Epithelial Cells and Tissues Flashcards

1
Q

What are tissues

A

A group of groups of cells whose type, organisation and architecture are integral to its function

Tissues are made up of cells, extracellular matrix and fluid

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2
Q

What are the five main cell types

A

Connective tissue cells - fibroblasts, condrocytes, osteocytes

Contractile tissues - skeletal muscle, cardiac muscle, smooth muscle

Haematopoietic cells - blood cells, tissue-resident immune cells, cells of bone marrow

Neural cells - cells of the nervous system, neurones and glial cells

Epithelial cells - cells forming continours layers which surface and separate tissue compartments

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3
Q

Tumours based on where they originate

A

Epithelial cells - carcinomas

Mesenchymal cells - sarcomas

Haematopoietic cancers - leukaemias or lymphomas

Neural cells - neuroblastomas or gliomas

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4
Q

Epithelial Classification

A

Shape: squamous, cuboidal, columnar

Layering: single layer, multi-layer

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5
Q

Single squamous epithelium

A

Found in the lung alveolar (air sac) epithelium

Mesothelium (lining major body cavities)

Endothelium lining blood vessels

Allow for exchange to happen

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6
Q

Simple cuboidal epithelium

A

Linings found in ducts - those lining the kidney collecting ducts

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7
Q

Simple columnar epithelium

A

Absorption and secretion of molecules

Enterocytes lining the gut involved in the take up of breakdown products of digestion

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8
Q

Stratified squamous epithelium

A

Keratinizing: epithelial cells which produce keratin and become thicker in doing so. Lose their cellular organelles and nuclei, not visible under light microscopy

Non-keratinizing: Epithelial cells which do not undergo keratinisation, retain their nuclei and organelles (line mouth, oesophagus, anus, cervix and vagina)

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9
Q

Keratinizing and non-keratinizing

A

Keratinizing epithelium can form thick layers that protect underlying tissues from various physical and chemical insults

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10
Q

Pseudo-stratified epithelium

A

Surface cells have contact with basal lamina

e.g. airway epithelium, various ducts in the urinary and reproductive tracts

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11
Q

What is the membrane between two adjacent cells

A

Lateral membrane

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12
Q

What is required to give directionality of the epithelial cells

A

epithelial polarity

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13
Q

Why can directionality only be achieved when transported is polarised

A

Only pumping on one aspect of the membrane

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14
Q

Where do tight junction form

A

Involved in sealing the gap between cells

Apical membrane

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15
Q

What is the adherens junction

A

Master junctions which controls the formation of the other junctions

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16
Q

What is the desmosomes junction

A

Form mechanically tough junction between cells

Resist mechanical stress

17
Q

What does the gap junction do

A

Form pores between cells to allow cells to share material

18
Q

What are the key features of transporting epithelia

A

Plasma membranes contain high concentrations of ion transporters

Mitochondria concentrated towards basal lamina

Ion and water transport will have directionality

19
Q

What are the key features of absorptive epithelium

A

Carriers transporting nutrients

found in Absorptive intestinal cells (enterocytes) and kidney proximal tubule cells

Secretory cells are found among the absorptive cells of the intestinal villi

20
Q

Picture of the brush-border membrane

A
21
Q

What are the key features of the secretory epithelium

A

Two main types of secretion: exocrine (into a duct or lumen) and endocrine (into the bloodstream)

22
Q

Picture of the secretory epithelium of exocrine cells

A
23
Q

Picture of secretory epithelium of an endocrine cell

A
24
Q

What other ways you can classify an endothelial cell

A

Constitutive - secretory vesicles move directly to plasma membrane and release contents as they are formed

Stimulated - secretory vesicles are stored in the cytoplasm and only fuse with the plasma membrane to relase their contents

25
Q

What are examples of epithelial proliferation

A

Cells in intestinal crypts replacing cells lost from the tips of intestinal villi

Cells of the basal layer of stratified squamous epithelia dividing to replace cells lost from the surface

26
Q

Why does cancer chemotherpay cause gastro-intestinal distrubances

A

Inhibition of the proliferation of intestinal crypt cells which results in the loss of the finger like villi

27
Q

What happens during hyperproliferation

A

Increased cell number and thickening of cell layers in response to repeated or constant pressure

If increase in cell production is greater than cell loss from surface, cells will accumulate creating hard skin of corns

28
Q

What are diagrams of papilloma virus

A

They hijack the cellulary machinery of stratified squamous epithelia