Epithelial tissue and defects in regulation of cell divisions

Question 1

what are the two types of stem cells?

Answer 1

Adult stem cells
Embryonic stem cells

Question 2

what are the features of adult stem cells?

Answer 2

• undifferentiated cell found amongst differentiated cells in tissue/organ
• can renew itself and can differentiate to major cell types of tissue/organ (multipotent)
• primary roles of adult stem cells in living tissue is maintenance and repair

Question 3

what are the features of embryonic stem cells?

Answer 3

• defined by origin, inner cell mass of blastocyst
• can become all types of cells in the body (pluripotents)

Question 4

what are the different types of stem cell plasticity?

Answer 4

-multipotent
-plurpotent

Question 5

what is multipotent?

Answer 5

able to generate many types of cells within a restricted tissue family

Question 6

what is plurypotent?

Answer 6

able to generable all tissue types

Question 7

what is the cell turn over of the epidermis?

Answer 7

~2 months

Question 8

how are skin cells regenerated?

Answer 8

skin stem cells are found in a bulge under the sebaceous gland. They translocate to the basal layer of the epidermis

Question 9

how are skin cells regenerated?

Answer 9

skin stem cells are found in a bulge under the sebaceous gland. They translocate to the basal layer of the epidermiswh

Question 10

what cells can the intestinal stem cells give rise too?

Answer 10

absorptive cells, goblet cells, Paneth cells, enteroendocrine cells

Question 11

what is the turnover of intestinal cells?

Answer 11

~few days

Question 12

how to cells adapt to environmental changes?

Answer 12

homeostatic mechanisms

• physiological conditions- to adapt to normal changes
  -Pathological conditions- to limit damage in response to disease processes

Question 13

what is hyperplasia?

Answer 13

increase in size of tissue/organ by increased cell reproduction rate

Question 14

what is hypertrophy?

Answer 14

increase in size of tissue/organ by increase of cell size

Question 15

what is cell/tissue atrophy?

Answer 15

decrease in size

Question 16

what is metaplasia?

Answer 16

reversible transition of one cell type to another

Question 17

what is dysplasia?

Answer 17

presence of abnormal type of cells

Question 18

what is neoplasia?

Answer 18

New, uncontrolled growth of cells

Question 19

how do cells alter their pattern of growth in response to tolerable environmental changes?

Answer 19

Cell size
Cell division
Cell differentiation

Question 20

what is an example of physiological adaptation?

Answer 20

breast epithelial cells increase in size and number during pregnancy under endocrine stimulation

Question 21

what is an example of pathological adaptation?

Answer 21

Endometrial cells increase in number under abnormal endocrine stimulation from oestrogen-secreting ovarian tumours.

Question 22

what is tissue atrophy?

Answer 22

decrease in cell number/size

Question 23

what is cell atrophy?

Answer 23

decrease in cell size

Question 24

what is metaplasia?

Answer 24

one mature, fully differentiated cell type adopts totally different fully differentiated cell type

morphology changes in response to cellular environment

adaptive response - cells are better equipped to withstand new environment

common in epithelial tissue

Question 25

what is Barrett's oesophagus?

Answer 25

-metaplastic transformation of the esophageal lining - squamous epithelium typical of normal oesophagus -columnar cells with goblet cells, typical of intestinal type of epithelium

Question 26

what is dysplasia?

Answer 26

-the presence of abnormal cells -increased rate of cell division coupled with incomplete maturation of immature cells

Question 27

what are some examples of dysplasia?

Answer 27

-epidermis of sun exposed skin -squamous epithelium at columnar junction of cevix

Question 28

how does dysplasia effect skin?

Answer 28

loss of cell maturation due to increase rate of cell division nuceli present in keratin layer

Question 29

how does dysplasia effect the cervical epithelium?

Answer 29

increased number of the more basal, nucleated cells reaching the vagina.

Question 30

how can dysplasia of the cervical epithelium lead to neoplasm?

Answer 30

there is a spectrum of progression, with the stratified layer losing its differentiation and becoming neoplastic

Question 31

what is a neoplastic state?

Answer 31

poorly regulated cell division in which mass of cells form (neoplasm) Cellular proliferation and growth occur in absence of any continuing external stimulus Neoplastic cells exhibit various states of differentiation and commonly fail to achieve highly differentiated state

Question 32

what are the events in neoplastic formation?

Answer 32

-stimulus causes genetic alteration to the cell - altered genes for, growth factors, growth factor receptors, signal transduction, transcription regulation, DNA repair, cell survival - transformed cell proliferates with poor regulation of growth as a result of genetic changes and develops additional mutations

Question 33

what is benign in surface epithelium?

Answer 33

papilloma

Question 34

what is malignant in surface epithelium?

Answer 34

carcinoma

Question 35

what is benign in solid glandular epithelium?

Answer 35

adenoma

Question 36

what is malignant in solid glandular epithelium?

Answer 36

adenocarcinoma

Question 37

what is benign?

Answer 37

well defined- similar structure to the tissue of origin Progress and slow

Question 38

what is malignant?

Answer 38

can lack differentiation Erratic growth Locally invasive Matastatic

Question 39

what are the cellular events needed for metastasis?

Answer 39

detachment from the main neoplasm breaking through the basememt membranse and connective tissue molility enter the passage for movement (lymph, blood stream) enter another tissue

Question 40

how do tumours spread?

Answer 40

4 main routes - local -trans-coelomic (peritoneal, pleural) -Lymphatic -Blood borne

Question 41

what are three ways to classify epithelium?

Answer 41

Morphologically Surface specializations Surface or glandular