Tissue is a…that have a…
They are absent in…
Group of cells (level of organisation)
Similar structure and function
Unicellular organisms
Mesenchymal cells are…and can differentiate all different….cells to form different types of….
Stem cells that are pluripotent
Progenitor cells (descendants of stem cells that then further differentiate to create specialized cell types)
Connective tissue
Mature connective tissue formed from mesenchymal cells are…
The mesenchyme is…and…together
Bone, cartilage and muscle
Extracellular matrix produced by mesenchymal cells (rich in hyaluronic acid) + the mesenchymal cells
The mesenchyme is an….connective tissue from which other…can form during…
Embryonic
Connective tissues
Embryogenesis
Stroma is the….of an organ
It contains….
Its appearance can change with…
Supporting tissue (plays structural role)
Fibroblasts, vasculature, lymph
Cancer (desmoplasia) or injury (reactive stroma)
Stoma is separate from….
Parenchyme (where functioning cells of organ are)
Organ is a…
Differentiated structure of group of cells that perform same function
When looking at tissues, 2 stains used are:
- Eosin (negatively charged acidic dye= pink/ red). Include cytoplasmic proteins structures
- Haematoxylin (haematein) (stain acidic structures purple). Include DNA, RNA in ribosomes and RER (phosphate group makes them acidic)
7 shared features of epithelial cells:
- Continuous (unlike connective)
- Retain polarity (have apical, lateral and basal surfaces)
- Intracellular junctions connect them
- Supported by lamina propria (connective tissue)
- Do not contain blood vessels (nutrients diffuse across basal/ apical surface)
- They have potential to regenerate
In epithelial, cells are joined together by…and they maintain…between apical and basal side
Intercellular junctions
Polarity
5 types of epithelial junctions are…
- Tight junction
- Adherens junction
- Desmosome junction
(4. Hemi-desmosome junction)- not in slide - Gap junction
Loss of cell-cell adhesion between epithelial cells causes 2 diseases:
- Bullous pemphigoid (rare/ affects old people)= autoimmune subepidermal blistering
- Pemphigus vulgaris = autoimmune intraepidermal blistering disease
Adult cell types:
- Labile= high turnover (ie: bowel, skin, bone marrow)
- Stable= ability to regenerate but lower turnover (hepatocytes/ liver= 3months, bone)
- Permanent= once its gone its gone= cell loss replaced by scarring (nerve, cardiac and skeletal)
Mitosis/ cell division is also known as….
Proliferation
2 types of epithelia:
- Simple= one layer
- Stratified= more than one layer
4 types of simple epithelia:
- Simple squamous= flat central nuclei
- Simple cuboidal= round central nuclei
- Simple columnar= ovoid, basal nuclei
- Pseudo-stratified columnar= columnar cells of different heights= gives stratified appearance
4 types of stratified epithelia:
- Stratified squamous (keratinised and nonkeratinised)
- Stratified cuboidal
- Stratified columnar
- Transitional (change shape)= apical cells dome-shaped when relaxed and flattened when stretched
Difference between stratified squamous keratinized and nonkeratinized epithelium
Keratinised= apical cells dead (no nucleus or cytoplasm) and flaky and filled with keratin. Cuboidal cells produced at basal end (bottom)
Nonkeratinised= apical cells living and very flat, and basal cells cuboidal
3 epithelial site-specific adaptations:
1.keratinised stratified squamous= skin (top layer dead and flakes off/ keratin contains waterproof properties= protect against abrasion and water loss)
2.simple columnar epithelial with cilia on apical surface= GI tact and female reproductive organ
- Transitional stratified epithelium in urothelium in urinary tract (ability for bladder to stretch to increase vol. + tight gaps to limit transcellular and paracellular permeability (impermeable to water and ions)
3 histological layers of urothelium:
- Apical=umbrella cells that form an impermeable barrier
- Intermediate= 2/3 layers of polygonal cells (polygon shaped)
- Basal= 2/3 layers of small cuboidal cells
Mesoderm is the….between endoderm and ectoderm that appears….
Middle layer
Early in development of embryo
7 major cell types derived from mesoderm are:
- Fibroblasts= form connective tissue such as capsules/ tendons/ ligaments
- Mesothelium= single layer cuboidal cell lining of cavities (synovial cavity of knee joint)
- Endothelium= inner surface of vessels (arteries/ lymphatics)
- Adipocytes= store lipids
- Myoblasts= form muscle (skeletal/ cardiac/ smooth)
- Chondroblasts= form cartilage
- Osteoblasts= form bone
5 main mesenchymal tissues:
- Adipose= steatocytes that store fat + ‘brown fat’ for more energy in foetus and infants
- Tendons= collagen fibres from fibroblasts= tensile strengths but flexible
- Muscle= skeletal, cardiac (striated), and smooth
- Bone= 3 major cell types
- Cartilage= mainly collagen and have 3 types
3 types of bone cells/ tissue and 3 types of cartilage:
- Osteoblasts= divide + new cells
- Osteoclasts= macrophage like function + reduce bone in remodelling process
- Osteocytes= inert and inactive but regulate remodelling of skeleton
1.hyaline cartilage= form synoval lining of joint (barrier that lines inside of joints)
2. Fibrocartilage= stiff, durable and connects bones
3. Elastic cartilage (2 types)= elastic fibres interwoven and present in external structure like ear/ nose/ epiglottis
