Lecture 3 Flashcards
How is E-cadherin linked to the cytoskeleton?
Linked indirectly to cytoskeleton through adaptor proteins
What is beta-catenin
an adaptor protein
If there is an increase in N-cadherin what will happen to the cell?
Go through EMT
describe the interactions of hemidesmosomes and desmosomes?
Desmosomes: Cell-cell interactions through cytoplasmic plaque
Hemidesmosomes: Cell-matrix interactions, binds to alpha-beta integrin which links to adaptor protein linking hemidesmosomes to the intermediate filaments
whats a tight junction?
Prevents free exchange of solutes: gate function
maintain polarity separates apical and basolateral end: fence function
what are the 4 classes of tissues
Muscle, Epithelial, Connective, Neural
what are the functions of epithelial tissue?
Protection from physical and chemical injury
Protection against microbial invasion
Contains receptors which respond to stimuli
Permeability barrier: filters, secretes & reabsorbs materials
Secretes serous fluids to lubricate structures.
What are the classifications of epithelial
According to thickness/ layers: simple (one layer), stratified (more than one layer)
According to shape: Squamous (wider than tall), Cuboidal (as tall as wide), columnar (taller than wide)
What are the differences between benign and malignant tumours
Benign: Primary location, distinct borders, grow slow
Malignant: grow uncontrollably, irregular shape and border, spread, metastasis can occur anywhere in body
Requires urgent treatment
What is neoplasm?
new growth that can be benign or malignant
types of neoplasia
Atrophy, hypertrophy, hyperplasia (increased numbers), metaplasia (conversion o f one type to another), dysplasia
what are the termination differences between epithelial and mesenchymal (connective) benign and malignant forms?
Epithelial:
- benign: ends in oma
- Malignant: ends in carcinoma
Mesenchymal:
- Benign: ends in oma
- Malignant: ends in sarcoma
are carcinomas or sarcomas more common?
Carcinomas
what are the 3 types of proteins that constitute tight junctions? What happens when you remove each one?
Occludin: no phenotype change
Claudins: lethal
JAM: increased intestinal epithelial proliferation
What is the function of Claudins?
20-27 kDa, Signaling pathways by C-terminal interaction with signaling molecules
The function of GAP junctions? Structure?
cylinders of six dumbbell-shaped connexin molecules (26-60 kDa)
12 connexin molecules
Allows passage of ions and molecules smaller than 1200 Da
Transmission of ionic signals in heart-muscle contraction
Transmission of ionic signals
secondary messenger
What are the 2 classes of epithelial cells? 7 subclasses?
simple: squamous, cuboidal, columnar
Stratified: squamous, cuboidal, pseudostratified columnar, transitional
2 types of connective tissue? (2 extras)
bone, blood,
extra: cartilage, fibrous
what’s the functions of epithelial tissue
protection from physical/chemical injury, protection against microbes, response to stimuli, permeability barrier, lubricate structures
whats adenocarcinoma?
dunno
describe sarcomas from connective tissues, hematopoeitic tissues, and central and peripheral nervous systems?
connective: arise from non-epithelial cells, connective tissues, mesoderm origin, 1% of tumours
Hematopoeitic: blood-forming, arise from non-epithelial, embryonic mesoderm origin, erythrocytes, plasma cells, white blood cells, B and T lymphocytes, 7% of mortality of cancer
Nervous: Neuroectodermal tumors, 1.3% of all diagnoses, 1.% of cancer deaths
