Lecture 3

Question 1

How is E-cadherin linked to the cytoskeleton?

Answer 1

Linked indirectly to cytoskeleton through adaptor proteins

Question 2

What is beta-catenin

Answer 2

an adaptor protein

Question 3

If there is an increase in N-cadherin what will happen to the cell?

Answer 3

Go through EMT

Question 4

describe the interactions of hemidesmosomes and desmosomes?

Answer 4

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

Question 5

whats a tight junction?

Answer 5

Prevents free exchange of solutes: gate function
maintain polarity separates apical and basolateral end: fence function

Question 6

what are the 4 classes of tissues

Answer 6

Muscle, Epithelial, Connective, Neural

Question 7

what are the functions of epithelial tissue?

Answer 7

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.

Question 8

What are the classifications of epithelial

Answer 8

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)

Question 9

What are the differences between benign and malignant tumours

Answer 9

Benign: Primary location, distinct borders, grow slow
Malignant: grow uncontrollably, irregular shape and border, spread, metastasis can occur anywhere in body
Requires urgent treatment

Question 10

What is neoplasm?

Answer 10

new growth that can be benign or malignant

Question 11

types of neoplasia

Answer 11

Atrophy, hypertrophy, hyperplasia (increased numbers), metaplasia (conversion o f one type to another), dysplasia

Question 12

what are the termination differences between epithelial and mesenchymal (connective) benign and malignant forms?

Answer 12

Epithelial:
- benign: ends in oma
- Malignant: ends in carcinoma
Mesenchymal:
- Benign: ends in oma
- Malignant: ends in sarcoma

Question 13

are carcinomas or sarcomas more common?

Answer 13

Carcinomas

Question 14

what are the 3 types of proteins that constitute tight junctions? What happens when you remove each one?

Answer 14

Occludin: no phenotype change
Claudins: lethal
JAM: increased intestinal epithelial proliferation

Question 15

What is the function of Claudins?

Answer 15

20-27 kDa, Signaling pathways by C-terminal interaction with signaling molecules

Question 16

The function of GAP junctions? Structure?

Answer 16

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

Question 17

What are the 2 classes of epithelial cells? 7 subclasses?

Answer 17

simple: squamous, cuboidal, columnar
Stratified: squamous, cuboidal, pseudostratified columnar, transitional

Question 18

2 types of connective tissue? (2 extras)

Answer 18

bone, blood,
extra: cartilage, fibrous

Question 19

what’s the functions of epithelial tissue

Answer 19

protection from physical/chemical injury, protection against microbes, response to stimuli, permeability barrier, lubricate structures

Question 20

whats adenocarcinoma?

Answer 20

dunno

Question 21

describe sarcomas from connective tissues, hematopoeitic tissues, and central and peripheral nervous systems?

Answer 21

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