inflammatory response
Store and release histamine, heparin, leukotrienes etc.
Plasma cells function
Produce antibodies
Short lived (10-20 days)
Clock faced heterochromatin
Lymphocytes (T and B cells) function
Dark staining nuclei
T cells:long lived, helper and cytoxic
B cells: produce plasma
Neutrophils and eosinophils functions
First responders
Eosinophils stain more red
3 types of fibers
Collagen (type 1)
Reticular (type 3)
Elastic
Collagen/type 1 characteristics
Most abundant
Resist stretch
Thicker fibers
Reticular/Type 3 characteristics
Able to stretch more but still gives structure
Elastic fibers function
Found in places that need to stretch.
What are GAGs
Linear chains of repeating disaccharide
Negatively charged
Forms bristle of proteoglycan to resist compression
Characteristics of loose CT
Most abundant
More cells fewer fibers
Characteristic of dense irregular CT
More fibers few cells
Random arrangement
Organ capsules, intestinal submucosa
Characteristics of dense regular CT
Fibers in same direction
Tendons and ligaments
3 Basic cells involved in wound healing
Neutrophils
Macrophages
Fibroblasts/myofibroblasts
What are the 4 basic types of tissue?
- nervous
- epithelial
- muscle
- connective
Where is simple squamous found?
Capillaries, alveoli
Where is simple cuboidal found?
Glands
Where is urothelium found?
Bladder and urethra (stretches)
Pseudostratified columnar epithelium is found where?
Respiratory tract. Also called respiratory epithelium
Where is stratified squamous found?
Skin, esophagus, mouth and vagina
Stratified columnar is found where?
Male urethra
Keratinized simple squamous is found where?
Skin
What do goblet cells do?
Secret mucous
